ADVANCED RADIO TELECOM CORP
S-1/A, 1996-07-19
CABLE & OTHER PAY TELEVISION SERVICES
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<PAGE>
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 19, 1996
 
                                                      REGISTRATION NO. 333-03735
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                           --------------------------
                                AMENDMENT NO. 2
                                       TO
                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
                          ADVANCED RADIO TELECOM CORP.
              (Currently Advanced Radio Technologies Corporation)
             (Exact name of registrant as specified in its charter)
 
<TABLE>
<S>                                   <C>                                   <C>
             DELAWARE                                4812                               52-1348016
  (State or Other Jurisdiction of        (Primary Standard Industrial                (I.R.S. Employer
  Incorporation or Organization)          Classification Code Number)               Identification No.)
</TABLE>
 
                           --------------------------
 
<TABLE>
<S>                                              <C>
                                                            VERNON L. FOTHERINGHAM
                                                            CHIEF EXECUTIVE OFFICER
        ADVANCED RADIO TELECOM CORP.                     ADVANCED RADIO TELECOM CORP.
     500 108TH AVENUE, N.E., SUITE 2600               500 108TH AVENUE, N.E., SUITE 2600
         BELLEVUE, WASHINGTON 98004                       BELLEVUE, WASHINGTON 98004
               (206) 688-8700                                   (206) 688-8700
 (Address, Including Zip Code, and Telephone        (Name, Address, Including Zip Code, and
Number, Including Area Code, of Registrant's        Telephone Number, Including Area Code,
        Principal Executive Offices)                         of Agent for Service)
</TABLE>
 
                           --------------------------
 
                                   COPIES TO:
 
<TABLE>
<S>                                   <C>                                   <C>
        JAMES KARDON, ESQ.                   JOHN D. WATSON, ESQ.             W. THEODORE PIERSON, JR., ESQ.
         HAHN & HESSEN LLP                     LATHAM & WATKINS                   PIERSON & BURNETT, LLP
         350 FIFTH AVENUE                1001 PENNSYLVANIA AVE., N.W.         1667 K. STREET, N.W., SUITE 801
     NEW YORK, NEW YORK 10118               WASHINGTON, D.C. 20004                WASHINGTON, D.C. 20006
          (212) 736-1000                        (202) 637-2200                        (202) 466-3044
</TABLE>
 
                           --------------------------
 
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
  AS SOON AS PRACTICABLE AFTER THIS REGISTRATION STATEMENT BECOMES EFFECTIVE.
                           --------------------------
 
    If  any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to  Rule 415 under the Securities Act  of
1933, check the following box.  / /
 
    If  this Form  is filed  to register  additional securities  for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list  the  Securities  Act  registration statement  number  of  the  earlier
effective registration statement for the same offering.  / /
 
    If  this Form  is a post-effective  amendment filed pursuant  to Rule 462(c)
under the Securities Act,  check the following box  and list the Securities  Act
registration  statement number  of the earlier  effective registration statement
for the same offering.  / /
 
    If delivery of the prospectus is expected  to be made pursuant to Rule  434,
please check the following box.  / /
                           --------------------------
 
                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<CAPTION>
                                                                             PROPOSED MAXIMUM
                                                           PROPOSED MAXIMUM     AGGREGATE
        TITLE OF EACH CLASS OF              AMOUNT TO       OFFERING PRICE       OFFERING         AMOUNT OF
      SECURITIES TO BE REGISTERED         BE REGISTERED      PER UNIT (1)       PRICE (1)      REGISTRATION FEE
<S>                                      <C>               <C>               <C>               <C>
Units (2)..............................       Units               $            $175,000,000        $60,345
Senior Discount Notes due 2006.........        (2)               N/A               N/A               (3)
Warrants to Purchase Common Stock......        (2)               N/A               N/A               (3)
</TABLE>
 
(1)  Estimated solely for purposes of  calculating the registration fee pursuant
    to Rule 457 under the Securities Act.
 
(2) The  Units will  consist of  an aggregate  principal amount  at maturity  of
    Senior  Discount Notes  due 2006 and  Warrants to purchase  shares of Common
    Stock to raise an aggregate of $175,000,000 gross proceeds.
 
(3) As such securities are to be provided without additional cost to purchasers,
    no registration fee is required with respect thereto.
                           --------------------------
 
    THE REGISTRANT HEREBY  AMENDS THIS  REGISTRATION STATEMENT ON  SUCH DATE  OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE  A  FURTHER  AMENDMENT  WHICH SPECIFICALLY  STATES  THAT  THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE  IN ACCORDANCE WITH SECTION 8(A)  OF
THE  SECURITIES ACT  OF 1933  OR UNTIL  THE REGISTRATION  STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION  8(A),
MAY DETERMINE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                             CROSS-REFERENCE SHEET
           PURSUANT TO ITEM 501(B) OF REGULATION S-K SHOWING LOCATION
           IN PROSPECTUS OF INFORMATION REQUIRED BY ITEMS OF FORM S-1
 
<TABLE>
<CAPTION>
                  ITEM AND CAPTION IN FORM S-1                                    CAPTION IN PROSPECTUS
- ----------------------------------------------------------------  -----------------------------------------------------
<C>        <S>                                                    <C>
       1.  Forepart of the Registration Statement and Outside
            Front Cover Page of Prospectus......................  Outside Front Cover Page of Prospectus
       2.  Inside Front and Outside Back Cover Pages of
            Prospectus..........................................  Inside Front Cover Page of Prospectus; Outside Back
                                                                   Cover Page of Prospectus
       3.  Summary Information, Risk Factors and Ratio of
            Earnings to Fixed Charges...........................  Prospectus Summary; Risk Factors
       4.  Use of Proceeds......................................  Use of Proceeds
       5.  Determination of Offering Price......................  Outside Front Cover Page of Prospectus; Risk Factors;
                                                                   Underwriting
       6.  Dilution.............................................  Not Applicable
       7.  Selling Security Holders.............................  Not Applicable
       8.  Plan of Distribution.................................  Outside Front Cover Page of Prospectus; Underwriting
       9.  Description of Securities to be Registered...........  Outside Front Cover Page of Prospectus; Prospectus
                                                                   Summary; Description of Units; Description of Notes;
                                                                   Description of Warrants; Description of Capital
                                                                   Stock; Certain Federal Income Tax Considerations
      10.  Interests of Named Experts and Counsel...............  Legal Matters; Experts
      11.  Information with Respect to the Registrant...........  Prospectus Summary; Risk Factors; The Company;
                                                                   Dividend Policy; Capitalization; Selected Historical
                                                                   Combined and Pro Forma Financial Data; Management's
                                                                   Discussion and Analysis of Financial Condition and
                                                                   Results of Operations; Business; Management;
                                                                   Principal Stockholders; Certain Transactions;
                                                                   Description of Units; Description of Notes;
                                                                   Description of Warrants; Description of Capital
                                                                   Stock; Description of Certain Indebtedness;
                                                                   Financial Statements.
      12.  Disclosure of Commission Position on Indemnification
            for Securities Act Liabilities......................  Not Applicable.
</TABLE>
<PAGE>
INFORMATION   CONTAINED  HEREIN  IS  SUBJECT   TO  COMPLETION  OR  AMENDMENT.  A
REGISTRATION STATEMENT  RELATING TO  THESE SECURITIES  HAS BEEN  FILED WITH  THE
SECURITIES  AND EXCHANGE  COMMISSION. THESE SECURITIES  MAY NOT BE  SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR  TO THE TIME THE REGISTRATION STATEMENT  BECOMES
EFFECTIVE.  THIS  PROSPECTUS  SHALL  NOT  CONSTITUTE AN  OFFER  TO  SELL  OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE  SECURITIES
IN  ANY STATE IN WHICH SUCH OFFER,  SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
<PAGE>
                             SUBJECT TO COMPLETION
                   PRELIMINARY PROSPECTUS DATED JULY   , 1996
                                                                  [LOGO]
PROSPECTUS
                          $175,000,000 GROSS PROCEEDS
                          ADVANCED RADIO TELECOM CORP.
                                  UNITS CONSISTING OF
                         SENIOR DISCOUNT NOTES DUE 2006
                AND WARRANTS TO PURCHASE SHARES OF COMMON STOCK
                               ------------------
    Advanced  Radio  Telecom  Corp.,  a  Delaware  corporation  ("ART"  or   the
"Company"),  is hereby offering          units (the "Units"), each consisting of
$1,000 principal  amount at  maturity of  Senior Discount  Notes due  2006  (the
"Notes") and    warrants (the "Warrants") to purchase    shares of common stock,
par  value $.001 per share  (the "Common Stock"), of  the Company. The Notes and
the Warrants will not be separable until the  earlier of (i)             ,  1997
and  (ii) such date as  the Underwriters (as defined)  may, in their discretion,
deem appropriate.  Concurrently  with  the  offering of  the  Units  (the  "Unit
Offering"),  the  Company  is  offering,  pursuant  to  a  separate  prospectus,
7,500,000 shares of its Common Stock (the "Common Stock Offering" and,  together
with  the Unit Offering, the "Offerings"). The Unit Offering is conditioned upon
the consummation of the Common Stock Offering.
    The issue price of the Units will be $    per Unit. The Notes will mature on
           , 2006. The issue price of  the Notes represents a yield to  maturity
of       % (computed  on a  semi-annual bond  equivalent basis)  calculated from
           , 1996.  The Notes  will  accrete at  a  rate of       %,  compounded
semiannually,  to an aggregate principal amount of $    million by             ,
2001. Cash interest will  not accrue on  the Notes prior to             ,  2001.
Commencing              , 2002, cash interest on the Notes will be payable, at a
rate of      % per annum,  semiannually in  arrears on  each                 and
           .  See  "Description  of  Notes"  and  "Certain  Federal  Income  Tax
Considerations."
    The Notes will be redeemable  at the option of the  Company, in whole or  in
part,  at any time on or after              ,  2001 at the redemption prices set
forth herein,  plus  accrued  and  unpaid  interest, if  any,  to  the  date  of
redemption.  In addition,  in the event  that the Company  receives net proceeds
from the sale of its Common Stock  in either an Equity Offering (as defined)  or
an investment by one or more Strategic Equity Investors (as defined) on or prior
to              , 1999, the Company may,  at its option, use all or a portion of
any such net  proceeds to redeem  up to a  maximum of 33  1/3% of the  initially
outstanding  aggregate principal amount at maturity of the Notes at a redemption
price equal to     % of the Accreted Value  (as defined) of the Notes;  PROVIDED
that  not less  than 66  2/3% of  the initially  outstanding aggregate principal
amount at maturity of  the Notes remain  outstanding following such  redemption.
See  "Description  of  Notes --  Redemption  -- Optional  Redemption."  Upon the
occurrence of a Change in Control (as defined), the Company is obligated to make
an offer  to purchase  all outstanding  Notes  at a  price of  (i) 101%  of  the
Accreted  Value thereof, if such purchase is prior to            , 2001, or (ii)
101% of the principal amount at maturity thereof, plus accrued interest thereon,
if any, to the date of  purchase, if such purchase is on  or after             ,
2001.  See "Description  of Notes  -- Certain  Covenants --  Change in Control."
There can be no assurance that the Company will have sufficient funds  available
at  the time of any Change in Control  to purchase all Notes tendered. See "Risk
Factors."
    The Notes will represent unsecured, senior obligations of the Company,  will
rank  PARI PASSU  in right  of payment with  all existing  and future unsecured,
senior indebtedness of the Company and will  rank senior in right of payment  to
all  existing and future subordinated indebtedness  of the Company. At March 31,
1996, on a pro  forma basis after giving  effect to indebtedness incurred  after
March 31, 1996, the Offerings and the application of the net proceeds therefrom,
the  aggregate principal amount of indebtedness  of the Company (excluding trade
payables,  other  accrued  liabilities,  deferred  taxes  and  the  Notes)   was
approximately $3.4 million, which consisted of the EMI Note (as defined) and the
Equipment  Note (as defined) and all of  which ranked PARI PASSU with the Notes.
$1.9 million of such indebtedness  constituted secured indebtedness which  would
effectively  rank senior to the  Notes with respect to  the assets securing such
indebtedness. Although the Indenture (as defined) will limit the ability of  the
Company  and its subsidiaries to incur additional indebtedness, including senior
indebtedness, the  Indenture will  permit  the Company  to incur  a  substantial
amount of secured indebtedness under the Credit Facility (as defined), which, if
incurred,  will effectively rank senior to the  Notes with respect to the assets
securing  such  indebtedness.  See  "Risk  Factors  --  Possible  Incurrence  of
Substantial  Secured Indebtedness,"  "Description of Notes"  and "Description of
Certain Indebtedness."
    Each Warrant will entitle the holder thereof, subject to certain conditions,
to purchase    shares of Common  Stock at an exercise  price of $    per  share,
subject to adjustment under certain circumstances. Upon exercise, the holders of
Warrants  would  be  entitled,  in  the  aggregate,  to  purchase  Common  Stock
representing      % of  the Common Stock  on a fully-diluted  basis on the  date
hereof,  after giving effect to the  Offerings. The Warrants will be exercisable
at any time  on or after                 , 1997. Unless  earlier exercised,  the
Warrants will expire on            , 2006. See "Description of Warrants."
    There  is  no  existing trading  market  for  the Units,  the  Notes  or the
Warrants, and the Company does  not intend to list the  Units, the Notes or  the
Warrants  on any  securities exchange.  The Common  Stock has  been approved for
quotation on  the Nasdaq  National Market  under the  symbol "ARTT."  See  "Risk
Factors -- Absence of Public Market; Possible Volatility of Stock Price."
    AN  INVESTMENT IN THE UNITS  OFFERED HEREBY INVOLVES A  HIGH DEGREE OF RISK.
SEE "RISK FACTORS"  BEGINNING ON  PAGE 11 FOR  A DISCUSSION  OF CERTAIN  FACTORS
WHICH  SHOULD BE CONSIDERED BY PROSPECTIVE INVESTORS IN EVALUATING AN INVESTMENT
IN THE UNITS.
                             ---------------------
THESE SECURITIES  HAVE  NOT  BEEN  APPROVED OR  DISAPPROVED  BY  THE  SECURITIES
  AND  EXCHANGE  COMMISSION  OR  ANY  STATE  SECURITIES  COMMISSION,  NOR  HAS
    THE  SECURITIES  AND  EXCHANGE   COMMISSION  OR  ANY  STATE   SECURITIES
      COMMISSION   PASSED   UPON  THE   ACCURACY   OR  ADEQUACY   OF  THIS
       PROSPECTUS. ANY  REPRESENTATION  TO  THE CONTRARY  IS  A  CRIMINAL
       OFFENSE.
<TABLE>
<CAPTION>
                                    PRINCIPAL AMOUNT          PRICE TO       UNDERWRITERS'     PROCEEDS TO
                                AT MATURITY OF THE NOTES      PUBLIC(1)       DISCOUNT(2)     COMPANY(1)(3)
<S>                            <C>                         <C>              <C>              <C>
Per Unit.....................              %                      %                %                %
Total........................              $                      $                $                $
</TABLE>
 
(1)  Plus accrued original issue  discount, if any, on the  Notes from         ,
    1996.
(2) The  Company  has  agreed  to indemnify  the  Underwriters  against  certain
    liabilities,  including  liabilities under  the Securities  Act of  1933, as
    amended. See "Underwriting."
(3) Before deducting expenses payable by the Company estimated at $        .
                         ------------------------------
    The Units are  being offered  by the  Underwriters, subject  to prior  sale,
when,  as  and if  delivered to  and  accepted by  the Underwriters,  subject to
approval of certain legal  matters by counsel for  the Underwriters and  certain
other  conditions. The  Underwriters reserve  the right  to withdraw,  cancel or
modify such offer and to reject orders in whole or in part. It is expected  that
delivery  of the Units will be made in  New York, New York on or about         ,
1996.
                         ------------------------------
MERRILL LYNCH & CO.
                             MONTGOMERY SECURITIES
                                                               SMITH BARNEY INC.
                         ------------------------------
 
                 The date of this Prospectus is        , 1996.
<PAGE>
                         [INSIDE FRONT COVER GATE FOLD]
 
                      38 GHz TECHNOLOGY PROVIDES SUPERIOR
                BANDWIDTH PER CHANNEL WHICH ALLOWS SIGNIFICANTLY
                          FASTER DATA TRANSFER RATES.
 
                   [GRAPHIC DISPLAYING BANDWIDTH PER CHANNEL
                  OF FREQUENCIES BETWEEN 530 KHz AND 38 GHz.]
<PAGE>
                        [GRAPHIC DISPLAYING 38 GHz LINKS
                        BETWEEN METROPOLITAN FIBER RING,
              OFF-FIBER NET BUILDINGS AND ON-FIBER NET BUILDINGS.]
 
    IN CONNECTION WITH THIS OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR  EFFECT
TRANSACTIONS  WHICH STABILIZE  OR MAINTAIN  THE MARKET  PRICE OF  THE SECURITIES
OFFERED HEREBY AT LEVELS ABOVE THOSE  WHICH MIGHT OTHERWISE PREVAIL IN THE  OPEN
MARKET. SUCH STABILIZING, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.
<PAGE>
                               PROSPECTUS SUMMARY
 
    THE  FOLLOWING SUMMARY SHOULD BE READ  IN CONJUNCTION WITH, AND IS QUALIFIED
IN ITS ENTIRETY BY, THE MORE DETAILED INFORMATION, INCLUDING "RISK FACTORS"  AND
THE  HISTORICAL  AND  PRO  FORMA FINANCIAL  STATEMENTS  AND  THE  NOTES THERETO,
APPEARING  ELSEWHERE  IN  THIS  PROSPECTUS.  UNLESS  OTHERWISE  INDICATED,   ALL
INFORMATION IN THIS PROSPECTUS ASSUMES (I) THE COMPLETION OF THE PROPOSED MERGER
(THE "MERGER"), AS A CONDITION OF THE OFFERINGS, OF A WHOLLY-OWNED SUBSIDIARY OF
ADVANCED  RADIO TECHNOLOGIES  CORPORATION ("ART")  WITH AND  INTO ADVANCED RADIO
TELECOM CORP.  ("TELECOM"),  (II)  THE  CONVERSION  (THE  "CONVERSION")  OF  ALL
OUTSTANDING  SHARES OF PREFERRED STOCK OF TELECOM INTO SHARES OF COMMON STOCK OF
TELECOM PRIOR  TO  THE MERGER,  (III)  THE  AMENDMENT OF  ART'S  CERTIFICATE  OF
INCORPORATION  TO CHANGE  ITS NAME TO  "ADVANCED RADIO TELECOM  CORP.," (IV) THE
29,450.16 FOR ONE SPLIT  OF THE COMMON  STOCK EFFECTED IN JUNE  1996 AND (V)  NO
EXERCISE  OF  THE  UNDERWRITERS'  OVER-ALLOTMENT  OPTION  IN  THE  COMMON  STOCK
OFFERING. FOLLOWING THE  MERGER, TELECOM  WILL BE A  WHOLLY-OWNED SUBSIDIARY  OF
ART.  AS USED IN THIS PROSPECTUS, THE  TERMS "ART" OR THE "COMPANY" REFER EITHER
TO ART ON A STAND-ALONE BASIS OR ON A COMBINED BASIS WITH TELECOM AS THE CONTEXT
MAY REQUIRE. SEE "THE  COMPANY." SEE "GLOSSARY" FOR  THE DEFINITIONS OF  CERTAIN
TERMS AND ACRONYMS USED HEREIN.
 
                                  THE COMPANY
 
    Advanced  Radio  Telecom Corp.  ("ART" or  the "Company")  provides wireless
broadband   telecommunications   services    using   point-to-point    microwave
transmissions  in the 37.0 to 40.0 gigahertz  portion of the radio spectrum ("38
GHz"). The Company is seeking to address the growing demand for high speed, high
capacity digital  telecommunications  services  on  the  part  of  business  and
government  end users who require cost effective, high bandwidth local access to
voice, video,  data  and  Internet  services. Upon  completion  of  its  pending
acquisition  of  129 38  GHz wireless  broadband authorizations  (the "CommcoCCC
Assets") from CommcoCCC, Inc.  ("CommcoCCC"), the Company will  own or manage  a
total  of 237  authorizations granted  by the  Federal Communications Commission
("FCC") covering an  aggregate population  of approximately 143  million in  169
U.S. markets. ART's footprint will allow it to provide 38 GHz wireless broadband
services  in 47 of the top 50 markets  and 82 of the top 100 markets. Presently,
the Company  owns or  manages  108 authorizations  (exclusive of  the  CommcoCCC
Assets)  that  allow it  to provide  38  GHz wireless  broadband services  in 89
markets.  See  "Risk   Factors  --   Risk  of   Non-Consummation  of   CommcoCCC
Acquisition,"   "Business   --   38   GHz   Wireless   Broadband   Licenses  and
Authorizations" and "--  Agreements Relating to  Licenses and Authorizations  --
CommcoCCC Acquisition."
 
    The ability to access and distribute information quickly has become critical
to   business  and   government  users   of  telecommunications   services.  The
proliferation  of  local  area  networks  ("LANs"),  rapid  growth  of  Internet
services,  rising demand for video teleconferencing and other demand factors are
significantly increasing the volume of broadband telecommunications traffic. The
inability of the existing infrastructure to meet this demand is creating a "last
mile" bottleneck in  the copper wire  networks of the  incumbent local  exchange
carriers  ("LECs").  This  increasing  demand,  together  with  changes  in  the
regulatory environment, are  creating an  opportunity to  offer cost  effective,
high  capacity last mile access using  both wireline and wireless solutions. See
"Business -- Telecommunications Industry Overview."
 
38 GHZ TECHNOLOGY
 
    The Company is positioned to solve the need for broadband last mile  access,
linking  end  users  to competitive  access  providers  ("CAPs"), inter-exchange
carriers ("IXCs"),  cellular and  mobile radio  service providers  and  Internet
service  providers  ("ISPs") using  38  GHz technology.  The  Company's wireless
broadband services are engineered to  provide 99.999% availability, with  better
than  a 10-13 (unfaded) bit  error rate. This level  of availability exceeds the
performance of copper based networks and is a viable alternative to fiber  optic
based  networks. See  "Business -- The  ART Solution." In  addition, the Company
believes that  ART's  last  mile  solution is  competitively  priced  with  most
broadband  wireline solutions. See  "Business -- 38 GHz  Technology" and "-- The
ART Solution." The 38 GHz band provides for the following additional  advantages
as compared to other spectrum bands and wireline alternatives:
 
                                       3
<PAGE>
    -  HIGH DATA TRANSFER RATES.  The total amount of  bandwidth for each 38 GHz
     channel is  100 MHz,  which  exceeds the  bandwidth  of any  other  present
     terrestrial   wireless  channel  allotment   and  supports  full  broadband
     capability. For example, one 38 GHz DS-3 link at 45 Mbps today can transfer
     data at a rate which  is over 1,500 times the  rate of the fastest  dial-up
     modem  currently in  use (28.8  Kbps) and  over 350  times the  rate of the
     fastest integrated services digital network ("ISDN") line currently in  use
     (128   Kbps).  In  addition  to   accommodating  standard  voice  and  data
     requirements, 45 Mbps data  transmission rates allow  end users to  receive
     real  time, full motion video and 3-D graphics at their workstations and to
     utilize highly interactive applications on the Internet and other networks.
 
    - SIGNIFICANT CHANNEL CAPACITY. Because 38 GHz radio emissions have a narrow
     beam width, a relatively short range  and in many instances the  capability
     to  intersect without creating  interference, 38 GHz  service providers can
     efficiently  reuse  their  bandwidth   within  a  licensed  area,   thereby
     increasing  the number of customers to which such services can be provided.
     Management believes  that by  using technology  currently employed  by  the
     Company it can serve virtually all of the immediately addressable market in
     its market areas.
 
    -  RAPID DEPLOYMENT.  38 GHz  technology can  be deployed  considerably more
     rapidly than wireline and other wireless technologies, generally within  72
     hours  after  obtaining access  to customer  premises.  In contrast  to the
     relative ease of installing a 38 GHz transmission link, extending fiber  or
     copper-based  networks to reach new customers requires significant time and
     expense. In addition, unlike providers of point-to-point microwave  service
     in other spectrum bands, a 38 GHz license holder can install and operate as
     many  transmission links  as it can  engineer in the  licensed area without
     obtaining  additional  approvals  from  the  FCC.  This  is  a  substantial
     advantage  over other portions of the microwave radio spectrum that must be
     licensed on a link-by-link basis following frequency coordination, which in
     total can take from three to five months.
 
    - EASE OF INSTALLATION. The  equipment used for point-to-point  applications
     in  38 GHz  (I.E., antennae, transceivers  and digital  interface units) is
     smaller, less obtrusive  and less  expensive than that  used for  microwave
     equipment  applications at lower frequencies, making it less susceptible to
     zoning restrictions. In addition, 38 GHz equipment can be easily redeployed
     to meet changing customer requirements.
 
    -  ADDITIONAL  ADVANTAGES  OVER  OTHER  PORTIONS  OF  RADIO  SPECTRUM.    At
     frequencies above 38 GHz, point-to-point applications become less practical
     because attenuation increases and the maximum distance between transceivers
     accordingly  decreases. Additionally, the FCC has specified the use of many
     portions of the spectrum for  applications other than point-to-point,  such
     as  satellite and wireless cable services, and, accordingly, these portions
     of  the  radio  spectrum  often   are  not  available  for   point-to-point
     applications.  Finally,  38 GHz  has  characteristics which  provide better
     signal quality and performance in  inclement weather than those offered  in
     other portions of the radio spectrum.
 
BUSINESS STRATEGY
 
    ART began providing 38 GHz wireless broadband services in the fourth quarter
of  1995 and has generated only nominal revenues from such services to date. The
Company is seeking to capitalize on its broad footprint of 38 GHz authorizations
to become a leading provider of wireless broadband solutions to a diverse  group
of  traditional and emerging telecommunications  service providers and end users
of telecommunications services. See "Business -- Business Strategy." The Company
plans  to  implement  the  following  strategic  initiatives  to  achieve   this
objective:
 
    -  EXPLOIT SPECTRUM POSITION IN KEY  MARKETS. Upon completion of its pending
     acquisition of the CommcoCCC Assets, the Company will own or manage a total
     of 237  authorizations  that will  allow  it  to provide  38  GHz  wireless
     broadband  services  in 169  U.S. markets.  The  Company currently  owns or
     manages 108 authorizations (exclusive of  the CommcoCCC Assets) that  allow
     it to provide 38 GHz wireless broadband services in 89 markets, 73 of which
     are owned by the Company and the
 
                                       4
<PAGE>
     remaining  35 of  which are  managed by  the Company  through the Company's
     interests in or arrangements with  other companies. The Company has  agreed
     to  acquire all of  the authorizations which it  currently manages but does
     not own. These spectrum assets provide  the Company with the foundation  on
     which  to  create  a  large  scale commercial  system  of  38  GHz wireless
     broadband operations.  As  of June  28,  1996, the  Company  was  operating
     revenue-generating,  wireless  broadband links  in  15 cities.  The Company
     plans to continue  to build  out its  infrastructure and  to intensify  its
     marketing effort in its market areas in order to exploit the value inherent
     in its spectrum assets. The Company may seek to acquire additional spectrum
     rights  in  new and  existing  markets in  order  to expand  its geographic
     footprint or enhance its services. See "Business -- Agreements Relating  to
     Licenses and Authorizations."
 
    -  MARKET INITIALLY  AS A  CARRIER'S CARRIER.  The Company's  initial target
     customers include CAPs, IXCs, cellular  and mobile radio service  providers
     and  ISPs. The Company's wireless broadband  services enable CAPs to extend
     their broadband services to locations where it is either not cost-efficient
     or too  difficult to  extend  their fiber  optic  network due  to  physical
     limitations,  franchise fees or other  restrictions. The Company's services
     may also be attractive  to certain LECs, which  generally do not  currently
     have   broadband  networks  capable  of  reaching  the  majority  of  their
     customers. All telecommunications service  providers can use the  Company's
     services  as alternate or redundant routes to increase network reliability.
     The Company  has  entered  into a  strategic  distribution  agreement  (the
     "Ameritech   Strategic  Distribution   Agreement")  with   Ameritech  Corp.
     ("Ameritech") for  delivery of  the Company's  wireless broadband  services
     throughout  Ameritech's  midwest  operating region  and  for  certain large
     customers located  outside  its  region.  The  Company  currently  provides
     services   to  Ameritech,  Bell  Atlantic  NYNEX  Mobile,  UUNet,  Electric
     Lightwave,  NEXTLINK,  American  Personal  Communications,  American   Show
     Management,  Capital Area Internet Service, Brooks Fiber Communications and
     Western  Wireless,   among  others.   See   "Business  --   Customers   and
     Applications."  As regulatory and competitive  conditions permit and as the
     Company's customer base  and market presence  develop, the Company  expects
     that  its market focus will expand  from a wholesale "carrier's carrier" to
     include provision of services directly to commercial end users.
 
    - PURSUE  OPPORTUNITIES TO  PROVIDE VALUE-ADDED  SERVICES. The  Company  has
     identified  and  plans to  pursue additional  market niches  with immediate
     needs for reliable, high bandwidth last mile access services. For  example,
     the  market for  Internet services  urgently requires  broadband "pipes" to
     facilitate high  speed  access for  corporate  users, and  the  Company  is
     pursuing  agreements to package  its 38 GHz solutions  with the services of
     leading  ISPs.   Other   potential   value-added   uses   include   desktop
     videoconferencing,   high  resolution   imaging  for   healthcare  and  law
     enforcement applications and video on  demand. The Company may also  decide
     to  offer switched-based services  to end users who  desire a single source
     telecommunications solution.
 
    - MAINTAIN  TECHNOLOGY LEADERSHIP  IN SPECTRUM  MANAGEMENT. The  Company  is
     currently developing proprietary site selection and network design software
     which it believes will provide for faster site development at a lower cost.
     In addition, through the Company's internal technology development efforts,
     as  well as on-going participation in equipment manufacturers' research and
     development activities, the  Company is  seeking to  achieve a  competitive
     advantage through proprietary methods designed to increase the capacity and
     quality of its networks.
 
    -  ESTABLISH AND EXPAND KEY STRATEGIC ALLIANCES. The Company has established
     and will seek to continue to  establish key strategic alliances with  major
     service   providers,  equipment  manufacturers,   systems  integrators  and
     enhanced  service  providers.  Ameritech  owns  a  5.5%  beneficial  equity
     interest  in the Company as  of June 28, 1996  (4.3% after giving effect to
     the Common  Stock  Offering)  and  entered  into  the  Ameritech  Strategic
     Distribution  Agreement in April 1996. The Company also has agreements with
     Harris Corporation, Farinon Division ("Harris") for marketing ART's 38  GHz
     services   to  PCS   providers  and   with  GTE   Corporation  ("GTE")  for
     installation, field  servicing and  network  monitoring. In  addition,  the
     Company  is seeking  to develop  relationships with  a number  of equipment
     manufacturers focusing on 38 GHz technology development, wireless broadband
     standards and joint sales efforts.  The Company plans to utilize  strategic
     alliances to bundle its services with those of its partners, to provide for
     alternative  distribution  channels  and to  gain  access  to technological
     advancements. See "Business -- Strategic Alliances."
 
                                       5
<PAGE>
                                  THE OFFERING
 
THE UNITS
 
<TABLE>
<S>                                 <C>
Gross Proceeds....................  $175,000,000.
Units Offered.....................  Units, each  consisting of  $1,000 principal  amount  at
                                    maturity of the Company's Senior Discount Notes due 2006
                                    and    Warrants to purchase       shares of Common Stock
                                    of the Company. The Notes  and the Warrants will not  be
                                    separable  until the earlier  of (i)          , 1997 and
                                    (ii)  such  date  as  the  Underwriters  may,  in  their
                                    discretion, deem appropriate (the "Separation Date").
Issue Price.......................  $      per Unit.
Use of Proceeds...................  To  fund capital expenditures, including the purchase of
                                    equipment  and  the  acquisition  of  certain   spectrum
                                    rights,   to  repay  outstanding  indebtedness  and  for
                                    general corporate  purposes,  including the  funding  of
                                    operating  cash flow  shortfalls, technology development
                                    and acquisitions  of  additional  spectrum  rights  and,
                                    potentially, related businesses.
THE NOTES
Maturity Date.....................  , 2006.
Yield and Interest................  % (computed on a semi-annual bond equivalent basis) cal-
                                    culated  from             , 1996. The Notes will accrete
                                    at a  rate of       %,  compounded semiannually,  to  an
                                    aggregate   principal  amount   of  $        million  by
                                                , 2001. Cash interest will not accrue on the
                                    Notes prior to           , 2001. Commencing            ,
                                    2002,  cash interest on the Notes  will be payable, at a
                                    rate of    % per annum, semiannually in arrears on  each
                                                and              . For United States federal
                                    income tax  purposes, purchasers  of the  Notes will  be
                                    required  to include amounts in  gross income in advance
                                    of the receipt of the cash payments to which the  income
                                    is   attributable.  See  "Certain   Federal  Income  Tax
                                    Considerations."
Mandatory Redemption..............  None.
Optional Redemption...............  The Notes  will  be  redeemable at  the  option  of  the
                                    Company,  in whole or  in part, at any  time on or after
                                              , 2001  at  the redemption  prices  set  forth
                                    herein, plus accrued and unpaid interest, if any, to the
                                    date  of redemption. In addition,  in the event that the
                                    Company receives  net  proceeds  from the  sale  of  its
                                    Common   Stock  in  either  an  Equity  Offering  or  an
                                    investment by one or more Strategic Equity Investors  on
                                    or  prior to             , 1999, the Company may, at its
                                    option, use all or a portion of any such net proceeds to
                                    redeem up  to a  maximum  of 33  1/3% of  the  initially
                                    outstanding  aggregate principal  amount at  maturity of
                                    the Notes at  a redemption  price equal to     % of  the
                                    Accreted Value of the Notes; PROVIDED that not less than
                                    66  2/3%  of the  initially outstanding  aggregate prin-
                                    cipal amount at maturity of the Notes remain outstanding
                                    following such redemption. See "Description of Notes  --
                                    Redemption -- Optional Redemption."
Change in Control.................  Upon  the occurrence of a Change in Control, the Company
                                    is  obligated  to   make  an  offer   to  purchase   all
                                    outstanding Notes at
</TABLE>
 
                                       6
<PAGE>
<TABLE>
<S>                                 <C>
                                    a  price of (i)  101% of the  Accreted Value thereof, if
                                    such purchase is prior to               , 2001, or  (ii)
                                    101%  of the principal amount  at maturity thereof, plus
                                    accrued  interest  thereon,  if  any,  to  the  date  of
                                    purchase,  if such purchase is on or after             ,
                                    2001. See "Description of Notes -- Certain Covenants  --
                                    Change  in Control." There can  be no assurance that the
                                    Company will have sufficient funds available at the time
                                    of any Change in Control to purchase all Notes tendered.
                                    See "Risk Factors -- Risk of Inability to Satisfy Change
                                    in Control Offer."
Ranking...........................  The Notes will  represent unsecured, senior  obligations
                                    of the Company, will rank PARI PASSU in right of payment
                                    with   all   existing  and   future   unsecured,  senior
                                    indebtedness of  the Company  and  will rank  senior  in
                                    right of payment to all existing and future subordinated
                                    indebtedness of the Company. At March 31, 1996, on a pro
                                    forma basis after giving effect to indebtedness incurred
                                    after  March 31, 1996, the Offerings and the application
                                    of the net proceeds  therefrom, the aggregate  principal
                                    amount  of indebtedness of  the Company (excluding trade
                                    payables, other accrued liabilities, deferred taxes  and
                                    the   Notes)  was  approximately   $3.4  million,  which
                                    consisted of EMI Note and the Equipment Note and all  of
                                    which  ranked PARI PASSU with the Notes. $1.9 million of
                                    such indebtedness constituted secured indebtedness which
                                    would effectively rank senior to the Notes with  respect
                                    to  the assets securing  such indebtedness. Although the
                                    Indenture will limit the ability of the Company and  its
                                    subsidiaries   to  incur  additional  indebtedness,  the
                                    Indenture will permit the Company to incur a substantial
                                    amount  of   secured  indebtedness   under  the   Credit
                                    Facility,  which,  if  incurred,  will  effectively rank
                                    senior to the Notes with respect to the assets  securing
                                    such   indebtedness.  See  "Risk   Factors  --  Possible
                                    Incurrence   of   Substantial   Secured   Indebtedness,"
                                    "Description  of  Notes"  and  "Description  of  Certain
                                    Indebtedness."
Original Issue Discount...........  The  Notes  are  being  offered  at  an  original  issue
                                    discount  for United States federal income tax purposes.
                                    Thus, although cash interest will not be payable on  the
                                    Notes  prior to                  ,  2001, original issue
                                    discount (I.E., the difference between the principal and
                                    interest payable  on the  Notes and  their issue  price)
                                    will accrue from the issue date of the Notes and will be
                                    included  as interest income periodically (including for
                                    periods ending prior to              , 2001) in a  Note-
                                    holder's  gross income for  United States federal income
                                    tax purposes in advance of receipt of the cash  payments
                                    to  which  the  income  is  attributable.  See  "Certain
                                    Federal Income Tax Considerations."
Certain Covenants.................  The Indenture  will  contain  certain  covenants  which,
                                    among  other things,  will restrict  the ability  of the
                                    Company and its Restricted Subsidiaries (as defined)  to
                                    (i)  incur  indebtedness,  (ii)  pay  dividends  or make
                                    distributions in respect of the Company's capital  stock
                                    or  make certain other restricted payments, (iii) create
                                    certain liens, (iv) enter into certain transactions with
                                    affiliates  or  related  persons,  (v)  conduct  certain
                                    businesses or (vi) sell certain assets. In addition, the
                                    Indenture will limit the
</TABLE>
 
                                       7
<PAGE>
<TABLE>
<S>                                 <C>
                                    ability of the Company to consolidate, merge or sell all
                                    or  substantially all of its assets. These covenants are
                                    subject to important exceptions and qualifications.  See
                                    "Description of Notes -- Certain Covenants."
THE WARRANTS
Warrants..........................  Warrants   which,  when  exercised,  would  entitle  the
                                    holders thereof to purchase an aggregate of       shares
                                    of Common Stock of  the Company (the "Warrant  Shares"),
                                    representing     % of the Common Stock of the Company on
                                    a  fully  diluted  basis  after  giving  effect  to  the
                                    Offerings.
Registration Rights...............  The  Company has agreed, subject to certain limitations,
                                    that, from the  earlier of  the Separation  Date and  45
                                    days  after the occurrence of  a Change in Control until
                                    the expiration  of all  Warrants, it  will maintain  the
                                    effectiveness  of a registration  statement with respect
                                    to the issuance of the  Warrant Shares upon exercise  of
                                    the Warrants.
Separation Date...................  The  Notes and the Warrants  will not be separable until
                                    the earlier of (i)         , 1997 and (ii) such date  as
                                    the   Underwriters  may,   in  their   discretion,  deem
                                    appropriate.
Exercise..........................  Each Warrant will entitle the holder thereof, subject to
                                    certain conditions, to purchase        shares of  Common
                                    Stock  at an exercise price of $      per share, subject
                                    to adjustment under certain circumstances. The  Warrants
                                    will   be   exercisable  at   any   time  on   or  after
                                                , 1997 and  prior to the  expiration of  the
                                    Warrants,  as set  forth below.  The exercise  price and
                                    number of shares of Common Stock issuable upon  exercise
                                    of  the Warrants will be subject to adjustment from time
                                    to time upon the occurrence of certain changes with  re-
                                    spect   to   the   Common   Stock,   including   certain
                                    distributions of shares  of Common  Stock, issuances  of
                                    options   or   convertible  securities,   dividends  and
                                    distributions  and  certain   changes  in  options   and
                                    convertible  securities of  the Company.  A Warrant does
                                    not entitle the holder thereof to receive any  dividends
                                    paid on shares of Common Stock.
Expiration........................  , 2006.
</TABLE>
 
    For additional information concerning the Units, the Notes, the Warrants and
the  Common Stock, and the definitions  of certain capitalized terms used above,
see "Description of  Units," "Description of  Notes," "Description of  Warrants"
and "Description of Capital Stock."
 
                              CONCURRENT OFFERING
 
    Concurrently  with the Unit Offering, the Company is offering, pursuant to a
separate prospectus,  7,500,000  shares of  Common  Stock of  the  Company  (the
"Common  Stock Offering" and, together with the Unit Offering, the "Offerings").
The Unit  Offering is  conditioned upon  the consummation  of the  Common  Stock
Offering.
 
                                  RISK FACTORS
 
    An  investment in the Units  offered hereby involves a  high degree of risk.
See "Risk Factors"  beginning on  page 11 for  a discussion  of certain  factors
which  should be considered by prospective investors in evaluating an investment
in the Units.
 
                                       8
<PAGE>
              SUMMARY HISTORICAL AND PRO FORMA FINANCIAL DATA (1)
 
<TABLE>
<CAPTION>
                                     YEAR ENDED DECEMBER 31, 1995                 THREE MONTHS ENDED MARCH 31, 1996
                             ---------------------------------------------  ---------------------------------------------
                              HISTORICAL                      PRO FORMA      HISTORICAL                      PRO FORMA
                             COMBINED (2)   PRO FORMA (3)  AS ADJUSTED (4)  COMBINED (2)   PRO FORMA (3)  AS ADJUSTED (4)
                             -------------  -------------  ---------------  -------------  -------------  ---------------
<S>                          <C>            <C>            <C>              <C>            <C>            <C>
STATEMENT OF OPERATIONS
 DATA:
Operating revenue..........   $     5,793    $     5,793    $       5,793    $     9,620    $     9,620    $       9,620
Non-cash compensation
 expense...................     1,089,605      1,089,605        1,089,605      7,221,000      7,221,000        7,221,000
Depreciation and
 amortization..............        15,684         15,684        5,418,452         89,279         89,279        1,439,971
Interest, net..............       121,986      1,974,275       23,931,008        131,145        528,739        5,989,300
Net loss...................     3,234,843      5,087,132       30,609,692     10,694,588     11,092,182       17,444,199
Pro forma net loss per
 share of Common Stock
 (5).......................       --         $      0.16    $        0.55        --         $      0.35    $        0.31
Pro forma weighted average
 number of shares of Common
 Stock outstanding (5).....       --          31,651,605       55,651,605        --          31,651,605       55,651,605
 
OTHER FINANCIAL DATA:
EBITDA (6).................   $(1,936,141)   $(1,936,141)   $  (1,936,141)   $(2,156,893)   $(2,156,893)   $  (2,156,893)
Capital expenditures.......     3,585,144      3,585,144        3,585,144      2,861,241      2,861,241        2,861,241
</TABLE>
 
<TABLE>
<CAPTION>
                                                     AS OF                     AS OF MARCH 31, 1996
                                               DECEMBER 31, 1995   ---------------------------------------------
                                                   HISTORICAL       HISTORICAL                      PRO FORMA
                                                  COMBINED (2)     COMBINED (2)   PRO FORMA (3)  AS ADJUSTED (4)
                                               ------------------  -------------  -------------  ---------------
 
<S>                                            <C>                 <C>            <C>            <C>
BALANCE SHEET DATA:
Working capital surplus (deficit)............     $ (3,008,510)     $(1,128,130)   $ 1,116,870    $ 214,516,870
Property and equipment, net..................        3,581,561        6,380,895      6,380,895        6,380,895
FCC licenses.................................        4,235,734        4,235,734      4,235,734      216,110,734
Total assets.................................        9,876,559       15,036,337     20,432,236      448,589,961
Short-term debt..............................          --               --           2,975,000         --
Long-term debt, including
 current portion.............................        6,450,000        5,483,082      7,394,521      163,211,439
Total stockholders' equity (deficit).........         (312,860)       5,339,738      5,849,198      230,675,005
</TABLE>
 
- ------------------------------
(1) The unaudited summary historical and  pro forma financial data were  derived
    from,  and  should  be  read  in  conjunction  with,  the  audited financial
    statements of ART and Telecom and  the notes thereto, the unaudited  interim
    condensed financial statements of ART and Telecom and the notes thereto, and
    the  unaudited pro forma  condensed financial statements  of the Company and
    the notes thereto, included elsewhere in this Prospectus. The pro forma  and
    pro  forma as adjusted financial data are not necessarily indicative of what
    the actual financial position and results of operations of the Company would
    have been as of and  for the three months ended  March 31, 1996 and for  the
    year ended December 31, 1995, nor do they purport to represent the Company's
    future financial position and results of operations.
 
(2) The unaudited summary financial data under the caption "Historical Combined"
    are  presented as if the historical  financial statements of ART and Telecom
    had been  combined  and reflect  (i)  the elimination  of  transactions  and
    balances  between  ART  and  Telecom  and  (ii)  the  elimination  of  ART's
    investment in Telecom and Telecom's investment in ART.
 
(3) The  unaudited summary  financial data  under the  caption "Pro  Forma"  are
    presented  as if the following transactions had occurred as of the beginning
    of the respective  periods for the  Statement of Operations  Data and  Other
    Financial  Data and as of the balance sheet date for the Balance Sheet Data:
    (i) the  March  8,  1996  issuance  of the  Bridge  Notes  (as  defined)  in
    connection  with the Bridge Financing (as defined); (ii) the receipt of $2.2
    million in  cash  proceeds from  the  issuance  of the  Equipment  Note  and
    Indemnity  Warrants (as defined) in  connection with the Equipment Financing
    (as defined), after deducting related  fees and expenses of $225,000;  (iii)
    the  receipt of $3.0 million  in cash proceeds from  the CommcoCCC Notes (as
    defined)  and  CommcoCCC  Warrants  (as  defined)  in  connection  with  the
    CommcoCCC  Financing (as defined); (iv) the  Conversion; and (v) the Merger,
    including the  issuance of  Common  Stock to  Telecom stockholders  and  the
    cancellation   of  all  outstanding  Telecom   common  stock.  See  "Certain
    Transactions."
 
(4) The  unaudited  summary financial  data  under  the caption  "Pro  Forma  As
    Adjusted"  are presented as if the transactions referred to in (3) above and
    the  following  transactions  had  occurred  as  of  the  beginning  of  the
    respective  periods for the Statement of Operations Data and Other Financial
    Data and as of the  balance sheet date for the  Balance Sheet Data: (i)  the
 
                                       9
<PAGE>
    sale  by the  Company of  7,500,000 shares  of Common  Stock offered  in the
    Common Stock Offering based on an  assumed initial public offering price  of
    $9.00  per share and the Units offered  in the Unit Offering assuming $175.0
    million of gross proceeds, and, in each case, after deducting the  estimated
    underwriting   discount  and   offering  expenses,  (ii)   the  receipt  and
    application of the net proceeds therefrom to repay the Bridge Notes and  the
    CommcoCCC  Notes and to acquire  the 50% ownership interest  of ART West (as
    defined) held by Extended (as defined) for $6.0 million in cash and the  DCT
    Assets  (as defined)  for $3.6  million in  cash and  (iii) the  issuance of
    16,500,000 shares of Common Stock based  upon an assumed value of $9.00  per
    share in connection with the CommcoCCC Acquisition. See "Use of Proceeds."
 
(5)  Pro forma net loss per  share is computed based on  the loss for the period
    divided by the weighted average number of shares of Common Stock outstanding
    during the period, including the Conversion, the Merger and the issuance  of
    potentially  dilutive  instruments  issued  within  one  year  prior  to the
    Offerings at exercise prices below the assumed initial public offering price
    of $9.00 per share.  Pro forma as  adjusted net loss  per share include  the
    items  noted above plus the issuance of  7,500,000 shares of Common Stock in
    the Common Stock Offering  and the issuance of  16,500,000 shares of  Common
    Stock  in  connection  with  the  CommcoCCC  Acquisition.  In  measuring the
    dilutive effect, the treasury stock method was used.
 
(6) EBITDA means loss before interest expense, income tax expense,  depreciation
    and  amortization expense, non-cash compensation expense and non-cash market
    development expense. Information with respect  to EBITDA is included  herein
    because  a similar measure will  be used in the  Indenture (as defined) with
    respect to the computation of certain  covenants. EBITDA is not intended  to
    represent  cash flows from operating activities, as determined in accordance
    with generally accepted accounting principles, nor has it been presented  as
    an  alternative to operating income as an indicator of operating performance
    and should not  be considered as  a substitute for  measures of  performance
    prepared in accordance with generally accepted accounting principles.
 
                                       10
<PAGE>
                                  RISK FACTORS
 
    IN  ADDITION  TO THE  OTHER INFORMATION  CONTAINED  IN THIS  PROSPECTUS, THE
FOLLOWING  RISK  FACTORS  SHOULD  BE  CONSIDERED  CAREFULLY  IN  EVALUATING   AN
INVESTMENT IN THE UNITS OFFERED HEREBY.
 
                         BUSINESS AND REGULATORY RISKS
 
LIMITED OPERATIONS; HISTORY OF NET LOSSES
 
    Although the Company's business commenced in 1993, the Company has generated
only  nominal revenues from operations to date. The Company's primary activities
have focused  on  the acquisition  of  wireless authorizations,  the  hiring  of
management  and other key personnel, the  raising of capital, the acquisition of
equipment and the  development of operating  systems. As of  June 28, 1996,  the
Company  was operating revenue-generating, wireless broadband links in 15 cities
using 38  GHz  technology.  Prospective investors  have  limited  operating  and
financial  data  about the  Company  upon which  to  base an  evaluation  of the
Company's performance and an investment in the Common Stock offered hereby.  The
Company's  ability to  provide commercial service  on a widespread  basis and to
generate positive operating cash flow will depend on its ability to, among other
things, (i)  deploy its  38 GHz  technology on  a market-by-market  basis,  (ii)
attract  and retain an adequate customer base, (iii) develop its operational and
support systems  and (iv)  acquire  appropriate sites  for its  operations.  See
"Business  -- Business Strategy." Given the Company's limited operating history,
there can  be no  assurance that  it will  be able  to achieve  these goals,  to
develop  a sufficiently large  revenue-generating customer base,  to service its
indebtedness or to compete successfully in the telecommunications industry.
 
    The development of the Company's business and the deployment of its services
and systems will require significant capital expenditures, a substantial portion
of which  will  need  to  be incurred  before  the  realization  of  significant
revenues.  Together  with  the  associated  start-up  operating  expenses, these
capital expenditures will result in negative cash flow until an adequate revenue
generating customer base is established. On a historical combined basis for  the
year  ended December 31, 1995  and the three-month period  ended March 31, 1996,
the Company reported net losses of $3.2 million and $10.7 million, respectively.
On a  combined historical  basis, from  inception through  March 31,  1996,  the
Company  reported net losses  of $14.1 million. The  financial statements of the
Company included in this Prospectus have been prepared on a going concern basis.
See "Management's Discussion and Analysis of Financial Condition and Results  of
Operations."  Through  1997,  the  Company currently  expects  to  incur capital
expenditures of approximately $100.0 million as the development and expansion of
its wireless  broadband  business continues.  The  Company expects  to  generate
significant  operating losses for at least the  next several years. There can be
no assurance that the Company will develop a revenue-generating customer base or
will achieve or sustain profitability in the future.
 
EMERGING MARKET; UNCERTAIN ACCEPTANCE OF 38 GHZ SERVICES
 
    The Company  has  only  recently  begun to  market  its  wireless  broadband
services to potential customers and has generated only nominal revenues to date.
The provision of wireless broadband services on 38 GHz frequencies represents an
emerging  sector of  the telecommunications  industry, and  the demand  for such
services is uncertain. Market acceptance may be adversely affected by historical
perceptions of  the unreliability  and lack  of security  of previous  microwave
technologies  using  frequencies other  than  38 GHz.  See  "Business --  38 GHz
Technology." There can be no assurance that substantial markets will develop for
38 GHz wireless broadband  services, or, if such  markets were to develop,  that
the   Company   would   be   able  to   attract   and   maintain   a  sufficient
revenue-generating customer base or operate profitably.
 
    The Company's success in providing wireless broadband services is subject to
certain factors beyond  the Company's  control. These  factors include,  without
limitation,  changes in general  and local economic  conditions, availability of
equipment, changes in telecommunications service rates charged by other  service
providers,  changes in  the supply and  demand for  wireless broadband services,
competition from
 
                                       11
<PAGE>
wireline and wireless operators in the same market area, changes in the  federal
and  state  regulatory schemes  affecting  the operation  of  wireless broadband
systems (including the enactment of new statutes and the promulgation of changes
in the interpretation or enforcement of  existing or new rules and  regulations)
and  changes in  technology that  have the  potential of  rendering obsolete the
Company's wireless broadband equipment. In addition, the extent of the potential
demand for wireless broadband services in  the Company's market areas cannot  be
estimated  with certainty. There can  be no assurance that  one or more of these
factors will not have an adverse effect on the Company's financial condition and
results of operations.
 
RISK OF NON-CONSUMMATION OF COMMCOCCC ACQUISITION
 
    On July  3, 1996,  the Company  entered into  an agreement  (the  "CommcoCCC
Agreement")  to  acquire the  CommcoCCC  Assets from  CommcoCCC  (the "CommcoCCC
Acquisition") in exchange for 16,500,000  shares of Common Stock. See  "Business
- -- Agreements Relating to Licenses and Authorizations -- CommcoCCC Acquisition."
The  CommcoCCC Acquisition is subject to various conditions including receipt of
FCC and  other approvals  (including Hart-Scott-Rodino  approval, if  required),
receipt by CommcoCCC of an opinion as to the tax-free nature of the transaction,
consummation  of the  Offerings on  terms reasonably  satisfactory to CommcoCCC,
minimum population  coverage  requirements for  the  authorizations of  ART  and
CommcoCCC,  accuracy of representations and  warranties except for breaches that
do not have in the aggregate a material adverse effect, no pending or threatened
material litigation  and other  customary closing  conditions. There  can be  no
assurance  that  all  such  conditions  will  be  satisfied.  See  "Business  --
Agreements Relating to Licenses and Authorizations -- CommcoCCC Acquisition." In
particular, to obtain FCC  approval, the Company will  need to demonstrate  that
the  shareholders  of  CommcoCCC  acquired the  authorizations  that  are  to be
assigned to the Company with the intent  of providing service to the public  and
not  for the speculative  purpose of reselling such  authorizations and may need
certain waivers or consents from the FCC. The FCC may be unwilling to grant  its
approval  or may grant its approval subject to conditions that may be adverse to
the Company. There can be no assurance  that the FCC will grant such waivers  or
that  there would not be substantial delays in its doing so. If the Company were
unable to  complete the  CommcoCCC  Acquisition for  any reason,  the  Company's
footprint  would be considerably  smaller than planned  and the Company's growth
could be limited.
 
COMPETITION
 
    The telecommunications services industry is highly competitive. The  Company
has  only recently begun to market  its wireless broadband services to potential
customers and is currently providing services on a limited basis. In each market
area in  which  the Company  is  authorized  to provide  services,  the  Company
competes  or will compete with several other service providers and technologies.
The Company expects  to compete  primarily on  the basis  of wireless  broadband
service  features,  quality,  price,  reliability,  customer  service  and rapid
response to customer needs. The Company faces significant competition from other
38 GHz  providers  and incumbent  LECs,  such  as the  Regional  Bell  Operating
Companies  ("RBOCs"). The Company  may also compete  with CAPs, cable television
operators, electric  utilities,  LECs  operating  outside  their  current  local
service  areas and IXCs. There can be no assurance that the Company will be able
to  compete  effectively  in  any  of   its  market  areas.  See  "Business   --
Competition."
 
    COMPETITION  FROM 38 GHZ  SERVICE PROVIDERS.   The Company faces competition
from other  38  GHz service  providers,  such as  WinStar  Communications,  Inc.
("WinStar") and BizTel Communications, Inc. ("BizTel"), within its market areas.
In  many cases, one or both of  these service providers hold licenses to operate
in other portions  of the 38  GHz band  in geographic areas  which encompass  or
overlap  the Company's market  areas. In certain of  the Company's market areas,
other 38 GHz service providers may have a longer history of operations, a larger
geographic footprint  or  substantially  greater financial  resources  than  the
Company. WinStar commenced its 38 GHz operations approximately one year prior to
the  Company, has raised significant capital  and has the competitive advantages
inherent in being the
 
                                       12
<PAGE>
first to market 38 GHz services. In addition to WinStar and BizTel, at least one
other substantial  entity,  Milliwave,  L.P. ("Milliwave"),  and  several  dozen
smaller  ones have been  granted 38 GHz authorizations  in geographic regions in
which the  Company  plans  to  operate. WinStar  has  recently  entered  into  a
definitive  agreement  with Milliwave  to acquire  Milliwave's 38  GHz licenses,
subject to FCC  approval, and  has agreed to  manage such  licenses pending  the
consummation  of  such  acquisition.  Due  to the  relative  ease  and  speed of
deployment  of  38  GHz  technology,  the  Company  could  face  intense   price
competition  and competition  for customers  (including other telecommunications
service providers) from other 38 GHz service providers.
 
    The Company also faces potential competition from new entrants to the 38 GHz
market, including LECs and other leading telecommunications companies. The  NPRM
(as  defined) contemplates an auction of  certain spectrum assets, including the
lower fourteen proposed 100 MHz channels (which are similar to those used by the
Company) and four proposed 50  MHz channels in the  38 GHz spectrum band,  which
have  not  been  previously available  for  commercial use.  See  "-- Government
Regulation." The grant  of additional authorizations  by the FCC  in the 38  GHz
band,  or other  portions of  the spectrum  with similar  characteristics, could
result in  increased  competition.  The Company  believes  that,  assuming  that
additional  channels  are made  available as  proposed  by the  NPRM, additional
entities having greater resources than the Company could acquire  authorizations
to  provide 38 GHz  services. See "Business --  Government Regulation -- Federal
Regulation -- FCC Rulemaking."
 
    COMPETITION FROM  INCUMBENT  LECS.    The  Company  also  faces  significant
competition  from incumbent  LECs, irrespective of  whether they  provide 38 GHz
services. Incumbent LECs have long-standing relationships with their  customers,
generally  own  significant  PCS  or  cellular  assets,  have  the  potential to
subsidize competitive services with  revenues from a  variety of businesses  and
benefit  from favorable federal  and state policies  and regulations. Regulatory
decisions and recent  legislation, such  as the Telecommunications  Act of  1996
(the "Telecommunications Act"), have partially deregulated the
telecommunications  industry and reduced barriers to  entry into new segments of
the industry. In particular, the Telecommunications Act, among other things, (i)
enhances local exchange competition  by preempting laws prohibiting  competition
in  the  local exchange  market  by requiring  LECs  to provide  fair  and equal
standards for  interconnection  and  by  requiring  incumbent  LECs  to  provide
unbundling of services and (ii) permits an RBOC to compete in the interLATA long
distance  service market once certain competitive characteristics emerge in such
RBOC's service  area.  The Company  believes  that this  trend  towards  greater
competition will continue to provide opportunities for broader entrance into the
local  exchange markets. However, as LECs face increased competition, regulatory
decisions are likely to provide  them with increased pricing flexibility,  which
in  turn may result  in increased price  competition. There can  be no assurance
that such increased price competition will not have a material adverse effect on
the Company's results of operations.
 
    OTHER COMPETITORS.  The Company may  compete with CAPs for the provision  of
last  mile access and additional services in  most of its market areas. However,
the Company believes  that many CAPs  may utilize 38  GHz transmission links  to
augment  their own service offerings to IXCs and end users, and that the Company
is well positioned to provide such 38  GHz services to CAPs. However, there  can
be  no assurance that  CAPs will utilize  the Company's 38  GHz services or that
CAPs will not  seek to  acquire their  own 38  GHz licenses  or use  the 38  GHz
licenses  of other licensees. Furthermore, the ability of CAPs to compete in the
local exchange market is limited by regulations relating to number  portability,
dialing  parity  and  reasonable  interconnection.  The  Telecommunications  Act
requires the FCC and the  states to implement regulations  that place CAPs on  a
more  equal  competitive footing  with  LECs. To  the  extent these  changes are
implemented, CAPs may be  able to compete more  effectively with LECs.  However,
there  can be no  assurance that CAPs or  38 GHz service  providers, such as the
Company, will be  able to  compete effectively for  the provision  of last  mile
access and other services.
 
    The  Company  may  also  face competition  from  cable  television operators
deploying cable modems, which provide high speed data capability over  installed
coaxial  cable  television  networks.  Although  cable  modems  are  not  widely
available currently, the Company  believes that the  cable industry may  support
 
                                       13
<PAGE>
the  deployment of cable  modems to residential  cable customers through methods
such as price subsidies. Notwithstanding the cable industry's interest in  rapid
deployment  of  cable modems,  the  Company believes  that  in order  to provide
broadband capacity  to a  significant number  of business  and government  users
cable  operators will be required to spend significant time and capital in order
to upgrade  their existing  networks  to the  next  generation of  hybrid  fiber
coaxial  network architecture.  However, there  can be  no assurance  that cable
television operators will not emerge as a source of competition to the Company.
 
    The  Company  may  also  face  competition  from  electric  utilities,  LECs
operating  outside their current local service  areas, IXCs and other providers.
These entities provide transmission services using technologies which may  enjoy
a  greater degree of market acceptance than 38 GHz wireless broadband technology
in the provision of last mile  broadband services. In addition, the Company  may
face  competition  from  new market  entrants  using wireless,  fiber  optic and
enhanced copper based networks to provide local service and from wireless  cable
providers  and other  service providers operating  in frequencies  other than 38
GHz.
 
    Many of  the Company's  competitors  have long-standing  relationships  with
customers  and  suppliers,  greater  name  recognition  and  greater  financial,
technical  and  marketing  resources  than  the  Company.  As  a  result,  these
competitors  may be  able to  more quickly develop  and exploit  new or emerging
technologies, adapt  to  changes  in customer  requirements  or  devote  greater
resources to the marketing of their services than the Company. The consolidation
of  telecommunications companies  and the  formation of  strategic alliances and
cooperative relationships  in the  telecommunications and  related industry,  as
well  as the development of new technologies, could give rise to significant new
competitors to the Company. In  such case, there can be  no assurance as to  the
degree to which the Company will be able to compete effectively.
 
GOVERNMENT REGULATION
 
    The  telecommunications  services  offered  by the  Company  are  subject to
regulation by  federal, state  and  local government  agencies. At  the  federal
level,  the FCC  has jurisdiction over  the use of  the electromagnetic spectrum
(I.E., wireless services)  and has  exclusive jurisdiction  over all  interstate
telecommunications  services, that  is, those  that originate  in one  state and
terminate in another state. State regulatory commissions have jurisdiction  over
intrastate  communications, that is,  those that originate  and terminate in the
same state.  Municipalities  may  regulate  limited  aspects  of  the  Company's
business   by,  for   example,  imposing   zoning  requirements   and  requiring
installation permits. See "Business -- Government Regulation."
 
    The Company  is  licensed  by  the  FCC as  a  common  carrier  provider  of
facilities-based  local telecommunications services. For  many of its intrastate
services, the Company will need to  seek authorizations from the states, and  in
most  cases, file tariffs. The  Company is in the  process of filing tariffs for
some of its  services with  the FCC  and with  certain state  authorities on  an
ongoing  basis. Certain of its proposed services  have not yet been permitted in
most states. Although the Telecommunications Act requires the states to open  up
all  of the Company's  services to competition,  there can be  no assurance that
this  will  occur  on  a  timely  basis.  Challenges  to  its  applications  for
authorizations  or its tariffs by third parties could cause the Company to incur
substantial legal and administrative expenses and time delay in implementing its
business  plan.   Although  many   of  the   Company's  applications   for   FCC
authorizations  were subject to  challenge, the Company  nonetheless was granted
authorizations for  a  majority of  its  applications. The  Company's  remaining
applications  were  either  dismissed,  voluntarily  or  involuntarily,  or  are
currently pending before the FCC.
 
    Twenty of the Company's applications were dismissed by the FCC because  they
overlapped  either with  authorizations granted to  third parties  or with third
party applications that held  superior rights by virtue  of the timing of  their
filing.  Five of  the Company's applications  were dismissed  voluntarily by the
Company because they could not be  granted under FCC policies. In one  instance,
the geographic area sought was larger than that permitted by the FCC's September
1994 Policy Statement. In the other four
 
                                       14
<PAGE>
instances  the dismissed applications overlapped with  each other and thus could
not be granted  under then-existing FCC  policies. None of  the dismissals  will
impact  the financial condition  or operations of the  Company because they have
not  been  included  in  the  Company's  business  plan.  Some  of  the  pending
applications propose the same channel in part of the same geographic area as one
or  more applications filed by third parties  and therefore could not be granted
under the  FCC  rules  generally prohibiting  the  grant  of  mutually-exclusive
applications.  Elimination of the conflicts generally would require dismissal of
a majority of  the applications  as part  of a  settlement. All  of the  pending
applications are subject to the freeze on the grant of additional authorizations
pending   completion  of  the  NPRM,  which   proposes  dismissal  of  all  such
applications. The  Company's business  plans do  not assume  that any  of  these
pending  applications  will be  granted.  The Company  does  not believe  that a
failure to grant  these applications  will impair  its ability  to operate.  See
"Business -- Government Regulation."
 
    In its provision of local wireless broadband services, the Company currently
is  not subject to rate  regulation by the FCC, but  is subject to regulation by
most states. Additionally, the Company is required to comply with all applicable
local zoning and  other laws  governing the  installation and  operation of  its
wireless broadband services.
 
    Changes  in existing laws  and regulations, including  those relating to the
provision of wireless local telecommunications services via 38 GHz licenses,  or
any  failure or significant  delay in obtaining  necessary regulatory approvals,
could have a material adverse effect on  the Company. On November 13, 1995,  the
FCC  released an  order barring  the acceptance of  new applications  for 38 GHz
authorizations. On December 15, 1995, the FCC announced the issuance of a notice
of proposed rulemaking (the "NPRM"), pursuant to which it proposed to amend  its
current rules to provide for, among other things, (i) the adoption of an auction
procedure  for the issuance  of authorizations in  the 38 GHz  band, including a
possible auction of the  lower fourteen 100 MHz  channels (which are similar  to
those used by the Company) and the lower four 50 MHz channels in the 38 GHz band
that   have  not  been  previously  available   for  commercial  use,  (ii)  the
continuation of  the  100 MHz-based  channeling  plan and  licensing  rules  for
point-to-point  microwave operations in  the lower 14  channels, (iii) licensing
frequencies using predefined geographic  service areas ("Basic Trading  Areas"),
(iv)  the  imposition of  substantially  stricter construction  requirements for
authorizations that are not received pursuant to auctions as a condition to  the
retention of such authorizations and (v) the implementation of certain technical
rules  designed  to  avoid  radio  frequency  interference  among  licensees. In
addition, the FCC ordered that those applications subject to mutual  exclusivity
with  other applicants or placed on public notice by the FCC after September 13,
1995 would be held in abeyance pending the outcome of the NPRM and might then be
dismissed. Final rules issued  in connection with the  NPRM may require that  38
GHz service providers share other yet-to-be licensed portions of the 38 GHz band
with  other telecommunications service  providers. The implementation  of such a
measure could materially affect the Company's ability to provide services to its
customers by  imposing power  and other  limitations upon  existing  operations.
There  can be no  assurance that the  final rules (if  any) issued in connection
with the NPRM will resemble the rules proposed in the NPRM. There also can be no
assurance that any  proposed or  final rules will  not have  a material  adverse
effect  on the Company. Statutes and  regulations which may become applicable to
the Company  as  it  expands could  require  the  Company to  alter  methods  of
operations  at costs which could be substantial  or otherwise limit the types of
services offered by the Company.
 
    The Company manages the systems of ART West, DCT, Telecom One and  CommcoCCC
(during the pendency of certain acquisitions) pursuant to management agreements.
See  "Business  --  Agreements  Relating to  Licenses  and  Authorizations." The
Company believes that the provisions of these management agreements comply  with
the  FCC's  policies  concerning licensee  control  of  FCC-licensed facilities.
Because the 38 GHz service is a new service, however, there is no FCC  precedent
addressing  the  limits of  such management  arrangements  for this  service. No
assurance can be given that the management arrangements or proposed acquisitions
will,  if  challenged,  be  found  to   satisfy  the  FCC's  policies  or   what
modifications, if any, may need to be made to satisfy those policies. If the FCC
were  to  void  or require  modifications  of the  management  arrangements, the
operations of the Company could be adversely affected.
 
                                       15
<PAGE>
RISK OF FORFEITURE, NON-RENEWAL AND FLUCTUATION IN VALUE OF FCC LICENSES
 
    Upon completion of the CommcoCCC Acquisition, the Company will own or manage
a total of  237 authorizations that  will allow  it to provide  38 GHz  wireless
broadband  services in 169  U.S. markets. The Company  currently owns or manages
108 authorizations (exclusive of the CommcoCCC Assets) that allow it to  provide
38  GHz wireless broadband services in 89 markets,  73 of which are owned by the
Company and the  remaning 35 of  which are  managed by the  Company through  the
Company's  interests in or arrangements with  other companies. Under the current
FCC rules, the recipient of an authorization for 38 GHz microwave facilities  is
required  to complete  construction of such  facilities within 18  months of the
date of grant of the authorization  (authorizations for facilities that are  not
constructed  are referred  to in this  Prospectus as  "construction permits" and
authorizations for  facilities that  are  constructed are  referred to  in  this
Prospectus  as  "licenses"). Upon  completion of  construction, the  licensee is
required to certify that the station is operational and ready to provide service
to the public. Although under current FCC regulations the term "operational"  is
not  defined, the industry custom is to  establish at least one link between two
transceivers in each market area for which a construction permit is held. In the
event that the  recipient fails to  comply with the  construction deadline,  the
construction  permit  is  subject  to forfeiture,  absent  an  extension  of the
deadline. Of the 108 authorizations that the Company owns or manages  (exclusive
of  the CommoCCC Assets), 77  are licenses. Under the  terms of its remaining 31
construction permits, the Company must  complete construction of facilities  for
the  majority of such construction  permits between mid-August and mid-September
1996. Under  the  terms  of  the  CommcoCCC  authorizations  and  the  Company's
management  agreement with CommcoCCC, the  Company must complete construction of
facilities for eight construction permits by mid-September 1996, 39 construction
permits by  December 1996  and  the remaining  82 construction  permits  between
mid-April  and mid-August 1997.  The Company believes that,  in light of current
FCC practice, extensions of construction  periods are highly unlikely.  Although
the Company believes that it can complete the construction of all of its own and
CommcoCCC's  facilities using  the proceeds  of the  Offerings within respective
time limits, there can be no assurance that it will be able to do so or that the
Company will  be  able  to  comply with  whatever  more  stringent  construction
requirements  the FCC ultimately  adopts as a  result of the  NPRM. As a result,
some of the Company's construction permits could be subject to forfeiture, which
could have a material adverse effect on the Company's development and results of
operations. See  "Business --  Government Regulation"  and "--  38 GHz  Wireless
Broadband Licenses and Authorizations."
 
    The  FCC's current  policy is to  align the  expiration dates of  all 38 GHz
licenses held  by a  particular  licensee such  that  all such  licenses  mature
concurrently  and then to  require renewal of  all such licenses  for a matching
ten-year period. All  of the  38 GHz  licenses owned or  to be  acquired by  the
Company will expire in February 2001. Although the Company currently anticipates
that  its licenses will be  renewed based upon the  FCC's custom and practice in
connection with other services which have established a presumption in favor  of
licensees  that  have complied  with regulatory  obligations during  the initial
license period, there can be no assurance  that all or any of the licenses  will
be  renewed upon expiration  of their initial  terms. In the  event that the FCC
does not renew one or more of  the licenses, the Company's business and  results
of operations could be materially adversely affected.
 
    The  Company plans to  use its authorizations  to develop wireless broadband
systems in all  of its  market areas. In  addition, a  limited secondary  market
exists for 38 GHz authorizations, and the Company may from time to time purchase
such  authorizations. The value of authorizations  held or acquired hereafter by
the Company will  depend upon the  success of the  Company's wireless  broadband
operations,   fluctuations  in  the   level  of  supply   and  demand  for  such
authorizations  and   the   telecommunications  industry's   response   to   the
availability  and efficacy of  wireless broadband systems.  In addition, federal
and  state  regulations   limit  the   ability  of  licensees   to  sell   their
authorizations.  Assignments of authorizations and  changes of control involving
entities holding authorizations require prior FCC and, in some instances,  state
regulatory  approval  and are  subject to  restrictions  and limitations  on the
identity and status of the assignee or successor. These regulatory  restrictions
on  transfer of authorizations  may adversely affect the  value of the Company's
authorizations.
 
                                       16
<PAGE>
MANAGEMENT OF GROWTH
 
    The Company  is currently  experiencing  a period  of  rapid growth  and  is
pursuing  a  business plan  that, if  successfully  implemented, will  result in
expansion of its operations and the provision of 38 GHz services on a widespread
basis over the next two to five years. The Company's success will depend on  its
ability  to manage growth effectively, to  enhance its operational and financial
control and information systems and to attract, assimilate and retain additional
qualified personnel. Failure by the Company to meet the demands of customers and
to manage the  expansion of its  business and operations  could have a  material
adverse effect on the Company's development and results of operations.
 
LINE OF SIGHT; ROOF RIGHTS; OTHER LIMITATIONS
 
    Wireless broadband services over 38 GHz frequencies require a direct line of
sight between two transceivers comprising a link and are subject to distance and
rain  attenuation. The maximum length  of a single link  is generally limited to
three to five miles, and, as  a result, intermediate links (or "repeaters")  are
required  to permit wireless broadband transmission to extend beyond this limit.
In the  absence  of  a direct  line  of  sight, repeaters  may  be  required  to
circumvent  obstacles, such as buildings in urban areas or hills in rural areas.
In addition, in areas of heavy rainfall, the intensity of rainfall and the  size
of   raindrops  can  affect  the  transmission   quality  of  38  GHz  services.
Transmission links  in these  areas  are engineered  for shorter  distances  and
greater power to maintain transmission quality. The use of intermediate links to
overcome  obstructions or rain  fade increases the cost  of service. While these
increased costs  may not  be significant  in all  cases, such  costs may  render
wireless broadband services uneconomical in certain circumstances.
 
    Due  to  line  of  sight limitations,  the  Company  currently  installs its
transceivers and  antennas  on the  rooftops  of  buildings and  on  other  tall
structures.  In order to obtain the necessary access, the Company generally must
secure roof rights from the owners of each building or other structure on  which
its  equipment is installed. Line of sight and distance limitations generally do
not present problems in urban areas due to the ability of the licensee to select
unobstructed  structures  from  which  to  transmit  and  the  concentration  of
customers  within  a  limited area  although  the  Company may  have  to install
intermediate links. Line of  sight and distance  limitations in non-urban  areas
can  arise  due to  lack of  structures  with sufficient  height to  clear local
obstructions. The  Company has  generally been  able to  construct  intermediary
repeater  links  and  other  solutions  to reduce  line  of  sight  and distance
limitations in urban or non-urban areas; however, in a minority of instances the
Company has encountered line of sight and distance limitations that could not be
solved economically. In  such instances,  sales to  certain potential  customers
have  been or in  the future may be  adversely affected, and  in some cases, the
Company may determine to provide certain services on terms that are uneconomical
in the near  term as  a result  of these limitations.  While the  effect on  the
financial condition and results of operations of the Company resulting from such
cases has been minimal, there can be no assurance that such limitations will not
have  a material adverse effect on  the Company's future development and results
of operations.  Failure to  obtain roof  rights in  a timely  fashion may  cause
potential  customers  to use  alternative  providers of  38  GHz services  or to
refrain from using 38  GHz services altogether. There  can be no assurance  that
the  Company will  succeed in obtaining  the roof rights  necessary to establish
wireless broadband services to  all potential customers in  its market areas  on
favorable  terms, if at  all, or that  delays in obtaining  such rights will not
have a  material adverse  effect on  the Company's  development and  results  of
operations.
 
    The relative significance of the size of a market area served depends on the
concentration  within  that area  of potential  customers. The  Company's market
areas were defined by the Company in  preparing its FCC applications for 38  GHz
licenses. The definitions of these areas were based on the Company's analysis of
the  then existing  local demographic  characteristics in  each market,  such as
concentrations of  employees and  income  levels. In  certain of  the  Company's
market  areas, other 38 GHz service  providers have larger geographic footprints
or greater bandwidth.  To the extent  that the Company's  authorizations do  not
track  the appropriate  growth and  development patterns  of potential customers
within its market areas or that  other 38 GHz providers have greater  geographic
coverage or more bandwidth, the Company may have a competitive disadvantage.
 
                                       17
<PAGE>
RELIANCE ON EQUIPMENT SUPPLIERS; LACK OF INDUSTRY STANDARDS
 
    The  Company  currently  purchases the  majority  of  its telecommunications
equipment pursuant  to an  agreement  with P-Com,  Inc. ("P-Com")  and  recently
entered  into  an equipment  purchase agreement  with  Harris. Any  reduction or
interruption in supply from  either supplier could have  a disruptive effect  on
the  Company.  Although six  manufacturers currently  produce or  are developing
equipment that will meet the Company's current and anticipated requirements,  no
industry  standard or  uniform protocol currently  exists for  38 GHz equipment.
Consequently, a single manufacturer's equipment  must be used in establishing  a
link  and generally will be used across an  entire market area. As a result, the
failure of the  Company to  procure sufficient  equipment produced  by a  single
manufacturer  for service in a particular market area could adversely affect the
Company's results of operations. See "Business -- Strategic Alliances."
 
DEPENDENCE ON THIRD PARTIES FOR MARKETING AND SERVICE
 
    The Company  is  partly  dependent  upon third  parties  for  marketing  its
services  and maintaining its operational  systems. The Company recently entered
into the Ameritech Strategic Distribution  Agreement, which allows Ameritech  to
resell  the Company's 38 GHz services to customers within Ameritech's midwestern
region and  to  major  Ameritech  customers nationwide.  The  Company  also  has
agreements  with  subsidiaries  of  GTE to  provide  field  service  and network
monitoring and a joint  marketing agreement with Harris.  The failure of any  of
these third parties to perform or the loss of any of these agreements could have
a  material adverse effect on the Company's results of operations or its ability
to service its customers.  The Company plans to  enter into sales and  marketing
agreements with other companies, and the failure to successfully implement these
agreements could have an adverse effect on the Company's development and results
of operations. See "Business -- Strategic Alliances."
 
ACQUISITION OF ADDITIONAL BANDWIDTH IN SELECTED AREAS
 
    Although  the Company believes the 38 GHz authorizations it owns, manages or
has agreed to acquire  are sufficient in  each of its  markets to implement  its
current  business strategy, the Company may  seek to acquire or lease additional
authorizations to expand its geographic footprint  or to enhance its ability  to
provide  service to its current target market  or customers it may target in the
future.  The  FCC  has  suspended  granting  additional  licenses,  subject   to
resolution  of the NPRM. The Company does  not believe that the FCC's suspension
on acceptance of new applications will  have a material effect on the  Company's
financial  condition,  results of  operation and  plans  of expansion  since the
Company's business plan does not depend  on the grant thereof. See "Business  --
Government  Regulation." However, the Company  believes that additional channels
may become available by virtue  of (i) the obligations  of other 38 GHz  service
providers  as  common carriers  to make  their services  available and  (ii) FCC
auctions of and  adoption of other  licensing procedures for  additional 38  GHz
authorizations.   Nevertheless,  there  can  be  no  assurance  that  access  to
additional 38 GHz authorizations will be acquired on favorable terms, if at all.
See "Business -- Business Strategy," "-- 38 GHz Wireless Broadband Licenses  and
Authorizations" and "-- Government Regulation."
 
NEW SERVICES; TECHNOLOGICAL CHANGE
 
    The   telecommunications   industry   has   been   characterized   by  rapid
technological advances, changes in end  user requirements, frequent new  service
introductions,  evolving  industry  standards  and  decreases  in  the  cost  of
equipment. The Company expects these changes to continue, and believes that  its
long-term  success will increasingly  depend on its  ability to exploit advanced
technologies and anticipate or adapt  to evolving industry standards. There  can
be  no assurance that (i) the Company's  wireless broadband services will not be
outmoded by technology or services now existing or developed and implemented  in
the  future,  (ii) the  Company  will have  sufficient  resources to  develop or
acquire new technologies or to introduce new services capable of competing  with
future  technologies  or service  offerings,  (iii) the  Company's  inventory of
equipment will not be  rendered obsolete or  (iv) the cost  of 38 GHz  equipment
will decline as rapidly as that of competitive alternatives. See "Business."
 
                                       18
<PAGE>
DEPENDENCE ON KEY EMPLOYEES
 
    The  success of the Company is dependent, in part, on its ability to attract
and retain  qualified  technical,  marketing, sales  and  management  personnel,
especially  the Company's executive officers.  Competition for such personnel is
intense, and  the  Company's inability  to  attract and  retain  additional  key
employees  or the loss of one or more  of its current key employees could have a
material adverse affect on the Company's business and results of operations. The
Company has employment agreements with each of its officers. See "Management."
 
                                FINANCIAL RISKS
 
SIGNIFICANT CAPITAL REQUIREMENTS; UNCERTAINTY OF ADDITIONAL FINANCING
 
    Management anticipates  that,  based on  its  current plan  of  development,
assuming  that no material new acquisitions are consummated, the net proceeds of
the Offerings, after  the use of  approximately $8.0 million  to repay  existing
indebtedness  and  $9.6  million  to complete  pending  acquisitions  of certain
spectrum  rights  will  be  sufficient  to  fund  the  operations  and   capital
requirements  of  the Company  for  at least  the next  two  years. See  "Use of
Proceeds." Management also believes that the Company's future capital needs will
continue to be significant and that it will be necessary for the Company to seek
additional  sources  of  financing.  The   Company  expects  to  incur   capital
expenditures of approximately $100.0 million through 1997 as the development and
expansion  of its wireless broadband business  continues. The Company expects to
generate significant operating losses for at  least the next several years.  The
Company   will  require   substantial  investment  capital   for  the  continued
development and expansion  of its wireless  broadband operations, the  continued
funding  of related operating losses, and the possible acquisition of additional
licenses, other assets or other businesses. On a historical combined basis, from
its inception through March 31, 1996, the  Company reported a net loss of  $14.1
million.  In addition, if  (i) the Company's plan  of development or projections
change or prove to be inaccurate,  (ii) the proceeds of the Offerings,  together
with  other existing financial  resources, prove to be  insufficient to fund the
Company for at  least the  next two  years or  (iii) the  Company completes  any
material  acquisitions not  now under contract,  the Company may  be required to
seek additional financing sooner  than currently anticipated. See  "Management's
Discussion and Analysis of Financial Condition and Results of Operations." There
can  be no  assurance that  the Company  will be  able to  obtain any additional
financing, or, if such financing is available, that the Company will be able  to
obtain  it on acceptable  terms. In the  event that the  Company fails to obtain
additional financing, such failure  could result in  the modification, delay  or
abandonment of some or all of the Company's development and expansion plans. Any
such  modification, delay  or abandonment is  likely to have  a material adverse
effect on the Company's business, which could adversely affect the value of  the
Common  Stock, the Notes and the Warrants and may limit the Company's ability to
make principal and interest payments on its indebtedness.
 
POSSIBLE INCURRENCE OF SUBSTANTIAL SECURED INDEBTEDNESS
 
    The Notes will represent unsecured, senior obligations of the Company,  will
rank  PARI PASSU  in right  of payment with  all existing  and future unsecured,
senior indebtedness of the Company and will  rank senior in right of payment  to
all  existing and future subordinated indebtedness  of the Company. At March 31,
1996, on a pro  forma basis after giving  effect to indebtedness incurred  after
March 31, 1996, the Offerings and the application of the net proceeds therefrom,
the  aggregate principal amount of indebtedness  of the Company (excluding trade
payables,  other  accrued  liabilities,  deferred  taxes  and  the  Notes)   was
approximately  $3.4 million, which  consisted of the EMI  Note and the Equipment
Note and all of  which ranked PARI  PASSU with the Notes.  $1.9 million of  such
indebtedness  constituted  secured  indebtedness  which  would  effectively rank
senior to  the Notes  with respect  to the  assets securing  such  indebtedness.
Although   the  Indenture  will  limit  the  ability  of  the  Company  and  its
subsidiaries to incur  additional indebtedness,  including senior  indebtedness,
the  Indenture will permit the Company to  incur a substantial amount of secured
indebtedness under the Credit  Facility (as defined),  which, if incurred,  will
effectively  rank senior to the  Notes with respect to  the assets securing such
indebtedness.
 
                                       19
<PAGE>
In  addition,  the  Indenture  will  permit  the  subsidiaries  of  the  Company
(including  any subsidiary holding all or any part of the Company's FCC licenses
and authorizations)  to guarantee  the  indebtedness of  the Company  under  the
Credit  Facility on  a secured  basis, which  guarantees and  security interests
would effectively rank senior in right of payment to the Notes. In such a  case,
if  the Company or any such subsidiary were to become insolvent or be liquidated
or if any of such  secured indebtedness were to  be accelerated, the holders  of
such secured indebtedness would be entitled to payment in full out of the assets
securing  such indebtedness  prior to  payment to holders  of the  Notes. If the
lenders party  to, or  the holders  of, any  such secured  indebtedness were  to
foreclose  on the collateral  securing the Company's  obligations to them, there
can be  no assurance  that  there would  be  sufficient assets  remaining  after
payment of all such secured indebtedness to satisfy the claims of holders of the
Notes  in full. See "Description of Notes -- Certain Covenants" and "Description
of Certain Indebtedness."
 
HIGH LEVERAGE; ABILITY TO SERVICE INDEBTEDNESS
 
    Following the Offerings, the Company will be highly leveraged and will  have
certain  restrictions on its  operations. As of  March 31, 1996,  on a pro forma
basis after giving effect to  the Equipment Financing, the CommcoCCC  Financing,
the Conversion, the Merger, the Offerings and use of the proceeds therefrom, and
completion  of the CommcoCCC  Acquisition, all as  if they had  occurred on that
date,  the  Company  would  have  had  approximately  $163.2  million  of  total
indebtedness  and  stockholders'  equity  of  approximately  $230.7  million. In
addition, the accretion of the principal amount of the Notes over time (based on
an assumed rate of accretion of 13.5%)  will result in an increase in the  total
indebtedness  represented  by  the  Notes  of  approximately  $161.3  million by
          , 2001.  After giving  effect  to such  transactions  as if  they  had
occurred  at the  beginning of the  respective periods, the  Company's pro forma
earnings for the three months ended March  31, 1996 and the year ended  December
31,  1995 would have  been insufficient to cover  fixed charges by approximately
$17.9 million and $32.4 million, respectively.
 
    The indebtedness expected to  be incurred as a  result of the Unit  Offering
will  have  several  important  consequences to  the  holders  of  the Company's
securities, including,  but not  limited to,  the following:  (i) a  substantial
portion  of the Company's cash flow  from operations will ultimately be required
to be dedicated to the payment of  interest with respect to the Notes; (ii)  the
Company's  flexibility may be  limited in responding to  changes in the industry
and economic conditions  generally; (iii)  the Indenture relating  to the  Notes
(the   "Indenture")  will  contain  numerous  financial  and  other  restrictive
covenants, the failure to comply with which  may result in an event of  default,
which,  if not  cured or  waived, could  have a  material adverse  effect on the
Company; (iv) the ability of the Company to satisfy its obligations pursuant  to
such  indebtedness will be dependent upon its future performance which, in turn,
will be subject to management,  financial, business and other factors  affecting
the  business and operations of the Company; (v) the Company's ability to obtain
any necessary financing in the future may  be limited; (vi) the Company will  be
more  highly  leveraged than  many of  its competitors,  which may  put it  at a
competitive disadvantage and (vii) the Company's high leverage may make it  more
vulnerable  in the event of  an economic downturn or  if the Company's cash flow
does not significantly increase. Some of these factors are beyond the control of
the Company. See "Unaudited Pro Forma Condensed Financial Statements," "Selected
Historical and  Pro  Forma  Financial Data"  and  "Management's  Discussion  and
Analysis  of  Financial  Condition  and  Results  of  Operations."  In addition,
although  the  Indenture  will  limit  the  ability  of  the  Company  and   its
subsidiaries  to incur  additional indebtedness,  the Indenture  will permit the
Company to incur substantial  additional indebtedness, which may  or may not  be
secured,  during the next few years to finance the construction of networks, the
purchase  of  equipment  and  the  introduction  of  new  services.   Additional
indebtedness  of the Company  may rank PARI  PASSU in right  of payment with the
Notes in certain circumstances. See "Description of Notes -- Certain  Covenants"
and   "Description  of  Certain  Indebtedness  --  Credit  Facility."  Any  such
indebtedness may contain covenants that  may limit the Company's flexibility  in
responding  to changes in  industry and economic  conditions generally. The debt
service requirements of any additional indebtedness could make it more difficult
for the Company to make principal and  interest payments on the Notes and  could
exacerbate any of the foregoing consequences.
 
                                       20
<PAGE>
    There  can  be  no assurance  that  the  Company will  be  able  to generate
sufficient cash flow to meet required interest and principal payments associated
with the Notes and its other indebtedness. If the Company is unable to  generate
sufficient  cash flow to meet its debt  obligations, the Company may be required
to renegotiate  the payment  terms  or to  refinance all  or  a portion  of  its
indebtedness,  to sell assets or to  obtain additional financing. If the Company
is unable to  refinance such  indebtedness, substantially all  of the  Company's
long-term  debt would be  in default and  could be declared  immediately due and
payable. Furthermore, the  Indenture contains numerous  financial and  operating
covenants,  including, among  others, covenants  restricting the  ability of the
Company and its  subsidiaries to incur  indebtedness or to  create or suffer  to
exist certain liens. In the event the Company fails to comply with these various
covenants,  it could  be in default  under the  Indenture. In the  event of such
default, substantially all  of the  Company's long-term debt  could be  declared
immediately due and payable. See "Description of Notes -- Certain Covenants."
 
ORIGINAL ISSUE DISCOUNT
 
    The Notes will be issued at a substantial original issue discount from their
principal amount at maturity. Consequently, purchasers of Notes will be required
to include amounts in gross income for federal income tax purposes in advance of
receipt of the cash payments to which the income is attributable. In addition, a
portion  of the purchase price  for each Unit will  be allocable to the Warrants
for federal income tax purposes. See "Certain Federal Income Tax Considerations"
for a more  detailed discussion of  the federal income  tax consequences to  the
purchasers  of the Units  resulting from the  purchase, ownership or disposition
thereof.
 
    If a bankruptcy case is commenced by  or against the Company under Title  11
of the United States Code, as amended (the "Bankruptcy Code") after the issuance
of  the Units, the claim of a holder  of the Notes with respect to the principal
amount thereof may be limited to an amount  equal to the sum of (i) the  initial
public  offering price of the Notes and  (ii) that portion of the original issue
discount that is not deemed to  constitute "unmatured interest" for purposes  of
the Bankruptcy Code. Any original issue discount that was not accrued as of such
bankruptcy filing would constitute "unmatured interest." A holder of a Note will
not  have any claim  with respect to that  portion of the issue  price of a Unit
allocated to the Warrants issued as part of such Unit.
 
RISK OF INABILITY TO SATISFY CHANGE IN CONTROL OFFER
 
    Upon the occurrence of a Change in Control, the Company will be required  to
make  an offer to purchase  all of the outstanding Notes  at a purchase price in
cash equal to (i) 101%  of the Accreted Value thereof,  in the case of any  such
purchase prior to       , 2001, or (ii) 101% of the principal amount at maturity
thereof,  together with  accrued and  unpaid interest,  if any,  to the  date of
purchase, in the case of any such purchase on or  after       , 2001. There  can
be  no assurance that the Company will have the funds necessary to effect such a
purchase if such an event were to occur. In the event a Change in Control occurs
at a time when the  Company is unable to purchase  the Notes, the Company  could
seek  to refinance the Notes. If the  Company is unsuccessful in refinancing the
Notes, the  Company's failure  to purchase  tendered Notes  would constitute  an
Event  of  Default under  the Indenture.  See "Description  of Notes  -- Certain
Covenants -- Change in Control."
 
                            LEGAL AND TRADING RISKS
 
ABSENCE OF PUBLIC MARKET; POSSIBLE VOLATILITY OF STOCK PRICE
 
    There is  currently  no  public market  for  the  Units, the  Notes  or  the
Warrants.  The Company does  not intend to  apply for listing  of the Units, the
Notes or the Warrants on any securities exchange or for quotation of the  Units,
the  Notes or the Warrants  on the Nasdaq National  Market. The Company has been
advised by the Underwriters that they presently  intend to make a market in  the
Units,  the  Notes  and  the  Warrants,  as  permitted  by  applicable  laws and
regulations, after  the consummation  of the  sale of  the Units;  however,  the
Underwriters  are not  obligated to  do so  and any  such market-making activity
 
                                       21
<PAGE>
may be discontinued at any  time without notice at  the sole discretion of  each
Underwriter.  Accordingly, there  can be  no assurance  as to  whether an active
public market for the  Units, the Notes  or the Warrants will  develop or, if  a
public  market does develop, as  to the liquidity of  the trading market for the
Units, the Notes or the Warrants. If  an active public market does not  develop,
the  market price and liquidity for the Units,  the Notes or the Warrants may be
adversely affected. See "Underwriting."
 
    Prior to the Offerings,  there has been no  public market for the  Company's
Common  Stock. While  the Common Stock  (including the Warrant  Shares) has been
approved for quotation on the Nasdaq National Market, there can be no  assurance
that  an active  public trading  market will develop  or be  sustained after the
Offerings or that the initial public offering price will correspond to the price
at which  the Common  Stock will  trade  in the  public market  thereafter.  The
Company  believes that factors such as (i) announcements of developments related
to the Company's business, (ii) announcements of new services by the Company  or
its  competitors,  (iii) developments  in the  Company's relationships  with its
suppliers  or  customers,  (iv)  fluctuations   in  the  Company's  results   of
operations,  (v)  a  shortfall in  revenues  or earnings  compared  to analysts'
expectations and changes in analysts' recommendations or projections, (vi) sales
of substantial amounts of securities of the Company into the marketplace,  (vii)
regulatory  developments  affecting the  telecommunications  industry or  38 GHz
services or (viii) general conditions in the telecommunications industry or  the
worldwide  economy,  could cause  the  price of  the  Company's Common  Stock to
fluctuate, perhaps substantially.
 
CONTROL BY MANAGEMENT AND PRINCIPAL STOCKHOLDERS
 
    Upon consummation  of  the  Offerings,  the  Company's  executive  officers,
directors  and their affiliates, as a group, will beneficially own approximately
28.3% of  the Company's  outstanding Common  Stock (27.4%  if the  underwriters'
over-allotment  option is exercised  in full and 19.3%  upon consummation of the
CommcoCCC  Acquisition).  In   addition,  upon  completion   of  the   CommcoCCC
Acquisition,  Columbia Capital  Corporation, as  general partner  of two  of the
stockholders of  CommcoCCC, and  Commco, L.L.C.,  the remaining  stockholder  of
CommcoCCC, will beneficially own approximately 16.3% and 14.2%, respectively, of
the  Company's outstanding Common  Stock (15.9% and  13.9%, respectively, if the
underwriters' over-allotment option in the Common Stock Offering is exercised in
full), and the Company has agreed  to nominate one individual designated by  the
CommcoCCC  Stockholders  and acceptable  to  the Company  as  a director  of the
Company after the CommcoCCC  Acquisition. As a  result, these stockholders  will
have  the ability  to exercise  significant influence  over the  Company and the
election of its directors, the appointment of new management and the approval of
any action requiring the approval of the holders of the Company's voting  stock,
including   adopting  certain   amendments  to  the   Company's  Certificate  of
Incorporation and  approving  mergers  or  sales of  substantially  all  of  the
Company's  assets. The  directors elected  by these  stockholders will  have the
authority to effect decisions  affecting the capital  structure of the  Company,
including  the issuance of additional capital stock, the implementation of stock
repurchase  programs   and  the   declaration  of   dividends.  See   "Principal
Stockholders."
 
ABSENCE OF DIVIDENDS ON COMMON STOCK
 
    The  Company has not paid and does  not anticipate paying any cash dividends
on its Common Stock in the foreseeable future. The Company intends to retain its
earnings, if any,  for use in  the Company's growth  and ongoing operations.  In
addition, the terms of the Indenture will restrict the ability of the Company to
pay  dividends  on  the  Common  Stock. See  "Description  of  Notes  -- Certain
Covenants."
 
ANTITAKEOVER PROVISIONS; POSSIBLE FUTURE ISSUANCES OF PREFERRED STOCK
 
    The Company's Certificate of Incorporation and Bylaws and the provisions  of
the  Delaware  General  Corporation  Law (the  "Delaware  GCL")  contain certain
provisions which may have  the effect of discouraging,  delaying or making  more
difficult  a  change in  control of  the  Company or  preventing the  removal of
incumbent directors.  The existence  of  these provisions  may have  a  negative
impact  on the price of the Common Stock, the Units, the Notes and the Warrants,
may discourage third  party bidders from  making a  bid for the  Company or  may
reduce any premiums paid to stockholders for their
 
                                       22
<PAGE>
Common Stock. Furthermore, the Company is subject to Section 203 of the Delaware
GCL,  which could have the effect of  delaying or preventing a change in control
of the  Company.  See  "Description  of  Capital  Stock  --  Change  in  Control
Provisions."
 
    The  Company's  Certificate  of  Incorporation  also  allows  the  Board  of
Directors to issue up  to 10,000,000 shares  of Preferred Stock  and to fix  the
rights,  privileges and preferences  of such shares without  any further vote or
action by the stockholders. The  rights of the holders  of Common Stock will  be
subject  to, and may be adversely affected by,  the rights of the holders of any
Preferred Stock that  may be  issued in  the future.  While the  Company has  no
present intention to issue shares of Preferred Stock, any such issuance could be
used  to discourage,  delay or make  more difficult  a change in  control of the
Company. See "Description of Capital Stock -- Preferred Stock."
 
SHARES ELIGIBLE FOR FUTURE SALE
 
    Sales of a substantial number of shares of Common Stock in the public market
following the Offerings could  adversely affect the market  price of the  Common
Stock.  Upon consummation  of the Offerings,  the Company  will have outstanding
37,586,498 shares of Common Stock, assuming no exercise of outstanding  options,
warrants,  rights or other  convertible securities, 30,086,498  of which will be
subject to  resale  restrictions. Beginning  90  days  after the  date  of  this
Prospectus,  approximately 10,013,055 of  the restricted shares  of Common Stock
will become available for sale in the  public market pursuant to Rule 144  under
the  Securities  Act,  subject  in  certain cases  to  volume  and  other resale
limitations under Rule 144. All of the restricted shares are subject to  lock-up
agreements  with Montgomery Securities  which expire 180 days  after the date of
this Prospectus or such earlier time  as Montgomery Securities may, in its  sole
discretion,  determine.  See  "Underwriting."  The  balance  of  the outstanding
restricted shares of Common Stock (20,073,443 shares) will become available  for
sale  in the public market under Rule 144 approximately two years after the date
of this Prospectus. Upon  the closing of  the CommcoCCC Acquisition,  16,500,000
shares  will  be  issued for  the  CommcoCCC  Assets, which  shares  will become
available for sale in the public market under Rule 144 two years after the  date
of consummation of the CommcoCCC Acquisition. Under a proposal currently pending
before  the Securities and  Exchange Commission (the  "Commission"), the date on
which such shares of Common Stock will become available for sale under Rule  144
may  be accelerated to one  year after the date of  this Prospectus (or one year
after the date of the  closing of the CommcoCCC Acquisition  in the case of  the
16,500,000 shares issued for the CommcoCCC Assets). Holders of 30,086,498 shares
(46,586,498  shares upon  consummation of  the CommcoCCC  Acquisition) of Common
Stock and warrants to purchase 1,475,000 shares of Common Stock have contractual
rights to have  those shares registered  with the Commission  for resale to  the
public.
 
                                       23
<PAGE>
                                  THE COMPANY
 
    Advanced  Radio Telecom Corp. provides wireless broadband telecommunications
services using  point-to-point  microwave  transmissions in  the  37.0  to  40.0
gigahertz  portion of the radio  spectrum ("38 GHz"). The  Company is seeking to
address  the   growing   demand   for  high   speed,   high   capacity   digital
telecommunications services on the part of business and government end users who
require  cost effective, high  bandwidth local access to  voice, video, data and
Internet services.  The Company's  last mile  services are  a complement  and  a
viable alternative to fiber optic networks and offer rapidly deployable coverage
throughout  the 89 markets in  which the Company is  currently authorized by the
FCC to provide services.
 
    The business of  the Company is  comprised of (i)  the business of  Advanced
Radio  Technologies Corporation ("ART" or the "Company"), a company organized by
Vernon L. Fotheringham and W. Theodore Pierson,  Jr. in 1993 for the purpose  of
acquiring 38 GHz licenses, and (ii) the business of Advanced Radio Telecom Corp.
("Telecom"),  a corporation organized  in Delaware in March  1995 under the name
Advanced Radio Technology, Ltd. for the purposes of acquiring additional 38  GHz
licenses and developing and operating the business of ART and Telecom on a joint
basis.  In April 1995, ART entered into the ART West Joint Venture Agreement (as
defined) to apply for, acquire and develop 38 GHz operations in 13 states in the
western  United  States.  In  November  1995,  the  Company  completed  the  EMI
Acquisition  (as  defined),  pursuant to  which  it acquired  thirty-two  38 GHz
licenses and certain  related assets  in the  northeast United  States. In  July
1996,  the Company entered into the CommcoCCC Agreement to acquire the CommcoCCC
Assets and other agreements to acquire authorizations it currently manages. Upon
completion of these pending acquisitions, the Company will own or manage a total
of 237 authorizations to provide 38 GHz wireless broadband services in 169  U.S.
markets.   See  "Risk   Factors  --   Risk  of   Non-Consummation  of  CommcoCCC
Acquisition," "Business -- Agreements Relating to Licenses and Authorizations --
ART West Joint Venture," "-- EMI Acquisition" and "-- CommcoCCC Acquisition."
 
    To date,  the  business  of  the  Company  has  been  operated  and  managed
(including  all FCC licenses  and construction permits held  by ART and Telecom)
pursuant to a services agreement. On June 26, 1996, ART and Telecom entered into
the Merger Agreement (as  defined), pursuant to which  a subsidiary of ART  will
merge  with and  into Telecom. The  FCC has  indicated that it  will approve the
Merger. Upon  completion of  the  Merger, Telecom  will  become a  wholly  owned
subsidiary  of ART and  change its name  to "ART Licensing  Corp.," and ART will
change its name  to "Advanced  Radio Telecom  Corp." See  "Business --  Proposed
Merger" and "Certain Transactions -- Merger." Prior to completion of the Merger,
Telecom  will manage the  combined businesses of the  Company in accordance with
the terms  of  the existing  services  agreement. See  "Business  --  Agreements
Relating to Licenses and Authorizations -- ART Services Agreement."
 
    DIGIWAVE,  ART, OZ BOX and  ADVANCED RADIO TELECOM are  service marks of the
Company. The  Company's principal  executive offices  are located  at 500  108th
Avenue, N.E., Suite 2600, Bellevue, Washington 98004 and its telephone number is
(206) 688-8700.
 
                                       24
<PAGE>
                                USE OF PROCEEDS
 
    The  net proceeds  to the  Company from  the Offerings  are estimated  to be
approximately $231.0 million in the aggregate, giving effect to the sale by  the
Company  of  7,500,000  shares  of  Common Stock  offered  in  the  Common Stock
Offering, based on an assumed initial public offering price of $9.00 per  share,
and  the  Units offered  in the  Unit Offering,  assuming $175,000,000  of gross
proceeds, and, in each case, after deducting the estimated underwriting discount
and offering expenses.
 
    Of the net proceeds, approximately $100.0 million is expected to be used for
capital expenditures through December  31, 1997 and  an additional $9.6  million
will  be used for the  acquisition of certain spectrum  rights from ART West and
DCT. See "Business -- Agreements Relating to Licenses and Authorizations --  ART
West  Joint Venture" and "-- DCT System Purchase Agreements." Approximately $8.0
million will be used for the repayment of indebtedness, consisting of the Bridge
Notes, which were issued  on March 8,  1996 and which bear  interest at 10%  per
annum,  and the CommcoCCC Notes,  which were issued on June  27 and July 3, 1996
and  which  bear  interest  at  the  prime  rate.  See  "Certain  Transactions,"
"Description  of  Certain  Indebtedness  --  Bridge  Notes"  and  "--  CommcoCCC
Financing." The  expected  amount  of capital  expenditures  includes  estimated
construction  costs under service  agreements with CommcoCCC,  ART West, DCT and
Telecom  One.   See   "Business  --   Agreements   Relating  to   Licenses   and
Authorizations."  Such amount also includes the cost to complete construction of
initial transmission facilities estimated at less than $5.0 million.
 
    The remainder  of  the net  proceeds  will  be used  for  general  corporate
purposes,  including the funding  of operating cash  flow shortfalls, technology
development and  acquisitions of  additional spectrum  rights and,  potentially,
related  businesses. Although the Company  considers potential acquisitions from
time to  time, no  agreement,  agreement in  principle, understanding  or  other
arrangement,  other than the Extended Agreement (as defined), the DCT Agreements
(as defined),  the  Telecom  One  Agreements  (as  defined)  and  the  CommcoCCC
Agreement,  has  been  reached  with respect  to  any  acquisition.  The Company
anticipates that it  will fund approximately  an aggregate of  $3.5 million  for
research  and development activities and  other investment upon the consummation
of currently anticipated agreements with American Wireless (as defined), QuestTV
(as defined) and Helioss  (as defined). Although the  Company does not have  any
other  material  commitments  to  fund  research  and  development  or  to  make
investments in other companies, the Company expects to incur additional research
and development expenses or  to make other such  investments from time to  time.
Management  anticipates  that,  based on  its  current plan  of  development and
assuming that no material new  acquisitions or investments are consummated,  the
remaining  net  proceeds  of  the  Offerings  will  be  sufficient  to  fund the
operations of  the  Company  for  the  next two  years.  See  "Risk  Factors  --
Significant Capital Requirements; Uncertainty of Additional Financing."
 
                                DIVIDEND POLICY
 
    The  Company has not paid and does  not anticipate paying any cash dividends
on the Common Stock in the foreseeable future. The Company intends to retain its
earnings, if any,  for use in  the Company's growth  and ongoing operations.  In
addition, the terms of the Indenture will restrict the ability of the Company to
pay  dividends  on  the  Common  Stock. See  "Description  of  Notes  -- Certain
Covenants."
 
                                       25
<PAGE>
                                 CAPITALIZATION
 
    The following table sets forth the capitalization of the Company as of March
31, 1996 (i) on a historical combined basis, giving effect to the elimination of
balances between ART  and Telecom  and the  elimination of  ART's investment  in
Telecom  and Telecom's  investment in  ART, (ii)  on a  pro forma  basis, giving
effect to the Conversion,  the Merger and  certain other financing  transactions
occurring  subsequent to March 31, 1996 as specified in Note 1 hereto, and (iii)
on a pro forma as adjusted basis, giving  effect to (A) the sale by the  Company
of  7,500,000 shares of Common Stock offered  in the Common Stock Offering based
on an assumed initial  public offering price  of $9.00 per  share and the  Units
offered  in the Unit Offering assuming $175.0 million of gross proceeds, and, in
each case,  after deducting  the estimated  underwriting discount  and  offering
expenses, (B) the receipt and application of the net proceeds therefrom to repay
the  Bridge Notes and the CommcoCCC Notes and to acquire certain spectrum rights
from ART West and DCT (See "Use of Proceeds") and (C) the issuance of 16,500,000
shares of  Common Stock  based  upon an  assumed value  of  $9.00 per  share  in
connection  with the  CommcoCCC Acquisition. The  capitalization information set
forth in the table below is qualified by the more detailed information contained
in, and should be read in conjunction with, the audited financial statements  of
ART and Telecom and the notes thereto, the unaudited interim condensed financial
statements  of ART and Telecom and the notes thereto and the unaudited pro forma
condensed financial  statements  of  the  Company and  the  notes  thereto,  all
appearing elsewhere in this Prospectus.
 
<TABLE>
<CAPTION>
                                                                            AS OF MARCH 31, 1996
                                                            -----------------------------------------------------
                                                              HISTORICAL                            PRO FORMA
                                                               COMBINED        PRO FORMA (1)       AS ADJUSTED
                                                            ---------------  ------------------  ----------------
<S>                                                         <C>              <C>                 <C>
Cash and cash equivalents.................................  $     3,024,161  $     8,244,161     $    218,669,161
                                                            ---------------  ------------------  ----------------
                                                            ---------------  ------------------  ----------------
Short-term debt:
  CommcoCCC Notes.........................................  $            --  $     2,975,000     $             --
                                                            ---------------  ------------------  ----------------
                                                            ---------------  ------------------  ----------------
Long-term debt:
  Note payable to EMI.....................................  $     1,500,000  $     1,500,000     $      1,500,000
  Bridge Notes............................................        3,983,082        3,983,082                   --
  Equipment Note..........................................               --        1,911,439            1,911,439
  Senior Discount Notes offered hereby (2)................               --               --          159,800,000
                                                            ---------------  ------------------  ----------------
    Total long-term debt..................................        5,483,082        7,394,521          163,211,439
                                                            ---------------  ------------------  ----------------
Stockholders' equity:
  Telecom convertible serial preferred stock (3)..........              921               --                   --
  Common Stock (4)........................................           10,013           30,086               54,086
  Telecom common stock (5)................................           18,114               --                   --
  Additional paid-in capital..............................       19,375,335       19,883,757          245,727,482
  Deficit accumulated during the development stage........      (14,064,645)     (14,064,645)         (15,106,563)
                                                            ---------------  ------------------  ----------------
    Total stockholders' equity............................        5,339,738        5,849,198          230,675,005
                                                            ---------------  ------------------  ----------------
      Total capitalization................................  $    10,822,820  $    13,243,719     $    393,886,444
                                                            ---------------  ------------------  ----------------
                                                            ---------------  ------------------  ----------------
</TABLE>
 
- ------------------------
(1)  Reflects  pro forma adjustments  for the following  transactions as if they
     had occurred as of March 31, 1996: (i) the receipt of $2.2 million in  cash
     proceeds  from the issuance of the Equipment Note and Indemnity Warrants in
     connection with the Equipment  Financing, after deducting related  expenses
     of  $225,000; (ii) the  receipt of $3.0  million in cash  proceeds from the
     issuance of the CommcoCCC Notes  and CommcoCCC Warrants in connection  with
     the  CommcoCCC  Financing;  (iii)  the  Conversion  and  (iv)  the  Merger,
     including the  issuance  of  Common Stock  to  Telecom's  stockholders  and
     cancellation   of  all  outstanding  Telecom  common  stock.  See  "Certain
     Transactions."
 
(2)  The Company anticipates  gross proceeds  from the Unit  Offering of  $175.0
     million.  The  estimated value  of the  Warrants  ($15.2 million)  has been
     reflected as both  a debt  discount and  an element  of additional  paid-in
     capital.
 
(3)  Consists of Telecom convertible serial preferred stock, $.001 par value per
     share:  10,000,000 shares authorized; historical combined -- 455,550 shares
     of Series A, 114,679 shares of Series  B, 7,363 shares of Series C,  61,640
     shares  of Series D, 232,826 shares of Series E and 48,893 shares of Series
     F issued and outstanding; pro forma and pro forma as adjusted -- no  shares
     issued and outstanding.
 
(4)  Consists  of Common  Stock, $.001 par  value per  share: 100,000,000 shares
     authorized;  historical   combined   --  10,013,055   shares   issued   and
     outstanding;  pro forma  -- 30,086,498  shares issued  and outstanding; pro
     forma as adjusted -- 54,086,498 issued and outstanding.
 
(5)  Consists of Telecom  common stock,  $.001 par value  per share:  60,000,000
     shares  authorized;  historical combined  --  18,114,135 shares  issued and
     outstanding; pro forma and  pro forma as adjusted  -- no shares issued  and
     outstanding.
 
                                       26
<PAGE>
                SELECTED HISTORICAL AND PRO FORMA FINANCIAL DATA
 
THE COMPANY -- HISTORICAL COMBINED AND PRO FORMA DATA
 
    The  unaudited  selected historical  combined and  pro forma  financial data
presented below as of and for the three months ended March 31, 1996 and for  the
year  ended December  31, 1995 and  the unaudited  historical combined financial
data presented below as of December 31, 1995 were derived from the unaudited pro
forma condensed financial statements of  the Company included elsewhere in  this
Prospectus.  For definitions  of certain  terms and  more information  about the
transactions cited in the notes thereto, see "Certain Transactions."
 
    The unaudited  selected historical  combined and  pro forma  financial  data
should  be read in conjunction with the  audited financial statements of ART and
Telecom, and  the  notes  thereto, the  unaudited  condensed  interim  financial
statements  of ART  and Telecom,  and the notes  thereto, and  the unaudited pro
forma condensed  financial statements  of the  Company, and  the notes  thereto,
included   elsewhere  in  the  Prospectus.  The  unaudited  selected  historical
combined, pro forma and pro forma as adjusted financial data are not necessarily
indicative of what the  actual financial position and  results of operations  of
the  Company would have been as of and for the three months ended March 31, 1996
and as of  and for  the year ended  December 31,  1995, nor do  they purport  to
represent the Company's future financial position and results of operations.
<TABLE>
<CAPTION>
                                           YEAR ENDED DECEMBER 31, 1995               THREE MONTHS ENDED MARCH 31, 1996
                               -----------------------------------------------------  ---------------------------------
                                 HISTORICAL                          PRO FORMA AS       HISTORICAL
                                COMBINED (1)     PRO FORMA (2)       ADJUSTED (3)      COMBINED (1)     PRO FORMA (2)
                               --------------  -----------------  ------------------  --------------  -----------------
<S>                            <C>             <C>                <C>                 <C>             <C>
STATEMENT OF OPERATIONS DATA:
Operating revenue............   $      5,793     $       5,793       $      5,793      $      9,620     $       9,620
Non-cash compensation
 expense.....................      1,089,605         1,089,605          1,089,605         7,221,000         7,221,000
Depreciation and
 amortization................         15,684            15,684          5,418,452            89,279            89,279
Interest, net................        121,986         1,974,275         23,931,008           131,145           528,739
Net loss.....................      3,234,843         5,087,132         30,609,692        10,694,588        11,092,182
Pro forma net loss per share
 of Common Stock (4).........             --   $          0.16    $          0.55                --   $          0.35
Pro forma weighted average
 number of shares of Common
 Stock outstanding (4).......             --        31,651,605         55,651,605                --        31,651,605
OTHER FINANCIAL DATA:
EBITDA (5)...................  $  (1,936,141 ) $    (1,936,141  ) $    (1,936,141   ) $  (2,156,893 ) $    (2,156,893 )
Capital expenditures.........      3,585,144         3,585,144          3,585,144         2,861,241         2,861,241
Ratio of earnings to fixed
 charges (6).................             --                --                 --                --                --
 
<CAPTION>
 
                                  PRO FORMA AS
                                  ADJUSTED (3)
                               ------------------
<S>                            <C>
STATEMENT OF OPERATIONS DATA:
Operating revenue............     $      9,620
Non-cash compensation
 expense.....................        7,221,000
Depreciation and
 amortization................        1,439,971
Interest, net................        5,989,300
Net loss.....................       17,444,199
Pro forma net loss per share
 of Common Stock (4).........  $          0.31
Pro forma weighted average
 number of shares of Common
 Stock outstanding (4).......       55,651,605
OTHER FINANCIAL DATA:
EBITDA (5)...................  $    (2,156,893   )
Capital expenditures.........        2,861,241
Ratio of earnings to fixed
 charges (6).................               --
</TABLE>
 
<TABLE>
<CAPTION>
                                                AS OF                        AS OF MARCH 31, 1996
                                          DECEMBER 31, 1995   --------------------------------------------------
                                              HISTORICAL       HISTORICAL                        PRO FORMA AS
                                             COMBINED (1)     COMBINED (1)    PRO FORMA (2)      ADJUSTED (3)
                                          ------------------  -------------  ----------------  -----------------
<S>                                       <C>                 <C>            <C>               <C>
BALANCE SHEET DATA:
Working capital surplus (deficit).......     $ (3,008,510)     $(1,128,130)    $  1,116,870      $ 214,516,870
Property and equipment, net.............        3,581,561        6,380,895        6,380,895          6,380,895
FCC licenses............................        4,235,734        4,235,734        4,235,734        216,110,734
Total assets............................        9,876,559       15,036,337       20,432,236        448,589,961
Short term debt.........................               --               --        2,975,000                 --
Long-term debt, including current
 portion................................        6,450,000        5,483,082        7,394,521        163,211,439
Deficit accumulated during the
 development stage......................       (3,370,057   )  (14,064,645 )    (14,064,645  )     (15,106,563  )
Total stockholders' equity (deficit)....         (312,860   )    5,339,738        5,849,198        230,675,005
</TABLE>
 
                                       27
<PAGE>
ART -- HISTORICAL FINANCIAL DATA
 
    The  selected historical financial data of ART below as of and for the years
ended December 31, 1995 and 1994, and for the period from August 23, 1993  (date
of  inception) to  December 31, 1993,  were derived  from and should  be read in
conjunction with the audited financial statements  of ART and the related  notes
thereto,  included elsewhere in this Prospectus.  The selected financial data of
ART below as of March 31, 1996 and for the three months ended March 31, 1996 and
1995 were derived  from and  should be read  in conjunction  with the  unaudited
condensed  interim financial  statements of  ART and  the related  notes thereto
included elsewhere in this Prospectus.
 
<TABLE>
<CAPTION>
                              AUGUST 23, 1993
                            (DATE OF INCEPTION)                YEAR ENDED                       THREE MONTHS ENDED
                                    TO           --------------------------------------  --------------------------------
                             DECEMBER 31, 1993   DECEMBER 31, 1994   DECEMBER 31, 1995   MARCH 31, 1995   MARCH 31, 1996
                            -------------------  ------------------  ------------------  ---------------  ---------------
<S>                         <C>                  <C>                 <C>                 <C>              <C>
STATEMENT OF OPERATIONS
 DATA:
Operating revenue.........       $      --           $  137,489         $         --        $      --      $          --
Depreciation and
 amortization.............             688                8,281               10,378               --              2,595
Net loss..................       $   6,594           $  128,620         $  1,267,655        $  41,753      $   3,654,775
Pro forma net loss per
 share of Common Stock
 (4)......................              --                   --         $       0.04               --      $        0.12
Pro forma weighted average
 number of shares of
 Common Stock outstanding
 (4)......................              --                   --           31,651,605               --         31,651,605
OTHER FINANCIAL DATA:
EBITDA (5)................         $(5,906)           $(115,964    )     $(1,151,699   )     $(40,878   )    $(3,582,833 )
Capital expenditures......              --                5,175                   --               --                 --
Ratio of earnings to fixed
 charges (6)..............              --                   --                   --               --                 --
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                                              AS OF
                                                                AS OF DECEMBER 31,                          MARCH 31,
                                            -----------------------------------------------------------  ---------------
                                                   1993                 1994                1995              1996
                                            -------------------  ------------------  ------------------  ---------------
<S>                                         <C>                  <C>                 <C>                 <C>
BALANCE SHEET DATA:
Working capital surplus (deficit).........       $  13,958           $  (76,556)        $   (976,563)     $    (494,630)
Property and equipment, net...............              --                3,448                1,723              1,292
FCC licenses..............................              --                   --                8,913              8,913
Total assets..............................          74,513               42,611            5,784,624          3,281,788
Long-term debt, including current
 portion..................................              --                   --            4,950,000                 --
Redeemable Preferred Stock................              --                   --               44,930             44,930
Deficit accumulated during the development
 stage....................................          (6,594     )       (135,214    )      (1,402,869   )     (5,057,644 )
Total stockholders' equity (deficit)......          54,542              (39,078    )        (404,481   )      2,736,258
</TABLE>
 
                                       28
<PAGE>
TELECOM -- HISTORICAL FINANCIAL DATA
 
    The selected historical financial data of  Telecom below as of December  31,
1995  and for the period from March 28, 1995 (date of inception) to December 31,
1995 were  derived from  and should  be  read in  conjunction with  the  audited
financial statements of Telecom and the related notes thereto included elsewhere
in  this Prospectus. The selected financial data  of Telecom below as of and for
the three months ended March  31, 1996 were derived from  and should be read  in
conjunction with the unaudited condensed interim financial statements of Telecom
and the related notes thereto, included elsewhere in this Prospectus.
<TABLE>
<CAPTION>
                                                                                 MARCH 28, 1995
                                                                                    (DATE OF
                                                                                   INCEPTION)         THREE MONTHS
                                                                                       TO                ENDED
                                                                               DECEMBER 31, 1995     MARCH 31, 1996
                                                                               ------------------  ------------------
<S>                                                                            <C>                 <C>
STATEMENT OF OPERATIONS DATA:
Operating revenue............................................................     $      5,793        $      9,620
Non-cash compensation expense................................................        1,089,605           7,221,000
Depreciation and amortization................................................            5,306              86,684
Net loss.....................................................................     $  2,981,073        $ 10,666,383
OTHER FINANCIAL DATA:
EBITDA.......................................................................     $ (1,798,327)       $ (2,156,794)
Capital expenditures.........................................................        3,585,144           2,861,241
Ratio of earnings to fixed charges (6).......................................               --                  --
 
<CAPTION>
 
                                                                                     AS OF               AS OF
                                                                                  DECEMBER 31,         MARCH 31,
                                                                                      1995                1996
                                                                               ------------------  ------------------
<S>                                                                            <C>                 <C>
BALANCE SHEET DATA:
Working capital surplus (deficit)............................................      $(2,031,947)    $      (633,500   )
Property and equipment, net..................................................        3,579,838           6,379,603
FCC licenses.................................................................        4,226,821           4,226,821
Total assets.................................................................        9,830,615          15,254,980
Long-term debt...............................................................        6,500,000           5,483,082
Deficit accumulated during the development stage.............................       (2,981,073   )     (13,647,456   )
Total stockholders' equity (deficit).........................................         (119,922   )       5,560,881
</TABLE>
 
- ------------------------------
(1)  The  unaudited  selected  financial  data  under  the  caption  "Historical
     Combined" are presented as  if the historical  financial statements of  ART
     and   Telecom  had  been  combined  and  reflect  (i)  the  elimination  of
     transactions and balances between ART and Telecom and (ii) the  elimination
     of ART's investment in Telecom and Telecom's investment in ART.
 
(2)  The  unaudited selected  financial data under  the caption  "Pro Forma" are
     presented as if the following transactions had occurred as of the beginning
     of the respective periods  for the Statement of  Operations Data and  Other
     Financial Data and as of the balance sheet date for the Balance Sheet Data:
     (i)  the March 8, 1996 issuance of  the Bridge Notes in connection with the
     Bridge Financing; (ii) the  receipt of $2.2 million  in cash proceeds  from
     the  issuance of  the Equipment Note  and Indemnity  Warrants in connection
     with the Equipment Financing, after deducting related fees and expenses  of
     $225,000,  (iii)  the receipt  of $3.0  million in  cash proceeds  from the
     issuance of the CommcoCCC Notes  and CommcoCCC Warrants in connection  with
     the  CommcoCCC Financing, (iv) the Conversion and (v) the Merger, including
     the  issuance  of  ART  Common  Stock  to  Telecom  stockholders  and   the
     cancellation   of  all  outstanding  Telecom  common  stock.  See  "Certain
     Transactions."
 
(3)  The unaudited  selected financial  data  under the  caption "Pro  Forma  As
     Adjusted" are presented as if the transactions referred to in (2) above and
     the  following  transactions  had  occurred  as  of  the  beginning  of the
     respective periods for the Statement of Operations Data and Other Financial
     Data and as of the balance sheet  date for the Balance Sheet Data: (i)  the
     sale  by the  Company of  7,500,000 shares of  Common Stock  offered in the
     Common Stock Offering based on an assumed initial public offering price  of
     $9.00  per share and the Units offered in the Unit Offering assuming $175.0
     million of gross proceeds, and, in each case, after deducting the estimated
     underwriting  discount  and  offering   expenses,  (ii)  the  receipt   and
     application of the net proceeds therefrom to repay the Bridge Notes and the
     CommcoCCC  Notes and to acquire the 50% ownership interest of ART West held
     by Extended for $6.0 million in cash and the DCT Assets for $3.6 million in
     cash and (iii) the issuance of 16,500,000 shares of Common Stock based upon
     an assumed  value of  $9.00  per share  in  connection with  the  CommcoCCC
     Acquisition. See "Use of Proceeds."
 
                                       29
<PAGE>
(4)  Pro  forma net loss per share is computed  based on the loss for the period
     divided  by  the  weighted  average  number  of  shares  of  Common   Stock
     outstanding  during the period including the Conversion, the Merger and the
     issuance of potentially dilutive instruments  issued within one year  prior
     to  the  Offerings  at exercise  prices  below the  assumed  initial public
     offering price of $9.00  per share. In measuring  the dilutive effect,  the
     treasury stock method was used.
 
(5)  EBITDA means loss before interest expense, income tax expense, depreciation
     and amortization expense, non-cash compensation expense and non-cash market
     development  expense. Information with respect to EBITDA is included herein
     because a similar measure will be used in the Indenture with respect to the
     computation of certain covenants. EBITDA is not intended to represent  cash
     flows from operating activities, as determined in accordance with generally
     accepted accounting principles, nor has it been presented as an alternative
     to operating income as an indicator of operating performance and should not
     be  considered  as a  substitute for  measures  of performance  prepared in
     accordance with generally accepted accounting principles.
 
(6)  For the purposes  of determining  earnings coverage of  fixed charges,  net
     losses   include  fixed  charges  representing   interest  expense  on  all
     indebtedness (including the  amortization of deferred  debt issuance  costs
     and  original issue discount).  For the purposes of  the pro forma combined
     information,  fixed  charges  include  interest  expense  from  the  Bridge
     Financing,  the Equipment Financing and  the CommcoCCC Financing (including
     the amortization  of  deferred  debt  issuance  costs  and  original  issue
     discount)  and the  reversal of interest  expense on the  Advent Notes that
     were converted into Telecom Series E  preferred stock. For the purposes  of
     the  Pro Forma As  Adjusted information, fixed  charges include interest on
     the Notes (including the amortization  of deferred debt issuance costs  and
     original  issue discount) at an effective interest rate of 15.2%, offset by
     the reversal of  interest expense  on the  Bridge Notes  and the  CommcoCCC
     Notes  (including  the amortization  of  deferred debt  issuance  costs and
     original issue discount) which are assumed to be repaid out of the proceeds
     therefrom. If  the interest  rate on  the  Notes were  to change  by  0.5%,
     interest  expense would change  by approximately $765,000  and $191,250 for
     the year ended December 31, 1995 and  for the three months ended March  31,
     1996,  respectively. Earnings were deficient to  cover fixed charges by the
     following amounts for the periods indicated:
 
<TABLE>
<S>                                                                                    <C>
The Company -- Historical Combined and Pro Forma
  Three months ended March 31, 1996
    Historical combined..............................................................  $10,694,588
    Pro forma........................................................................   11,092,182
    Pro forma as adjusted............................................................   17,903,435
  Year ended December 31, 1995
    Historical combined..............................................................    3,234,843
    Pro forma........................................................................    5,087,132
    Pro forma as adjusted............................................................   32,446,633
ART -- Historical
    Three months ended March 31, 1996................................................    3,654,775
    Three months ended March 31, 1995................................................       41,753
    Year ended December 31, 1995.....................................................    1,267,655
    Year ended December 31, 1994.....................................................      128,620
    August 23, 1993 (date of inception) to December 31, 1993.........................        6,594
Telecom -- Historical
    Three months ended March 31, 1996................................................   10,666,383
    March 28, 1995 (date of inception) to December 31, 1995..........................    2,981,073
</TABLE>
 
                                       30
<PAGE>
               MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                      CONDITION AND RESULTS OF OPERATIONS
 
GENERAL
 
    The  Company provides  wireless broadband  telecommunications services using
point-to-point microwave  transmissions  in the  38  GHz portion  of  the  radio
spectrum.  The Company is seeking to address  the growing demand for high speed,
high capacity digital telecommunications  services on the  part of business  and
government  end users who require cost effective, high bandwidth local access to
voice, video, data and Internet services.
 
    To facilitate a meaningful comparison, the following discussion and analysis
is based  on the  historical combined  financial information  of Advanced  Radio
Technologies Corporation ("ART") and Advanced Radio Telecom Corp. ("Telecom") as
of  all dates  and for  all periods  ending after  March 28,  1995, the  date of
Telecom's inception, and the  historical financial statements of  ART as of  all
dates  and for all the periods  ended prior to March 28,  1995. All of the above
financial  statements  appear  elsewhere  in  this  Prospectus.  The  historical
combined  financial  statements  include  the  elimination  of  transactions and
balances between the  two entities as  well as ART's  investment in Telecom  and
Telecom's investment in ART.
 
    The  following discussion includes certain forward-looking statements. For a
discussion of  important  factors,  including, but  not  limited  to,  continued
development  of the  Company's business,  actions of  regulatory authorities and
competitors, and  other  factors  that  could cause  actual  results  to  differ
materially from the forward-looking statements, see "Risk Factors."
 
OVERVIEW
 
    The Company's business commenced in 1993, and the Company has generated only
nominal  revenues from operations to date. The Company's primary activities have
focused on the acquisition of wireless construction permits (authorizations  for
facilities that are not constructed) and licenses (authorizations for facilities
that  are constructed),  the hiring of  management and other  key personnel, the
raising of capital,  the acquisition  of equipment  and the  development of  its
operating and support systems and infrastructure. The Company has obtained radio
spectrum  rights under FCC  issued licenses and  construction permits throughout
the United States by applying  to the FCC directly  and through the purchase  of
such rights held by others. The Company's ability to provide commercial services
on  a widespread basis and to generate  positive operating cash flow will depend
on its ability, among  other things, to  (i) deploy its 38  GHz technology on  a
market-by-market basis, (ii) attract and retain an adequate customer base, (iii)
successfully  develop and  deploy its operational  and support  systems and (iv)
acquire appropriate sites for its operations. Proper management of the Company's
anticipated growth and quality of its service will require the Company to expand
its technical, accounting and internal  management systems at a pace  consistent
with  the  Company's  planned  business  roll-out.  This  roll-out  will require
substantial capital  expenditures. See  "Liquidity  and Capital  Resources"  and
"Risk Factors."
 
    The  Company  has  experienced  significant  operating  and  net  losses and
negative operating cash flow in  connection with the development and  deployment
of  its  wireless broadband  services  and systems  and  expects to  continue to
experience net losses  and negative operating  cash flow until  such time as  it
develops  a  revenue-generating  customer  base  sufficient  to  fund  operating
expenses attributable to the Company's wireless broadband operations. See  "Risk
Factors." The Company expects to achieve positive operating margins over time by
(i)  increasing the  number of  revenue generating  customers and  responding to
growing demand for capacity among its customers without significantly increasing
related   hardware   and   roof   rights   costs   and   (ii)   inducing   other
telecommunications  service  providers  to  utilize  and  market  the  Company's
wireless broadband services as part of their own services, thereby reducing  the
Company's  related  marketing  costs.  The  Company  anticipates  that operating
revenues will  increase in  1996; however,  the Company  also expects  that  net
losses  and negative operating cash flow will increase as the Company implements
its   growth   strategy   and   that   under   its   current   business    plan,
 
                                       31
<PAGE>
net  losses and negative operating cash flow will continue for at least the next
several years. Accordingly, the Company  will be dependent on various  financing
sources  to fund  its growth  as well as  continued losses  from operations. See
"Liquidity and Capital Resources."
 
ACQUISITIONS, BUSINESS DEVELOPMENT AND CAPITAL EXPENDITURES
 
    From inception through March 31, 1996, the Company has invested an aggregate
of $4.2  million  to  obtain  interests  in  FCC  authorizations  and  licenses,
including  those acquired from EMI, and invested  $285,000 in the ART West Joint
Venture. From inception, expenditures for  property and equipment have  totalled
$6.5  million. In addition, the Company has incurred significant other costs and
expenses in the development of its  business and has recorded cumulative  losses
from  inception through March 31, 1996 of approximately $14.1 million, including
$9.4 million of non-cash  compensation and marketing expenses  and used cash  in
operating  activities of approximately  $3.1 million. The  Company has agreed to
acquire,  subject  to  FCC  approval   and  other  conditions,  additional   FCC
authorizations  and licenses for an aggregate  purchase price of $9.6 million in
cash and 16,500,000 shares of the Company's Common Stock. The Company may,  when
and  if the opportunity arises, acquire  other spectrum rights and, potentially,
related businesses, incur expenses  in the development  of new technologies  and
expand its wireless broadband services into new market areas.
 
    The   recoverability  of  property  and   equipment  and  intangible  assets
representing FCC authorizations is dependent upon the successful development  of
systems  in each  of the  respective markets,  or through  sale of  such assets.
Management estimates that it will recover  the carrying amounts of those  assets
from  cash flow generated by the systems once they have been developed. However,
it is possible that such estimate will change as a result of any failure by  the
Company  to develop its FCC authorizations  on a timely basis, or technological,
regulatory  or  other  changes.  The  Company  anticipates  that  it  will  fund
approximately  an  aggregate  of  $3.5  million  for  research  and  development
activities and other investment upon  the consummation of currently  anticipated
agreements  with American  Wireless, QuestTV  and Helioss.  Although the Company
does not have any other material commitments to fund research and development or
to make investments in other companies, the Company expects to incur  additional
research and development expenses or to make other such investments from time to
time.
 
    The  Company  is  exploring  the  possibilities  of  providing  its wireless
broadband services  in  other countries  including  Canada and  in  Europe.  The
Company  has  entered into  agreements  with certain  consultants  and potential
partners to identify foreign opportunities and expects to file applications  for
licenses  or to acquire 38 GHz licenses in several European countries. There can
be no  assurance that  the Company  can  acquire such  licenses or  develop  and
operate such systems.
 
    The  Company entered into a management consulting agreement in November 1995
with Landover  Holdings  Corporation  ("LHC")  to  provide  strategic  planning,
corporate  development  and general  management  services. Under  the agreement,
which terminates on the  date of this Prospectus,  the Company pays LHC  $35,000
per month for an initial one year term. In 1995 the Company paid $140,000 to LHC
for  consulting services and  $391,750 for expenses in  connection with the $7.0
million  investment  made  under  the  LHC  Purchase  Agreement.  See   "Certain
Transactions."
 
RESULTS OF OPERATIONS
 
    The  Company has  generated nominal  revenue from  operations to  date. From
inception through March 31, 1996, the Company has incurred aggregate expenses of
approximately $14.2 million, including $9.4 million of non-cash compensation and
marketing expenses. The remaining expenses consist of compensation and benefits,
sales and marketing  expenses, consulting and  legal fees, facilities  expenses,
systems  development  costs,  management consulting  expenses  and  net interest
expenses related to building the Company's business infrastructure and marketing
its wireless  broadband  services. The  Company  expects to  generate  increased
revenues  beginning  in  1996; however,  there  can  be no  assurance  that this
objective will  be  achieved. The  Company  expects  that it  will  not  achieve
profitable operations at least through fiscal 1998. See "Risk Factors -- Limited
Operations; History of Net Losses."
 
                                       32
<PAGE>
    THREE MONTHS ENDED MARCH 31, 1996 COMPARED TO MARCH 31, 1995
 
    Revenue  for the three months ended March 31, 1996 was $9,620 compared to no
revenue in 1995. The increase in  revenues was due to operating revenues  earned
from wireless broadband telecommunications services provided by the Company.
 
    Operating  expenses other  than interest  were $10.6  million for  the three
months ended  March 31,  1996 compared  to  $40,878 in  1995. The  increase  was
primarily  due to $7.2 million of  non-cash compensation expense, including $6.8
million arising  from  the  termination  of the  Escrow  Share  Arrangement  (as
defined)  and subsequent  release of shares  to certain  employees in connection
with the February 1996 Reorganization (as  defined), as well as, higher  general
and  administrative, increased market development,  and research and development
expenses.  See  "Certain  Transactions."  Excluding  the  non-cash  compensation
expense,  general and administrative expenses  increased primarily due to higher
payroll and  consulting costs  relating  to the  ramp-up  in operations  of  the
Company.  Market  development expenses  increased  primarily due  to  a non-cash
marketing  expense  of   $1.1  million  related   to  the  Ameritech   Strategic
Distribution  Agreement.  Research and  development costs  were incurred  as the
Company initiated its  research and development  of microwave radio  technology.
The  Company expects cash expenses for general and administrative, marketing and
research and  development to  increase substantially  in future  periods as  the
development and deployment of the Company's business continues.
 
    Interest  expense was  $174,416 for  the three  months ended  March 31, 1996
compared to $875 in 1995. The increase in interest expense was primarily due  to
interest  on the EMI Note  and the Bridge Notes.  Interest expense in the second
quarter of  1996 will  increase primarily  due  to a  full quarter  of  interest
expense on the Bridge Notes and also due to the Equipment Note executed in April
1996,  and the  issuance of  the Notes will  cause interest  expense to increase
substantially in future periods. The write-off of unamortized offering  discount
and  deferred  finance costs  associated with  the Bridge  Notes is  expected to
result in  a non-cash  extraordinary  loss of  approximately $1.0  million  upon
repayment at the closing of the Offerings.
 
    FISCAL 1995 COMPARED TO FISCAL 1994
 
    ART was formed in 1993, and, accordingly, the Company's historical financial
statements for 1994 reflect ART's activities in applying for 38 GHz licenses and
building operating systems.
 
    The  Company had $137,489 in consulting  services income for engineering and
management services related  to filing of  applications for 38  GHz licenses  on
behalf of others, including Extended, in 1994 and $5,793 in operating revenue in
1995  derived from customers for wireless broadband services attributable to the
markets for  which  licenses  were  acquired from  EMI  in  November  1995.  See
"Business   --  Agreements  Relating  to  Licenses  and  Authorizations  --  EMI
Acquisition."
 
    Total expenses other than interest increased  from $261,734 in 1994 to  $3.1
million  in 1995  due to the  expansion of  the business and  the recognition of
non-cash  compensation  expenses  associated  with  employee  stock  options  of
$287,603  and certain Escrow Shares (as defined) of $802,002 associated with the
release to  certain employees  of the  Company as  a result  of meeting  certain
performance objectives for an aggregate of $1.1 million of non-cash compensation
expenses.  See "Certain Transactions -- LHC  Purchase Agreement -- February 1996
Reorganization." General and administrative  expenses, including these  non-cash
compensation  expenses, increased to $2.9 million for fiscal 1995, from $253,453
for 1994. Market development expenses increased  to $191,693 in 1995 from $0  in
1994.  Net interest expenses increased to $121,986  in 1995 from $4,375 in 1994.
As a result, the net loss for 1995  was $3.2 million, as compared to a net  loss
of $128,620 in 1994.
 
    FISCAL 1994 COMPARED TO FISCAL 1993
 
    The  Company had $137,489 in consulting  services income in 1994 compared to
no revenue  in  1993. The  increase  in 1994  was  primarily due  to  consulting
services related to 38 GHz license applications.
 
                                       33
<PAGE>
    Total  expenses other  than interest expense  increased to  $261,734 in 1994
from $6,594 in 1993.  The increases were due  primarily to consulting and  legal
fees related to the initial operations of the Company.
 
LIQUIDITY AND CAPITAL RESOURCES
 
    The  Company's operations  have required substantial  capital investment for
the acquisition  of  FCC authorizations  and  related assets,  the  purchase  of
telecommunications equipment, staffing, and the development and expansion of the
Company's  infrastructure to support anticipated  growth. From inception through
March 31,  1996,  the  Company  used  $3.1 million  of  cash  in  its  operating
activities  and $7.3  million of  cash in  its investing  activities. These cash
outflows were financed  primarily through  private equity  and debt  placements,
including  the issuance of convertible notes  payable to the Advent Partnerships
which were converted  into equity  in February 1996.  At December  31, 1995  the
Company  had a working capital deficit of  $3.0 million and cash of $633,654, as
compared to a working capital deficit of $76,556 and cash of $5,133 at  December
31,  1994. The Company had a working capital deficit of $1.1 million and cash of
$3.0 million at March 31, 1996. Subsequent to March 31, 1996, the Company raised
$2.2 million in  cash (net of  expenses) from the  Equipment Financing and  $3.0
million in cash from the CommcoCCC Financing. See "Certain Transactions."
 
    The Company's total assets increased from $42,611 as of December 31, 1994 to
$9.9  million at December 31, 1995 and $15.0 million at March 31, 1996. Property
and equipment, net of accumulated depreciation, comprised $3.6 million of  total
assets at December 31, 1995 and $6.4 million at March 31, 1996. FCC licenses and
the  investment  in the  ART West  Joint  Venture increased  to $4.5  million at
December 31, 1995 and March 31, 1996, as compared to $0.0 at December 31, 1994.
 
    Cash used in operating activities increased by $1.4 million to $1.5  million
in  1995 over 1994. The  increase in cash used  in operating activities resulted
primarily from the  increase in net  loss to $3.2  million, partially offset  by
non-cash compensation expenses of $1.1 million and increased payables in 1995.
 
    Cash used in investing activities increased by $4.2 million in 1995 compared
to  minimal amounts in 1994. The increase was primarily due to $3.0 million paid
for the  EMI  acquisition, and  approximately  $600,000 used  for  property  and
equipment additions in 1995.
 
    Cash provided by financing activities increased by $6.2 million in 1995 over
1994.  The  increase  was  primarily  due to  the  issuances  of  the Advent/ART
Securities of  $5.0  million and  of  Telecom  serial preferred  stock,  net  of
redemptions  of $2.0 million issued in 1995, partially offset by the use of cash
for stock and debt issuance costs.
 
    Capital expenditures, including  deposits on equipment  for fiscal 1995  and
1994,  were  $3.9  million  and  $5,175,  respectively.  The  Company  currently
purchases the  majority of  its wireless  transmission equipment  from a  single
vendor,  P-Com, Inc., under an equipment purchase agreement which expires at the
end of 1998. The Company  is committed to purchase a  total of $13.3 million  of
equipment  under this agreement. The Company  has also entered into an equipment
purchase agreement, expiring in 1997, with Harris, providing for the purchase of
wireless transmission equipment.
 
    Cash used in operating  activities increased to $1.5  million for the  three
months ended March 31, 1996 compared to $49,212 for the three months ended March
31, 1995. The increase was primarily due to higher operating costs. Cash used in
investing  activities was approximately $3.1 million  for the three months ended
March 31, 1996 compared to $0.0 for  the three months ended March 31, 1995.  The
increase  was  due to  additions  to property  and  equipment. Cash  provided by
financing activities increased to $6.9 million  in the three months ended  March
31,  1996 compared  to $44,334 for  the three  months ended March  31, 1995. The
increase was primarily due  to the private equity  placement with Ameritech  and
the Bridge Notes.
 
    The  Company does  not currently  manufacture, nor does  it have  or plan to
develop  the  capability  to  manufacture,  any  of  the  wireless  transmission
equipment necessary to provide its services. Although there are a limited number
of  manufacturers  who  have,  or  are  developing,  equipment  that  would meet
 
                                       34
<PAGE>
the Company's requirements, there can be no assurance that such equipment  would
be  available to the Company on comparable terms or on terms more favorable than
those included in its current arrangements  in the event that such  arrangements
are  terminated.  Moreover, a  change  in vendors  could  cause a  delay  in the
Company's ability to provide its  services, which would affect future  operating
results adversely.
 
    The  Company has  entered into an  agreement with American  Wireless to fund
$700,000 to $1.0 million of research  and development costs related to  wireless
transmission  equipment. Vernon L. Fotheringham, the Chairman of the Company, is
a director and a 6% shareholder of American Wireless. The Company will receive a
first right of refusal on production capacity and a license fee in exchange  for
its  funding. The Company has also entered  into a letter of intent with Helioss
Communications Corporation ("Helioss")  for the development  of advanced 38  GHz
radios.   Under  the   letter  of  intent,   which  is   subject  to  definitive
documentation, the Company will fund up to $1.0 million of Helioss' research and
development expenses.  The  Company  will  have a  right  of  first  refusal  on
production  capacity of the radios  and will receive a royalty  on the sale of a
certain number of radios  to customers other than  the Company. The Company  has
also  entered into  a letter  of intent  to invest  $1.5 million  in QuestTV (as
defined), a provider of  video and data transmission  and storage services.  See
"Certain  Transactions  --  American  Wireless  Development  Agreement"  and "--
QuestTV Investment."  Although the  Company  does not  have any  other  material
commitments  to fund  research and development  or to make  investments in other
companies, it expects to incur additional expenses for research and  development
or to make other such investments from time to time.
 
    The  Company currently expects that  its capital expenditures (excluding the
acquisition of  certain spectrum  rights)  will aggregate  approximately  $100.0
million  through  December  31,  1997.  The  Company  currently  expects capital
expenditures through December 31, 1997 to consist of approximately $65.0 million
for wireless  transmission equipment,  approximately $20.0  million for  network
design and development and related equipment and approximately $15.0 million for
computer  equipment and other related capital. Included in these amounts are the
costs of initial construction of all owned and managed authorizations, estimated
to be  less  than  $5.0  million,  including  wireless  transmission  equipment.
Although  the Company does not anticipate substantial difficulties in completing
such initial construction on a timely basis,  the failure to do so could have  a
material  adverse effect on the  number of licenses available  to the Company to
carry out  its  business. The  Company  expects that  capital  expenditures  for
wireless  transmission equipment  will be  largely variable  with market demand,
increasing over the remainder of 1996 and  the next several years as demand  for
the  Company's 38 GHz services increases  in the targeted geographic markets and
industry segments. In addition, the Company has agreed to acquire authorizations
and licenses for $9.6  million from DCT  and ART West.  The Company has  entered
into  an  agreement  to acquire  129  38  GHz authorizations  from  CommcoCCC in
exchange for 16,500,000  shares of Common  Stock. CommcoCCC has  entered into  a
management  agreement with the  Company under which  the Company will construct,
manage and operate the authorization to be acquired pending consummation of  the
CommcoCCC  Acquisition.  If  the  Company  does  not  consummate  the  CommcoCCC
Acquisition, the Company expects that approximately 25% of its expected  capital
expenditures  through 1997 would  be deferred until later  years and incurred in
the Company's other markets.  See "Business --  Agreements Relating to  Licenses
and Authorization -- CommcoCCC Acquisition."
 
    The  Company  is obliged  to  pay all  costs  and expenses  of construction,
operation and  management of  the  authorizations managed  by the  Company.  The
Company  is also  obligated under the  terms of the  service agreements covering
such authorizations to pay fees to  the current holders of those  authorizations
approximating  10%  to  15%  of  the revenue  generated  from  such  assets. See
"Business -- Agreements Relating to Licenses and Authorizations."
 
    The Company  expects  that it  will  continue to  have  substantial  capital
requirements in connection with (i) the acquisition of appropriate sites for its
operations,  (ii)  deployment of  its 38  GHz  technology on  a market-by-market
basis, (iii) capturing  and retaining  an adequate  revenue generating  customer
base
 
                                       35
<PAGE>
and  (iv)  developing and  deploying its  operational  and support  systems. The
Company believes it has an opportunity to expand its wireless broadband services
business significantly and that access to capital will enable it to expand  more
quickly and effectively.
 
    The  Company has incurred significant operating  and net losses and negative
operating cash flow attributable  to the development  of its wireless  broadband
services  and anticipates that such losses and negative operating cash flow will
increase as the Company implements its growth strategy. Accordingly, the Company
will be dependent on additional capital to  fund its growth, as well as to  fund
continued losses from operations.
 
    Management anticipates that, based on current plans of development, assuming
that  no new material  acquisitions (other than  those currently under contract)
are consummated, the net proceeds of the Offerings after the use of $8.0 million
to repay existing indebtedness and $9.6 million to complete pending acquisitions
and the proceeds of  the Credit Facility (as  defined), if consummated, will  be
sufficient  to fund  the operations  of the  Company for  at least  the next two
years. See "Description of Certain  Indebtedness." Management believes that  the
Company's  future  capital  needs  will  continue  to  be  significant  and that
thereafter it will be  necessary for the Company  to seek additional sources  of
financing.  In addition, if (i) the Company's plan of development or projections
change or prove to be inaccurate,  (ii) the proceeds of the Offerings,  together
with  other existing financial  resources, prove to be  insufficient to fund the
Company for at least the next two  years, (iii) the Company fails to  consummate
the  Credit Facility  or (iv) the  Company completes  any material acquisitions,
other than those now under contract or buys spectrum at auction, the Company may
be required  to seek  additional financing  sooner than  currently  anticipated.
There can be no assurance that the Company will be able to obtain any additional
financing,  or, if such financing is available, that the Company will be able to
obtain it on acceptable  terms. In the  event that the  Company fails to  obtain
additional  financing, such failure  could result in  the modification, delay or
abandonment of some or all of the Company's development and expansion plans. Any
such modification, delay  or abandonment is  likely to have  a material  adverse
effect  on the Company's business, which could adversely affect the value of the
Common Stock, the Notes and the Warrants and may limit the Company's ability  to
make principal and interest payments on its indebtedness.
 
NEW ACCOUNTING PRONOUNCEMENT
 
    In  October 1995, the Financial  Accounting Standards Board issued Statement
of  Financial  Accounting  Standards   No.  123,  "Accounting  for   Stock-Based
Compensation."  This Statement encourages, but  does not require, accounting for
stock compensation awards granted to employees based on their fair value at  the
date  the awards are granted.  Companies may elect to  continue to apply current
accounting requirements for employee stock compensation awards, which  generally
will  result in no compensation cost for  most fixed stock option plans, such as
the Company's Equity Incentive Plan.  The expense measurement provisions of  the
Statement apply to all equity instruments issued for goods and services provided
by  persons other than employees. All companies  are required to comply with the
disclosure requirements  of  the  Statement. The  Company  expects  to  continue
accounting  for  employee  stock compensation  awards  using  current accounting
requirements.
 
INFLATION
 
    Management does not believe that its business is impacted by inflation to  a
significantly different extent than is the general economy.
 
                                       36
<PAGE>
                                    BUSINESS
 
    Advanced  Radio  Telecom Corp.  ("ART" or  the "Company")  provides wireless
broadband   telecommunications   services    using   point-to-point    microwave
transmissions  in the 37.0 to 40.0 gigahertz  portion of the radio spectrum ("38
GHz"). The Company is seeking to address the growing demand for high speed, high
capacity digital  telecommunications  services  on  the  part  of  business  and
government  end users who require cost effective, high bandwidth local access to
voice, video,  data  and  Internet  services. Upon  completion  of  its  pending
acquisition  of  129 38  GHz wireless  broadband authorizations  (the "CommcoCCC
Assets") from CommcoCCC, Inc.  ("CommcoCCC"), the Company will  own or manage  a
total  of 237  authorizations granted  by the  Federal Communications Commission
("FCC") covering an  aggregate population  of approximately 143  million in  169
U.S. markets.
 
TELECOMMUNICATIONS INDUSTRY OVERVIEW
 
    The   current  telecommunications   landscape  is  being   reshaped  by  the
convergence of three  major trends: (i)  the accelerating growth  in demand  for
high   speed,  high  capacity  digital  telecommunications  services,  (ii)  the
deregulation of  telecommunications  markets and  (iii)  the rapid  advances  in
wireless   technologies.   The  growth   in  demand   for  high   speed  digital
telecommunications services is being driven by the revolution in  microprocessor
power  and  advances in  new  multimedia and  on-line  applications such  as the
Internet. The ability to  access and distribute  information quickly has  become
critical  to business and  government users of  telecommunications services. The
proliferation  of  local  area  networks  ("LANs"),  rapid  growth  of  Internet
services,  rising demand for video teleconferencing and other demand factors are
significantly increasing the volume of broadband telecommunications traffic. The
inability of the existing infrastructure to meet this demand is creating a "last
mile" bottleneck in  the copper wire  networks of the  incumbent local  exchange
carriers  ("LECs").  This  increasing  demand,  together  with  changes  in  the
regulatory environment, are  creating an  opportunity to  offer cost  effective,
high capacity last mile access using both wireline and wireless solutions.
 
    The  present structure  of the  U.S. telecommunications  industry was shaped
principally by  the 1984  court-directed  divestiture of  the Bell  System  (the
"Divestiture").  As  part  of  the Divestiture,  seven  Regional  Bell Operating
Companies ("RBOCs") were created  and separated from  the long distance  service
provider,  AT&T, resulting in two  distinct telecommunications industries: local
exchange and inter-exchange  (commonly known as  long distance). Local  exchange
services typically involve the carriage of telecommunications within FCC-defined
local  access and  transport areas  ("LATAs"), and  the provision  of access, or
connections,  between  LECs  and   inter-exchange  carriers  ("IXCs")  for   the
completion of long distance calls.
 
    Since  the Divestiture, the local exchange segment of the telecommunications
market has remained the domain of LECs. Recently, however, regulatory policy has
shifted away from  monopoly protection of  the LECs. U.S.  court decisions,  FCC
actions  and most recently the  Telecommunications Act have dramatically changed
the regulatory environment. These  changes have permitted increased  competition
in  the local exchange market and  created opportunities for new companies, such
as competitive access providers ("CAPs").
 
    Beginning in the late 1980s, CAPs emerged to compete with LECs by  providing
dedicated  private line transmission and access services. CAP networks typically
consist of fiber  optic facilities  connecting IXC points  of presence  ("POPs")
with  customer locations  and LEC switches  within a  limited metropolitan area.
Initially, demand for alternative local access  was driven by access charges  of
approximately  40% to 45% of the cost of  a long distance call levied by LECs on
the IXCs.  In  addition to  providing  lower  access charges,  CAP  fiber  optic
services,  where available, have  generally been considered  to provide superior
quality and  higher capacity  services than  those available  from LECs'  legacy
copper  wire networks.  A leading research  company estimates that  in 1994 CAPs
captured approximately  $1.3 billion  of  the revenues  generated by  the  local
exchange  market.  Such research  company  also projects  that,  as a  result of
increased competition and the growth  of enhanced services, CAPs' revenues  will
grow in excess
 
                                       37
<PAGE>
of  150% per year over the next two years.  In addition to CAPs, a wide range of
alternative access  providers, including  cable television  operators,  wireless
local loop service providers and others, are expected to emerge.
 
    Continued  growth  in the  quality and  number of  competitors in  the local
telecommunications market will be driven principally by (i) the growing interest
among business customers  for an  alternative to the  LEC networks  in order  to
obtain   higher  capacity  and  better  pricing,  (ii)  the  increases  in  data
applications  and  capacity  requirements  for  local  and  wide  area   network
connections,  high speed Internet access  and videoconferencing, (iii) the LECs'
inability to  upgrade their  copper  networks quickly,  (iv) the  preference  of
competing  telecommunications providers to  control the points  of connection to
their  customers  and  prevent   LECs  from  obtaining  confidential   marketing
information  and (v) new state and federal legislation mandating interconnection
and competition in the local exchange market.
 
    Wireless broadband  telecommunications services  are developing  rapidly  to
handle these growing needs for alternative access. In particular, the successful
deployment  of 38  GHz links by  European cellular service  providers and recent
advances  in  38  GHz  technology,  coupled  with  metropolitan-wide   footprint
licensing,  has enabled the  provision of greater capacity  and reliability at a
lower cost per customer than  traditional copper wire networks. Furthermore,  38
GHz  facilities  can be  installed, deinstalled  and reinstalled  elsewhere with
minimal time and cost compared to both fiber optic and copper wire facilities.
 
38 GHZ TECHNOLOGY
 
    The FCC has allocated  fourteen 100 MHz channels  between 38.6 GHz and  40.0
GHz  for wireless  broadband transmissions and  has allocated  the 37.0-38.5 GHz
band to  wireless  broadband  transmissions  (the 37.0-38.5  GHz  band  and  the
38.6-40.0  GHz band are collectively referred to  as "38 GHz"), which enable the
licensee to  provide  point-to-point  services  within  a  specified  geographic
footprint usually of up to a 50-mile radius.
 
    38  GHz technology was first widely deployed in Europe by cellular telephone
service providers for the  interconnection of cell sites  with switches. In  the
early  1990s, technological advances resulted in  a substantial reduction in the
cost and size of millimetric  microwave components with a simultaneous  increase
in  reliability and  quality, allowing for  the provision  of wireless broadband
telecommunication links  at competitive  prices.  By 1993,  advances in  38  GHz
technology,  combined with its growing use in Europe and Central America, led to
increasing awareness of  and interest in  the potential  uses of 38  GHz in  the
United States.
 
    The 38 GHz band provides for the following additional advantages as compared
to other spectrum bands and wireline alternatives:
 
    - HIGH  DATA TRANSFER RATES.  The total  amount of bandwidth for each 38 GHz
      channel is  100 MHz,  which exceeds  the bandwidth  of any  other  present
      terrestrial   wireless  channel  allotment  and  supports  full  broadband
      capability. For example, one  38 GHz DS-3 link  at 45 megabits per  second
      ("Mbps")  today can transfer data at a  rate which is over 1,500 times the
      rate of the fastest  dial-up modem currently in  use (28.8 Kbps) and  over
      350  times the  rate of  the fastest  integrated services  digital network
      ("ISDN") line currently in  use (128 Kbps).  In addition to  accommodating
      standard  voice  and data  requirements, 45  Mbps data  transmission rates
      allow end users to receive real  time, full motion video and 3-D  graphics
      at  their workstations and  to utilize highly  interactive applications on
      the Internet and other networks.
 
    - SIGNIFICANT CHANNEL  CAPACITY.   Because  38 GHz  radio emissions  have  a
      narrow  beam width,  a relatively  short range  and in  most instances the
      capability to  intersect without  creating  interference, 38  GHz  service
      providers  can efficiently reuse  their bandwidth within  a licensed area,
      thereby increasing the number of customers  to which such services can  be
      provided.  Management believes that by using technology currently employed
      by the Company it can serve  virtually all of the immediately  addressable
      market in its market areas.
 
                                       38
<PAGE>
    - RAPID  DEPLOYMENT.   38 GHz technology  can be  deployed considerably more
      rapidly than wireline and other wireless technologies, generally within 72
      hours after  obtaining access  to customer  premises. In  contrast to  the
      relative ease of installing a 38 GHz transmission link, extending fiber or
      copper-based networks to reach new customers requires significant time and
      expense. In addition, unlike providers of point-to-point microwave service
      in  other spectrum bands, a 38 GHz  license holder can install and operate
      as many transmission links as it can engineer in the licensed area without
      obtaining additional  approvals  from  the  FCC.  This  is  a  substantial
      advantage over other portions of the microwave radio spectrum that must be
      licensed  on a link-by-link basis  following frequency coordination, which
      in total can take from three to five months.
 
    - EASE OF INSTALLATION.  The equipment used for point-to-point  applications
      in  38 GHz (I.E.,  antennae, transceivers and  digital interface units) is
      smaller, less obtrusive and  less expensive than  that used for  microwave
      equipment applications at lower frequencies, making it less susceptible to
      zoning   restrictions.  In  addition,  38  GHz  equipment  can  be  easily
      redeployed to meet changing customer requirements.
 
    - ADDITIONAL  ADVANTAGES  OVER  OTHER  PORTIONS  OF  RADIO  SPECTRUM.     At
      frequencies   above  38  GHz,   point-to-point  applications  become  less
      practical because attenuation increases  and the maximum distance  between
      transceivers  accordingly decreases.  Additionally, the  FCC has specified
      the use  of many  portions of  the spectrum  for applications  other  than
      point-to-point,  such  as  satellite  and  wireless  cable  services, and,
      accordingly, these portions of the radio spectrum often are not  available
      for point-to-point applications. Finally, 38 GHz has characteristics which
      provide  better signal quality  and performance in  inclement weather than
      those offered in other portions of the radio spectrum.
 
THE ART SOLUTION
 
    The Company is positioned to solve the need for broadband last mile  access,
linking   end  users  to  fiber  optic   based  facilities  of  CAPs  and  other
telecommunications service providers without  the need to  deploy fiber all  the
way to end users' premises. The Company provides point-to-point wireless digital
circuits  ranging in  capacity from  DS-1 (capable  of carrying  24 simultaneous
voice conversations at 1.544 Mbps) to DS-3 (capable of carrying 672 simultaneous
voice conversations at 45 Mbps).  The Company's wireless broadband services  are
engineered  to provide 99.999% availability, with  better than a 10-13 (unfaded)
bit error rate.  This level of  availability exceeds the  performance of  copper
based  networks  and  is a  viable  alternative  to fiber  based  networks. When
measured as the  total amount  of time  "out of  service" over  a year,  99.999%
availability under conditions of no path fading equates to less than six minutes
of  down-time  compared to  a  range of  four hours  to  44 hours  of historical
performance of  similar  copper-based LEC  circuits.  In addition,  the  Company
believes  that  ART's  last  mile solution  is  competitively  priced  with most
broadband wireline solutions.
 
    The Company's  initial target  customers include  CAPs, IXCs,  cellular  and
mobile  radio service  providers and  ISPs. The  Company's services  may also be
attractive to certain LECs which do  not currently have broadband networks  that
reach  the majority of their customers. The Company has entered into a strategic
distribution agreement with  Ameritech for  delivery of  the Company's  wireless
broadband  services  throughout  Ameritech's midwest  operating  region  and for
certain large customers located outside its region. See "-- Strategic  Alliances
- -- Ameritech Strategic Distribution Agreement."
 
    The  Company believes  that the  following factors  provide it  with certain
significant competitive  advantages  in  offering broadband  last  mile  access,
including:
 
    - The  characteristics  of  38  GHz technology  (high  data  transfer rates,
      significant channel  capacity,  rapid deployment,  easy  installation  and
      efficient network design) are ideal for the provision of last mile access.
 
                                       39
<PAGE>
    - The  Company  minimizes its  initial capital  expenditures because  of the
      installation-to-meet-demand  and  redeployable  nature  of  the  Company's
      wireless  broadband  equipment, as  compared to  the significant  cost and
      expense of installation of fiber based networks.
 
    - As  one  of  the   first  38  GHz  service   providers,  the  Company   is
      well-positioned to capture a large percentage of early adopters, which are
      generally among the heaviest users.
 
    - The  Company's industry relationships should  enable it to forge strategic
      alliances  with   other  carriers,   equipment  vendors   and   technology
      development  companies,  thus  gaining  access  to  important  channels of
      distribution and early deployment of advanced technologies.
 
    - The scope  of the  Company's  market area  enables  it to  offer  wireless
      broadband  services  targeting  much of  the  United  States's addressable
      business market.
 
    As regulatory and competitive conditions permit, the Company's market  focus
will  evolve  from a  wholesale "carrier's  carrier"  orientation to  the retail
provision of services directly to  government and commercial end-user  customers
of  telecommunications services. The Company will focus on its initial wholesale
"carrier's carrier" strategy at  least through the first  half of 1997. At  that
time,  the  Company anticipates  it will  have developed  its customer  base and
market presence to a  level that will  enable the Company  to expand its  direct
sales  efforts. At the same  time, the Company anticipates  it will commence the
development of switched services to expand the Company's service offerings  both
geographically  and  demographically,  to  business  and  residential customers,
offering a  wider  array  of  voice, data,  Internet  and  multimedia  services,
depending on further advances in wireless technology.
 
BUSINESS STRATEGY
 
    ART began providing 38 GHz wireless broadband services in the fourth quarter
of  1995 and has generated only nominal revenues from such services to date. The
Company is seeking to capitalize on its broad footprint of 38 GHz authorizations
to become a leading provider of wireless broadband solutions to a diverse  group
of  traditional and emerging telecommunications  service providers and end users
of telecommunications services.  The Company  plans to  implement the  following
strategic initiatives to achieve this objective:
 
    -  EXPLOIT SPECTRUM POSITION IN KEY  MARKETS. Upon completion of its pending
     acquisition of the CommcoCCC Assets, the Company will own or manage a total
     of 237  authorizations  that will  allow  it  to provide  38  GHz  wireless
     broadband  services  in 169  U.S. markets.  The  Company currently  owns or
     manages 108 authorizations (exclusive of  the CommcoCCC Assets) that  allow
     it to provide 38 GHz wireless broadband services in 89 markets, 73 of which
     are  owned by the Company and the remaining  35 of which are managed by the
     Company through  the  Company's interests  in  or arrangements  with  other
     companies.  The Company  has agreed  to acquire  all of  the authorizations
     which it currently manages but does not own. These spectrum assets  provide
     the Company with the foundation on which to create a large scale commercial
     system  of 38 GHz wireless  broadband operations. As of  June 28, 1996, the
     Company was  operating revenue-generating  wireless broadband  links in  15
     cities.  The Company plans to continue  to build out its infrastructure and
     to intensify its marketing effort in  its market areas in order to  exploit
     the  value inherent in its spectrum  assets. See "-- Agreements Relating to
     Licenses and Authorizations."  The Company may  seek to acquire  additional
     spectrum  rights  in  new  and  existing markets  in  order  to  expand its
     geographic footprint or enhance its services.
 
    - MARKET  INITIALLY AS  A CARRIER'S  CARRIER. The  Company's initial  target
     customers  include CAPs, IXCs, cellular  and mobile radio service providers
     and ISPs. The Company's wireless  broadband services enable CAPs to  extend
     their broadband services to locations where it is either not cost-efficient
     or  too  difficult to  extend  their fiber  optic  network due  to physical
     limitations, franchise fees or  other restrictions. The Company's  services
     may  also be attractive  to certain LECs, which  generally do not currently
     have  broadband  networks  capable  of  reaching  the  majority  of   their
     customers.  All telecommunications service providers  can use the Company's
     services as alternate
 
                                       40
<PAGE>
     or redundant  routes  to  increase network  reliability.  The  Company  has
     entered  into a strategic distribution  agreement (the "Ameritech Strategic
     Distribution Agreement") with Ameritech Corp. ("Ameritech") for delivery of
     the Company's wireless  broadband services  throughout Ameritech's  midwest
     operating  region  and  for  certain large  customers  located  outside its
     region. The Company currently provides services to Ameritech, Bell Atlantic
     NYNEX  Mobile,  UUNet,  Electric  Lightwave,  NEXTLINK,  American  Personal
     Comunications,  American  Show Management,  Capital Area  Internet Service,
     Brooks Fiber Communications  and Western  Wireless, among  others. See  "--
     Customers  and  Applications."  As  regulatory  and  competitive conditions
     permit and as the Company's customer base and market presence develop,  the
     Company  expects  that  its  market  focus  will  expand  from  a wholesale
     "carrier's carrier" to include provision of services directly to commercial
     end users.
 
    - PURSUE  OPPORTUNITIES TO  PROVIDE VALUE-ADDED  SERVICES. The  Company  has
     identified  and  plans to  pursue additional  market niches  with immediate
     needs for reliable, high bandwidth last mile access services. For  example,
     the  market for  Internet services  urgently requires  broadband "pipes" to
     facilitate high speed  access for corporate  users. The amount  of time  it
     takes  to  download  graphics  and images  from  the  Internet  to personal
     computers over dial-up copper circuits hinders demand for the Internet. For
     example, a 38 GHz DS-1 circuit (1.544 Mbps), linking a corporate user to an
     ISP's POP, is approximately 53 times faster than a 28.8 kbps dial-up  modem
     and   12  times  faster  than  the  fastest  ISDN  connection  (128  Kbps).
     Alternatively, one 38 GHz DS-3 link at 45 Mbps can currently transfer  data
     at  a rate that is  over 1,500 times the rate  of the fastest dial-up modem
     currently in use (28.8  Kbps) and over  350 times the  rate of the  fastest
     ISDN line currently in use (128 Kbps). Each of the Company's DS-3 links can
     support 28 DS-1 circuits per channel. The Company is pursuing agreements to
     package  its  38 GHz  solutions with  the services  of leading  ISPs. Other
     potential  value-added   uses  include   desktop  videoconferencing,   high
     resolution  imaging  for healthcare  and  law enforcement  applications and
     video on  demand.  The Company  may  also decide  to  offer  switched-based
     services  to  end  users  who  desire  a  single  source telecommunications
     solution.
 
    - MAINTAIN  TECHNOLOGY LEADERSHIP  IN SPECTRUM  MANAGEMENT. The  Company  is
     currently developing proprietary site selection and network design software
     which it believes will provide for faster site development at a lower cost.
     In addition, through the Company's internal technology development efforts,
     as  well as on-going participation in equipment manufacturers' research and
     development activities, the  Company is  seeking to  achieve a  competitive
     advantage through proprietary methods designed to increase the capacity and
     quality of its networks.
 
    -  ESTABLISH AND EXPAND KEY STRATEGIC ALLIANCES. The Company has established
     and will seek to continue to  establish key strategic alliances with  major
     service   providers,  equipment  manufacturers,   systems  integrators  and
     enhanced  service  providers.  Ameritech  owns  a  5.5%  beneficial  equity
     interest  in the Company as  of June 28, 1996  (4.3% after giving effect to
     the Common  Stock  Offering)  and  entered  into  the  Ameritech  Strategic
     Distribution  Agreement in April 1996. The Company also has agreements with
     Harris Corporation, Farinon Division ("Harris") for marketing ART's 38  GHz
     services  to PCS providers and with GTE Corporation for installation, field
     servicing and network monitoring.  In addition, the  Company is seeking  to
     develop  relationships with a number of equipment manufacturers focusing on
     38 GHz technology development, wireless broadband standards and joint sales
     efforts. The Company  plans to  utilize strategic alliances  to bundle  its
     services   with  those  of   its  partners,  to   provide  for  alternative
     distribution channels and to gain access to technological advancements. See
     "-- Strategic Alliances."
 
WIRELESS BROADBAND SERVICES
 
    The Company's wireless broadband links  deliver high quality voice and  data
transmissions  at a level of performance which exceeds the performance of copper
based networks and is  a viable alternative to  fiber optic based networks.  The
Company  provides point-to-point  wireless digital circuits  ranging in capacity
from DS-1  (capable of  carrying 24  simultaneous voice  conversations at  1.544
Mbps) to DS-3
 
                                       41
<PAGE>
(capable  of  carrying 672  simultaneous voice  conversations  at 45  Mbps). The
Company believes that it generally owns  or manages sufficient 38 GHz  bandwidth
to  satisfy the anticipated service requirements of its target customers in each
of the Company's existing markets and  the additional 78 markets to be  acquired
under the CommcoCCC Agreement.
 
    Significant  features of  the Company's wireless  broadband services include
(i) sufficient bandwidth and  flexibility in each channel  for most present  day
applications,  (ii) minimal  channel interference from  other sources, resulting
from dedicated spectrum, (iii)  range of up to  five miles between  transmission
links  (depending  upon  moisture conditions),  (iv)  performance  engineered to
provide a minimum of 99.999% availability, (v) transmission accuracy  engineered
to provide bit error rates of better than 10-13 (unfaded), (vi) optional forward
error  correction for  even higher data  reliability, insuring  the integrity of
transmitted data over  wireless broadband paths,  (vii) rapid deployment  (where
roof  rights have  been previously obtained),  (viii) 24-hour, seven-days-a-week
network monitoring  by the  Company's network  management control  center,  (ix)
available  nationwide  four-hour  emergency  restoral  time  from  GTE  in  most
circumstances and (x) optional  "hot" standby links that  remain powered up  and
switch "on line" if the primary link fails.
 
    Each  of ART's wireless  broadband links consists  of paired millimeter wave
radio transceivers installed at a distance of up to five miles from one  another
within  a direct line of  sight. The transceivers currently  used by the Company
are supplied principally by P-Com, Inc. ("P-Com") and are installed primarily on
rooftops and on other tall structures. In order to deploy its links quickly, the
Company plans to  obtain roof  rights on buildings  with fiber  optic points  of
termination  for transceiver sites. To accomplish this objective, the Company is
developing proprietary site  selection and  network design  software which  will
significantly  reduce the  amount of  time necessary  to select  optimal network
sites. In coordination with its marketing plans, the Company will dispatch  site
acquisition  specialists  to such  locations  to obtain  renewable  options. The
Company intends  to use  a  combination of  its  own employees  and  independent
contractors for site acquisition.
 
CUSTOMERS AND APPLICATIONS
 
    The  Company introduced its wireless broadband services in November 1995 and
began marketing its  services in January  1996. The Company  has generated  only
nominal  revenues  from  its  operations  to  date.  Currently,  the  Company is
providing or has received orders to provide carrier's carrier wireless broadband
services to CAPs, a LEC, ISPs,  cellular and mobile carriers and, several  IXCs,
and  is in the process of becoming a qualified vendor to all the major IXCs. The
Company currently provides services to  Ameritech, Bell Atlantic, NYNEX  Mobile,
UUNet,  Electric Lightwave, NEXTLINK, American Personal Communications, American
Show Management, Capital Area Internet Service, Brooks Fiber Communications  and
Western  Wireless, among others. As of June  28, 1996, the Company was operating
revenue-generating wireless broadband links in 15 cities.
 
    The Company currently provides, or anticipates providing, wireless broadband
services to the following types of customers, among others:
 
                                       42
<PAGE>
    COMPETITIVE ACCESS PROVIDERS AND LOCAL  EXCHANGE CARRIERS.  Currently,  CAPs
compete  with LECs by installing fiber optic  cable rings in the highest density
business locations to  connect with  long distance carriers  and for  intra-ring
transmissions.  Due to the  high cost inherent in  building fiber networks, CAPs
generally target  densely  populated areas  with  high concentrations  of  large
end-users.  In order  to reach  "off-net" customers,  CAPs must  either lease or
purchase facilities and services from  LECs or alternative suppliers until  such
time  as  it  becomes economical  to  extend  the CAP  fiber  networks  to these
customers.
 
    CAPs face  certain  implementation  obstacles that  the  Company's  wireless
broadband  services can assist in solving. CAPs need to reach new customers that
are off-net quickly  and inexpensively,  and are  expected to  prefer to  obtain
additional  network  facilities from  (and  share proprietary  information with)
someone other than  a direct competitor,  such as  a LEC. CAPs  can utilize  the
Company's  wireless broadband services as  an alternative to copper, fiber-based
or other  such network  facilities provided  to the  CAPs by  LECs (see  diagram
below),  to extend  their own  networks to reach  areas where  such extension is
neither  cost-efficient  nor  feasible,   because  of  rights-of-way  or   other
restrictions,  or to  provide redundant and  back-up capacity  to their existing
networks.
 
    The Company anticipates that LECs will encounter many of the same  obstacles
CAPs  are encountering in seeking to enhance their networks to deliver broadband
services. The  Company also  believes that  LECs  will seek  to utilize  38  GHz
technology to expand the range of their service offerings to match those offered
by  CAPs. Further,  as LECs  are permitted  to provide  inter-LATA long distance
services, they may seek to use 38 GHz technology to bypass other LECs outside of
their region. See  "-- Strategic Alliances  -- Ameritech Strategic  Distribution
Agreement."
 
                                   [GRAPHIC]
 
                                       43
<PAGE>
    INTERNET  SERVICE PROVIDERS.  The expanding  demand for Internet access, the
growing importance of  audio, video  and graphic Internet  applications to  both
business  and  consumers and  the  lack of  high  capacity access  through local
telephone company facilities  has created  a growing market  for ART's  wireless
broadband  services.  The  Company  offers  Internet  service  providers timely,
reliable and affordable access at the required high speed data rates -- both  45
Mbps  and 1.544 Mbps --  allowing ISPs to keep  pace with their customer growth.
The Company provides wireless  broadband links between  customers and their  ISP
providers  and between ISP POPs and the  Internet backbone. A single 38 GHz DS-1
circuit linking  a corporate  user to  an ISP's  POP is  approximately 53  times
faster  than a 28.8 Kbps dial-up modem and 12 times faster than the fastest ISDN
connection. Each of the Company's 38 GHz DS-3 links can support 28 DS-1 circuits
per channel or one DS-3 circuit per  channel, which can transfer data at a  rate
which  is over 1,500 times  the rate of the  fastest dial-up modems currently in
use (28 Kbps) and over 350 times the rate of the fastest ISDN lines currently in
use (128 Kbps).
 
                               [GRAPHIC]
 
                                       44
<PAGE>
    MOBILE COMMUNICATIONS SERVICE PROVIDERS.  ART's wireless broadband  services
can  help  cellular,  wireless dispatch  and  emerging PCS  carriers  compete in
expanding domestic  mobile communications  markets by  providing  cost-effective
backbone  network  connections between  cell sites,  base stations  and wireline
networks,  regardless  of  location.   Similar  38  GHz  mobile   communications
connections  have been proven  effective in Europe,  and ART's easily installed,
economical  wireless  broadband  links  can  give  domestic  mobile  carriers  a
competitive  edge  in  building  or  expanding  their  networks  through reduced
construction time and installation costs.
 
                               [GRAPHIC]
 
                                       45
<PAGE>
    INTER-EXCHANGE CARRIERS.  To minimize costly LEC access charges and to  gain
more  direct contact with the consumer,  IXCs can utilize the Company's wireless
broadband services  to connect  call origination  or termination  points  either
directly  to the  IXCs' POPs or  by way  of CAP intermediate  fiber rings. These
providers can  also  use  38 GHz  services  to  connect two  or  more  of  their
respective  POPs in  a single market  area. By utilizing  the Company's wireless
broadband services, IXCs can avoid the capacity barriers inherent in copper wire
connections, which have typically prevented them from providing their  customers
with  the end-to-end,  high bandwidth,  full digital  services available  from a
fiber optic or wireless-based  system. Wireless broadband  services also may  be
utilized  to  provide carriers  with  viable, cost-efficient  physical diversity
routes (I.E., back-up capacity)  for traffic in  situations when primary  routes
become   incapacitated   or  network   reliability  concerns   demand  alternate
telecommunications paths.
 
                                [GRAPHIC]
 
                                       46
<PAGE>
    PRIVATE USER NETWORKS.  ART's  wireless broadband services enable  business,
government and other heavy usage customers to create efficient, high speed, high
capacity  private voice, data and video communications networks within and among
their local  facilities and  buildings.  These customers  include  universities,
hospitals,  hotels, shopping centers  and multi-location manufacturing, business
and  governmental  institutions.  Working  directly  with  ART  or  through  ART
resellers,  customers will be able to  access cost-effective alternatives to LEC
copper networks.
 
    Providing high speed data transmission and real time communications services
by  linking   customer  computers   in  local,   metropolitan  and   wide   area
configurations  will be an important part  of ART's private networking business.
The ability  to  send large  amounts  of data  quickly  and efficiently  and  to
interconnect  personal  computers  both  within and  among  buildings  in campus
settings is  a growing  customer  need. ART's  wireless broadband  services  are
designed to serve this rapidly expanding market.
 
                               [GRAPHIC]
 
                                       47
<PAGE>
    INTERACTIVE VIDEO SERVICES USERS.  ART's wireless broadband services provide
high  speed, high capacity  access to communications  networks for customers who
require  reliable  videoconferencing,  video  on  demand,  and  Internet   video
services.  The  Company  believes the  increasing  popularity and  use  of these
services, particularly by  large business  and government  customers, provide  a
promising market for ART's wireless links. Videoconferencing requires high speed
communications  both to and  from the participants.  The Company's services meet
this requirement for high bandwidth, full duplex communications.
 
                                   [GRAPHIC]
 
MARKETING PLANS
 
    In January  1996,  the Company  commenced  implementation of  its  marketing
program.  The Company  is addressing its  initial target markets  as a carrier's
carrier, while building the internal capability to expand its marketing  efforts
to  include direct sales to end users of its services. The Company is augmenting
its marketing  and  sales  channels through  resale  agreements  with  strategic
marketing  partners and through alliances with  selected CAPs, LECs, ISPs, IXCs,
interconnect providers (PBX suppliers), LAN, MAN and WAN systems integrators and
other telecommunications equipment manufacturers and service providers.
 
    The Company's  internal  salesforce  is currently  marketing  the  Company's
wireless  broadband services  by (i) performing  field demonstrations  of 38 GHz
service, (ii) making presentations at  industry trade shows, (iii) providing  an
interactive  Internet  home  page, (iv)  running  promotional  advertisements in
selected trade media and (v)  conducting extensive one-on-one presentations  and
demonstrations  through  its direct  sales  force with  major telecommunications
service providers and end users of telecommunications services.
 
    The Company currently expects to price  its services on a monthly  flat-rate
non-distance  sensitive basis. As  a non-dominant carrier, ART  does not have to
cost-justify its rates to regulatory bodies  and usually has a wide latitude  in
changing  customer-specific  rates.  As  a result,  ART  expects  to  enter into
customer and service specific arrangements,  which include volume, capacity  and
term  discounts and customized billing and payment options. The services offered
by ART are expected to be competitively
 
                                       48
<PAGE>
priced with those of the incumbent LECs. The Company also intends to charge  for
installation and network monitoring services where appropriate. The Company also
anticipates  offering metered  services to various  end users  at an appropriate
point in the future.
 
38 GHZ WIRELESS BROADBAND LICENSES AND AUTHORIZATIONS
 
    The Company was  granted the first  of its authorizations  to construct  and
operate  38 GHz wireless  broadband facilities in  February 1995. Authorizations
for facilities that are  not constructed are referred  to in this Prospectus  as
"construction  permits"; authorizations for facilities  that are constructed are
referred to in this Prospectus as  "licenses". Upon completion of the  CommcoCCC
Acquisition,  the Company will own or manage  a total of 237 authorizations that
will allow it to provide 38 GHz wireless broadband services in 169 U.S. markets.
The Company  currently owns  or  manages 108  authorizations (exclusive  of  the
CommcoCCC Assets) that allow it to provide 38 GHz wireless broadband services in
89  markets, 73 of which are owned by  the Company and the remaining 35 of which
are managed by the  Company through the Company's  interests in or  arrangements
with other companies.
 
    The table below lists, for the top 100 U.S. markets, the amount of bandwidth
covered  by authorizations which  the Company owns, manages  or has a definitive
agreement to acquire, in the top 100  U.S. markets, in descending order of  size
based on the estimated population of the market:
 
<TABLE>
<CAPTION>
                                                   BANDWIDTH COVERED BY AUTHORIZATIONS (MHZ)
                                            --------------------------------------------------------
                                                                              UNDER
                                                                           DEFINITIVE
                                                                            AGREEMENT
                  MARKET                       OWNED       MANAGED(1)      TO ACQUIRE       TOTAL
- ------------------------------------------  -----------  ---------------  -------------     -----
<S>                                         <C>          <C>              <C>            <C>
300 MHZ OR MORE MARKETS
New York, NY                                       300             --              --           300
Washington, D.C.                                   300             --              --           300
Boston, MA                                         200             --             100           300
Baltimore, MD                                      200            100              --           300
Cincinnati, OH                                     100             --             200           300
Portland, OR                                        --            100             200           300
Norfolk/Virginia Beach, VA                          --            100             300           400
Columbus, OH                                        --            100             200           300
Providence, RI/Fall River, MA                      200             --             200           400
Memphis, TN                                        100             --             200           300
Oklahoma City, OK                                   --            100             200           300
Birmingham, AL                                     100             --             200           300
Buffalo/Niagara Falls, NY                          300             --             100           400
Dayton/Springfield, OH                             100            100             100           300
Richmond/Petersburg, VA                            100             --             200           300
Rochester, NY                                      300             --             200           500
Hartford, CT                                       200            100             200           500
Albany/Schenectady, NY                             300             --             200           500
Knoxville, TN                                      100             --             200           300
New Haven/Waterbury, CT                            200             --             100           300
Syracuse, NY                                       200             --             100           300
Harrisburg, PA                                     200             --             100           300
Scranton/Wilkes-Barre, PA                          300             --             100           400
Springfield/Holyoke, MA                            200             --             200           400
Jackson, MS                                        100             --             200           300
Shreveport, LA                                     100             --             200           300
</TABLE>
 
                                       49
<PAGE>
<TABLE>
<CAPTION>
                                                   BANDWIDTH COVERED BY AUTHORIZATIONS (MHZ)
                                            --------------------------------------------------------
                                                                              UNDER
                                                                           DEFINITIVE
                                                                            AGREEMENT
                  MARKET                       OWNED       MANAGED(1)      TO ACQUIRE       TOTAL
- ------------------------------------------  -----------  ---------------  -------------     -----
<S>                                         <C>          <C>              <C>            <C>
200 MHZ MARKETS
Philadelphia, PA/Trenton, NJ                       200             --              --           200
Miami/Fort Lauderdale, FL                          100             --             100           200
Cleveland/Akron, OH                                100             --             100           200
Seattle/Tacoma, WA                                  --            100             100           200
St. Louis, MO                                      100             --             100           200
Pittsburgh, PA                                     200             --              --           200
Charlotte/Gastonia, NC                              --             --             200           200
Nashville, TN                                      100             --             100           200
Indianapolis, IN                                   100             --             100           200
Louisville, KY                                     100             --             100           200
Greensboro/Winston-Salem, NC                        --            100             100           200
Las Vegas, NV                                       --            100             100           200
Austin, TX                                          --            100             100           200
Grand Rapids, MI                                    --            100             100           200
Omaha, NE                                           --             --             200           200
Honolulu, HI                                        --            100             100           200
Albuquerque, NM                                     --            100             100           200
Des Moines, IA                                     100             --             100           200
Tuscon, AZ                                          --            100             100           200
El Paso, TX                                         --             --             200           200
Worcester, MA                                      200             --              --           200
Allentown/Bethlehem, PA                            200             --              --           200
Baton Rouge, LA                                    100             --             100           200
Charleston, SC                                     100            100              --           200
Mobile, AL                                         100            100              --           200
 
100 MHZ MARKETS
Chicago, IL                                        100             --              --           100
Detroit, MI                                         --             --             100           100
Dallas/Fort Worth, TX                              100             --              --           100
Houston, TX                                        100             --              --           100
Atlanta, GA                                        100             --              --           100
Minneapolis, MN                                    100             --              --           100
Phoenix, AZ                                         --            100              --           100
San Diego, CA                                       --            100              --           100
Tampa-St. Petersburg, FL                            --             --             100           100
Denver, CO                                          --            100              --           100
Kansas City, MO                                    100             --              --           100
Sacramento, CA                                      --            100              --           100
Milwaukee, WI                                       --             --             100           100
San Antonio, TX                                    100             --              --           100
Salt Lake City, UT                                  --            100              --           100
Orlando, FL                                         --             --             100           100
New Orleans, LA                                    100             --              --           100
Raleigh-Durham, NC                                  --             --             100           100
Little Rock, AR                                     --             --             100           100
Tulsa, OK                                           --             --             100           100
Greenville/Spartanburg, SC                          --             --             100           100
</TABLE>
 
                                       50
<PAGE>
<TABLE>
<CAPTION>
                                                   BANDWIDTH COVERED BY AUTHORIZATIONS (MHZ)
                                            --------------------------------------------------------
                                                                              UNDER
                                                                           DEFINITIVE
                                                                            AGREEMENT
                  MARKET                       OWNED       MANAGED(1)      TO ACQUIRE       TOTAL
- ------------------------------------------  -----------  ---------------  -------------     -----
<S>                                         <C>          <C>              <C>            <C>
Toledo, OH                                          --             --             100           100
Spokane, WA                                         --            100              --           100
Kingsport, TN/Bristol, VA                           --             --             100           100
Fort Wayne, IN                                      --             --             100           100
Madison, WI                                        100             --              --           100
Wichita, KS                                        100             --              --           100
Springfield, MO                                     --             --             100           100
Sarasota/Bradenton, FL                              --             --             100           100
Corpus Christi, TX                                  --             --             100           100
Chattanooga, TN                                     --             --             100           100
</TABLE>
 
- ------------------------------
(1)  Includes authorizations (i) held by ART West; (ii) managed by ART under the
     DCT  services agreement; and  (iii) managed under  the Telecom One services
     agreement pursuant  to  a  revenue-sharing arrangement.  Does  not  include
     authorizations  included in the  CommcoCCC Assets which  are managed by the
     Company on  a  short-term  basis pending  the  CommcoCCC  Acquisition.  The
     Company  recently  has entered  into definitive  agreements to  acquire all
     outstanding interests  in the  authorizations  held by  ART West,  DCT  and
     Telecom   One.  See  "Business  --  Agreements  Relating  to  Licenses  and
     Authorizations."
 
    In addition to  the above  authorizations, the Company  has 71  applications
pending  before  the  FCC for  additional  authorizations. However,  due  to the
"freeze" imposed by  the NPRM and  the conflicts with  other applicants in  same
markets,  there can be  no assurance that  it or any  other company will receive
additional authorizations with  respect to any  pending applications. See  "Risk
Factors -- Government Regulation" and "-- Government Regulation."
 
    Excluding  the  CommcoCCC  Assets,  the Company  presently  owns  or manages
between 100 and  300 MHz of  transmission capacity within  each of its  markets.
Because  38 GHz paths  are very narrow  and because certain  microwave paths can
intersect each  other  without  creating  interference,  each  market  area  can
accommodate  thousands  of  paths. The  Company  believes it  generally  owns or
manages  sufficient  38  GHz  bandwidth  to  satisfy  the  anticipated   service
requirements  of its target customers in  each of the Company's existing markets
and the additional  80 markets  to be  acquired under  the CommcoCCC  Agreement.
Consistent  with the Company's  growth strategy, the Company  may seek to obtain
additional spectrum  by  either  leasing  excess  capacity  from  other  38  GHz
licensees,  entering into management agreements  or acquiring interests in other
38 GHz authorizations. See "Risk Factors -- Acquisition of Additional  Bandwidth
in Selected Areas."
 
    Under  the terms of its 31  construction permits (exclusive of the CommcoCCC
Assets), the Company must complete  construction of facilities for the  majority
of  such construction permits  between mid-August and  mid-September 1996. Under
the terms of the CommcoCCC authorizations and the Company's management agreement
with CommcoCCC, the Company must  complete construction of facilities for  eight
construction  permits by mid-September 1996, 39 construction permits by December
1996 and the remaining 82 construction permits between mid-April and  mid-August
1997.  The Company has begun installing the number of links required to complete
construction and currently expects it will meet the FCC deadlines. However,  the
FCC  may impose more stringent construction  requirements, as it has proposed to
do in the NPRM, which may jeopardize the status of the Company's authorizations.
All of the 38  GHz licenses owned or  to be acquired by  the Company are due  to
expire  in February 2001. The Company believes  that, in keeping with common FCC
practices, the  licenses will  be renewed  for successive  10-year periods  upon
expiration.
 
                                       51
<PAGE>
AGREEMENTS RELATING TO LICENSES AND AUTHORIZATIONS
 
    COMMCOCCC  ACQUISITION.    On July  3,  1996,  the Company  entered  into an
agreement (the "CommcoCCC Agreement") to  acquire 129 38 GHz wireless  broadband
authorizations  (the "CommcoCCC  Assets") from  CommcoCCC, Inc.  (the "CommcoCCC
Acquisition") in exchange for 16,500,000  shares of Common Stock. CommcoCCC  was
formed in a transaction arranged by Columbia Capital Corporation to acquire, own
and  operate the 38 GHz authorizations owned by Columbia Capital Corporation and
its affiliates and those  owned by Commco, L.L.C.  The CommcoCCC Acquisition  is
subject  to various  conditions including  receipt of  FCC and  other approvals,
receipt by CommcoCCC of an opinion as to the tax-free nature of the transaction,
consummation of the  Offerings on  terms reasonably  satisfactory to  CommcoCCC,
minimum  population coverage requirements for  the authorizations of the Company
and CommcoCCC, accuracy  of representations and  warranties except for  breaches
that  do not  have in  the aggregate  a material  adverse effect,  no pending or
threatened material litigation and other customary closing conditions. There can
be no assurance that  all such conditions will  be satisfied. In particular,  to
obtain  FCC approval, the  Company will need  to make certain "anti-trafficking"
showings and may need certain waivers or  consents from the FCC. The FCC may  be
unwilling  to grant its approval or may grant its approval subject to conditions
that may be adverse to the Company. The CommcoCCC Agreement may be terminated by
CommcoCCC if the Offerings are not completed  within 90 days of the date of  the
CommcoCCC  Agreement  or by  either party  if the  CommcoCCC Acquisition  is not
consummated within one year  of the date of  the CommcoCCC Agreement. See  "Risk
Factors -- Risk of Non-Consummation of CommcoCCC Acquisition."
 
    In  the CommcoCCC Agreement, the Company  and Telecom have each agreed that,
prior to the consummation of the transaction, except in certain circumstances or
with the consent of CommcoCCC, they  will not issue equity, incur debt,  acquire
spectrum,  make investments, consolidate, merge or sell all or substantially all
of its  assets. CommcoCCC  has  entered into  a  management agreement  with  the
Company  pursuant  to  which the  Company  bears the  responsibility  during the
pendency of  the CommcoCCC  Acquisition  to construct,  manage and  operate  the
CommcoCCC  Assets, consistent  with FCC  rules. Under  the management agreement,
CommcoCCC is  obligated  to  reimburse  ART for  up  to  $100,000  of  operating
expenses,  which obligation  will be cancelled  if the  CommcoCCC Acquisition is
consummated. In the event the management agreement is terminated other than as a
result of the consummation of the CommcoCCC Acquisition, CommcoCCC is  obligated
to  purchase and  ART is obligated  to sell  at the Company's  original cost the
equipment purchased by ART necessary  to meet the FCC construction  requirements
for the CommcoCCC authorizations.
 
    The  stockholders  of  CommcoCCC  loaned the  Company  $3.0  million payable
September 30, 1996  pursuant to  a subordinated bridge  financing facility  (the
"CommcoCCC   Financing")  and,  in  connection  therewith,  received  three-year
warrants to purchase  50,000 shares of  Common Stock  at a price  of $15.00  per
share  (the  "CommcoCCC  Warrants"). The  CommcoCCC  Financing is  secured  by a
security interest in all of the assets of the Company, including a pledge of the
Company's stock in Telecom. If the CommcoCCC Financing is not paid in full  when
due, the unpaid principal and interest could be converted into Common Stock on a
formula  basis at  the option  of the holders.  The CommcoCCC  Financing will be
repaid with the proceeds of the Offerings.
 
    The Company has given Commco, L.L.C., a stockholder of CommcoCCC, an  option
(the  "Commco Option")  to purchase  one authorization  in each  of 12 specified
market areas in which the Company  will have more than one authorization,  which
authorizations  cover  in the  aggregate  approximately 19  million  people. The
Commco Option  will be  exercisable only  if (i)  the CommcoCCC  Acquisition  is
consummated  and (ii) Commco, L.L.C.  obtains authorizations pursuant to certain
pending applications frozen under the NPRM in market areas covering an aggregate
population of at least 40  million people, and will  terminate on the date  nine
months  after the consummation of the  Common Stock Offering. The purchase price
for any  authorizations acquired  under the  Commco Option  is determined  by  a
formula  based  upon the  fair market  value at  the time  the Commco  Option is
exercised of up to approximately 2,600,000 shares of Common Stock depending upon
the number of authorizations purchased. The purchase price is payable in cash or
if the Commco Option is exercised within the later
 
                                       52
<PAGE>
of 120 days after the closing of the CommcoCCC Acquisition or the date of  grant
by the FCC of the authorizations necessary to exercise the Commco Option, with a
two  year note secured by shares  of Common Stock having a  value on the date of
exercise equal to two times the principal amount of the note.
 
    In arranging the CommcoCCC Acquisition, Columbia Capital Corporation and its
affiliates agreed not to compete with  the Company in the provision of  wireless
broadband  telecommunication services in  the 38 GHz band  of the radio spectrum
for a five year period commencing upon the closing of the CommcoCCC  Acquisition
and  has  granted the  Company a  right of  first  offer to  acquire any  38 GHz
authorizations that Columbia Capital Corporation  or its affiliates may  acquire
in the future with respect to their pending applications.
 
    Promptly  upon closing of the CommcoCCC  Acquisition, the Company has agreed
to nominate one individual designated by CommcoCCC's stockholders and acceptable
to the Company as a director of the Company.
 
    In late  1994 and  1995, Columbia  Capital Corporation  and certain  of  its
affiliates  ("Columbia")  entered into  several  letter agreements  (the "Letter
Agreements") with Video/Phone  Systems, Inc.  ("Video/Phone"). In  consideration
for  services to  be rendered under  the Letter Agreements,  Columbia granted or
agreed to grant to Video/Phone options to purchase minority equity interests  in
entities  formed or to be  formed to apply for  38 GHz licenses. Columbia agreed
not to assign these licenses to  any person controlling, controlled by or  under
common  control with Columbia  unless such transferee  granted to Video/Phone an
equivalent option. The CommcoCCC Assets include 67 authorizations transferred by
Columbia to CommcoCCC, subject to FCC approval. Columbia and Video/Phone are  in
a  dispute with respect to the performance  and obligations of the parties under
the Letter Agreements. Columbia  has agreed to indemnify  and hold harmless  the
Company with respect to any loss or damage resulting from the Letter Agreements.
 
    EMI  ACQUISITION.  On April 4, 1995,  ART entered into an agreement with EMI
Communications Corporation ("EMI") to acquire  EMI's thirty two 38 GHz  wireless
broadband  licenses and  related assets in  the northeastern  United States (the
"EMI Assets") in exchange for $3.0 million in cash and a $1.5 million three-year
non-negotiable  and  non-transferable  promissory  note  (the  "EMI  Note").  In
November 1995, ART assigned all of its rights and obligations under the purchase
agreement  to Telecom.  The FCC  subsequently approved  the transfer  of the EMI
Assets to Telecom, and the EMI Assets were acquired by Telecom in November 1995.
ART has also agreed to provide wireless  broadband services to EMI for a  period
of  five years from the date of the  agreement and to certain of EMI's customers
on behalf of EMI for the terms provided in such EMI service agreements, and  EMI
agreed  to provide certain services to Telecom for an initial period of one year
from the date of the agreement. See "Description of Certain Indebtedness --  EMI
Note."
 
    ART  WEST JOINT VENTURE.  On April 4, 1995, ART and Extended Communications,
Inc. ("Extended")  entered  into  a  joint  venture  agreement  (the  "ART  West
Agreement"),  resulting in the formation of ART West Joint Venture ("ART West"),
a Delaware partnership equally owned by ART and Extended. Under the terms of the
ART West Agreement, ART and Extended agreed to transfer to ART West all of their
respective interests  in  all of  their  38 GHz  authorizations  (currently,  12
authorizations)   in  Alaska,  Arizona,  California,  Colorado,  Hawaii,  Idaho,
Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming (the "ART West
Markets"), subject  to  FCC  approval. Under  a  separate  management  agreement
between  ART  and ART  West, ART  is obligated  to bear  all costs  and expenses
relating to construction, operation and management  of the ART West Markets  and
has  agreed to utilize  the ART West  authorizations before other authorizations
owned or managed by ART in the  ART West Markets. As compensation, ART  receives
90% of the recurring revenues of ART West, with ART West receiving the remaining
10%.  To date, Extended has had  no significant responsibilities with respect to
ART West and is not expected to invest in or contribute any services to ART West
pending the proposed  acquisition of  Extended's interest  described below.  See
"Certain Transactions -- ART West Joint Venture."
 
                                       53
<PAGE>
    In  June  1996,  the  Company  entered  into  an  agreement  (the  "Extended
Agreement") to acquire Extended's interest in ART West for an aggregate of  $6.0
million  in  cash,  subject  to adjustment  and  subject  to  closing conditions
including final FCC approval. Of the  $6.0 million purchase price, $3.0  million
is  payable upon consummation of the  Offerings as a non-refundable deposit (the
"ART West  Deposit")  and  the  balance is  payable  upon  consummation  of  the
transaction.  Under this agreement, upon payment by ART of the ART West Deposit,
Extended has agreed to surrender its rights under the ART West Agreement (i)  to
participate  in  the acquisition  of  additional licenses  or  authorizations in
certain of  the ART  West Markets  through ART  West and  (ii) to  prohibit  the
acquisition by ART of additional licenses or authorizations in certain other ART
West Markets.
 
    DCT  SYSTEM PURCHASE AGREEMENTS.  On July 1, 1996 the Company entered into a
definitive agreement (the "DCT Agreement") with DCT to acquire DCT's interest in
certain 38 GHz  licenses (the  "DCT Systems") in  exchange for  $3.6 million  in
cash, subject to FCC approval, consummation of the DCT Agreement by September 1,
1997   and   other   customary   closing   conditions   including   accuracy  of
representations and warranties, absence of litigation and receipt of opinion  of
counsel.  ART has entered into  a services agreement with  DCT pursuant to which
ART bears the responsibility for  the construction, operation and management  of
the  DCT  Systems.  The  agreement  expires on  December  31,  1998  and  may be
terminated earlier by DCT  if the DCT Agreement  terminates. Under the terms  of
the services agreement, ART is obligated to bear all costs and expenses relating
to  construction, operation and management of  the DCT Systems. As compensation,
ART is entitled  to receive all  of the  revenues generated by  the DCT  Systems
until December 31, 1996. From January 1, 1997 until the later of January 1, 1998
and  the termination  of the DCT  Agreement, a license  fee equal to  15% of the
gross revenue generated by the DCT Systems will be paid to DCT, and thereafter a
license fee based on the number and  types of circuits operated by ART over  the
DCT  Systems will be paid to DCT. After  December 31, 1997, DCT has the right to
market to  third  parties utilizing  the  DCT Systems.  The  services  agreement
terminates  with respect to each DCT 38  GHz license upon the acquisition by ART
of such license. The  Company is currently  completing the initial  construction
requirements of the DCT Systems and expects such construction to be completed in
the third quarter of 1996.
 
    TELECOM  ONE SERVICES AGREEMENT.  On April 24, 1996, the Company and Telecom
One, Inc. ("Telecom One")  entered into a services  agreement (the "Telecom  One
Services  Agreement") pursuant to which the Company agreed to construct, operate
and manage all 38 GHz wireless broadband licenses and related telecommunications
systems owned by Telecom One that are granted by the FCC. At present Telecom One
has been granted two authorizations.  Under the Telecom One Services  Agreement,
the  Company is obligated to pay all costs and expenses related to construction,
operation and management of the  systems. As compensation, the Company  receives
90%  of the net revenues  generated by the systems  and Telecom One receives the
remaining 10% for ten years.
 
    TELECOM ONE PURCHASE AGREEMENT.  On  June 27, 1996, the Company and  Telecom
One  entered  into an  agreement  pursuant to  which  the Company  will acquire,
subject  to  FCC  approval,   from  Telecom  One   the  two  currently   granted
authorizations  that are the  subject of the Telecom  One Services Agreement for
approximately $111,000 in cash.  In addition, the Company  will have a right  of
first  refusal on all future  grants of 38 GHz  authorizations to Telecom One or
its current stockholders.
 
STRATEGIC ALLIANCES
 
    AMERITECH STRATEGIC DISTRIBUTION AGREEMENT.  On April 29, 1996, the  Company
and  Ameritech entered into  a three-year strategic  distribution agreement (the
"Ameritech Strategic  Distribution Agreement")  pursuant  to which  the  Company
provides  38 GHz services  to Ameritech, who  will in turn  market the Company's
services under  the Ameritech  name.  Ameritech has  agreed  to be  the  primary
provider  of  the  Company's  services  in  the  midwest.  Under  the agreement,
Ameritech is targeting certain sales objectives and will spend internally up  to
$7.0  million on its sales and marketing  of the Company's services. The Company
believes that  Ameritech's  sales and  marketing  expertise and  its  access  to
extensive distribution
 
                                       54
<PAGE>
channels within its region will accelerate the rollout of the Company's business
plan.  The Ameritech Strategic Distribution  Agreement is subject to termination
at any time by either party on 90 days' notice. See "Risk Factors --  Dependence
on Third Parties for Marketing and Service."
 
    GTE  SERVICES AGREEMENT.   On  April 25,  1996, the  Company entered  into a
two-year agreement with GTE Government Systems Corporation, a subsidiary of  GTE
Corporation  ("GTE"). GTE  will provide  equipment staging  and outfitting, site
preparation, equipment installation and  maintenance for the Company's  wireless
broadband services. Under the agreement, it is anticipated that GTE will perform
at least 75% of the Company's installations. The Company will pay a fee equal to
$1,550  for the installation of each link and a maintenance fee equal to $85 per
hour. The aggregate  amount of  the fee  will depend  on the  Company's rate  of
growth.  The Company believes that GTE's nationwide presence and experience will
provide the Company with efficient, quality installation and maintenance for its
nationwide services.  See  "Risk Factors  --  Dependence on  Third  Parties  for
Marketing and Service."
 
    GTE SOFTWARE LICENSE AGREEMENT.  On March 29, 1996, the Company entered into
a  software license agreement with  GTE's Network Management Organization. Under
this agreement, the Company  will purchase software  and centralize its  network
management functions to reduce costs and increase reliability. GTE's "Integrated
Network  Management  Products" enable  the Company  to quickly  identify service
interruptions and to simultaneously alert the field service teams, who are  able
to  restore services in a  timely manner. The Company will  pay a license fee of
approximately  $2.4  million   and  an   annual  maintenance   support  fee   of
approximately  $300,000. The  license fee will  be paid  in monthly installments
commencing January 1, 1997 of $67,000  per month, including interest. After  the
first  year,  fees  are subject  to  renegotiation  based on  market  prices and
conditions. See "Risk Factors -- Dependence  on Third Parties for Marketing  and
Service."
 
    HARRIS  AGREEMENTS.  On April 26,  1996, the Company and Harris Corporation,
Farinon Division ("Harris") entered into a one-year PCS marketing agreement (the
"Harris Marketing Agreement") pursuant  to which the  Company granted to  Harris
the  right to use  its 38 GHz  authorizations, including associated coordination
services, installation and  network monitoring and  field services. Pursuant  to
the  Harris Marketing Agreement, Harris agreed  to market the Company's services
in the  emerging PCS  market. The  Harris Marketing  Agreement is  automatically
renewable  for successive one-year terms unless  either party delivers notice of
non-renewal at  least 60  days prior  to  the end  of the  initial term  or  any
successive  term. The agreement  is also subject  to termination at  any time by
either party on 90 days' notice.
 
    Concurrently with the Harris Marketing Agreement, the parties entered into a
one-year purchase agreement (the "Harris Purchase Agreement") pursuant to  which
the  Company  agreed  to  purchase  certain  microwave  transmission  equipment,
software and services  relating thereto (the  "Harris Products"). The  agreement
sets  minimum purchase goals for the purchase by the Company of Harris Products.
If either the Harris Purchase Agreement or the Harris Marketing Agreement  shall
terminate, the other shall also terminate.
 
    TECHNOLOGY  DEVELOPMENT AGREEMENTS.   The  Company has  had discussions with
several microwave equipment or technology development companies for  development
of  technologies, owned by such companies, for advanced 38 GHz radios, highspeed
converters, innovative telecommunications platforms and other technologies.  The
Company will continue to monitor new developments in technology and may elect to
fund  research and development activity in  such new technology. The Company has
also entered  into  a  letter  of  intent  with  American  Wireless  Corporation
("American  Wireless") providing for  the funding by the  Company of $700,000 to
$1.0 million for research and development. In consideration of such funding, the
Company will  have  a first  right  to purchase  American  Wireless'  production
capacity  of the new radios for a period of 18 months from the date of the first
order and will receive  a per-unit fee  on radios sold  by American Wireless  to
third  parties, and  the Company  will have  no other  rights to  any technology
developed.  See   "Certain  Transactions   --  American   Wireless   Development
Agreement." This arrangement is subject to definitive documentation. The Company
has entered into a
 
                                       55
<PAGE>
non-binding arrangement with QuestTV providing for an investment of $1.5 million
in  the development of a nationwide network of franchises offering retail access
to sophisticated video  data transmission and  storage technology. See  "Certain
Transactions -- QuestTV Investment."
 
    The  Company  has  also  entered  into  a  letter  of  intent  with  Helioss
Communications Corporation ("Helioss")  for the development  of advanced 38  GHz
radios.   Under  the   letter  of  intent,   which  is   subject  to  definitive
documentation, the Company will fund up to $1.0 million of Helioss' research and
development expenses.  The  Company  will  have a  right  of  first  refusal  on
production  capacity of the  radios for three  years from delivery  of the first
radios produced, and will receive a royalty  on the sale of a certain number  of
radios  to customers other than the Company,  and the Company will have no other
rights to any technology developed.
 
    Through June 15, 1996,  the Company has  incurred approximately $600,000  of
research  and  development expenses  under such  arrangements.  There can  be no
assurance that the Company can complete  definitive agreements with any of  such
companies  or that such companies can develop technologies with commercial value
for the  Company.  Although  the  Company  does  not  have  any  other  material
commitments  to fund  research and development  or to make  investments in other
companies, the  Company expects  to incur  additional research  and  development
expenses or to make other such investments from time to time.
 
FOREIGN MARKETS
 
    The  Company  is  exploring  the  possibilities  of  providing  its wireless
broadband services in other countries  including Canada and in Europe.  Pursuant
to  a  consulting agreement,  the  Company has  retained  the services  of Trond
Johannessen for a period of two years  to assist the Company in the  exploration
of  foreign  opportunities,  including  the  acquisition  of  wireless broadband
licenses and identification of local operating partners. In addition to payments
of $6,500 per  month to  Mr. Johannessen, Mr.  Johannessen will  be entitled  to
purchase,  on the  same terms as  the Company,  up to 20%  of the  equity of any
entity formed to exploit any such opportunities. The Company has entered into  a
letter  of  intent with  Advantage Telecom,  Inc. ("ATI").  ATI has  received an
experimental license to provide 38  GHz services in Vancouver, British  Columbia
and  intends to seek authority to provide 38 GHz services in other major markets
in Canada whenever Canadian regulators adopt appropriate policies. The letter of
intent anticipates that the Company would provide initial funds and services  to
ATI  in amounts to be determined. There can be no assurance that the Company can
acquire such licenses or develop and operate such systems.
 
COMPETITION
 
    The telecommunications services industry is highly competitive. The  Company
has  only recently begun to market  its wireless broadband services to potential
customers and is currently providing services on a limited basis. In each market
area in  which  the Company  is  authorized  to provide  services,  the  Company
competes  or will compete with several other service providers and technologies.
The Company expects  to compete  primarily on  the basis  of wireless  broadband
service  features, quality, price, reliability, customer service and response to
customer needs.  The Company  faces significant  competition from  other 38  GHz
providers  and incumbent LECs, such  as the RBOCs. The  Company may also compete
with CAPs,  cable  television  operators,  electric  utilities,  LECs  operating
outside  their current local service  areas and IXCs. There  can be no assurance
that the Company will be able to compete effectively in any of its market areas.
 
    COMPETITION FROM 38 GHZ  SERVICE PROVIDERS.   The Company faces  competition
from  other 38  GHz service  providers, such as  WinStar and  BizTel, within its
market areas.  In  many cases,  one  or both  of  these service  providers  hold
licenses  to operate in  other portions of  the 38 GHz  band in geographic areas
which encompass  or  overlap the  Company's  market  areas. In  certain  of  the
Company's market areas, other 38 GHz service providers may have a longer history
of  operations, a larger geographic footprint or substantially greater financial
resources  than  the   Company.  WinStar   commenced  its   38  GHz   operations
approximately  one year prior to the Company, has raised significant capital and
has the
 
                                       56
<PAGE>
competitive advantages inherent in being the first to market 38 GHz services. In
addition  to  WinStar  and  BizTel,  at  least  one  other  substantial  entity,
Milliwave,  L.P. ("Milliwave"), and several dozen smaller ones have been granted
38 GHz  authorizations in  geographic  regions in  which  the Company  plans  to
operate. Winstar has recently entered into a definitive agreement with Milliwave
to  acquire Milliwave's 38 GHz licenses, subject to FCC approval, and has agreed
to manage such licenses pending the consummation of such acquisition. Due to the
relative ease and speed  of deployment of 38  GHz technology, the Company  could
face  intense price competition  and competition for  customers (including other
telecommunications service providers) from other 38 GHz service providers.
 
    The Company also faces potential competition from new entrants to the 38 GHz
market, including LECs and other leading telecommunications companies. The  NPRM
contemplates an auction of certain spectrum assets, including the lower fourteen
proposed  100 MHz channels (which are similar  to those used by the Company) and
four proposed 50 MHz channels in the  38 GHz spectrum band, which have not  been
previously  available  for  commercial  use.  See  "Risk  Factors  -- Government
Regulation." The grant  of additional authorizations  by the FCC  in the 38  GHz
band,  or other  portions of  the spectrum  with similar  characteristics, could
result in  increased  competition.  The Company  believes  that,  assuming  that
additional  channels  are made  available as  proposed  by the  NPRM, additional
entities having greater resources than the Company could acquire  authorizations
to provide 38 GHz services.
 
    COMPETITION  FROM  INCUMBENT  LECS.    The  Company  also  faces significant
competition from incumbent  LECs, irrespective  of whether they  provide 38  GHz
services.  Incumbent LECs have long-standing relationships with their customers,
generally own  significant  PCS  or  cellular  assets,  have  the  potential  to
subsidize  competitive services with  revenues from a  variety of businesses and
benefit from favorable  federal and state  policies and regulations.  Regulatory
decisions  and  recent legislation,  such  as the  Telecommunications  Act, have
partially deregulated the  telecommunications industry and  reduced barriers  to
entry  into new segments of the  industry. In particular, the Telecommunications
Act, among other things, (i)  enhances local exchange competition by  preempting
laws  prohibiting competition in the local  exchange market by requiring LECs to
provide fair and equal standards for interconnection and by requiring  incumbent
LECs  to provide unbundling of  services and (ii) permits  an RBOC to compete in
the  interLATA   long  distance   service   market  once   certain   competitive
characteristics  emerge in such  RBOC's service area.  The Company believes that
this trend towards  greater competition will  continue to provide  opportunities
for  broader entrance  into the  local exchange  markets. However,  as LECs face
increased competition,  regulatory decisions  are likely  to provide  them  with
increased  pricing  flexibility, which  in turn  may  result in  increased price
competition. There can  be no  assurance that such  increased price  competition
will not have a material adverse effect on the Company's results of operations.
 
    OTHER  COMPETITORS.  The Company may compete  with CAPs for the provision of
last mile access and additional services  in most of its market areas.  However,
the  Company believes that  many CAPs may  utilize 38 GHz  transmission links to
augment their own service offerings to IXCs and end users, and that the  Company
is  well positioned to provide such 38  GHz services to CAPs. However, there can
be no assurance that  CAPs will utilize  the Company's 38  GHz services or  that
CAPs  will not  seek to  acquire their  own 38  GHz licenses  or use  the 38 GHz
licenses of other licensees. Furthermore, the ability of CAPs to compete in  the
local  exchange market is limited by regulations relating to number portability,
dialing  parity  and  reasonable  interconnection.  The  Telecommunications  Act
requires  the FCC and the  states to implement regulations  that place CAPs on a
more equal  competitive footing  with  LECs. To  the  extent these  changes  are
implemented,  CAPs may be  able to compete more  effectively with LECs. However,
there can be no  assurance that CAPs  or 38 GHz service  providers, such as  the
Company,  will be  able to  compete effectively for  the provision  of last mile
access and other services.
 
    The Company  may  also  face competition  from  cable  television  operators
deploying  cable modems, which provide high speed data capability over installed
coaxial  cable  television  networks.  Although  cable  modems  are  not  widely
available  currently, the Company  believes that the  cable industry may support
 
                                       57
<PAGE>
the deployment of cable  modems to residential  cable customers through  methods
such  as price subsidies. Notwithstanding the cable industry's interest in rapid
deployment of  cable modems,  the  Company believes  that  in order  to  provide
broadband  capacity to  a significant  number of  business and  government users
cable operators will be required to spend significant time and capital in  order
to  upgrade  their existing  networks  to the  next  generation of  hybrid fiber
coaxial network  architecture. However,  there can  be no  assurance that  cable
television operators will not emerge as a source of competition to the Company.
 
    The  Company  may  also  face  competition  from  electric  utilities,  LECs
operating outside their current local  service areas, IXCs and other  providers.
These  entities provide transmission services using technologies which may enjoy
a greater degree of market acceptance than 38 GHz wireless broadband  technology
in  the provision of last mile broadband  services. In addition, the Company may
face competition  from  new market  entrants  using wireless,  fiber  optic  and
enhanced  copper based networks to provide local service and from wireless cable
providers and other  service providers  operating in frequencies  other than  38
GHz.
 
    Many  of  the Company's  competitors  have long-standing  relationships with
customers  and  suppliers,  greater  name  recognition  and  greater  financial,
technical  and  marketing  resources  than  the  Company.  As  a  result,  these
competitors may be  able to  more quickly develop  and exploit  new or  emerging
technologies,  adapt  to changes  in  customer requirements,  or  devote greater
resources to the marketing of their services than the Company. The consolidation
of telecommunications companies  and the  formation of  strategic alliances  and
cooperative  relationships in  the telecommunications  and related  industry, as
well as the development of new technologies, could give rise to significant  new
competitors  to the Company. In  such case, there can be  no assurance as to the
degree to which the Company will be able to compete effectively.
 
GOVERNMENT REGULATION
 
    The Company's  wireless  broadband services  are  subject to  regulation  by
federal,  state and local governmental agencies. The Company believes that it is
in  substantial  compliance  with  all  material  laws,  rules  and  regulations
governing  its operations and has  obtained, or is in  the process of obtaining,
all authorizations, tariffs and approvals  necessary and appropriate to  conduct
its   operations.  Nevertheless,  changes  in  existing  laws  and  regulations,
including those relating to the  provision of wireless local  telecommunications
services  via 38 GHz and/or the future granting of 38 GHz authorizations, or any
failure or significant delay in obtaining necessary regulatory approvals,  could
have a material adverse effect on the Company.
 
    FEDERAL REGULATION
 
    At  the  federal  level,  the  FCC has  jurisdiction  over  the  use  of the
electromagnetic  spectrum   (I.E.,   wireless  services)   and   has   exclusive
jurisdiction  over all  interstate telecommunications  services, that  is, those
that originate in  one state and  terminate in another  state. State  regulatory
commissions  have jurisdiction  over intrastate  communications, that  is, those
that originate  and terminate  in the  same state.  Municipalities may  regulate
limited  aspects  of the  Company's business  by,  for example,  imposing zoning
requirements and requiring installation permits. The Company also is subject  to
taxation at the federal and state levels and may be subject to varying taxes and
fees from local jurisdictions.
 
    FCC  LICENSING.  The  Communications Act of  1934 (the "Communications Act")
imposes certain requirements relating to licensing, common carrier  obligations,
reporting  and treatment of competition. Under  current FCC rules, the recipient
of an authorization  for 38  GHz microwave  facilities is  required to  complete
construction  of such facilities  within 18 months  of the date  of grant of the
authorization (authorizations  for  facilities  that  are  not  constructed  are
referred  to in this Prospectus as "construction permits" and authorizations for
facilities  that  are  constructed  are  referred  to  in  this  Prospectus   as
"licenses").  Upon  completion  of  construction, the  licensee  is  required to
certify that the  station is operational  and ready to  provide services to  the
public.  Although, under current FCC regulations,  the term "operational" is not
defined,  the   industry   custom   is   to  establish   at   least   one   link
 
                                       58
<PAGE>
between  two transceivers in each market area  for which it holds a construction
permit. In the event  that the recipient fails  to comply with the  construction
deadline,  the construction permit is subject to forfeiture, absent an extension
of the deadline. Effective August 1, 1996,  the Company will not be required  to
file  a form with the FCC certifying  that its station is operational (i.e. that
construction is  completed); however,  the licensee  will still  be required  to
complete   construction  within  18   months  of  the  date   of  grant  of  the
authorization. In  addition,  effective  August  1,  1996,  a  station  will  be
operational  when  construction  is  complete  and  the  station  is  capable of
providing service. Upon  completion of  the CommcoCCC  Acquisition, the  Company
will  own or manage a total of 237  authorizations that will allow it to provide
38 GHz wireless broadband  services in 169 U.S.  markets. The Company  currently
owns  or manages  108 authorizations  (exclusive of  the CommcoCCC  Assets) that
allow it  to  provide  38 GHz  wireless  broadband  services in  89  markets  to
construct  and operate  38 GHz  wireless broadband  facilities, 73  of which are
owned by the Company and  the remaining 35 of which  are managed by the  Company
through  the Company's interests in or arrangements with other companies. Of the
108 authorizations (exclusive of the CommcoCCC Assets) which the Company owns or
manages, 77  are licenses.  Under the  terms of  its remaining  31  construction
permits,  the Company must complete construction  of facilities for the majority
of such authorizations between mid-August and mid-September 1996, but it expects
to complete construction of  all such construction permits  by the beginning  of
August  1996. Under the terms of  the CommcoCCC authorizations and the Company's
management agreement with CommcoCCC, the  Company must complete construction  of
facilities for eight construction permits by mid-September 1996, 39 construction
permits by December 1996 and the remaining 82 between mid-April and August 1997.
The  Company  believes that,  in light  of current  FCC practice,  extensions of
construction  periods  are  highly  unlikely.  See  "Risk  Factors  --  Risk  of
Forfeiture, Non-Renewal and Fluctuation in Value of FCC Licenses."
 
    COMMON  CARRIER REGULATION.  Under the terms of its licenses, the Company is
classified as a common carrier,  and as such is required  to offer service on  a
non-discriminatory  basis  at just  and  reasonable rates  to  anyone reasonably
requesting such service. Although the  Communications Act prohibits the  Company
from  discriminating among its  customers, the Communications  Act, as currently
interpreted by  the  FCC, does  permit  the Company  substantial  discretion  in
classifying  its customers  and discriminating  among such  classifications. The
Company generally is obligated to furnish  service to its competitors and  might
be  obligated to allow other 38 GHz providers to install links within one of the
Company's market areas for a non-discriminatory fee. Under the FCC's streamlined
regulation of non-dominant  carriers, the  Company, as  a non-dominant  carrier,
must  file tariffs with  the FCC for  certain interstate services  on an ongoing
basis. The Company  is in the  process of filing  tariffs with the  FCC, to  the
extent  required, with respect  to its provision of  interstate service. The FCC
has recently initiated a  rulemaking proceeding to  eliminate the tariff  filing
requirement   pursuant   to   new  forbearance   authority   contained   in  the
Telecommunications Act. The Company, as a non-dominant carrier, is not currently
subject to rate regulation, and it may install and operate non-radio  facilities
for  the transmission  of interstate communications  without prior  FCC or state
authorization.
 
    The Company manages the systems of ART West, DCT, Telecom One and  CommcoCCC
(during the pendency of certain acquisitions) pursuant to management agreements.
See  "Business  --  Agreements  Relating to  Licenses  and  Authorizations." The
Company believes that the provisions of these management agreements comply  with
the  FCC's  policies  concerning licensee  control  of  FCC-licensed facilities.
Because the 38 GHz service is a new service, however, there is no FCC  precedent
addressing  the limits  of such management  arrangements for  these services. No
assurance can be given that the management arrangements or proposed acquisitions
will,  if  challenged,  be  found  to   satisfy  the  FCC's  policies  or   what
modifications, if any, may need to be made to satisfy those policies. If the FCC
were  to  void  or require  modifications  of the  management  arrangements, the
Company's operating results would be adversely affected.
 
                                       59
<PAGE>
    FCC REPORTING.    The Company,  as  an  operator of  millimeter  wave  radio
facilities,  is  subject to  the  FCC's semiannual  reporting  requirements with
respect to the deployment of  wireless local telecommunications services in  its
licensed  areas.  The  Company believes  that  it  has fully  complied  with its
reporting obligation. Effective August 1, 1996,  the FCC rules will not  require
semiannual reporting.
 
    COMPETITION.   Over the last  several years, the FCC  has issued a series of
decisions and Congress  has recently enacted  legislation making the  interstate
access  services  market  more  competitive  by  requiring  reasonable  and fair
interconnection  by  LECs.  Concomitant  with  its  decision  to  require   such
interconnection,  the FCC has  provided LECs with a  greater degree of increased
pricing flexibility between services (such as the ability to reduce local access
charges paid  by long  distance  carriers utilizing  LECs' local  networks)  and
between   geographic  markets  (such  as  cross-subsidizing  price  cuts  across
geographic markets). The Company anticipates that this pricing flexibility  will
result  in LECs lowering their prices in  high density zones. To the extent that
LECs choose to take  advantage of increased pricing  flexibility to lower  their
rates,  the ability of the  Company and CAP customers  of the Company to compete
for certain markets  and services  and the  Company's operating  results may  be
adversely affected.
 
    THE  TELECOMMUNICATIONS  ACT.    The  Telecommunications  Act  substantially
departs  from   prior  legislation   in  the   telecommunications  industry   by
establishing local exchange competition as a national policy through the removal
of  state  regulatory  barriers  to  competition  and  the  preemption  of  laws
restricting competition  in the  local exchange  market. The  Telecommunications
Act,  among other things, mandates that LECs (i) permit resale of their services
and facilities on reasonable and nondiscriminatory terms and at wholesale rates,
(ii) allow customers to retain the same telephone number ("number  portability")
when  they switch  carriers, (iii)  permit interconnection  by competitors  to a
LEC's network at any technically feasible point on the same terms as LEC charges
for its own  services, (iv) unbundle  their network services  and facilities  by
permitting competitors and others to use some but not all of their facilities at
cost-based and nondiscriminatory rates and (v) ensure that the end user does not
have to dial any more digits to reach local competitors than to reach the LEC to
the  extent technically feasible ("dialing  parity"). The Telecommunications Act
also allows  RBOCs  to  provide  interLATA  services  once  certain  competitive
characteristics  emerge in their  local exchange markets.  The provisions of the
Telecommunications Act are designed to ensure that RBOCs take affirmative  steps
to  level the playing  field for their  competitors so that  CAPs and others can
compete effectively. The FCC, with advice  from the United States Department  of
Justice,  and the states  are given jurisdiction  to enforce these requirements.
There can be no assurance, however, that  the states and the FCC will  implement
the  Telecommunications  Act  in  a  manner favorable  to  the  Company  and its
customers.
 
    FCC RULEMAKING.  On November 13, 1995, the FCC released an order barring the
acceptance of new applications for 38 GHz authorizations. On December 15,  1995,
the  FCC announced the  issuance of the  NPRM, pursuant to  which it proposed to
amend its current rules to provide for, among other things, (i) the adoption  of
an  auction procedure  for the  issuance of authorizations  in the  38 GHz band,
including a possible auction of the  lower fourteen 100 MHz channels (which  are
similar  to those used by the Company) and the lower four 50 MHz channels in the
38 GHz band that have not been previously available for commercial use, (ii) the
continuation of  the  100 MHz-based  channeling  plan and  licensing  rules  for
point-to-point  microwave operations in  the lower 14  channels, (iii) licensing
frequencies using predefined geographic  service areas ("Basic Trading  Areas"),
(iv)  the  imposition of  substantially  stricter construction  requirements for
authorizations that are not received pursuant to auctions as a condition to  the
retention of such authorizations and (v) the implementation of certain technical
rules  designed  to  avoid  radio  frequency  interference  among  licensees. In
addition, the FCC ordered that those applications subject to mutual  exclusivity
with  other applicants or placed on public notice by the FCC after September 13,
1995 would be held in abeyance pending the outcome of the NPRM and might then be
dismissed. Final rules issued  in connection with the  NPRM may require that  38
GHz service providers share other yet-to-be licensed portions of the 38 GHz band
with  other telecommunications service  providers. The implementation  of such a
measure could materially affect the Company's ability to provide services to its
customers by imposing power or  other limitations upon its existing  operations.
 
                                       60
<PAGE>
The  NPRM proposes substantial strengthening of the current rules concerning the
steps that a grantee of  a 38 GHz authorization must  take to satisfy the  FCC's
construction  requirements. At present,  the holder of  a construction permit is
only required to  certify that  it is  operational. Although  under current  FCC
regulations  the term  "operational" is not  defined, the industry  custom is to
install one link, which may be only  temporary and may not be producing  revenue
for  the operator. The  NPRM expresses concern that  this lenient standard might
allow the warehousing of  38 GHz spectrum. As  a consequence, the NPRM  proposes
much  more  stringent construction  requirements  for authorizations  other than
those received pursuant to an auction. There can be no assurance that the  final
rules  (if  any) issued  in connection  with  the NPRM  will resemble  the rules
proposed in the NPRM. There also can be no assurance that any proposed or  final
rules  will not  have a  material adverse  effect on  the Company.  Statutes and
regulations which  may become  applicable to  the Company  as it  expands  could
require  the Company  to alter  methods of  operations at  costs which  could be
substantial or otherwise limit the types of services offered by the Company.
 
    The NPRM also proposes that 38 GHz authorizations be awarded by auction. The
NPRM would  specify the  geographic  areas that  could  be licensed  instead  of
continuing  to allow the  applicants to design  the geographic circumferences of
the licenses. The Company has not determined whether to seek additional licenses
in the event of an auction. The Company believes that the FCC is likely to award
38 GHz authorizations by auction, but there  can be no assurance that this  will
occur.
 
    STATE REGULATION
 
    Many  of  the  Company's services,  either  now  or in  the  future,  may be
classified as intrastate and therefore may  be subject to state regulation.  The
Company  is  in  the process  of  obtaining  state authorizations  deemed  to be
sufficient to  conduct  most,  if not  all,  of  its proposed  business  in  the
near-term,  but there  can be  no assurance that  some portion  of the Company's
proposed  transmissions  might  not  be  considered  to  be  subject  to   state
jurisdiction  in  a  state  in  which  the  Company  does  not  have appropriate
authority. The Company expects that as its business and product lines expand and
the requirements  of  the Telecommunications  Act  favoring competition  in  the
provision  of local  communications services are  implemented, it  will offer an
increased number and type of intrastate services. The Company is implementing  a
program  to expand the  scope of its intrastate  certifications in various state
jurisdictions as its product line expands  and as the Telecommunications Act  is
implemented.
 
    Under  current state regulatory  schemes, entities can  compete with LECs in
the provision  of (i)  local access  services, (ii)  dedicated access  services,
(iii) private network services, including WAN services, for businesses and other
entities   and   (iv)  long   distance  toll   services.  The   remaining  local
telecommunications  services,   including  switched   local  exchange   services
encompassing  calls originating  and terminating within  a single  LATA, are not
currently subject  to  competition in  most  states. The  Telecommunication  Act
requires  each  of these  states  to remove  these  barriers to  competition. No
assurance can be given as to how quickly and how effectively each state will act
to implement the new legislation.
 
INTELLECTUAL PROPERTY RIGHTS
 
    The Company has filed for protection  for four service marks: DigiWave  (the
Company's  wireless  broadband  trademark), OZ  Box  (the  Company's proprietary
network management  interface),  ART and  Advanced  Radio Telecom.  These  first
filings  are  block  mark  applications,  which if  allowed  by  the  Patent and
Trademark Office, would  protect future  variations. The Company  will seek  the
maximum  protection for its future service marks. There can be no assurance that
the service marks  applied for  will be granted  nor that  the Company's  future
efforts   will  be  successful.  Although  the  Company  is  developing  various
proprietary processes, software  products and databases  and intends to  protect
its  rights vigorously and  to continue to develop  such proprietary systems and
databases, there can be no assurance  that these measures will be successful  in
establishing its proprietary rights in such assets.
 
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<PAGE>
EMPLOYEES
 
    As  of June 15, 1996, the Company had  a total of 70 employees, including 20
in  engineering  and  field  services,  25   in  sales  and  marketing,  13   in
administration  and finance, 8 in operations  and 4 in corporate development and
advanced  services.  None  of  the  Company's  employees  is  represented  by  a
collective  bargaining  agreement.  The  Company has  never  experienced  a work
stoppage and believes that its employee relations are good.
 
PROPERTIES
 
    The Company leases  approximately 22,000  square feet  of office,  technical
operations  and engineering field services  depot space in Bellevue, Washington.
The Company's  corporate headquarters,  network  operations center  and  western
regional  sales office occupy approximately 15,000  square feet under a sublease
expiring  in  January   2000.  The  Company's   engineering  department   leases
approximately  5,000 square feet and 2,000  square feet for technical operations
and an  engineering  field  services depot,  respectively,  pursuant  to  leases
expiring in May 1997. In addition the Company leases 1,100 square feet of office
space  in Portland, Oregon for sales and marketing personnel pursuant to a lease
expiring in  March 1998.  The  Company also  leases  temporary office  space  in
Washington,  D.C. under a sub-lease from  Pierson & Burnett, L.L.P. See "Certain
Transactions -- Pierson & Burnett Transactions."
 
LITIGATION
 
    The Company is not a party to any litigation.
 
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<PAGE>
                                   MANAGEMENT
 
EXECUTIVE OFFICERS AND DIRECTORS
 
    The  executive officers,  directors and  certain other  key officers  of the
Company, their ages and their positions  are as follows (after giving effect  to
the Merger):
 
<TABLE>
<CAPTION>
NAME                                         AGE      POSITION
- ---------------------------------------      ---      -------------------------------------------------------
<S>                                      <C>          <C>
Vernon L. Fotheringham (1)(2)(3).......          48   Chairman of the Board of Directors and Chief Executive
                                                       Officer
Steven D. Comrie.......................          40   President, Chief Operating Officer and Director
Thomas A. Grina........................          38   Executive Vice President and Chief Financial Officer
W. Theodore Pierson, Jr................          59   Executive Vice President, Secretary and General Counsel
James D. Miller........................          53   Senior Vice President, Sales and Marketing
James C. Cook (6)(7)(8)................          36   Director Designate
J.C. Demetree, Jr. (3)(4)(5)...........          37   Director
Mark C. Demetree (1)(2)................          39   Director
Andrew I. Fillat (2)(3)(4).............          48   Director
Matthew C. Gove (2)(4)(5)..............          31   Director
T. Allan McArtor (6)(8)(9).............          53   Director Designate
Laurence S. Zimmerman (1)(3)(5)........          36   Director
</TABLE>
 
- ------------------------------
(1)  Member of Option Committee.
 
(2)  Member of Compensation Committee.
 
(3)  Member of Finance Committee.
 
(4)  Member of Audit Committee.
 
(5)  These  directors will resign effective on  the date of this Prospectus, and
     James C.  Cook  and T.  Allan  McArtor will  be  elected to  the  Board  of
     Directors. See " -- Board Composition."
 
(6)  These directors have been elected effective on the date of this Prospectus.
     See "-- Board Composition."
 
(7)  Member of Option Committee effective on the date of this Prospectus.
 
(8)  Member of Audit Committee effective on the date of this Prospectus.
 
(9)  Member of Compensation Committee effective on the date of this Prospectus.
 
    VERNON  L. FOTHERINGHAM  has served as  Chairman of the  Board of Directors,
Chief Executive Officer of the Company and Telecom since inception. From 1993 to
1995, Mr. Fotheringham served as president and chief executive officer of Norcom
Networks Corporation, a  nationwide provider  of mobile  satellite services.  In
1992,  Mr.  Fotheringham co-founded  Digital Satellite  Broadcasting Corporation
("DSBC"), a  development  stage  company planning  to  provide  satellite  radio
services  nationwide, served  as its  chairman from  1992 to  1993 and currently
serves as one of its  directors. From 1988 to  1994, Mr. Fotheringham served  as
senior   vice  president  of   The  Walter  Group,   Inc.  ("TWG"),  a  wireless
telecommunications consulting and  project management firm.  From 1983 to  1986,
Mr.  Fotheringham served as vice president  of marketing of Omninet Corporation,
which was the original developer of the current Qualcomm OmniTRACS network. Over
the last  ten years,  Mr. Fotheringham  has advised  several businesses  in  the
telecommunications  industry, including  American Mobile  Satellite Corporation,
ClairCom Communications ("ClairCom") and McCaw Cellular Communications, Inc.
 
    STEVEN D. COMRIE  has served  as President,  Chief Operating  Officer and  a
director of the Company since July 1995. From 1992 to 1995, Mr. Comrie served as
vice   president   and  general   manager  of   Cypress  Broadcasting   Inc.,  a
California-based  television  subsidiary  of  Ackerley  Communications  Inc.,  a
diversified  media company based in Seattle,  Washington. From 1990 to 1992, Mr.
Comrie served as president of First Communication Media Inc. and as an investor,
advisor and manager of satellite, broadcast and telecommunications businesses in
the United States and Canada. In 1986, Mr. Comrie co-
 
                                       63
<PAGE>
founded  Netlink,  the  first  commercial  direct  broadcast  satellite  service
operating  in the  U.S. which  was subsequently  acquired by Tele-Communications
Inc. ("TCI"). Previously, Mr. Comrie served in a variety of management positions
with cable and media companies.
 
    THOMAS A. GRINA has served as  Executive Vice President and Chief  Financial
Officer of the Company since April 1996. From June 1989 to April 1996, Mr. Grina
was  Executive Vice President, Finance and  Chief Financial Officer of DialPage,
Inc. and  Executive Vice  President of  its wholly-owned  subsidiary, Dial  Call
Communications,  Inc.,  a  wireless  communications  company  operating  in  the
southeastern U.S.
 
    W. THEODORE PIERSON, JR. has served as Executive Vice President and  General
Counsel  of the Company and Telecom since inception. He has served as a director
of the  Company since  its inception  and  will resign  upon completion  of  the
Merger.  For more than five years, Mr. Pierson has been a partner of the firm of
Pierson & Burnett, L.L.P. (and its predecessor firms) in Washington, D.C., which
specializes in telecommunications law. As such, Mr. Pierson has advised a number
of start-up telecommunications companies,  including Home Box Office,  Satellite
Business Services, Omninet Corporation and DSBC. Mr. Pierson currently serves as
a  director  of DSBC.  Mr.  Pierson has  also  been counsel  to  the Competitive
Telecommunications  Association  (the  largest  association  of  long   distance
carriers)  and the Association for Local Telecommunications Services for several
years.
 
    JAMES D. MILLER has served as Senior Vice President, Sales and Marketing  of
the  Company  since  December 1995.  From  1993  to 1995,  Mr.  Miller  was vice
president and general  manager of U.S.  Intelco Wireless. Mr.  Miller served  as
executive  vice president  of Atlas  Telecom from 1987  to 1993  and as national
sales manager of Sidereal Corporation from 1977 to 1987.
 
    JAMES C. COOK will become  a director of the Company  upon the date of  this
Prospectus.  Mr. Cook is currently senior  vice president of First Union Capital
Partners, Inc. ("FUCPI"), the private equity investment affiliate of First Union
Corporation, where he has been employed since 1989. Prior to joining FUCPI,  Mr.
Cook  served in various capacities at The Bank of New York from 1982 to 1987 and
at Kidder, Peabody & Co. Inc. in 1988.
 
    J.C. DEMETREE, JR. has served as a  director of the Company since May  1995.
Since  1987, Mr. Demetree has served as  president of Demetree Brothers, Inc., a
real estate service company. Since  1980, he has been  a partner and trustee  of
Pentagon  Properties, a privately-held trust with investments in commercial real
estate and  other  operating  businesses including  banking  and  chemical.  Mr.
Demetree  has served since 1987 as a  director of Community First Bank and since
1995 as a director and officer of CFB Bancorp.
 
    MARK C. DEMETREE has  served as a  director of the  Company since May  1995.
Since  1993, Mr. Demetree has been president of North American Salt Company, the
second largest  salt producer  in North  America. From  1991 through  1993,  Mr.
Demetree  served as  president of  Trona Railway  Company, a  shortline railroad
division of  North  American  Chemical  Company. Mr.  Demetree  currently  is  a
director of J.C. Nichols Company, a real estate company, and serves on the Board
of  Governors  of  the  Canadian  Chamber of  Maritime  Commerce  for  the Great
Lakes/St. Lawrence Seaway and is the current chairman of the CEO Council of  the
Salt Institute.
 
    ANDREW  I. FILLAT  has served  as a director  of the  Company since November
1995.  Mr.  Fillat  has  been  employed  since  1989  by  Advent   International
Corporation  ("Advent"), a global venture  capital and private equity management
firm and currently serves  as senior vice president.  Prior to 1989, Mr.  Fillat
was  a  partner  at Fletcher  and  Company,  a consulting  firm  specializing in
assisting venture-backed  enterprises,  and  was  an  operating  executive  with
Fidelity  Investments.  Mr. Fillat  is also  a  director of:  Interlink Computer
Sciences, a systems management and communications software company; Lightbridge,
Inc., a company  providing customer acquisition  and marketing related  services
for  cellular  and PCS  carriers; Voxware,  Inc.,  a software  company providing
advanced voice compression and processing; and several private companies in  the
Advent portfolio.
 
    MATTHEW  C. GOVE  has served as  a director  of the Company  since May 1995.
Since  1994,  Mr.  Gove  has   been,  through  Hedgerow  Corporation  of   Maine
("Hedgerow"), a consultant to LHC, specializing in
 
                                       64
<PAGE>
domestic  and international  telecommunications transactions.  From 1991 through
1993, he attended the Columbia University Graduate School of Business and worked
as an independent consultant specializing in spreadsheet modeling and  financial
analysis. Prior to 1991, he was custodial manager of foreign currency derivative
funds at The Boston Company.
 
    T. ALLAN MCARTOR will become a director of the Company upon the date of this
Prospectus.  Since  1995,  Mr. McArtor  has  been chairman  and  chief executive
officer of  Quest  Computer Television  Company,  LLC, an  interactive  publicly
programmable  information network.  Since 1994,  Mr McArtor  has also  served as
chairman and chief executive officer  of Contrails, LLC, an aviation  consulting
firm.  From 1992 to 1994,  Mr. McArtor served as  president of FedEx Aeronautics
Corporation, a wholly-owned subsidiary of Federal Express Corporation ("FedEx").
From  1982  to  1987,  he  served   as  senior  vice  president  of  the   FedEx
Telecommunications  Division and from  1989 to 1992 as  senior vice president of
air operations at FedEx. From 1987 to 1989, Mr. McArtor was Administrator of the
Federal Aviation Administration. Mr.  McArtor currently serves  on the board  of
directors   of   Pilkington  Aerospace,   Inc.,   a  manufacturer   of  aviation
transparencies for fighter aircraft canopies, aircraft windshields and windows.
 
    LAURENCE S. ZIMMERMAN  has served  as a director  of the  Company since  May
1995.  Since  1985,  Mr.  Zimmerman  has  been  President  of  Landover Holdings
Corporation ("LHC"), of which he is the  founder and beneficial owner. LHC is  a
private  investment firm with  interests in wireless  cable, wireless telephone,
cellular and managed healthcare and specialty retail companies as well as  other
investments  in the United States  and abroad. From 1989  to 1990, Mr. Zimmerman
was a managing director  of Renaissance Capital Group  Inc., a leveraged  buyout
firm  which concentrated on emerging market and middle market telecommunications
and healthcare  opportunities. In  1993, Mr.  Zimmerman was  a founder  of,  and
provided the seed capital for, National Wireless Holdings Inc., a wireless cable
company  serving markets in Southern Florida. On February 1, 1995, Mr. Zimmerman
consented to the entry  of an order of  the Securities and Exchange  Commission,
without  admitting or denying the matters  referred to therein, barring him from
association with  any broker,  dealer, municipal  securities dealer,  investment
company  or investment adviser during the period February 1, 1995 to February 1,
1996 and  requiring  him  not  to violate  certain  provisions  of  the  Federal
securities  laws. The order relates to alleged violations arising out of alleged
conduct by Mr. Zimmerman in 1986 as  a broker for Breuer Capital, in  connection
with   trading  and  selling  shares  of  Balchem  Corporation.  See  "Principal
Stockholders -- Voting Trust Agreement."
 
BOARD COMPOSITION
 
    Under the  terms of  the Stockholders  Agreement (as  described in  "Certain
Transactions  -- February  1996 Reorganization"), the  Landover Stockholders (as
defined in the Stockholders Agreement) have the right to designate four  members
of  the Board of  Directors of the  Company and have  designated Messrs. Mark C.
Demetree, J.C.  Demetree, Jr.,  Gove and  Zimmerman as  directors. In  addition,
pursuant to the terms of the Stockholders Agreement, the Advent Partnerships (as
defined  in the Stockholders  Agreement) and Ameritech,  as holders of Telecom's
Series E and  F preferred stock  respectively, have the  right to designate  one
member  of the Board of Directors of  the Company and have designated Mr. Fillat
as a director. Pursuant to the  Stockholders Agreement, the right of the  Advent
Partnerships  to  designate a  director terminates  at such  time as  the Advent
Partnerships cease  to  own at  least  50% of  the  aggregate amount  of  equity
securities  of the Company currently owned by them. See "Certain Transactions --
LHC Purchase Agreement -- Advent Private Placement." The Stockholders  Agreement
will terminate upon consummation of the Offerings.
 
    All  directors  hold office  until their  successors  have been  elected and
qualified. Effective as of the date  of this Prospectus, Messrs. J.C.  Demetree,
Jr., Gove and Zimmerman will resign as directors, and James C. Cook and T. Allan
McArtor,  each of  whom is unaffiliated  with the  Company's present management,
will be elected to the Board. After consummation of the Offerings, Mr. Zimmerman
may attend meetings of the Board of Directors as an observer, at the  invitation
of  the Board of Directors. In addition, upon consummation of the Offerings, the
Company's Board of Directors will be divided into
 
                                       65
<PAGE>
three classes, with each class of directors to serve three-year staggered  terms
(after their initial terms). Messrs. Comrie and McArtor will be elected as Class
I  directors for  an initial  one-year term expiring  in 1997.  Messrs. Cook and
Fotheringham will be elected as Class II directors for an initial two-year  term
expiring  in 1998. Messrs. Mark C. Demetree  and Fillat will be elected as Class
III directors for an initial three-year term expiring in 1999.
 
    Promptly after closing of the CommcoCCC Acquisition, the Company has  agreed
to  nominate  one  individual  designated  by  the  CommcoCCC  stockholders  and
acceptable to the Company as a director of the Company.
 
DIRECTOR COMPENSATION
 
    Upon consummation of the Offerings, directors  who are not employees of  the
Company  will receive $4,000  per year for  services rendered as  a director and
$500 for  attending  each meeting  of  the Board  of  Directors or  one  of  its
Committees.  In  addition,  directors  may be  reimbursed  for  certain expenses
incurred in connection with attendance at any meeting of the Board of  Directors
or Committees. Other than reimbursement of expenses, directors who are employees
of the Company receive no additional compensation for service as a director.
 
    In  April 1996,  the Company adopted  the Directors Plan  (as defined) which
provides for automatic  grants of options  to purchase an  aggregate of  200,000
shares  of Common Stock to non-employee directors  of the Company. See "-- Stock
Option Plans."  Upon  consummation of  the  Offerings, options  to  purchase  an
aggregate  of 28,000 shares at  an exercise price equal  to the initial offering
price of  the  Common  Stock  are anticipated  to  be  granted  to  non-employee
directors under the Directors Plan.
 
BOARD COMMITTEES
 
    The  Company's bylaws, as amended (the  "Bylaws"), provide that the Board of
Directors may establish committees to  exercise certain powers delegated by  the
Board  of  Directors. Pursuant  to that  authority, the  Board of  Directors has
established an Option Committee,  Compensation Committee, Finance Committee  and
Audit Committee.
 
    The   Option  Committee  reviews,  interprets  and  administers  the  Equity
Incentive Plan (as defined), prescribes  rules and regulations relating  thereto
and  determines the stock options to be granted by the Company to its employees.
Messrs. Mark  C. Demetree,  Fotheringham and  Zimmerman currently  serve on  the
Option  Committee. Upon  consummation of  the Offerings,  Messrs. Cook,  Mark C.
Demetree and Fillat will serve on the Option Committee.
 
    The  Compensation   Committee   has   responsibility   for   reviewing   and
administering  the Company's  program with  respect to  the compensation  of its
officers,  employees  and  consultants  and  reviewing  transactions  with   its
officers, directors and affiliates. As a policy, the Compensation Committee pays
officers,  directors and affiliates of the Company for services rendered outside
the scope of  their respective obligations  to the Company,  in accordance  with
industry  standards  for  such  services, which  may  include  introducing major
transactions or  providing  legal  services  to the  Company.  Messrs.  Mark  C.
Demetree,  Fillat,  Fotheringham and  Gove currently  serve on  the Compensation
Committee. Upon consummation of the Offerings, Messrs. Mark C. Demetree, Fillat,
Fotheringham and McArtor will serve on the Compensation Committee.
 
    The Finance  Committee  has  responsibility for  reviewing  and  negotiating
financing  proposals for the Company and  submitting such proposals to the Board
of Directors for approval. Messrs. J.C. Demetree, Jr., Fillat, Fotheringham  and
Zimmerman  currently serve  on the Finance  Committee. Upon  consummation of the
Offerings, the Finance Committee will be disbanded.
 
    The Audit Committee recommends the engagement of independent accountants  to
audit  the Company's  financial statements and  perform services  related to the
audit, reviews the scope and results of the audit with the accountants,  reviews
with management and the independent accountants the
 
                                       66
<PAGE>
Company's  year-end operating  results, and  considers the  adequacy of internal
accounting procedures. Messrs.  J.C. Demetree,  Jr., Fillat  and Gove  currently
serve  on the Audit Committee. Upon consummation of the Offerings, Messrs. Cook,
Fillat and McArtor will serve on the Audit Committee.
 
RELATED PARTY TRANSACTIONS
 
    On February 2,  1996, the Company  adopted a policy  that all  transactions,
including  compensation,  between the  Company and  its officers,  directors and
affiliates will be  on terms  no less  favorable to  the Company  than could  be
obtained from unrelated third parties and shall be approved by a majority of the
disinterested  members of  the Compensation  Committee or  by a  majority of the
disinterested members of the Board of Directors.
 
EXECUTIVE COMPENSATION
 
    The following  table  sets  forth  all  compensation  received  by  (i)  the
Company's  Chief Executive Officer and (ii)  each person serving as an executive
officer of the Company whose  salary and bonus exceeded $100,000  (collectively,
the  "Named Executive  Officers"), for services  rendered to the  Company in all
capacities during the fiscal year ended December 31, 1995.
 
                           SUMMARY COMPENSATION TABLE
 
<TABLE>
<CAPTION>
                                                                                    LONG TERM
                                                                                   COMPENSATION
                                                                                      AWARDS
                                                                                  --------------
                                                         ANNUAL COMPENSATION        SECURITIES
                                                     ---------------------------    UNDERLYING      ALL OTHER
NAME AND PRINCIPAL POSITION                              SALARY         BONUS      OPTIONS (#)     COMPENSATION
- ---------------------------------------------------  --------------  -----------  --------------  --------------
<S>                                                  <C>             <C>          <C>             <C>
Vernon L. Fotheringham, Chief Executive Officer      $    97,167             --              --   $      9,600(1)
Steven D. Comrie, President and Chief Operating
 Officer(2)                                               77,000             --         756,691         33,200(1)(3)
W. Theodore Pierson, Jr., Executive Vice President        77,500             --              --        219,600(1)(4)
James D. Miller, Senior Vice President, Sales and
 Marketing (2)                                                --             --          50,000             --
</TABLE>
 
- ------------------------------
(1)  Automobile reimbursement benefits equal  to $9,600 in  the case of  Messrs.
     Fotheringham  and Pierson, $3,200 in  the case of Mr.  Comrie and $1,200 in
     the case of Mr. Menatti.
 
(2)  Reflects compensation for a partial year. See "-- Employment and Consulting
     Agreements."
 
(3)  Represents the  forgiveness of  a loan  on January  1, 1996  that has  been
     accounted  for as compensation expense on  the 1995 statement of operations
     of the Company.
 
(4)  The Company  paid Pierson  & Burnett,  L.L.P., of  which Mr.  Pierson is  a
     partner, $210,000 for services rendered to the Company through December 31,
     1995.
 
                                       67
<PAGE>
     OPTION  GRANTS.    The  following  table  sets  forth  certain  information
regarding stock option  grants made to  the Named Executive  Officers in  fiscal
year 1995.
 
                       OPTION GRANTS IN LAST FISCAL YEAR
 
<TABLE>
<CAPTION>
                                               INDIVIDUAL GRANTS (2)
                                ----------------------------------------------------  POTENTIAL REALIZABLE VALUE
                                 NUMBER OF      PERCENT OF                            AT ASSUMED ANNUAL RATES OF
                                 SECURITIES    TOTAL OPTIONS                           STOCK PRICE APPRECIATION
                                 UNDERLYING     GRANTED TO     EXERCISE                  FOR OPTION TERM (1)
                                  OPTIONS      EMPLOYEES IN    PRICE PER  EXPIRATION  --------------------------
NAME                              GRANTED       FISCAL YEAR      SHARE       DATE         5%            10%
- ------------------------------  ------------  ---------------  ---------  ----------  -----------  -------------
<S>                             <C>           <C>              <C>        <C>         <C>          <C>
Steven D. Comrie                    756,691          71.9%     $  0.5907   6/17/05    $   179,428  $     427,102
James D. Miller                      50,000           4.8%         1.652   12/29/00            --         14,031
</TABLE>
 
- ------------------------------
(1)  The  potential  realizable value  is calculated  based on  the term  of the
     option at its time of grant (five years). It is calculated by assuming that
     the stock price on  the date of grant  appreciates at the indicated  annual
     rate,  compounded annually  for the entire  term of the  option. The actual
     realizable value of the options based on the price to public in the  Common
     Stock  Offering will  substantially exceed  the potential  realizable value
     shown in  the  table. The  option  prices  were determined  by  the  Option
     Committee, who considered the fair market value of the Company's securities
     at  the time of grant  based upon analysis of  recent private placements of
     securities. Subsequently,  the Company  engaged an  independent expert  who
     conducted a more thorough analysis of the value of the Company's securities
     considering  such placements as well  as comparable market transactions and
     other relevant  factors  specific to  the  placements (such  as  underlying
     security  interest and  liquidity). In  all cases,  the exercise  price was
     equal to, or in excess of, the estimated fair value of the Company's Common
     Stock at the date of grant as determined by the independent expert.
 
(2)  See "-- Stock Option Plans -- Equity Incentive Plan -- Grants."
 
     AGGREGATE STOCK OPTION EXERCISES  IN LAST FISCAL  YEAR AND FISCAL  YEAR-END
OPTION  VALUES.   The  following table  sets forth  the number  and value  as of
December 31, 1995 of shares underlying  unexercised options held by each of  the
Named  Executive Officers. As  of December 31,  1995, no stock  options had been
exercised by any Named Executive Officers.
 
                         FISCAL YEAR-END OPTION VALUES
 
<TABLE>
<CAPTION>
                                                              NUMBER OF SHARES
                                                           UNDERLYING UNEXERCISED        VALUE OF UNEXERCISED
                                                                 OPTIONS AT             IN-THE-MONEY OPTIONS AT
                                                               FISCAL YEAR END            FISCAL YEAR END (1)
                                                         ---------------------------  ---------------------------
NAME                                                     EXERCISABLE  UNEXERCISABLE   EXERCISABLE  UNEXERCISABLE
- -------------------------------------------------------  -----------  --------------  -----------  --------------
<S>                                                      <C>          <C>             <C>          <C>
Steven D. Comrie                                            302,676        454,015     $ 184,420    $    276,631
James D. Miller                                              10,000         40,000            --              --
</TABLE>
 
- ------------------------------
(1)  Based on the estimated fair market  value of the Company's Common Stock  as
     of  December 31, 1995 of  $1.20 per share, less  the exercise price payable
     upon exercise  of such  options. Such  estimated fair  market value  as  of
     December  31, 1995 is substantially  lower than the price  to the public in
     the Common Stock Offering.
 
STOCK OPTION PLANS
 
    EQUITY INCENTIVE PLAN.
 
    The Equity Incentive Plan  was adopted by  the Company on  May 30, 1996  and
approved by the stockholders on June 25, 1996.
 
    The  Equity Incentive Plan is designed to advance the Company's interests by
enhancing its ability to attract and  retain employees and others in a  position
to  make  significant  contributions  to  the  success  of  the  Company through
ownership of shares of Common Stock. The Equity Incentive Plan provides for  the
grant   of  incentive  stock  options   ("ISOs"),  non-statutory  stock  options
("NQSOs"), stock appreciation  rights ("SARs"),  restricted stock,  unrestricted
stock,  deferred stock grants, and performance  awards, loans to participants in
connection  with   awards,  supplemental   grants   and  combinations   of   the
 
                                       68
<PAGE>
above.  A total of  2,500,000 shares of  common stock are  reserved for issuance
under the  Equity Incentive  Plan. The  maximum  number of  shares as  to  which
options  or SARs may be  granted to any participant in  any one calendar year is
800,000. The shares of common stock issuable under the Equity Incentive Plan are
subject to adjustment for stock dividends  and similar events. Awards under  the
Equity  Incentive  Plan  may  also include  provision  for  payment  of divident
equivalents with respect to the shares subject to the award.
 
    The Equity Incentive  Plan is administered  by the Option  Committee of  the
Board  of Directors (the "Option Committee"). The Option Committee shall consist
of at  least  two  directors.  If  the Common  Stock  is  registered  under  the
Securities  Exchange Act of 1934,  all members of the  Option Committee shall be
"outside directors" as  defiined. All employees  of the Company  and any of  its
subsidiaries  and other persons or entities (including non-employee directors of
the Company and its subsidiaries) who,  in the opinion of the Option  Committee,
are  in a  position to  make a  significant contribution  to the  success of the
Company or its subsidiaries are eligible to participate in the Equity  Incentive
Plan.
 
    STOCK  OPTIONS.   The  exercise price  of  an ISO  granted under  the Equity
Incentive Plan may not be less than 100% (110% in the case of 10%  shareholders)
of  the fair market value of the Common Stock at the time of grant. The exercise
price of  a nonstatutory  option  granted under  the  Equity Incentive  Plan  is
determined  by the Option Committee.  The term of each option  may be set by the
Option Committee but cannot exceed ten  years from grant (five years from  grant
in the case of an incentive stock option granted to a 10% shareholder), and each
option  will  be exercisable  at  such time  or  times as  the  Option Committee
specifies. The option  price may  be paid  in cash  or check  acceptable to  the
Company  or,  if  permitted  by  the Option  Committee  and  subject  to certain
additional limitations,  by  tendering  shares  of  Common  Stock,  by  using  a
promissory  note, by delivering to the  Company an unconditional and irrevocable
undertaking by a broker promptly to deliver sufficient funds to pay the exercise
price, or a combination of the foregoing.
 
    STOCK APPRECIATION RIGHTS.   SARs may be granted  either alone or in  tandem
with  stock option  grants. Each  SAR entitles  the participant,  in general, to
receive upon exercise  the excess  of a  share's fair  market value  in cash  or
common  stock at the date of exercise over  the share's fair market value on the
date the SAR was granted. The Option Committee may also grant SARs which provide
that following a change in  control of the Company  as determined by the  Option
Committee,  the  holder of  such right  will  be entitled  to receive  an amount
measured by  specified values  or averages  of  values prior  to the  change  in
control.  If  an SAR  is  granted in  tandem  with an  option,  the SAR  will be
exercisable only to  the extent  the option is  exercisable. To  the extent  the
option is exercised, the accompanying SAR will cease to be exercisable, and vice
versa.  An SAR  granted in  tandem with an  ISO may  be exercised  only when the
market price of common stock subject to the option exceeds the exercise price of
such option. SARs not granted in tandem  shall be exercisable at such time,  and
on such conditions, as the Option Committee may specify.
 
    STOCK   AWARDS.    The   Equity  Incentive  Plan   provides  for  awards  of
nontransferable shares of restricted Common Stock subject to forfeiture as  well
as of unrestricted shares of Common Stock. Awards may provide for acquisition of
restricted  and unrestricted Common Stock for  a purchase price specified by the
Option Committee, but in no event  less than par value. Restricted Common  Stock
is  subject to repurchase  by the Company  at the original  purchase price or to
forfeiture if no cash was paid by  the participant if the participant ceases  to
be  an employee  before the  restrictions lapse.  Other awards  under the Equity
Incentive Plan  may also  be settled  with restricted  Common Stock.  Restricted
securities   shall  become  freely  transferable  upon  the  completion  of  the
Restricted Period including  the passage of  any applicable period  of time  and
satisfaction  of any  conditions to vesting.  The Option Committee,  in its sole
discretion, may waive  all or  part of the  restrictions and  conditions at  any
time.
 
    The  Equity Incentive Plan  also provides for  deferred grants entitling the
recipient to receive shares of Common Stock  in the future at such times and  on
such conditions as the Option Committee may
 
                                       69
<PAGE>
specify,  and  performance awards  entitling the  recipient  to receive  cash or
Common Stock following  the attainment  of performance goals  determined by  the
Option  Committee. Performance conditions and  provisions for deferred stock may
also be attached to other awards under the Equity Incentive Plan.
 
    A loan may be made under the Equity Incentive Plan either in connection with
the purchase of Common Stock under an award or with the payment of any  federal,
state  and local tax with respect to income  recognized as a result of an award.
The Option  Committee  will determine  the  terms  of any  loan,  including  the
interest  rate (which may be zero). No loan  may have a term exceeding ten years
in duration. In connection with any award, the Option Committee may also provide
for and grant a cash award to offset federal, state and local income taxes or to
make a participant whole for certain taxes.
 
    Except as otherwise provided by the Option Committee, if a participant dies,
options and SARs  held by such  participant immediately prior  to death, to  the
extent  then  exercisable,  may  be  exercised  by  the  participant's executor,
administrator or transferee during a period of one year following such death (or
for the  remainder  of  their  original term,  if  less).  Except  as  otherwise
determined  by  the Option  Committee,  options and  SARs  not exercisable  at a
participant's death  terminate. Outstanding  awards of  restricted Common  Stock
must  be transferred to  the Company upon a  participant's death and, similarly,
deferred Common  Stock grants,  performance awards  and supplemental  awards  to
which  a  participant  was  not  irrevocably entitled  prior  to  death  will be
forfeited, except as otherwise determined by the Option Committee.
 
    In the case of termination of  a participant's association with the  Company
for reasons other than death, options and SARs remain exercisable, to the extent
they were exercisable immediately prior to termination, for three months (or for
the  remainder of  their original  term, if  less), shares  of restricted Common
Stock must be resold to the Company,  and other awards to which the  participant
was  not irrevocably  entitled prior  to termination  will be  forfeited, unless
otherwise determined  by  the  Option  Committee. If  any  such  association  is
terminated due to the participant's discharge for cause which, in the opinion of
the  Option Committee,  casts such  discredit on  the participant  as to justify
immediate termination  of  any  award  under the  Equity  Incentive  Plan,  such
participant's options and SARs may be terminated immediately.
 
    In  the event of a  consolidation or merger in which  the Company is not the
surviving corporation or which results  in the acquisition of substantially  all
of  the Company's outstanding Common Stock by a  single person or entity or by a
group of persons and/or entities acting in  concert or in the event of the  sale
or  transfer of substantially all of  the Company's assets, the Option Committee
may determine that (i) each outstanding  option and SAR will become  immediately
exercisable   unless  otherwise  provided  at  the  time  of  grant,  (ii)  each
outstanding share of restricted Common Stock will immediately become free of all
restrictions  and  conditions,   (iii)  all  conditions   on  deferred   grants,
performance  awards and supplemental grants which  relate only to the passage of
time and  continued employment  will be  removed and  (iv) all  loans under  the
Equity  Incentive Plan will be forgiven. The  Committee may also arrange to have
the surviving or acquiring corporation or  affiliate assume any award held by  a
participant  or grant a replacement award. If the optionee is terminated after a
change in  control by  the Company  without cause,  or in  the case  of  certain
officers  designated from  time to  time by  the Option  Committee resigns under
certain circumstances, within  two years  following the change  in control,  all
unvested  options will vest and all options  will be exercisable for the shorter
of four years or their original duration and all other awards will vest. If  the
option  committee makes no such determination,  outstanding awards to the extent
not fully vested will be forfeited.
 
    CERTAIN FEDERAL INCOME TAX CONSEQUENCES.  The following discussion, which is
based on the law as in effect on June 1, 1996, summarizes certain federal income
tax consequences of participation in the Equity Incentive Plan. The summary does
not purport to cover  federal employment tax or  other federal tax  consequences
that  may  be associated  with  the plans,  nor does  it  cover state,  local or
non-U.S. taxes.
 
    In general,  an  optionee realizes  no  taxable  income upon  the  grant  or
exercise of an ISO. However, the exercise of an ISO may result in an alternative
minimum tax liability to the optionee. With certain
 
                                       70
<PAGE>
exceptions, a disposition of shares purchased under an ISO within two years from
the  date of grant or within one year after exercise produces ordinary income to
the optionee (and a corresponding deduction  is available to the company)  equal
to  the value of the shares at the time of exercise less the exercise price. Any
additional gain recognized in the disposition  is treated as a capital gain  for
which  the Company  is not  entitled to  a deduction.  If the  optionee does not
dispose of the  shares until  after the expiration  of these  one- and  two-year
holding  periods, any gain or loss recognized  upon a subsequent sale is treated
as a long-term capital gain or loss for  which the Company is not entitled to  a
deduction.
 
    In general, in the case of a nonstatutory option the optionee has no taxable
income  at the time of grant but  realizes income in connection with exercise of
the option in an  amount equal to the  excess (at the time  of exercise) of  the
fair  market value of the shares acquired upon exercise over the exercise price,
a corresponding deduction  is available to  the Company, and  upon a  subsequent
sale  or exchange of the shares, appreciation  or depreciation after the date of
exercise is  treated as  capital  gain or  loss for  which  the Company  is  not
entitled  to a deduction. In  general, an ISO that  is exercised more than three
months after  termination of  employment (other  than termination  by reason  of
death)  is treated as  a nonstatutory option.  ISOs granted after  1986 are also
treated as nonstatutory options to the  extent they first become exercisable  by
an  individual  in any  calendar  year for  shares  having a  fair  market value
(determined as of the date of grant) in excess of $100,000.
 
    Under the so-called  "golden parachute" provisions  of the Internal  Revenue
Code,  the vesting or accelerated exercisability  of awards in connection with a
change in control of  the Company may  be required to be  valued and taken  into
account in determining whether participants have received compensatory payments,
contingent  on the  change in  control, in  excess of  certain limits.  If these
limits  are  exceeded,  a  substantial   portion  of  amounts  payable  to   the
participant,  including income  recognized by  reason of  the grant,  vesting or
exercise of  awards  under the  Equity  Incentive Plan,  may  be subject  to  an
additional 20% federal tax and may be nondeductible to the Company.
 
    GRANTS.  Mr. Comrie has been granted NQSOs expiring on various dates through
June  17, 2005 to purchase 756,691 shares of  Common Stock at a price of $0.5907
per share. Of  the NQSOs, 417,693  are currently exercisable,  and 111,990  will
become  exercisable on July 17, 1997 and up to an additional 227,008 shares (the
"Additional Shares") will become  exercisable on June 17,  2000. The vesting  of
NQSOs  to purchase  56,752 Additional  Shares will  be accelerated  in each year
based upon the  attainment of  certain performance  goals as  determined by  the
Board of Directors. Each of Mr. Comrie's options are exercisable for a period of
five years from the date of vesting.
 
    Mr. Grina has been granted NQSOs expiring on various dates through April 26,
2003  to purchase 300,000 shares of Common Stock  at a price of $6.25 per share.
The NQSOs are subject to vesting over a three-year period, of which 100,000  are
fully  vested and currently  exercisable. NQSOs to  purchase 200,000 shares will
become exercisable on April  26, 1999; however, the  vesting of 100,000 of  such
shares  will be accelerated on  each of the first  and second anniversary of the
date of grant based upon attainment  of certain performance goals as  determined
by  the Board of  Directors. Each of  Mr. Grina's options  are exercisable for a
period of five years from the date of vesting. Mr. Grina's options will be fully
vested, notwithstanding the attainment of performance goals, on April 26,  1999.
In  addition, all of his options  become immediately exercisable, without regard
to the  vesting period,  upon a  Change of  Control (as  defined in  the  Equity
Incentive  Plan) and  upon other  corporate changes  described in  the agreement
evidencing his options.
 
    Mr. Miller has  been granted NQSOs  expiring December 29,  2000 to  purchase
50,000  shares of Common Stock at a price of $1.652 per share. The NQSOs vest at
a rate of 20% on each anniversary of the date of grant.
 
    THE DIRECTORS PLAN.
 
    On May  30,  1996,  the  Company adopted  the  1996  Non-Employee  Directors
Automatic  Stock  Option Plan  (the "Directors  Plan"),  which provides  for the
automatic grant of stock options to non-employee directors to purchase up to  an
aggregate    of   200,000   shares.   Under    the   Directors   Plan,   options
 
                                       71
<PAGE>
to acquire  6,000 shares  of  Common Stock  are  automatically granted  to  each
non-employee  director who is a director on January 1 of each year. In addition,
each non-employee director serving  on the Board of  Directors effective on  the
date  of the Common  Stock Offering will  receive, and in  the future each newly
elected non-employee director  on the date  of his or  her first appointment  or
election  to the Board of Directors will  receive, an automatic grant of options
to acquire 7,000 shares of Common Stock.
 
    Although grants of the options under  the Directors Plan are automatic,  and
the  Directors Plan is intended to  be largely self-administering, the Directors
Plan will  be administered  by either  the  Board of  Directors or  a  committee
designated  by  the Board  of Directors,  which will,  to the  extent necessary,
administer and interpret  the Directors Plan  (the "Plan Administrator").  Stock
options awarded under the Directors Plan are priced automatically at an exercise
price  equal to the market price of the Common Stock on the date of grant. If at
any time no public market for the Common Stock exists, the Plan Administrator is
empowered to determine the fair market value. Under the Directors Plan,  initial
option  grants vest over a three-year period and are exercisable for a period of
10 years from  the date of  grant. On the  date of this  Prospectus, options  to
purchase an aggregate of 28,000 shares at an exercise price equal to the initial
offering  price of  the Common Stock  will be granted  to non-employee directors
under the Directors Plan.
 
EMPLOYMENT AND CONSULTING AGREEMENTS
 
    The Company  has entered  into a  three-year employment  agreement with  Mr.
Fotheringham  providing for full-time employment at an annualized base salary of
$250,000 for 1996,  $275,000 for 1997  and $300,000 for  1998. In addition,  Mr.
Fotheringham  is entitled to receive an annual bonus of up to $100,000 depending
on the achievement  of specified annual  link installation goals.  The goal  for
each  year will  be established  based on the  operating budget  approved by the
Board of Directors. The agreement precludes Mr. Fotheringham from competing with
the Company for one  year after the cessation  of his employment, regardless  of
the reason for such cessation.
 
    The  Company has  entered into  a three-year  employment agreement  with Mr.
Comrie providing  for full  time  employment at  an  annualized base  salary  of
$160,000  through December 31, 1995,  $200,000 from January 1,  1996 to July 16,
1997 and $240,000 from July 17, 1997 to July 16, 1998. Mr. Comrie is entitled to
receive an  annual bonus  of up  to  $100,000 depending  on the  achievement  of
specified  annual  link  installation goals.  The  goal  for each  year  will be
established based on the operating budget approved by the Board of Directors. As
part  of  the  employment  agreement,   the  Company  provided  Mr.  Comrie   an
interest-free  loan in the amount of $30,000 and forgave payment of such loan on
January 1,  1996.  The  forgiveness of  such  loan  has been  accounted  for  as
compensation  expense on  the 1995 statement  of operations of  the Company. The
agreement also precludes Mr. Comrie from competing with the Company for one year
after the cessation of employment, regardless of the reason for such  cessation.
The  agreement may be terminated at any  time by either party and provides that,
if the Company terminates Mr. Comrie without cause or Mr. Comrie's employment is
terminated due  to his  disability or  death,  Mr. Comrie  will be  entitled  to
continue to receive the full amount of his base salary and any other benefits to
which  he would have otherwise  been entitled for a period  of one year from the
date of such termination.  See "-- Stock Option  Plans" regarding stock  options
granted to Mr. Comrie pursuant to his employment agreement.
 
    The  Company  has  entered  into an  employment  agreement  with  Mr. Grina,
providing for full time  employment on an  at will basis  at an annualized  base
salary of $190,000 through April 30, 1997. In addition, Mr. Grina is entitled to
receive  an annual  bonus of  up to $100,000  depending upon  the achievement of
specified annual  link  installation goals.  The  goal  for each  year  will  be
established  based on the  operating budget approved by  the Board of Directors.
The agreement precludes Mr. Grina from  competing with the Company for one  year
after  the  cessation  of his  employment,  regardless  of the  reason  for such
cessation. The  agreement may  be terminated  at any  time by  either party  and
provides  that, if the Company terminates Mr. Grina without cause or Mr. Grina's
employment is  terminated due  to his  disability or  death, Mr.  Grina will  be
entitled    to   continue   to   receive   the   full   amount   of   his   base
 
                                       72
<PAGE>
salary and any other benefits to which he would have otherwise been entitled for
a period of six months from the  date of such termination. See "-- Stock  Option
Plans"  regarding stock options granted to  Mr. Grina pursuant to his employment
agreement.
 
    The Company has also entered into  an employment agreement with Mr.  Miller,
providing  for full time employment at an  annual base salary equal to $150,000.
His employment agreement provides  for the payment by  the Company of an  annual
bonus  in designated amounts based upon the achievement of specified performance
goals. The agreement has a term of three years and precludes him from  competing
with  the Company for one year after  the cessation of employment, regardless of
the reason  for such  cessation. See  "-- Stock  Option Plans"  regarding  stock
options  granted  to  Mr.  Miller  pursuant  to  his  employment  agreement. The
employment agreement may be terminated at any time by the Company or Mr.  Miller
and  provides that,  if the Company  terminates Mr.  Miller's employment without
cause or his employment is terminated due to his disability or death, Mr. Miller
may continue  to receive  the  full amount  of his  base  salary and  any  other
benefits  to which  he would have  otherwise been  entitled for a  period of six
months from the date of such termination.
 
    The Company  has entered  into a  three-year consulting  agreement with  Mr.
Pierson  on May 8,  1995, under which  Mr. Pierson agreed  to provide strategic,
business and other advisory services to the Company for base fees of $80,000 for
1995, $140,000 for 1996 and $80,000 for 1997, subject to extension at the option
of the Company. The agreement also precludes Mr. Pierson from competing with the
Company for  one year  after termination  of the  agreement, regardless  of  the
reason  for such  termination. The  agreement may be  terminated at  any time by
either party and provides  that, if the Company  terminates Mr. Pierson  without
cause  or Mr. Pierson terminates his  consulting agreement for "good reason" (as
specified in the agreement), Mr. Pierson will be entitled to continue to receive
the full amount of his base fees and  any other benefits to which he would  have
otherwise  been  entitled  for  a period  of  one  year from  the  date  of such
termination. See "Certain Transactions -- Pierson & Burnett Transactions."
 
                                       73
<PAGE>
                             PRINCIPAL STOCKHOLDERS
 
    The following table  sets forth certain  information, as of  June 19,  1996,
regarding  the beneficial  ownership of  the Company's  Common Stock  by (i) the
directors and executive officers of the  Company, (ii) each person known by  the
Company  to own beneficially more than five percent of the outstanding shares of
the Company's Common Stock and (iii)  all executive officers and directors as  a
group  assuming,  in each  case,  that the  Merger  has been  completed  and the
Landover Partnerships have been dissolved.
 
<TABLE>
<CAPTION>
                                                             BENEFICIAL OWNERSHIP         BENEFICIAL OWNERSHIP AFTER
                                                              PRIOR TO OFFERINGS                  OFFERINGS
                                                           -------------------------  ----------------------------------
NAME                                                          NUMBER       PERCENT           NUMBER           PERCENT
- ---------------------------------------------------------  -------------  ----------  --------------------  ------------
<S>                                                        <C>            <C>         <C>                   <C>
Vernon L. Fotheringham (1)...............................      3,545,063       11.8%      3,545,063                9.4%
W. Theodore Pierson, Jr. (2).............................      2,455,407        8.2       2,455,407                6.5
High Sky Inc. (3)........................................      1,748,604        5.8       1,748,604                4.7
Landover Holdings Corporation (4)........................      8,068,582       26.8       8,068,582               21.4
Advent International Corporation (5).....................      3,186,238       10.5       3,186,238                8.4
Ameritech Development Corp. (6)..........................      1,677,745        5.5       1,677,745                4.3
Steven D. Comrie (7).....................................        302,676        1.0         302,676                  *
James C. Cook (8)........................................        133,830          *         140,830(14)              *
J.C. Demetree, Jr. (9)...................................      1,055,288        3.5       1,055,288                2.8
Mark C. Demetree (10)....................................      1,055,288        3.5       1,062,288(14)            2.8
Andrew I. Fillat (5).....................................      3,186,238       10.5       3,193,238(14)            8.4
Matthew C. Gove (11).....................................        441,753        1.5         441,753                1.2
T. Allan McArtor.........................................              0          *           7,000(14)              *
Laurence S. Zimmerman (4)................................      8,068,582       26.8       8,068,582               21.4
Thomas A. Grina (12).....................................        100,000          *         100,000                  *
James D. Miller (13).....................................         10,000          *          10,000                  *
All executive officers and directors as a group               20,276,045       65.6%     10,816,502(8)(15)        28.2%
 (1)(2)(4)(5)(7)(8)(9)(10)(11)(12)(13)(14)...............
</TABLE>
 
- ------------------------
Unless otherwise indicated, the business address of each director and  executive
officer  named above is c/o Advanced Radio Telecom Corp., 500 108th Avenue N.E.,
Suite 2600, Bellevue, Washington 98004.
 
 *  Less than 1.0%.
 
 (1) Includes 104,273 shares of Common Stock subject to an option owned by SERP.
    See "Certain Transactions -- SERP Agreement."
 
 (2) Includes 2,455,407 shares of Common  Stock issuable upon completion of  the
    Merger.  Also includes 44,694 shares subject to an option owned by SERP. See
    "Certain Transactions  --  SERP Agreement."  Mr.  Pierson's address  is  c/o
    Pierson & Burnett L.L.P., 1667 K. Street, N.W., Washington, D.C. 20006.
 
 (3) High Sky Inc. is the general partner of High Sky and High Sky II and may be
    deemed  the  beneficial  owner  of all  shares  held  by  such partnerships.
    Includes  1,398,883  and  349,721  shares  of  Common  Stock  issuable  upon
    completion  of the Merger  to High Sky  and High Sky  II, respectively. Also
    includes 119,171  and  29,796 shares  held  by High  Sky  and High  Sky  II,
    respectively,  subject to an option owned by SERP. See "Certain Transactions
    -- SERP  Agreement."  High Sky  Inc.'s  address  is c/o  Frank  S.  Phillips
    Company, 6106 MacArthur Blvd., Bethesda, Maryland 20816.
 
 (4)  Includes 37,500 shares issuable upon  exercise of Indemnity Warrants. Does
    not include 100,000 shares and 100,000 shares respectively owned by the wife
    and a family trust of Laurence  S. Zimmerman, respectively, of which  shares
    LHC  and  Mr.  Zimmerman  disclaim beneficial  ownership.  Does  not include
    294,489  shares,  1,375,699  shares,  5,276,440  shares  and  95,719  shares
    issuable upon the Merger held by E1, E2, E2-2 and E2-3, respectively, each a
    limited  partnership whose  general partner is  controlled by  LHC. Upon the
    effectiveness of the Merger, these partnerships will dissolve. Including the
    shares owned by such partnerships,  LHC beneficially owns 15,310,929  shares
    of  Common Stock constituting 50.9%  of the Company's outstanding securities
    prior to the Offerings.  LHC is controlled by  Laurence S. Zimmerman.  LHC's
    address  is 667  Madison Avenue,  New York, New  York 10021.  See "-- Voting
    Trust Agreement."
 
 (5) Includes 2,882,659 shares,  3,029 shares and  141,050 shares issuable  upon
    the  Merger and  151,908 shares, 160  shares and 7,432  shares issuable upon
    exercise of Bridge Warrants, respectively owned by Global Private Equity II,
    L.P., Advent International II, L.P. and Advent Partners, L.P. (collectively,
    the "Advent Partnerships"), each a limited partnership whose general partner
    is controlled  by Advent  International Corp.  ("Advent"). Mr.  Fillat is  a
    director,  officer and stockholder of Advent. The address of Advent and each
    of the  Advent Partnerships  is 101  Federal Street,  Boston,  Massachusetts
    02110.
 
                                       74
<PAGE>
 (6)  Includes 635,609  shares issuable upon  the Merger and  877,136 shares and
    165,000 shares issuable upon  exercise of the  Ameritech Warrant and  Bridge
    Warrants,  respectively. The address of Ameritech  is 30 South Wacker Drive,
    Chicago, Illinois 60601. See  "Certain Transactions -- Ameritech  Financing;
    Ameritech Strategic Distribution Agreement."
 
 (7)  Includes 302,676 shares currently issuable  upon exercise of options. Does
    not include  454,015 issuable  upon exercise  of the  non-vested portion  of
    options. See "Management -- Stock Option Plans."
 
 (8)  Includes  140,830 shares  beneficially owned  by  James C.  Cook including
    22,000 shares issuable upon  exercise of Bridge  Warrants and 73,542  shares
    and  38,288 shares issuable upon the Merger  as a limited partner in E-2 and
    E2-3, respectively. Mr. Cook will become a director of the Company upon  the
    date of this Prospectus.
 
 (9)  Does not include 154,000 shares issuable upon exercise of Bridge Warrants,
    162,500 shares issuable  upon exercise  of Indemnity  Warrants or  4,221,152
    shares  issuable  upon  the Merger  held  in  each case  by  members  of Mr.
    Demetree's family (or  a trust  for their  benefit), of  which he  disclaims
    beneficial ownership. J.C. Demetree, Jr.'s address is c/o Demetree Brothers,
    3740 Beach Boulevard, Suite 300, Jacksonville, Florida 32207.
 
(10)  Does not include 154,000 shares issuable upon exercise of Bridge Warrants,
    48,750 shares issuable upon exercise  of Indemnity Warrants, 113,750  shares
    issuable  upon exercise of  Indemnity Warrants or  4,221,152 shares issuable
    upon the Merger held in each case by members of Mr. Demetree's family (or  a
    trust  for their benefit), of which  he disclaims beneficial ownership. Mark
    C. Demetree's address is 505 Lancaster Street, #8AB, Jacksonville, FL 32204.
 
(11) Includes  441,753  shares  issuable  upon  the  Merger  owned  by  Hedgerow
    Corporation of Maine ("Hedgerow"), which is controlled by Mr. Gove. Does not
    include  shares  owned  beneficially by  LHC,  of which  Mr.  Gove disclaims
    beneficial ownership. Hedgerow  from time to  time acts as  a consultant  to
    LHC. Mr. Gove's address is 215 West 84th Street, New York, New York 10024.
 
(12) Includes 100,000 shares currently issuable upon exercise of an option.
 
(13) Includes 10,000 shares currently issuable upon exercise of an option.
 
(14)  Includes 7,000 shares issuable upon  exercise of options anticipated to be
    granted under the Directors Plan upon the consummation of the Offerings.
 
(15) Reflects the resignations of Messrs. J.C. Demetree, Jr., Gove and Zimmerman
    and the elections as directors of Messrs. Cook and McArtor upon the date  of
    this Prospectus. Does not include 8,268,582 shares beneficially owned by LHC
    and  held in trust  by trustees, all  of whom are  directors of the Company,
    pursuant to  a  Voting Trust  Agreement,  of which  such  trustees  disclaim
    beneficial ownership. See "-- Voting Trust Agreement." Includes 7,000 shares
    beneficially  owned by  each of Messrs.  Mark C. Demetree,  Fillat, Cook and
    McArtor issuable upon exercise of options to be granted under the  Directors
    Plan upon the consummation of the Offerings.
 
    Upon  completion of the CommcoCCC Acquisition, Columbia Capital Corporation,
as general partner of two of the stockholders of CommcoCCC, and Commco,  L.L.C.,
the  remaining  stockholder of  CommcoCCC, will  beneficially own  8,842,154 and
7,707,846 shares, respectively,  of Common  Stock, including  26,715 and  23,285
shares,   respectively,  issuable  upon  exercise  of  the  CommcoCCC  Warrants,
constituting 16.3% and 14.2%, respectively, of the Company's Common Stock  after
the  Offerings (assuming  the underwriters'  overallotment option  in the Common
Stock Offering is not exercised). Assuming the consummation of the Offerings and
the CommcoCCC Acquisition as of the  date of this Prospectus, the Company  would
have 54,086,498 shares of Common Stock outstanding.
 
VOTING TRUST AGREEMENT
 
    Pursuant  to  a  proposed  Voting  Trust  and  Irrevocable  Proxy Agreement,
effective on the date of this Prospectus, LHC  and the wife and a trust for  the
benefit  of the family of Laurence S. Zimmerman will deposit all of their shares
of ART Common Stock in trust with Messrs. Mark C. Demetree, Andrew I. Fillat and
Vernon L. Fotheringham with irrevocable instructions to vote such shares on  all
matters  submitted to a vote of the stockholders of the Company in proportion to
the vote of other stockholders of the  Company. The voting trust will expire  on
the  tenth anniversary of the  date of this Prospectus,  but is subject to early
termination in the event of (i) the  death of Laurence S. Zimmerman or (ii)  the
sale  by LHC of such  shares to unaffiliated parties.  The trustees of the trust
will be indemnified by the Company.
 
                                       75
<PAGE>
                              CERTAIN TRANSACTIONS
 
FORMATION OF ART
 
    The Company was organized  in August 1993 by  Vernon L. Fotheringham and  W.
Theodore  Pierson, Jr., for  the purpose of  obtaining 38 GHz  licenses from the
FCC. The  initial  stockholders,  including Messrs.  Fotheringham  and  Pierson,
purchased  for $.01 per share ART Common Stock in a private placement which, net
of certain subsequent transfers, currently constitute an aggregate of  6,000,470
shares of Common Stock.
 
HIGH SKY PRIVATE PLACEMENTS
 
    In  November 1993 and March 1994, ART raised $60,000 and $30,000 through the
sale of its  common stock (which,  net of sales  and acquisitions of  additional
shares,  now constitute an  aggregate of 1,398,883 shares  and 349,721 shares of
Common Stock, respectively)  to High  Sky Limited  Partnership and  High Sky  II
Limited   Partnership  ("High   Sky  II"   and,  collectively,   the  "High  Sky
Partnerships"). In March 1994, ART borrowed  $70,000 from High Sky II. The  loan
was  evidenced by a promissory  note executed by ART and  payable to High Sky II
(the "High Sky Note"). Pursuant to an Agreement dated March 1, 1995, High Sky II
sold the High Sky Note to Vernon L. Fotheringham and W. Theodore Pierson, Jr. in
exchange for  two new  promissory notes,  bearing interest  at 7.5%  per  annum,
executed by Messrs. Fotheringham and Pierson in the principal amounts of $52,675
and  $22,575,  respectively  (the  "Fotheringham/Pierson  Notes"),  with payment
secured by pledges of  shares of Common  Stock owned by them.  The terms of  the
notes  were as  favorable as could  be negotiated with  unrelated third parties.
After the assignment and exchange, Messrs. Fotheringham and Pierson  transferred
the   High   Sky  Note   to  the   Company  as   a  capital   contribution.  The
Fotheringham/Pierson Notes,  which are  due in  August 1997  and which  are  now
unsecured, are currently held by LHC (as defined below).
 
ART WEST JOINT VENTURE
 
    The Company is party to the ART West Management Agreement, pursuant to which
it  manages the business and assets of ART West, a joint venture between ART and
Extended. Mark  T.  Marinkovich, Vice  President  and General  Manager,  Western
Region  of the Company is also the  President and a stockholder of Extended. See
"Business --  Agreements Relating  to Licenses  and Authorizations  -- ART  West
Joint  Venture" and  "Principal Stockholders." In  connection with  the ART West
Joint Venture, ART issued to Extended  368,127 shares of Common Stock. Of  these
368,127  shares,  15,678 shares  are  subject to  an  option owned  by Southeast
Research Partners. See "-- SERP Agreement." In June 1996, the Company agreed  to
acquire  Extended's interest in ART West for  $6,000,000 in cash, subject to FCC
approval.
 
ORGANIZATION OF TELECOM
 
    ART and  Landover  Holdings  Corporation ("LHC")  organized  Advanced  Radio
Telecom  Corp. ("Telecom") on March 28, 1995,  and purchased for $.001 per share
340,000 shares of  Class A common  stock and  640,000 shares of  Class B  common
stock  of  Telecom, respectively,  which, after  giving effect  to anti-dilution
adjustments resulting from issuances of preferred stock as described in "--  LHC
Purchase  Agreement," certain  transfers and  the transactions  described in "--
February 1996  Reorganization"  and "--  Merger,"  currently are  equivalent  to
10,013,055 shares and 7,512,076, shares respectively, after giving effect to the
November  1995  redemption  of shares  of  Common Stock.  In  addition, Hedgerow
Corporation of Maine  ("Hedgerow") and Toro  Financial Corp. ("Toro")  purchased
for  $.001 per  share 15,000 shares  and 5,000 shares,  respectively, of Telecom
Class A common stock which, after such anti-dilution adjustments and the Merger,
currently are equivalent to 441,753 shares  and 147,251 shares of Common  Stock,
respectively. LHC is controlled by Laurence S. Zimmerman. Hedgerow is controlled
by  Matthew  C. Gove,  a  director of  the  Company. Hedgerow  and  Toro provide
managment and strategic consulting services to LHC, including services  relating
to analysis and negotiation of acquisitions.
 
                                       76
<PAGE>
LHC PURCHASE AGREEMENT
 
    GENERAL.   Pursuant to a Purchase Agreement,  dated April 21, 1995 (the "LHC
Purchase Agreement") among ART,  LHC and Telecom, LHC,  on behalf of itself  and
its  designees, agreed  to purchase additional  securities of  Telecom (the "LHC
Stock") for an aggregate  purchase price of  $7,000,000 (the "Purchase  Price"),
which  additional securities would dilute only LHC's interest in the Company. In
addition, ART and Telecom entered into the ART Services Agreement. Moreover, ART
and its stockholders agreed  with Telecom and its  stockholders to enter into  a
revised  stockholders  agreement  (the  "May  1995  Stockholders  Agreement"), a
registration rights agreement and a  merger agreement. Messrs. Fotheringham  and
Pierson  deposited 2,017,704 and 1,816,559  shares of Common Stock, respectively
(the "Escrow Shares"), under such agreement  to be released upon achievement  by
the  Company of certain performance goals (the "Escrow Arrangement"). The Escrow
Shares were released to Messrs. Fotheringham and Pierson in part on November 13,
1995 as a result of the EMI  Asset Acquisition, and the balance was released  on
February  2,  1996  in  connection with  the  February  1996  Reorganization (as
defined).
 
    Upon the first  closing under the  LHC Purchase Agreement,  on May 8,  1995,
Telecom  received $700,000  from E2-2 Holdings,  L.P. ("E2-2")  and E2 Holdings,
L.P. ("E2"). In addition,  E2-2 committed to  subscribe for up  to 50.0% of  the
Purchase  Price, matching other investors under  the LHC Purchase Agreement with
protection from dilution to  the extent such matching  funds were not  required.
The general partner of E2-2 and E2 is controlled by LHC. E2-2's limited partners
include  J.C. Demetree, Jr. and Mark C.  Demetree, directors of the Company, and
their affiliates. In addition,  E2-2 granted to LHC  an option to purchase  from
E2-2  35,873  shares of  Series A  preferred stock  (which convert  into 466,349
shares of  Common Stock  prior  the Offerings).  This  option was  exercised  in
November 1995. See "Principal Stockholders."
 
    The  additional payments  on the  Purchase Price  were made  by the Landover
Partnerships (as defined  below) as  follows: $700,000  on August  22, 1995  and
$600,000  on October 19, 1995. On November 13, 1995, the Advent Partnerships (as
described below) paid  the $5.0 million  balance of the  Purchase Price and  the
Company  paid LHC an aggregate  of $391,750 for expenses.  Also, on November 13,
1995,  Telecom,  ART  and  LHC  agreed  that  the  LHC  Purchase  Agreement  was
substantially completed.
 
    ART  SERVICES AGREEMENT.   Pursuant to  the LHC Purchase  Agreement, ART and
Telecom entered into a Services Agreement, dated May 8, 1995 (the "ART  Services
Agreement")  pursuant to which, for a  20-year term, Telecom provides management
services for,  and  receives  75.0%  of the  cash  flow  from  operations  after
deducting certain related direct expenses under wireless licenses held by ART.
 
    LANDOVER  PARTNERSHIPS.  Between May 8, 1995  and November 13, 1995, the LHC
Stock was diluted by purchases of series of Telecom preferred stock by E2-2, E2,
E1 Holdings L.P. ("E1")  and E2-3 Holdings, L.P.  ("E2-3" and collectively  with
E1,  E2 and E2-2, the "Landover Partnerships"), each a limited partnership whose
general partner  is controlled  by LHC,  in separate  private placements.  E2-2,
which  committed  to purchase  up  to $3.5  million  of Telecom  preferred stock
matching other investors  under the  LHC Purchase  Agreement, purchased  405,880
shares  of Telecom Series  A preferred stock (which  will convert into 5,276,440
shares of Common Stock prior to the Offerings) for an aggregate of $946,600, and
LHC purchased 35,873 shares of such Series A preferred stock from E2-2 for  $1.1
million  pursuant to an option.  E2 purchased an aggregate  of 105,823 shares of
Telecom Series B preferred stock (which converts into 1,375,699 shares of Common
Stock prior to the Offerings) for an aggregate of $842,400. E1 purchased  13,797
shares  of Telecom Series A preferred  stock (which converts into 179,361 shares
of Common Stock prior to  the Offerings) for an  aggregate of $60,000 and  8,856
shares  of Telecom Series B preferred  stock (which converts into 115,128 shares
of Common  Stock prior  to the  Offerings)  for an  aggregate of  $38,300.  E2-3
purchased  an  aggregate of  7,363 shares  of Telecom  Series C  preferred stock
(which converts into 95,719 shares of  Common Stock prior to the Offerings)  for
an  aggregate of $112,700. All of  the Landover Partnerships will liquidate upon
effectiveness of the Merger. See "Principal Stockholders."
 
    ADVENT PRIVATE PLACEMENT.  On November 13, 1995, ART sold, for an  aggregate
of  $5.0 million, $4.95 million  principal amount of 10%  notes due May 13, 1997
(the "Advent Notes") and $50,000 stated  amount of ART Series A Preferred  Stock
(collectively,  with the  Advent Notes,  the "Advent/ART  Securities") to Global
Private Equity  II, L.P.,  Advent International  Investors II,  L.P. and  Advent
Limited  Partnership (collectively  the "Advent  Partnerships"), each  a limited
partnership whose general partner
 
                                       77
<PAGE>
is controlled by Advent International Corp. ("Advent") pursuant to a  Securities
Purchase Agreement, dated November 13, 1995, among the Advent Partnerships, ART,
Telecom,  Vernon  L.  Fotheringham and  W.  Theodore Pierson,  Jr.  (the "Advent
Agreement").  The  Advent  Agreement  provided  among  other  things  that   the
Advent/ART   Securities  were  convertible  into,   and  in  the  February  1996
Reorganization described below, were converted  into, 232,826 shares of  Telecom
Series  E preferred stock  (which convert into 3,026,738  shares of Common Stock
prior to the Offerings).  The Telecom Series E  preferred stock provides,  among
other  things, that the holders thereof have  a right to designate a director of
Telecom (and after the Merger, the Company), which director's term was  extended
to  an initial term  of three years  pursuant to the  Stockholders Agreement, as
described below.
 
LHC AGREEMENTS
 
    Pursuant to  the LHC  Purchase Agreement,  LHC and  Telecom entered  into  a
strategic and financial consulting agreement, dated May 8, 1995, under which LHC
agreed  to  provide  financial and  strategic  planning and  other  advisory and
management services to the Company for a fee of $10,000 per month. The strategic
and financial  consulting agreement  was terminated  on November  13, 1995,  and
Telecom  entered into a management consulting agreement with LHC, dated November
13, 1995, for an initial term of one  year under which the Company will pay  LHC
$420,000  per year and may  pay a fee in the  event LHC provides other services,
such as merger and acquisition advisory  services to the Company. Upon the  date
of  this  Prospectus, this  agreement will  be terminated  and LHC  will receive
amounts otherwise due under this agreement through November 13, 1996.
 
SERP AGREEMENT
 
    Pursuant to  a  letter  agreement,  dated July  12,  1995,  among  Southeast
Research  Partners ("SERP")  ART, Vernon  L. Fotheringham,  W. Theodore Pierson,
Jr., High Sky Limited Partnership, High Sky II Limited Partnership and  Extended
(the  "SERP  Agreement"), SERP  agreed to  procure additional  capitalization or
financial assistance on behalf of ART.  Under the SERP Agreement, SERP  received
options  from the other parties to such  agreement to purchase, for an aggregate
consideration of $210,000, 313,612 shares of Common Stock after giving effect to
the Merger and $245,000 in cash as a fee for introducing LHC to ART.
 
SERIES D PREFERRED STOCK ISSUANCE
 
    On November  9,  1995,  Telecom  sold 61,640  shares  of  Telecom  Series  D
preferred  stock (which convert into 801,320 shares of Common Stock prior to the
Offerings) for  $2.0  million in  a  private placement.  Telecom  simultaneously
redeemed  807,924 shares of Telecom  common stock from LHC  for $2.0 million. In
connection with the February 1996 Reorganization described below, LHC granted to
the holders of  such Series D  preferred stock a  contingent option to  purchase
400,634  shares of Telecom  common stock owned  by LHC at  a nominal price. This
option will expire unexercised upon consummation of the Offerings.
 
FEBRUARY 1996 REORGANIZATION
 
    On February 2, 1996, Telecom,  ART and their respective stockholders  agreed
(the  "February 1996 Reorganization") to an amendment and restatement of the May
1995 Stockholders Agreement (as amended, the "Stockholders Agreement") providing
for  (i)  termination   effective  on  consummation   of  the  Offerings,   (ii)
reorganization  of the capital structure of Telecom, including providing for the
conversion of  Telecom Class  A and  Class B  common stock  into Telecom  common
stock,  the revision of the terms and conversion into Telecom common stock (upon
consummation of  the Offerings)  of the  Telecom  Series A,  B, C,  D, E  and  F
preferred stock and a 13 for 1 stock split, (iii) the exchange of the Advent/ART
Securities for Telecom Series E preferred stock, (iv) revision of provisions for
election   of  directors,  (v)  amendment   and  restatement  of  the  Company's
registration rights agreement, including waiver of registration rights  relating
to  this offering, (vi) release  of the remaining Escrow  Shares to the original
owners thereof, (vii) the  change of name of  Telecom to Advanced Radio  Telecom
Corp.  and  (viii)  approval of  a  revised  merger agreement  (the  "Old Merger
Agreement") providing for the merger of ART into Telecom (the "Old Merger").
 
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<PAGE>
AMERITECH FINANCING; AMERITECH STRATEGIC DISTRIBUTION AGREEMENT
 
    On February 2, 1996, Ameritech Development Corp. ("Ameritech") purchased for
an aggregate of $2.5 million 48,893 shares of Telecom Series F preferred  stock,
par value $0.001 per share, (the "Ameritech Financing") convertible into 635,609
shares of Common Stock prior to the Offerings. In addition, Telecom entered into
a  letter of intent with Ameritech Corp., the parent of Ameritech, to enter into
the Ameritech  Strategic  Distribution  Agreement and  in  connection  therewith
granted  to Ameritech  a ten-year warrant  to purchase 877,136  shares of Common
Stock of the Company exercisable  at a price of  $.01 per share (the  "Ameritech
Warrant").  On  April 29,  1996, Telecom  entered  into the  Ameritech Strategic
Distribution Agreement.  See  "Business  --  Strategic  Alliances  --  Ameritech
Strategic Distribution Agreement."
 
BRIDGE FINANCING
 
    On  March 8, 1996, Telecom entered into a financing (the "Bridge Financing")
pursuant to which it issued $5.0 million of 10% unsecured notes due in 1998 (the
"Bridge Notes")  and  five-year warrants  to  purchase  up to  an  aggregate  of
1,100,000  shares of  Telecom common stock  at a  price of $6.25  per share (the
"Bridge Warrants")  to  private  investors  including  (i)  affiliates  of  J.C.
Demetree,  Jr. and Mark C.  Demetree, directors of the  Company, (ii) the Advent
Partnerships and (iii) Ameritech, who invested $700,000, $725,000 and  $750,000,
respectively,   in  the  Bridge  Notes   and  Bridge  Warrants.  See  "Principal
Stockholders."
 
EQUIPMENT FINANCING
 
    On April 1, 1996 CRA, Inc.  ("CRA") provided the Company with $2,445,000  in
equipment  financing (the "Equipment Financing") for  the purchase from P-Com of
38 GHz radio  equipment secured  by the  equipment, the  Company's $1.0  million
letter  of credit and a $500,000 letter of credit provided by J.C. Demetree, Jr.
and Mark C. Demetree, directors of the Company, and LHC, a principal stockholder
of the  Company  (the "Indemnitors").  To  evidence its  obligations  under  the
Equipment  Financing  the  Company  executed  in  favor  of  CRA  its $2,445,000
Promissory Note  (the "Equipment  Note") which  note is  payable in  24  monthly
installments  of $92,694 with a final payment of $642,305 due April 1, 1998. The
Indemnitors also agreed to provide the Company with funds and support for up  to
$2.0 million of its obligations in the event of default on the Equipment Note or
draw against the Company's letter of credit. Pursuant to an arrangement approved
by  the Company's disinterested directors on February 16, 1996, the Company paid
to the Indemnitors,  or their  designees an aggregate  of $225,000  in cash  and
five-year  warrants to purchase  an aggregate of 325,000  shares of Common Stock
(the "Indemnity Warrants") on terms substantially similar to the Bridge Warrants
as compensation  for such  indemnity.  LHC has  assigned Indemnity  Warrants  to
purchase 125,000 shares of Common Stock to a consultant to LHC.
 
PIERSON & BURNETT TRANSACTIONS
 
    W.  Theodore  Pierson, Jr.,  Executive Vice  President, General  Counsel and
Secretary of the Company is  a principal in the law  firm of Pierson &  Burnett,
L.L.P.,  which regularly provides legal services to the Company. During the year
ended December 31, 1995, the Company paid Pierson & Burnett, L.L.P. $210,000 for
such services. The  Company believes  that the  terms of  its relationship  with
Pierson  & Burnett, L.L.P. are at least as  favorable to the Company as could be
obtained from an unaffiliated party. See "Management -- Executive  Compensation"
and  "Principal  Stockholders" for  a  description of  Mr.  Pierson's consulting
agreement with the Company  and for information  regarding his share  ownership.
The  Company subleases office space for  its regional office in Washington, D.C.
from Pierson  & Burnett,  L.L.P. The  Company  believes that  the terms  of  its
sublease  are at least as favorable to the  Company as could be obtained from an
unaffiliated party. See "Business -- Properties."
 
AMERICAN WIRELESS DEVELOPMENT AGREEMENT
 
    The Company is party to a  letter of intent with American Wireless  pursuant
to which the Company will fund, subject to definitive documentation, $700,000 to
$1.0  million for  research and  development in  exchange for  a first  right to
purchase American  Wireless' production  capacity  of the  new radios  and  will
 
                                       79
<PAGE>
receive  a per unit  fee on radios  sold by American  Wireless to third parties.
Vernon L. Fotheringham, the Chairman  of the Company, is  a director and a  6.0%
stockholder  of American Wireless.  Mr. Fotheringham has  recused himself in all
negotiations regarding agreements between the Company and American Wireless.
 
QUESTTV INVESTMENT
 
    The Company has  a non-binding  arrangement with  Quest Computer  Television
Company,  L.L.C.  ("QuestTV")  pursuant  to which  the  Company  would purchase,
subject to, among other things, definitive documentation and consummation of the
Offerings, equity interests of QuestTV for  $1.5 million. QuestTV is seeking  to
develop   a  nationwide  network   of  franchises  offering   retail  access  to
sophisticated video  and  data transmission  and  storage technology.  T.  Allan
McArtor,  who  will become  a  director of  the Company  upon  the date  of this
Prospectus, is the president and chief executive officer of QuestTV.
 
COMMCOCCC ACQUISITION
 
    On July  3, 1996,  the Company  entered into  the CommcoCCC  Agreement  with
CommcoCCC which provides for the acquisition, subject to FCC approval, of 129 38
GHz  wireless  broadband authorizations  in  exchange for  16,500,000  shares of
Common Stock, or  30.5% of the  Company on  a fully diluted  basis after  giving
effect  to the  Offerings. The  stockholders of  CommcoCCC simultaneously loaned
$3.0 million to the Company, bearing interest  at the prime rate and payable  on
September  30,  1996, and  received  three-year warrants  to  purchase up  to an
aggregate of 50,000 shares of Common Stock  at a price of $15.00 per share.  The
CommcoCCC  Financing is secured by  a security interest in  all of the assets of
the Company, including a pledge of the Company's stock in Telecom. After closing
of the CommcoCCC Acquisition, the Company has agreed to nominate one  individual
designated  by  CommcoCCC's  stockholders and  acceptable  to the  Company  as a
director of the Company.
 
MERGER
 
    On June 26, 1996, Telecom, ART and a wholly owned subsidiary of ART ("Merger
Sub") entered  into  a revised  merger  agreement, superseding  the  Old  Merger
Agreement  (the "Merger Agreement"), which provides for the Merger of Merger Sub
into Telecom. Upon completion  of the Merger, the  stockholders of Telecom  will
receive   20,073,443  shares  of  Common  Stock,   and  Telecom  will  become  a
wholly-owned subsidiary of ART and change its name to "ART Licensing Corp."  The
consummation  of the Merger  is contingent on receipt  of FCC approval therefor,
approval of the holders  of Telecom capital stock  and all ART stockholders  and
receipt of a tax opinion. The FCC has indicated that it will approve the Merger,
and  the  Company expects  to  complete it  shortly prior  to  the date  of this
Prospectus. The Merger  Agreement further  provides that  if the  Merger is  not
effective  for any reason  by May 13,  1997, the shares  of Telecom common stock
owned by ART will be surrendered  to Telecom for nominal consideration, and  the
ART Services Agreement will be amended to provide that (i) the term thereof will
be  extended to 40 years,  (ii) ART will receive, in  the event of any dividends
paid by Telecom  to its stockholders,  an amount equal  to the percentage  share
that  the ART  stockholders would have  owned of the  combined corporation after
giving effect to the Merger of such aggregate dividends, (iii) ART would have  a
right  of co-sale, subject  to FCC approval, in  accordance with such percentage
share of  the  aggregate  consideration  payable to  Telecom  and  ART  in  such
transaction  in the event of any merger or sale of substantial assets by Telecom
and (iv)  in the  event ART  agrees  to merge  into another  entity or  to  sell
substantially  all its assets to another entity, Telecom shall, upon the request
of the Company, use  its best efforts,  subject to FCC  approval, to merge  into
such  entity or sell substantially  all its assets to  such entity for aggregate
consideration equal to the percentage share of the aggregate consideration to be
paid for ART and Telecom in such transaction.
 
                                       80
<PAGE>
                              DESCRIPTION OF UNITS
 
    Each  Unit offered hereby consists of $1,000 principal amount at maturity of
Notes and        Warrants,  each Warrant  initially  representing the  right  to
purchase        shares of Common  Stock. The Notes and  the Warrants will not be
separable until the earliest to occur of (i)               , 1997 and (ii)  such
earlier date as may be determined by the Underwriters (the "Separation Date").
 
                              DESCRIPTION OF NOTES
 
    The  Notes will be  issued under an Indenture  (the "Indenture") between the
Company and The Bank of New York, as trustee (the "Trustee"). A copy of the form
of the Indenture has been filed as  an exhibit to the Registration Statement  of
which  this Prospectus is a part. The following summary of certain provisions of
the Indenture  does  not purport  to  be complete  and  is subject  to,  and  is
qualified  in its entirety by reference to,  the Trust Indenture Act of 1939, as
amended (the  "Trust  Indenture Act"),  and  to all  of  the provisions  of  the
Indenture,  including the definitions  of certain terms  therein and those terms
made a part  of the Indenture  by reference to  the Trust Indenture  Act, as  in
effect  on the date of  the Indenture. The definitions  of certain terms used in
the following summary are set forth below under "-- Certain Definitions."
 
    As of the date of the Indenture,  all of the Company's Subsidiaries will  be
Restricted  Subsidiaries other  than foreign  subsidiaries that  the Company may
establish prior to such date. However, under certain circumstances, the  Company
will  be  able to  designate future  Subsidiaries as  Unrestricted Subsidiaries.
Unrestricted Subsidiaries  will  not  be  subject to  many  of  the  restrictive
covenants set forth in the Indenture.
 
GENERAL
 
    The  Notes  will be  unsecured senior  obligations of  the Company,  will be
limited to $     million aggregate principal amount at maturity and will  mature
on                 , 2006. The Notes  are being issued at  a discount from their
principal amount to  generate aggregate gross  proceeds of approximately  $175.0
million.  The Notes will accrete at a rate  of    %, compounded semiannually, to
an aggregate principal amount of  $      million by                , 2001.  Cash
interest  will not accrue on the Notes prior  to              , 2001. Commencing
            , 2002, cash interest  on the Notes  will be payable,  at a rate  of
   %  per annum, semi-annually in arrears on each              and
(each, an "Interest Payment  Date"), to the  holders of record  of Notes at  the
close  of business on the             and             immediately preceding such
Interest Payment Date.  Cash interest  on the Notes  will accrue  from the  most
recent  Interest Payment Date to  which interest has been  paid or duly provided
for, or, if no interest has been paid or duly provided for,             ,  2001.
Cash  interest will be computed on the basis  of a 360-day year of twelve 30-day
months. If, prior to             , 2001, the Company defaults in any payment  of
principal (including any accreted original issue discount), whether at maturity,
upon  redemption or otherwise, if  the payment of cash  interest on the Notes is
then permitted by law, cash interest will accrue on the amount in default at the
rate of interest borne by the Notes on or after              , 2001 and, if  the
payment  of such cash interest is not  permitted by law, original issue discount
will continue to accrete at the rate then in effect. On or after               ,
2001,  interest on  overdue principal  and, to the  extent permitted  by law, on
overdue installments of interest  will accrue at the  rate of interest borne  by
the Notes.
 
    Principal  of, premium, if any,  and interest on the  Notes will be payable,
and the Notes will be exchangeable and transferable, at the office or agency  of
the  Company  in  The City  of  New  York maintained  for  such  purposes (which
initially will be the office of the Trustee); PROVIDED, HOWEVER, the payment  of
interest  may be  made by  check mailed  to the  address of  the Person entitled
thereto as shown  on the security  register. The  Notes will be  issued only  in
fully  registered form without  coupons and only in  denominations of $1,000 and
any  integral  multiple  thereof.  No  service  charge  will  be  made  for  any
 
                                       81
<PAGE>
registration  of transfer, exchange or redemption  of Notes, but the Company may
require payment in certain circumstances of a sum sufficient to cover any tax or
other governmental charge that may be imposed in connection therewith.
 
REDEMPTION
 
    OPTIONAL REDEMPTION
 
    The Notes will be redeemable  at the option of the  Company, in whole or  in
part, at any time on or after             , 2001, upon not less than 30 nor more
than  60 days'  notice, at  the redemption  prices (expressed  as percentages of
principal amount at maturity) set forth below, plus accrued and unpaid interest,
if any, to  the date  of redemption,  if redeemed  during the  12- month  period
beginning on of the years indicated below:
 
<TABLE>
<CAPTION>
                                                             REDEMPTION
                           YEAR                                PRICE
                --------------------------                  ------------
<S>                                                         <C>
2001......................................................            %
2002......................................................            %
2003......................................................            %
2004 and thereafter.......................................     100.000%
</TABLE>
 
    Notwithstanding  the foregoing, in the event of a sale by the Company of its
Common Stock in  one or  more Equity  Offerings or  Investments by  one or  more
Strategic Equity Investors for an aggregate purchase price equal to or exceeding
$70.0  million, on or  prior to                 , 1999, the  Company may, at its
option, use all  or a  portion of the  net proceeds  thereof to redeem  up to  a
maximum  of 33 1/3%  of the initially outstanding  aggregate principal amount at
maturity of the Notes at a redemption price equal to    % of the Accreted  Value
of the Notes (determined as of the redemption date); PROVIDED that not less than
66  2/3% of the initially outstanding  aggregate principal amount at maturity of
the Notes remain outstanding following such redemption. Any such redemption must
be effected upon not less than 30 nor more than 60 days' notice given within  30
days  after any  such Equity  Offering or  sale to  a Strategic  Equity Investor
resulting in such gross proceeds, as the case may be.
 
    MANDATORY REDEMPTION
 
    The Company is not required to  make any mandatory sinking fund payments  in
respect  of the Notes. However, (i) upon  the occurrence of a Change in Control,
the Company is obligated to make an offer to purchase all outstanding Notes at a
price of (A)  101% of  the Accreted  Value thereof  (determined at  the date  of
purchase),  if such purchase is prior to              , 2001, or (B) 101% of the
principal amount at maturity thereof, plus accrued interest thereon, if any,  to
the  date of purchase, if such purchase  is on or after               , 2001 and
(ii) the Company may be  obligated to make an offer  to purchase Notes with  the
Net  Cash Proceeds of certain Asset Sales at a price of (A) 101% of the Accreted
Value thereof (determined at the date of purchase), if such purchase is prior to
            , 2001, or  (B) 101% of  the principal amount  at maturity  thereof,
plus  accrued and  unpaid interest,  if any,  to the  date of  purchase, if such
purchase is on or after             , 2001. See "-- Certain Covenants --  Change
in Control" and "-- Disposition of Proceeds of Asset Sales."
 
    SELECTION; EFFECT OF REDEMPTION NOTICE
 
    In  the case of a partial redemption,  selection of the Notes for redemption
will be made PRO RATA, by lot or by such other method as the Trustee in its sole
discretion deems fair  and appropriate or  in such manner  as complies with  the
requirements of the principal national securities exchange, if any, on which the
Notes being redeemed are listed. Upon giving of a redemption notice, interest on
the  Notes called for  redemption will cease  to accrue from  and after the date
fixed for redemption  (unless the Company  defaults in providing  the funds  for
such  redemption) and, upon redemption on  such redemption date, such Notes will
cease to be outstanding.
 
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<PAGE>
RANKING
 
    The Notes will represent unsecured, senior obligations of the Company,  will
rank  PARI PASSU  in right  of payment with  all existing  and future unsecured,
senior Indebtedness of the Company and will  rank senior in right of payment  to
all  existing and future subordinated indebtedness  of the Company. At March 31,
1996, on a pro  forma basis after giving  effect to indebtedness incurred  after
March 31, 1996, the Offerings and the application of the net proceeds therefrom,
the  aggregate principal amount of indebtedness  of the Company (excluding trade
payables,  other  accrued  liabilities,  deferred  taxes  and  the  Notes)   was
approximately  $3.4 million, which  consisted of the EMI  Note and the Equipment
Note and all of  which ranked PARI  PASSU with the Notes.  $1.9 million of  such
indebtedness  constituted  secured  indebtedness  which  would  effectively rank
senior to  the Notes  with respect  to the  assets securing  such  indebtedness.
Although   the  Indenture  will  limit  the  ability  of  the  Company  and  its
subsidiaries to incur  additional indebtedness,  including senior  indebtedness,
the  Indenture will permit the Company to  incur a substantial amount of secured
indebtedness under the  Credit Facility,  which, if  incurred, will  effectively
rank  senior to the Notes with respect to the assets securing such indebtedness.
In  addition,  the  Indenture  will  permit  the  subsidiaries  of  the  Company
(including  any subsidiary holding all or any part of the Company's FCC licenses
and authorizations)  to guarantee  the  indebtedness of  the Company  under  the
Credit  Facility on  a secured  basis, which  guarantees and  security interests
would effectively rank senior in right of payment to the Notes. See "--  Certain
Covenants,"   "Risk  Factors  --  Possible  Incurrence  of  Substantial  Secured
Indebtedness" and "Description of Certain Indebtedness."
 
CERTAIN COVENANTS
 
    LIMITATION ON INDEBTEDNESS
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of its Subsidiaries  to, Incur any  Indebtedness (including Acquired Debt);
PROVIDED that the Company may  Incur Indebtedness (including Acquired Debt)  if,
after  giving effect to the Incurrence of  such Indebtedness and the receipt and
application of the proceeds therefrom, the Indebtedness to EBITDA Ratio would be
greater than zero and less than 5 to 1.
 
    The foregoing provisions will not apply to:
 
      (i)
       Indebtedness of  the Company  outstanding  at any  time in  an  aggregate
       principal  amount  not  to  exceed $100.0  million,  less  any  amount of
Indebtedness permanently repaid as provided  under the "Disposition of  Proceeds
of Asset Sales" covenant described below;
 
     (ii)
       Indebtedness of any of the Company's Restricted Subsidiaries owing to the
       Company;  PROVIDED, HOWEVER, that (A) any subsequent issuance or transfer
of Capital Stock that results  in any such Indebtedness  being held by a  Person
other  than  the  Company  and  (B)  any sale  or  other  transfer  of  any such
Indebtedness to a Person that is not the Company shall be deemed, in each  case,
to constitute an Incurrence of such Indebtedness by the Company;
 
    (iii)
       Indebtedness  issued in  exchange for, or  the net proceeds  of which are
       used to refinance  or refund, then  outstanding Indebtedness, other  than
Indebtedness  Incurred  under clause  (i),  (ii), (v),  (vi)  or (viii)  of this
paragraph, and any refinancings thereof in an amount not to exceed the amount so
refinanced or refunded  (plus premiums,  accrued interest,  fees and  expenses);
PROVIDED that Indebtedness the proceeds of which are used to refinance or refund
the  Notes or Indebtedness that is PARI  PASSU with, or subordinated in right of
payment to, the Notes shall only be permitted under this clause (iii) if (A)  in
case  the Notes are refinanced  in part or the  Indebtedness to be refinanced is
PARI PASSU with the Notes, such new  Indebtedness (by its terms or by the  terms
of  any  agreement or  instrument  pursuant to  which  such new  Indebtedness is
outstanding) is PARI PASSU  with, or is expressly  made subordinate in right  of
payment  to, the remaining Notes, (B) in  case the Indebtedness to be refinanced
is subordinated in right of payment to the Notes, such new Indebtedness, by  its
terms  or by the terms of any agreement or instrument pursuant to which such new
Indebtedness   is    outstanding,    is   expressly    made    subordinate    in
 
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<PAGE>
right of payment to the Notes at least to the extent that the Indebtedness to be
refinanced  is  subordinated  to  the  Notes,  and  (C)  such  new Indebtedness,
determined as of the date of Incurrence of such new Indebtedness, does not  have
a  Stated  Maturity prior  to  the Stated  Maturity  of the  Indebtedness  to be
refinanced or refunded,  and the  Average Life of  such new  Indebtedness is  at
least  equal to the remaining Average Life  of the Indebtedness to be refinanced
or refunded;  and PROVIDED  FURTHER that  in no  event may  Indebtedness of  the
Company  be refinanced by means of any Indebtedness of any Restricted Subsidiary
of the Company pursuant to this clause (iii);
 
     (iv)
       Indebtedness (A)  in  respect  of performance,  surety  or  appeal  bonds
       provided  in  the  ordinary  course of  business;  and  (B)  arising from
agreements providing  for  indemnification,  adjustment  of  purchase  price  or
similar  obligations, or from  Guarantees or letters of  credit, surety bonds or
performance bonds  securing  any  obligations  of the  Company  or  any  of  the
Restricted  Subsidiaries pursuant  to such agreements,  in any  case Incurred in
connection with the disposition of any business, assets or Restricted Subsidiary
of the Company  (other than Guarantees  of Indebtedness Incurred  by any  Person
acquiring  all or any portion of  such business, assets or Restricted Subsidiary
of the Company for  the purpose of financing  such acquisition), in a  principal
amount  not to exceed the gross proceeds actually received by the Company or any
Restricted Subsidiary in connection with such disposition;
 
      (v)
       without duplication of clause (viii) hereof, Indebtedness of the  Company
       not  to exceed, at any one time outstanding, two TIMES an amount equal to
(A) the aggregate proceeds (less appropriate fees and expenses) (which  proceeds
may  consist  of cash,  Capital Stock  of an  entity  that as  a result  of such
transaction   becomes   a   Restricted    Subsidiary   of   the   Company,    or
Telecommunications  Assets which in connection with such transaction become held
by the Company or a Restricted Subsidiary of the Company, and the value of which
proceeds shall be the fair market value  thereof as determined in good faith  by
the Board, which in all events shall make any appropriate adjustments on account
of  any Indebtedness  associated with  such Capital  Stock or Telecommunications
Assets in making such determination) received  by the Company from the  issuance
and  sale of its Capital Stock (other  than Redeemable Stock and Preferred Stock
that provides for the payment  of dividends in cash)  MINUS (B) the fair  market
value  of any Directed Investments  made with the proceeds  of such issuances or
sales; PROVIDED that such Indebtedness (x) does not have a Stated Maturity prior
to the Stated  Maturity of the  Notes and has  an Average Life  longer than  the
Notes  and (y) is unsecured and is expressly subordinated in right of payment to
the Notes;
 
     (vi)
       Indebtedness  to  the  extent  such  Indebtedness  is  secured  by  Liens
       permitted under clause (xxiv) of the definition of "Permitted Liens;"
 
    (vii)
       Indebtedness  of  the Company,  to the  extent  the proceeds  thereof are
       immediately used to purchase Notes tendered in an Offer to Purchase  made
as a result of a Change in Control;
 
   (viii)
       without  duplication of  clause (v)  hereof, Indebtedness  of the Company
       Incurred in connection  with the acquisition  of (A) 38  GHz licenses  or
authorizations  through auctions conducted  by the FCC or  (B) other licenses or
authorizations through other spectrum auctions conducted by the FCC with respect
to other frequencies approved for microwave point-to-point transmissions, in  an
amount  not to  exceed, at any  one time  outstanding, the greater  of (1) $10.0
million and (2) an amount equal to the aggregate proceeds (less appropriate fees
and expenses) (which proceeds  may consist of cash,  Capital Stock of an  entity
that  as a  result of  such transaction becomes  a Restricted  Subsidiary of the
Company, or Telecommunications Assets which in connection with such  transaction
become  held by the Company  or a Restricted Subsidiary  of the Company, and the
value of which proceeds shall be the fair market value thereof as determined  in
good  faith  by  the Board,  which  in  all events  shall  make  any appropriate
adjustments on account of any Indebtedness associated with such Capital Stock or
Telecommunications Assets in making such determination) received by the  Company
from the issuance and sale of its Capital Stock (other than Redeemable Stock and
Preferred  Stock that provides for  the payment of dividends  in cash) MINUS the
fair market value  of any Directed  Investments made with  the proceeds of  such
issuances
 
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<PAGE>
of  sales; PROVIDED that such  Indebtedness (x) does not  have a Stated Maturity
prior to the Stated Maturity  of the Notes and has  an Average Life longer  than
the  Notes and (y)  is unsecured and is  PARI PASSU or  subordinated in right of
payment with the Notes;
 
     (ix)
       revolving credit  Indebtedness  of  any  Restricted  Subsidiary  Incurred
       pursuant  to a credit facility  in an aggregate amount  not to exceed, at
any one  time outstanding,  the greater  of 62.5%  and such  greater  percentage
permitted  pursuant to  such credit facility  of the accounts  receivable net of
reserves and allowances  for doubtful  accounts, determined  in accordance  with
GAAP,  of such  Restricted Subsidiary  and its  Restricted Subsidiaries (without
duplication); PROVIDED that such Indebtedness  is not Guaranteed by the  Company
or any of its other Restricted Subsidiaries;
 
      (x)
       the  Incurrence by the  Company or any of  its Restricted Subsidiaries of
       Hedging Obligations  that  are Incurred  for  the purpose  of  fixing  or
hedging interest rate risk with respect to any floating rate Indebtedness of the
Company  or any Restricted Subsidiary, as the  case may be, that is permitted by
the terms of the Indenture to be outstanding;
 
     (xi)
       the Incurrence by the Company's Unrestricted Subsidiaries of Non-Recourse
       Debt, PROVIDED,  HOWEVER, that  if  any such  Indebtedness ceases  to  be
Non-Recourse  Debt of an Unrestricted Subsidiary,  such event shall be deemed to
constitute an  incurrence of  Indebtedness  by a  Restricted Subsidiary  of  the
Company;
 
    (xii)
       the  Incurrence  by  Unrestricted  Subsidiaries  of  Indebtedness  to the
       Company or  any  Restricted  Subsidiary  of the  Company  to  the  extent
permitted by the "Limitation on Restricted Payments" covenant;
 
   (xiii)
       Indebtedness  of the Company in an  aggregate amount not to exceed $100.0
       million Incurred pursuant to the Credit Facility;
 
    (xiv)
       Guarantees by the Company's  Restricted Subsidiaries of the  Indebtedness
       referred to in clause (xiii) above;
 
     (xv)
       Indebtedness of the Company existing on the Issue Date; and
 
    (xvi)
       Indebtedness of the Company represented by the Notes and the Indenture.
 
    For   purposes   of  determining   compliance   with  this   "Limitation  on
Indebtedness" covenant, in  the event  that an  item of  Indebtedness meets  the
criteria  of more than one  of the types of  Indebtedness described in the above
clauses, the  Company, in  its  sole discretion,  shall  classify such  item  of
Indebtedness  and  only be  required  to include  the  amount and  type  of such
Indebtedness in one of such clauses.
 
    The Company will  not, and  will not  permit any  Restricted Subsidiary  to,
Incur any Guarantee of Indebtedness of any Unrestricted Subsidiary.
 
    The   Indenture  will  provide  that,  notwithstanding  the  foregoing,  ART
Licensing shall  not  Incur  any  Indebtedness or  issue  any  Preferred  Stock;
PROVIDED that ART Licensing may Incur Indebtedness of the type and in the amount
set  forth  in clause  (xiv)  of the  second  paragraph of  this  "Limitation on
Indebtedness" covenant.
 
    LIMITATION ON RESTRICTED PAYMENTS
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  Restricted Subsidiary  to, directly or  indirectly, (i) declare  or pay any
dividend or make any distribution on its or such Restricted Subsidiary's Capital
Stock (other than dividends or distributions payable solely in shares of its  or
such Restricted Subsidiary's Capital Stock (other than Redeemable Stock) held by
such  holders or in options, warrants or  other rights to acquire such shares of
Capital Stock) other than such Capital Stock  held by the Company or any of  its
Restricted  Subsidiaries (and other than pro  rata dividends or distributions on
Common Stock of  Restricted Subsidiaries),  (ii) repurchase,  redeem, retire  or
otherwise  acquire for  value any  shares of  Capital Stock  (including options,
warrants or other rights to acquire such shares of Capital Stock) of the Company
(other  than   any   such  Capital   Stock   held   by  the   Company   or   any
 
                                       85
<PAGE>
Wholly  Owned Restricted Subsidiary of the Company), (iii) make any voluntary or
optional principal  payment, or  voluntary or  optional redemption,  repurchase,
defeasance, or other acquisition or retirement for value, of Indebtedness of the
Company  that is subordinated in right of payment  to the Notes or (iv) make any
Investment, other than a Permitted Investment,  in any Person (such payments  or
any  other  actions described  in clauses  (i)  through (iv)  being collectively
"Restricted Payments")  if, at  the time  of, and  after giving  effect to,  the
proposed Restricted Payment:
 
       (A) a Default or Event of Default shall have occurred and be continuing;
 
       (B) except  with  respect to  any  Investment (other  than  an Investment
           consisting of  the  designation  of a  Restricted  Subsidiary  as  an
    Unrestricted  Subsidiary), the  Company could  not Incur  at least  $1.00 of
    Indebtedness under the first paragraph  of the "Limitation on  Indebtedness"
    covenant; and
 
       (C) the aggregate amount expended for all Restricted Payments (the amount
           so expended, if other than in cash, to be determined in good faith by
    the  Board,  whose  determination shall  be  conclusive and  evidenced  by a
    resolution of the Board) after  the Issue Date shall  exceed the sum of  (1)
    50%  of the aggregate amount of the Adjusted Consolidated Net Income (or, if
    the Adjusted Consolidated Net Income is  a loss, MINUS 100% of such  amount)
    (determined  by excluding income  resulting from transfers  of assets by the
    Company or a Restricted Subsidiary to an Unrestricted Subsidiary) accrued on
    a cumulative  basis  during the  period  (taken as  one  accounting  period)
    beginning  on the first day of  the fiscal quarter immediately following the
    Issue Date and ending on the last  day of the last fiscal quarter  preceding
    the  date  for  which reports  have  been  filed pursuant  to  the "Reports"
    covenant, PLUS (2) the aggregate Net  Cash Proceeds received by the  Company
    after  the Issue Date from the issuance  and sale permitted by the Indenture
    of its Capital Stock (other than Redeemable Stock) to a Person who is not  a
    Subsidiary  of the Company,  or from the issuance  to a Person  who is not a
    Subsidiary of  the Company  of  any options,  warrants  or other  rights  to
    acquire  Capital  Stock  of the  Company  (in  each case,  exclusive  of any
    convertible Indebtedness, Redeemable Stock or any options, warrants or other
    rights that are redeemable at the option  of the holder, or are required  to
    be  redeemed, prior to the  Stated Maturity of the  Notes), MINUS the actual
    amount of Net Cash Proceeds used to make such Directed Investments, PLUS (3)
    an amount equal to the net  reduction in Investments (other than  reductions
    in  Permitted Investments) in any Person resulting from payments of interest
    on Indebtedness,  dividends,  repayments  of loans  or  advances,  or  other
    transfers  of  assets,  in  each  case  to  the  Company  or  any Restricted
    Subsidiary (except  to  the extent  any  such  payment is  included  in  the
    calculation  of Adjusted Consolidated Net Income), or from the redesignation
    of Unrestricted Subsidiaries as Restricted Subsidiaries (valued in each case
    as provided in the definition of "Investments"), not to exceed the amount of
    Investments previously made by the  Company and its Restricted  Subsidiaries
    in such Person.
 
        The foregoing provision shall not be violated by reason of:
 
      (i)
       the  payment of any dividend within 60 days after the date of declaration
       thereof if, at said date of  declaration, such payment would comply  with
the foregoing paragraph;
 
     (ii)
       the redemption, repurchase, defeasance or other acquisition or retirement
       for value of Indebtedness that is subordinated in right of payment to the
Notes,  including premium,  if any,  and accrued  and unpaid  interest, with the
proceeds of, or in exchange for, Indebtedness Incurred under clause (iii) of the
second paragraph of the "Limitation on Indebtedness" covenant;
 
    (iii)
       the repurchase, redemption or other  acquisition of Capital Stock of  the
       Company  (or options,  warrants or other  rights to  acquire such Capital
Stock) in exchange  for, or out  of the proceeds  of a substantially  concurrent
offering  of, shares of  Capital Stock or  options, warrants or  other rights to
acquire such Capital Stock  (in each case, other  than Redeemable Stock) of  the
Company;
 
                                       86
<PAGE>
     (iv)
       the   making  of   any  principal  payment   or  repurchase,  redemption,
       retirement, defeasance or other acquisition for value of Indebtedness  of
the  Company which is subordinated in right  of payment to the Notes in exchange
for, or out of the proceeds  of, a substantially concurrent offering of,  shares
of the Capital Stock of the Company (other than Redeemable Stock);
 
      (v)
       payments  or distributions, in the  nature of satisfaction of dissenters'
       rights, pursuant  to or  in connection  with a  consolidation, merger  or
transfer of assets that complies with the provisions of the Indenture applicable
to  mergers, consolidations  and transfers  of all  or substantially  all of the
property and assets of the Company;
 
     (vi)
       any purchase or  acquisition from,  or withholding on  issuances to,  any
       employee  of  the  Company's  Capital  Stock  in  order  to  satisfy  any
applicable federal, state  or local tax  payments in respect  of the receipt  of
shares of the Company's Capital Stock;
 
    (vii)
       any  purchase or  acquisition from, or  withholding on  issuances to, any
       employee of the  Company's Capital  Stock in  order to  pay the  purchase
price  of such Capital Stock  or similar instrument pursuant  to a stock option,
equity incentive or other employee benefit  plan or agreement of the Company  or
any of its Restricted Subsidiaries;
 
   (viii)
       the  repurchase  of shares  of,  or options  to  purchase shares  of, the
       Company's Capital Stock from employees of the Company in connection  with
the  termination of their employment; PROVIDED that (A) the aggregate price paid
for all such repurchased shares of Capital Stock made in any twelve-month period
shall not  exceed $250,000  PLUS the  aggregate cash  proceeds received  by  the
Company  during such  twelve-month period  from any  reissuance of  such Capital
Stock by the Company to employees of the Company and its Restricted Subsidiaries
and (B) no Default shall have occurred and be continuing immediately after  such
transaction;
 
     (ix)
       payments  and distributions pursuant to any tax sharing agreement between
       the Company  and  any  other  Person  with  which  the  Company  files  a
consolidated  tax return  or with  which the Company  is part  of a consolidated
group, in each case, for federal income tax purposes;
 
      (x)
       cash payments in  lieu of  the issuance  of fractional  shares of  Common
       Stock  of the Company upon conversion of  any class of Preferred Stock of
the Company; and
 
     (xi)
       the issuance  of shares  of Common  Stock upon  exercise of  warrants  to
       purchase  shares of common  stock of ART Licensing  existing on the Issue
Date, including  any  contribution  of  such  shares  of  Common  Stock  to  ART
Licensing,  any payment by ART Licensing to the Company in consideration thereof
and any contribution by the Company to ART Licensing in respect thereof;
 
PROVIDED that, except in the case of  clauses (i) and (ii), no Default or  Event
of  Default shall have occurred  and be continuing or  occur as a consequence of
the actions or  payments set forth  herein. Any Investments  made other than  in
cash shall be valued, in good faith, by the Board.
 
    Each Restricted Payment permitted pursuant to the preceding paragraph (other
than the Restricted Payment referred to in clause (ii) thereof) and the Net Cash
Proceeds  from any issuance of Capital Stock referred to in clause (iii) or (iv)
shall be included  in calculating whether  the conditions of  clause (C) of  the
first  paragraph of this "Limitation on  Restricted Payments" covenant have been
met with  respect  to any  subsequent  Restricted  Payments. In  the  event  the
proceeds  of  an issuance  of  Capital Stock  of the  Company  are used  for the
redemption, repurchase or other acquisition of the Notes or Indebtedness that is
PARI PASSU with the Notes, then the Net Cash Proceeds of such issuance shall  be
included  in clause (C) of the first paragraph of this "Limitation on Restricted
Payments" covenant  only to  the extent  such  proceeds are  not used  for  such
redemption, repurchase or other acquisition of Indebtedness.
 
    The  Board may  designate any  Restricted Subsidiary  to be  an Unrestricted
Subsidiary if such designation would not cause a Default. For purposes of making
such  determination,  all  outstanding  Investments  by  the  Company  and   its
Restricted  Subsidiaries (except to the extent repaid in cash) in the Subsidiary
so designated will  be deemed  to be  Restricted Payments  at the  time of  such
designation and
 
                                       87
<PAGE>
will  reduce  the  amount  available for  Restricted  Payments  under  the first
paragraph of this covenant. All such  outstanding Investments will be deemed  to
constitute  Investments in an amount valued in accordance with the definition of
"Investment." Such designation will only be permitted if such Restricted Payment
would be permitted  at such  time and  if such  Restricted Subsidiary  otherwise
meets the definition of an Unrestricted Subsidiary.
 
    LIMITATION ON LIENS SECURING CERTAIN INDEBTEDNESS
 
    The  Indenture will provide that  the Company will not,  and will not permit
any Subsidiary to, create, Incur, assume or suffer to exist any Lien, other than
Permitted Liens, on any  of its assets  or properties of  any character, or  any
shares  of  Capital  Stock or  Indebtedness  of any  Subsidiary,  without making
effective provision for all  of the Notes  and all other  amounts due under  the
Indenture to be directly secured equally and ratably with (or, if the obligation
or  liability to be secured by such Lien  is subordinated in right of payment to
the Notes prior to) the obligation or liability secured by such Lien.
 
    LIMITATION ON DIVIDEND AND OTHER PAYMENT RESTRICTIONS AFFECTING RESTRICTED
SUBSIDIARIES
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  Restricted Subsidiary to, create  or otherwise cause or  suffer to exist or
become effective any consensual  encumbrance or restriction of  any kind on  the
ability  of  any  Restricted  Subsidiary  to (i)  pay  dividends  or  make other
distributions  permitted  by  applicable  law  on  any  Capital  Stock  of  such
Restricted  Subsidiary owned by the Company  or any other Restricted Subsidiary,
(ii) pay any Indebtedness owed to the Company or any other Restricted Subsidiary
that owns,  directly  or  indirectly,  any  Capital  Stock  of  such  Restricted
Subsidiary,  (iii) make loans or advances to the Company or any other Restricted
Subsidiary that  owns,  directly  or  indirectly,  any  Capital  Stock  of  such
Restricted  Subsidiary or  (iv) transfer  any of its  property or  assets to the
Company or any other  Restricted Subsidiary that  owns, directly or  indirectly,
any Capital Stock of such Restricted Subsidiary.
 
    The   foregoing   provisions  shall   not   prohibit  any   encumbrances  or
restrictions:
 
      (i)
       existing on the  Issue Date in  the Indenture or  any other agreement  in
       effect  on the  Issue Date,  and any  extension, refinancing,  renewal or
replacement  of  any  such  agreement;   PROVIDED  that  the  encumbrances   and
restrictions  in any such extension, refinancing,  renewal or replacement are no
less favorable in any material respect to the holders than those encumbrances or
restrictions that are then  in effect and that  are being extended,  refinanced,
renewed or replaced;
 
     (ii)
       existing under or by reason of applicable law;
 
    (iii)
       existing  with respect to  any Person or  the property or  assets of such
       Person acquired by the Company or any Restricted Subsidiary, at the  time
of   such  acquisition  and   not  Incurred  in   contemplation  thereof,  which
encumbrances or restrictions are not applicable to any Person or the property or
assets of any Person other  than such Person or the  property or assets of  such
Person so acquired;
 
     (iv)
       in  the case of clause (iv) of the first paragraph of this "Limitation on
       Dividend   and   Other   Payment   Restrictions   Affecting    Restricted
Subsidiaries"  covenant, (A) that restrict in a customary manner the subletting,
assignment or  transfer of  any property  or  asset that  is a  lease,  license,
conveyance  or contract or similar property or  asset, (B) existing by virtue of
any transfer of, agreement to transfer, option or right with respect to, or Lien
on, any property  or assets  of the Company  or any  Restricted Subsidiary,  not
otherwise  prohibited  by the  Indenture  or (C)  arising  or agreed  to  in the
ordinary course of business, not relating to any Indebtedness, and that do  not,
individually  or in the aggregate, detract from  the value of property or assets
of the  Company or  any Restricted  Subsidiary  in any  manner material  to  the
Company or any Restricted Subsidiary;
 
      (v)
       imposed  pursuant to an agreement that has been entered into for the sale
       or disposition of Capital Stock of, or property or assets of, the Company
or a Restricted Subsidiary; PROVIDED that such encumbrance or restriction  shall
only remain in force during the pendency of such acquisition or disposition; or
 
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     (vi)
       imposed  pursuant to  agreements governing  Indebtedness permitted  to be
       Incurred under clauses (xiii)  and (xiv) of the  second paragraph of  the
"Limitation of Indebtedness" covenant.
 
    Nothing  contained  in  this  "Limitation  on  Dividend  and  Other  Payment
Restrictions Affecting  Restricted  Subsidiaries"  covenant  shall  prevent  the
Company  or any Restricted Subsidiary from  (a) creating, Incurring, assuming or
suffering to exist  any Liens otherwise  permitted in the  "Limitation on  Liens
Securing  Certain Indebtedness"  covenant or (b)  restricting the  sale or other
disposition of  property or  assets of  the  Company or  any of  its  Restricted
Subsidiaries  that secure Indebtedness  of the Company or  any of its Restricted
Subsidiaries.
 
    LIMITATION ON TRANSACTIONS WITH AFFILIATES
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of  its  Restricted Subsidiaries  to,  sell, lease,  transfer  or otherwise
dispose of any  of its  properties or  assets to,  or purchase  any property  or
assets  from, or enter  into or make  any contract, agreement,  loan, advance or
Guarantee with, or any contract, agreement,  loan, advance or Guarantee for  the
specific  benefit  of,  any  Affiliate (each  of  the  foregoing,  an "Affiliate
Transaction"), unless (i)  such Affiliate Transaction  is on terms  that are  no
less  favorable to the Company or  the relevant Restricted Subsidiary than those
that would have been obtained in a comparable transaction by the Company or such
Restricted Subsidiary with an unrelated Person and (ii) the Company delivers  to
the  Trustee (A) with  respect to any  Affiliate Transaction involving aggregate
consideration in excess of $1.0 million, a resolution of the Board of  Directors
set forth in an Officers' Certificate certifying that such Affiliate Transaction
complies  with clause  (A) above  and that  such Affiliate  Transaction has been
approved by a majority  of the disinterested members  of the Board of  Directors
and   (B)  with  respect  to   any  Affiliate  Transaction  involving  aggregate
consideration in  excess  of  $5.0  million, a  written  opinion,  appraisal  or
certification   from  a   nationally  recognized   professional  experienced  in
evaluating similar  types  of  transactions  stating  that  the  terms  of  such
transaction  are fair to the Company or  such Restricted Subsidiary, as the case
may be, from a financial point of view; PROVIDED that the following shall not be
deemed to constitute Affiliate Transactions:
 
    (i)  the payment of reasonable fees to directors of the Company who are  not
employees of the Company;
 
    (ii) agreements and arrangements existing on the date hereof;
 
    (iii)  any employment agreement  entered into by  the Company or  any of its
Restricted Subsidiaries in  the ordinary course  of business of  the Company  or
such Restricted Subsidiary;
 
    (iv)  the  adoption of  employee  benefit plans  in  the ordinary  course of
business and payments and other transactions thereunder; PROVIDED that any  such
adoption, payment or other transaction shall have been approved by a majority of
the disinterested members of the Board;
 
    (v)  transactions  between  or among  the  Company and/or  its  Wholly Owned
Restricted Subsidiaries;
 
    (vi) any contract,  agreement, loan,  advance or Guarantee  for the  general
benefit  of the  Company and its  stockholders, including  stockholders that are
Affiliates of the Company; and
 
    (vii)  any  Affiliate  Transactions  permitted  by  the  provisions  of  the
Indenture  described  above  under  the  caption  "--  Limitation  on Restricted
Payments."
 
    LIMITATION ON ISSUANCES AND SALES OF CAPITAL STOCK OF WHOLLY OWNED
RESTRICTED SUBSIDIARIES
 
    The Indenture will  provide that  the Company will  not sell,  and will  not
permit  any Restricted Subsidiary, directly or  indirectly, to issue or sell any
shares of Capital  Stock of a  Restricted Subsidiary, other  than ART  Licensing
(including  options, warrants or other rights to purchase shares of such Capital
Stock), except (i) to the Company or a Wholly Owned Restricted Subsidiary,  (ii)
issuances  or sales to foreign  nationals of shares of  Capital Stock of foreign
Restricted Subsidiaries, to  the extent  required by applicable  law, (iii)  if,
immediately  after  giving  effect to  such  issuance or  sale,  such Restricted
 
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Subsidiary would no longer constitute a Restricted Subsidiary or (iv)  issuances
or  sales of Common  Stock of Restricted  Subsidiaries, if within  six months of
each such issuance or sale, the Company or such Restricted Subsidiary applies an
amount not less than the Net Cash  Proceeds thereof (if any) in accordance  with
clause  (A) or  (B) of the  first paragraph  of the "Disposition  of Proceeds of
Asset Sales" covenant.
 
    BUSINESS ACTIVITIES OF THE COMPANY
 
    The Company will  not, and  will not  permit any  Restricted Subsidiary  to,
engage  in (i) any business other  than the Telecommunications Business and such
business activities as are incidental or related thereto and (ii) any  business,
activities or services in which the Company and its Restricted Subsidiaries were
engaged on the Issue Date. In addition, the Company will (i) at such time and to
the  extent permitted by the FCC, transfer,  or cause to be transferred, all FCC
licenses and authorizations of  the Company and  its Restricted Subsidiaries  to
ART  Licensing and (ii) cause ART Licensing  to remain a Wholly Owned Restricted
Subsidiary of the Company.
 
    Notwithstanding the  foregoing, to  the  extent permitted  by the  FCC,  the
Company  will not permit  ART Licensing to  engage in any  business or activity,
other than the application for, acquisition of or ownership of FCC licenses  and
authorizations;  PROVIDED, HOWEVER, that ART Licensing shall be permitted to own
and operate any equipment or  assets that were owned  by ART Licensing prior  to
the Issue Date.
 
    CHANGE IN CONTROL
 
    In  the  event  of  a  Change in  Control,  the  Company  must  commence and
consummate an  Offer  to Purchase  for  all the  Notes  then outstanding,  at  a
purchase  price equal to (i) 101% of the  Accreted Value thereof, in the case of
any such purchase prior to               ,  2001, or (ii) 101% of the  principal
amount  at maturity thereof, together with  accrued and unpaid interest, if any,
to the  date  of  purchase, in  the  case  of  any such  purchase  on  or  after
            ,  2001. Not later than 20 days following any Change in Control, the
Company will  mail  a  notice  to each  holder  describing  the  transaction  or
transactions  that constitute the  Change in Control  and offering to repurchase
Notes pursuant to the procedures required by the Indenture and described in such
notice.
 
    The Indenture does  not contain provisions  that permit the  holders of  the
Notes to require that the Company repurchase or redeem the Notes in the event of
a  highly  leveraged  transaction,  including  a  takeover,  recapitalization or
similar restructuring, that  may adversely effect  the holders of  the Notes  if
such  transaction does  not otherwise  constitute a  Change in  Control. See "--
Certain Definitions."  In addition,  with the  consent of  at least  66 2/3%  in
principal  amount at  maturity of  the Notes  then outstanding,  the Company may
amend, and the holders of Notes may waive any Default in the performance of, the
provisions described in this  "Change in Control"  covenant. See "--  Amendments
and  Waivers." There can be  no assurance that the  Company will have sufficient
funds available at the time  of any Change in Control  to make any debt  payment
(including  repurchases of Notes) required by the foregoing covenant (as well as
may be contained in other securities  of the Company which might be  outstanding
at the time).
 
    DISPOSITION OF PROCEEDS OF ASSET SALES
 
    The  Indenture will provide that  the Company will not,  and will not permit
any Restricted  Subsidiary  to,  consummate  any  Asset  Sale,  unless  (a)  the
consideration  received by the Company or such Restricted Subsidiary is at least
equal to the  fair market value  of the assets  sold or disposed  of and (b)  at
least  85%  of the  consideration received  consists of  cash or  Temporary Cash
Investments, PROVIDED  that  any notes  or  other obligations  received  by  the
Company or any such Restricted Subsidiary as consideration that are converted by
the  Company or  such Restricted  Subsidiary into cash  within 30  days of their
receipt (to the extent  of the cash  received), shall be deemed  to be cash  for
purposes  of this provision.  In the event and  to the extent  that the Net Cash
Proceeds received by the Company or its Restricted Subsidiaries from one or more
Asset Sales occurring on or after the Issue Date in any period of 12 consecutive
months exceed 10% of Adjusted Consolidated Net Tangible Assets (determined as of
the
 
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<PAGE>
date  closest  to  the  commencement  of  such  12-month  period  for  which   a
consolidated  balance sheet of  the Company and  its Restricted Subsidiaries has
been prepared), then the  Company shall or shall  cause the relevant  Restricted
Subsidiary to (i) within six months after the date Net Cash Proceeds so received
exceed  10% of  Adjusted Consolidated  Net Tangible  Assets (A)  apply an amount
equal to  such excess  Net  Cash Proceeds  to permanently  repay  unsubordinated
Indebtedness  of the Company  or any of  its Restricted Subsidiaries  owing to a
Person other  than the  Company or  any of  its Restricted  Subsidiaries or  (B)
invest  an equal amount, or the amount not so applied pursuant to clause (A) (or
enter into a  definitive agreement  committing to  so invest  within six  months
after  the date of such agreement), in property or assets of a nature or type or
that are used in  a business (or in  a company having property  and assets of  a
nature  or type, or engaged  in a business) similar or  related to the nature or
type of the  property and assets  of, or the  business of, the  Company and  its
Restricted  Subsidiaries existing on the date  of such Investment (as determined
in good  faith  by  the  Board, whose  determination  shall  be  conclusive  and
evidenced  by a resolution of the Board and (ii) apply (no later than the end of
the six-month period referred  to in clause (i))  such excess Net Cash  Proceeds
(to  the extent not applied pursuant to clause (i)) as provided in the following
paragraph of this "Disposition of Proceeds of Asset Sales" covenant. The  amount
of  such excess Net Cash Proceeds required to  be applied (or to be committed to
be applied) during  such six-month  period as  set forth  in clause  (i) of  the
preceding  sentence and  not applied as  so required  by the end  of such period
shall constitute "Excess Proceeds."
 
    If, as of  the first  day of  any calendar  month, the  aggregate amount  of
Excess Proceeds not theretofore subject to an Offer to Purchase pursuant to this
"Limitation  on Asset Sales" covenant totals  at least $5.0 million, the Company
must commence, not  later than  the fifteenth business  day of  such month,  and
consummate  an  Offer  to Purchase  from  the holders  on  a pro  rata  basis an
aggregate principal amount of Notes equal  to the Excess Proceeds on such  date,
at  a purchase price equal to (i) 101% of the Accreted Value thereof (determined
at the date of purchase), if such purchase is  prior to              , 2001,  or
(ii)  101% of the principal amount at  maturity thereof, plus accrued and unpaid
interest, if any,  to the  date of  purchase, if such  purchase is  on or  after
            , 2001.
 
    NO AMENDMENT TO AGREEMENT
 
    The  Indenture will provide that the Company will not amend, modify or alter
the Voting Trust Agreement without having obtained the consent of the holders of
not less than  a majority  in principal  amount at  maturity of  the Notes  then
outstanding.
 
    REPORTS
 
    The  Indenture will provide that,  whether or not required  by the rules and
regulations of the  Securities and  Exchange Commission  (the "Commission"),  so
long  as any Notes are  outstanding, the Company will  furnish to the Holders of
Notes (i) all quarterly and annual financial information that would be  required
to  be contained in a filing  with the Commission on Forms  10-Q and 10-K if the
Company were required to file  such Forms, including a "Management's  Discussion
and Analysis of Financial Condition and Results of Operations" and, with respect
to  the annual  information only,  a report  thereon by  the Company's certified
independent accountants and (ii) all current  reports that would be required  to
be  filed with the Commission  on Form 8-K if the  Company were required to file
such reports. In addition, whether or not required by the rules and  regulations
of  the Commission,  the Company will  file a  copy of all  such information and
reports with the Commission for public availability (unless the Commission  will
not  accept such  a filing)  and make  such information  available to securities
analysts and prospective investors upon request.
 
CONSOLIDATION, MERGER, SALE OF ASSETS, ETC.
 
    The Indenture  will provide  that the  Company shall  not consolidate  with,
merge with or into, or sell, convey, transfer, lease or otherwise dispose of all
or substantially all of its property and assets (as an entirety or substantially
an  entirety in  one transaction  or a series  of related  transactions) to, any
Person (other  than  a consolidation  or  merger with  or  into a  Wholly  Owned
Restricted  Subsidiary with a  positive net worth;  PROVIDED that, in connection
with   any   such   merger    or   consolidation,   no   consideration    (other
 
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<PAGE>
than  Common Stock in  the surviving Person  or the Company)  shall be issued or
distributed to the stockholders  of the Company) or  permit any Person to  merge
with or into the Company unless: (i) the Company shall be the continuing Person,
or  the Person (if other than the  Company) formed by such consolidation or into
which the Company is merged or that acquired or leased such property and  assets
of  the Company shall be a corporation  organized and validly existing under the
laws of  the United  States of  America or  any jurisdiction  thereof and  shall
expressly  assume, by  a supplemental indenture,  executed and  delivered to the
Trustee, all of the obligations of the Company on all of the Notes and under the
Indenture; (ii) immediately after giving effect to such transaction, no  Default
or  Event of  Default shall have  occurred and be  continuing; (iii) immediately
after giving effect to such transaction  on a pro forma basis, the  Indebtedness
to Total Market Capitalization Ratio (determined as of a date no earlier than 10
days  prior to  such transaction)  of the  Company, or  any person  becoming the
successor  obligor  of  the  Notes,  would  be  no  greater  than  130%  of  the
Indebtedness  to Total  Market Capitalization  Ratio of  the Company immediately
prior to giving  effect to  such transaction;  PROVIDED that  this clause  (iii)
shall not apply to any transaction or series of transactions effected solely for
the  purpose of creating  a parent corporation  of which the  Company shall be a
Wholly Owned  Subsidiary  and whose  stockholders  shall be  identical  (without
regard  to the  exercise of  options or  warrants, or  securities convertible or
exchangeable into shares of  Common Stock) to those  of the Company  immediately
prior  thereto;  and  (iv) the  Company  delivers  to the  Trustee  an Officers'
Certificate (attaching  the arithmetic  computations to  demonstrate  compliance
with  clause (iii)) and an  Opinion of Counsel, in  each case, stating that such
consolidation, merger or transfer and such supplemental indenture complies  with
this provision and that all conditions precedent provided for herein relating to
such  transaction have been complied with;  PROVIDED, HOWEVER, that clause (iii)
above does not apply  if, in the  good faith determination  of the Board,  whose
determination  shall be  evidenced by a  resolution of the  Board, the principal
purpose of  such transaction  is to  change the  state of  incorporation of  the
Company; and PROVIDED FURTHER that any such transaction shall not have as one of
its purposes the evasion of the foregoing limitations.
 
EVENTS OF DEFAULT AND REMEDIES
 
    The following events are "Events of Default" under the Indenture:
 
      (i)
       default  in the payment of interest on  the Notes when it becomes due and
       payable, and continuance of such default for a period of 30 days or more;
or
 
     (ii)
       default in the payment of principal of, or premium, if any, on the  Notes
       when due; or
 
    (iii)
       default  in the performance,  or breach, of  any covenant described under
       "Certain Covenants -- Limitation on Restricted Payments," "--  Limitation
on  Indebtedness," "-- Change in Control,"  "-- Disposition of Proceeds of Asset
Sales" and "Consolidation, Merger, Sale of Assets, Etc."; or
 
     (iv)
       default in the performance, or breach,  of any covenant in the  Indenture
       (other  than defaults specified in clause  (i), (ii) or (iii) above), and
the continuance of such default or breach for a period of 30 days or more  after
written  notice to the Company by the Trustee  or to the Company and the Trustee
by the holders of at least 25% in aggregate principal amount at maturity of  the
outstanding  Notes  (in  each  case,  when such  notice  is  deemed  received in
accordance with the Indenture); or
 
      (v)
       default under any mortgage, indenture or instrument under which there may
       be issued or by which there may be secured or evidenced any  Indebtedness
for  money borrowed by the Company or any of its Restricted Subsidiaries (or the
payment of  which  is  Guaranteed  by  the Company  or  any  of  its  Restricted
Subsidiaries)  whether such Indebtedness or Guarantee  now exists, or is created
after the Issue Date, which default (A) is caused by a failure to pay  principal
of  or premium, if any, or interest on such Indebtedness prior to the expiration
of the grace period provided in such Indebtedness on the date of such default (a
"Payment Default") or (B) results in the acceleration of such Indebtedness prior
to its express  maturity and, in  each case,  the principal amount  of any  such
Indebtedness,  together with the principal amount of any other such Indebtedness
under which there has been a Payment Default, or the maturity of which has  been
so accelerated, aggregates $5.0 million or more; or
 
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<PAGE>
     (vi)
       any final judgment or order (not covered by insurance) for the payment of
       money  in excess  of $5.0  million in  the aggregate  for all  such final
judgments  or  orders  against  all  such  Persons  (treating  any  deductibles,
self-insurance  or retention  as not so  covered) shall be  rendered against the
Company or any Significant Subsidiary and  shall not be paid or discharged,  and
there  shall be any period  of 60 consecutive days  following entry of the final
judgment or order that causes the aggregate amount for all such final  judgments
or  orders outstanding and  not paid or  discharged against all  such Persons to
exceed $5.0 million during which a stay of enforcement of such final judgment or
order, by reason of a pending appeal or otherwise, shall not be in effect; or
 
    (vii)
       a court having jurisdiction in the premises enters a decree or order  for
       (A)  relief in respect of the Company or any Significant Subsidiary in an
involuntary case under  any applicable bankruptcy,  insolvency or other  similar
law  now or hereafter in effect, (B)  the appointment of a receiver, liquidator,
assignee, custodian, trustee, sequestrator or similar official of the Company or
any Significant Subsidiary or for all  or substantially all of the property  and
assets  of the Company  or any Significant  Subsidiary or (C)  the winding up or
liquidation of the affairs of the Company or any Significant Subsidiary and,  in
each case, such decree or order shall remain unstayed and in effect for a period
of 60 consecutive days; or
 
   (viii)
       the  Company or any Significant Subsidiary (A) commences a voluntary case
       under any applicable bankruptcy, insolvency  or other similar law now  or
hereafter  in effect,  or consents  to the entry  of an  order for  relief in an
involuntary case  under any  such law,  (B) consents  to the  appointment of  or
taking  possession  by  a receiver,  liquidator,  assignee,  custodian, trustee,
sequestrator or similar official of the Company or any Significant Subsidiary or
for all or substantially all  of the property and assets  of the Company or  any
Significant  Subsidiary or (C) effects any general assignment for the benefit of
creditors.
 
    If any Event of Default (other than an Event of Default specified in  clause
(vii)  or (viii) above  with respect to  the Company) occurs  and is continuing,
then the Trustee or the holders of at least 25% in principal amount at  maturity
of outstanding Notes may, by written notice, and the Trustee upon the request of
the  holders  of  not less  than  25% in  principal  amount at  maturity  of the
outstanding Notes shall,  declare the  Default Amount  of, and  any accrued  and
unpaid  interest on, all outstanding Notes to be immediately due and payable and
upon any such declaration such amounts shall become immediately due and payable.
If an Event of Default specified in clause (vii) or (viii) above with respect to
the Company  occurs and  is continuing,  then  the Default  Amount of,  and  any
accrued  and unpaid interest  on, all outstanding Notes  shall IPSO FACTO become
and be immediately due and payable without  any declaration or other act on  the
part of the Trustee or any holder.
 
    After  a declaration of acceleration, the holders of a majority in aggregate
principal amount at maturity of outstanding Notes may, by notice to the Trustee,
rescind such  declaration of  acceleration if  all existing  Events of  Default,
other  than nonpayment  of the  Default Amount  of, and  any accrued  and unpaid
interest on,  the  Notes  that  has  become due  solely  as  a  result  of  such
acceleration,  have been cured  or waived and if  the rescission of acceleration
would not conflict with  any judgment or  decree. The holders  of a majority  in
principal  amount at maturity  of the outstanding  Notes also have  the right to
waive past defaults under the Indenture, except a default in the payment of  the
Default  Amount of, or any interest on, any outstanding Note, or in respect of a
covenant or a provision that cannot  be modified or amended without the  consent
of all holders of Notes.
 
    No holder of any of the Notes has any right to institute any proceeding with
respect  to the  Indenture or  any remedy thereunder,  unless the  holders of at
least 25% in  principal amount at  maturity of the  outstanding Notes have  made
written request, and offered reasonable security or indemnity, to the Trustee to
institute  such proceeding as Trustee, the  Trustee has failed to institute such
proceeding within 60 days after receipt of  such notice and the Trustee has  not
within  such 60-day  period received  directions inconsistent  with such written
request by  holders  of  a majority  in  principal  amount at  maturity  of  the
outstanding  Notes. Such limitations do not apply, however, to a suit instituted
by a holder of a Note for the  enforcement of the payment of the Default  Amount
of,  or any accrued and unpaid interest on, such Note on or after the respective
due dates expressed in such Note.
 
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<PAGE>
    During the existence  of an  Event of Default,  the Trustee  is required  to
exercise  such rights and  powers vested in  it under the  Indenture and use the
same degree of care and skill in its exercise thereof as a prudent Person  would
exercise  under the circumstances  in the conduct of  such Person's own affairs.
Subject to  the  provisions of  the  Indenture relating  to  the duties  of  the
Trustee,  if an Event of  Default shall occur and  be continuing, the Trustee is
not under any  obligation to  exercise any  of its  rights or  powers under  the
Indenture  at the request or direction of any of the holders unless such holders
shall have offered to such Trustee reasonable security or indemnity. Subject  to
certain  provisions  concerning the  rights  of the  Trustee,  the holders  of a
majority in principal amount at maturity of the outstanding Notes have the right
to direct the time, method and place of conducting any proceeding for any remedy
available to  the Trustee  or exercising  any trust  or power  conferred on  the
Trustee.
 
    The  Indenture  provides that  the Trustee  will, within  45 days  after the
occurrence of any  Default, give  to the  holders of  the Notes  notice of  such
Default  known  to it,  unless such  Default  shall have  been cured  or waived;
PROVIDED that the Trustee  shall be protected in  withholding such notice if  it
determines  in good faith that the withholding of such notice is in the interest
of such holders.
 
    The Company is required to furnish to the Trustee annually a statement as to
its compliance with all conditions and covenants under the Indenture.
 
DEFEASANCE
 
    The Company may at any time terminate all of its obligations with respect to
the Notes  ("defeasance"),  except  for  certain  obligations,  including  those
regarding any trust established for a defeasance and obligations to register the
transfer  or exchange  of the  Notes, to  replace mutilated,  destroyed, lost or
stolen Notes as required by the Indenture and to maintain agencies in respect of
the Notes. The Company may at  any time terminate its obligations under  certain
covenants set forth in the Indenture, some of which are described under "Certain
Covenants"  above, and  any omission to  comply with such  obligations shall not
constitute a  Default with  respect  to the  Notes ("covenant  defeasance").  To
exercise  either defeasance or covenant defeasance, the Company must irrevocably
deposit in trust with the Trustee, for the benefit of the holders of the  Notes,
money  (in United States dollars) or U.S. government obligations (denominated in
United States dollars),  or a combination  thereof, in such  amounts as will  be
sufficient  to  pay the  principal  of, premium,  if  any, and  interest  on the
outstanding Notes  to  redemption or  maturity  and comply  with  certain  other
conditions, including the delivery of a legal opinion as to certain tax matters.
 
SATISFACTION AND DISCHARGE
 
    The  Indenture will  be discharged  and will cease  to be  of further effect
(except as to surviving rights or registration of transfer or exchange of Notes)
as to  all  outstanding  Notes  when  either  (a)  all  such  Notes  theretofore
authenticated  and delivered (except  lost, stolen or  destroyed Notes that have
been replaced or  paid and Notes  for whose payment  money has theretofore  been
deposited in trust or segregated and held in trust by the Company and thereafter
repaid  to the Company or discharged from such trust) have been delivered to the
Trustee for cancellation or (b)(i) all  such Notes not theretofore delivered  to
the Trustee for cancellation have become due and payable by their terms or shall
have  been called  for redemption and  the Company has  irrevocably deposited or
caused to be deposited with the Trustee as trust funds in trust for the  purpose
an  amount of money sufficient  to pay and discharge  the entire Indebtedness on
the  Notes  not  theretofore  delivered  to  the  Trustee  for  cancellation  or
redemption,  for the principal amount, premium,  if any, and accrued interest to
the date of such deposit; (ii) the Company has paid all other sums payable by it
under  the  Indenture;   and  (iii)  the   Company  has  delivered   irrevocable
instructions  to the Trustee to apply the  deposited money toward the payment of
the Notes  at maturity  or  on the  redemption  date, as  the  case may  be.  In
addition,  the Company must  deliver an Officers' Certificate  and an Opinion of
Counsel stating that all conditions precedent to satisfaction and discharge have
been complied with.
 
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<PAGE>
AMENDMENTS AND WAIVERS
 
    From time to time the Company, when authorized by resolutions of its  Board,
and  the Trustee, without  the consent of  the holders of  the Notes, may amend,
waive or supplement the Indenture or  the Notes for certain specified  purposes,
including,  among other things, curing  ambiguities, defects or inconsistencies,
maintaining the qualification of the Indenture under the Trust Indenture Act  or
making any change that does not adversely affect the rights of any holder. Other
amendments  and modifications of the Indenture and  the Notes may be made by the
Company and the  Trustee with  the consent  of the holders  of not  less than  a
majority  of the aggregate principal amount at maturity of the outstanding Notes
(including consents obtained in connection with a tender offer or exchange offer
for Notes); PROVIDED  that no such  modification or amendment  may, without  the
consent  of the holder of each outstanding Note affected thereby, (i) reduce the
principal amount at  maturity of,  extend the fixed  maturity of,  or alter  the
redemption  provisions of, the Notes  or amend or modify  the calculation of the
Accreted Value or the Default Amount so as to reduce the amount of the  Accreted
Value  or the Default Amount, (ii) change the currency in which any Notes or any
premium or the accrued interest thereon is payable, (iii) reduce the  percentage
in  principal amount  at maturity  outstanding of Notes  who must  consent to an
amendment, supplement  or  waiver  or  consent to  take  any  action  under  the
Indenture  or  the  Notes, (iv)  impair  the  right to  institute  suit  for the
enforcement of any payment on or with respect to the Notes, (v) waive a  default
in  payment with respect to  the Notes, (vi) reduce the  rate or extend the time
for payment of interest on  the Notes or (vii)  adversely affect the ranking  of
the Notes in a manner adverse to the holder of the Notes.
 
    In  addition, without the consent of at least 66 2/3% in principal amount at
maturity  of  the  Notes  then  outstanding  (including  consents  obtained   in
connection with a tender offer or exchange offer for Notes), no amendment to the
Indenture  may make any change in, and no waiver may be made with respect to any
Default in the performance of, the provisions described above under the captions
"Change in Control" and "Disposition of Proceeds of Asset Sales."
 
CONCERNING THE TRUSTEE
 
    The Indenture provides that,  except during the continuance  of an Event  of
Default, the Trustee will perform only such duties as are specifically set forth
in  the Indenture. If  an Event of  Default has occurred  and is continuing, the
Trustee will exercise such  rights and powers vested  in it under the  Indenture
and  use the same degree of  care and skill in its  exercise as a prudent Person
would exercise  under the  circumstances in  the conduct  of such  Person's  own
affairs.
 
    The  Indenture and the provisions of the Trust Indenture Act incorporated by
reference therein  contain certain  limitations  on the  rights of  the  Trustee
thereunder,  should it become  a creditor of  the Company, to  obtain payment of
claims in certain cases,  or to realize  on certain property  received by it  in
respect  of any such claims, as security  or otherwise. The Trustee is permitted
to engage in  other transactions;  PROVIDED, HOWEVER,  that if  it acquires  any
conflicting interest, it must eliminate such conflict or resign.
 
GOVERNING LAW
 
    The Indenture and the Notes will be governed by, and construed in accordance
with,  the laws of the State of New York without giving effect to the principles
of conflicts of law thereof.
 
CERTAIN DEFINITIONS
 
    Set forth below are certain defined  terms used in the Indenture.  Reference
is  made to the Indenture for any  other capitalized terms used herein for which
no definition is provided.
 
    "ACCRETED VALUE" as of any Specified Date, means with respect to each $1,000
principal amount at maturity of Notes:
 
                                       95
<PAGE>
       (i) if the Specified Date occurs on  one of the following dates (each,  a
           "Semi-Annual Accrual Date"), the amount set forth below opposite such
    date:
 
<TABLE>
<CAPTION>
SEMI-ANNUAL ACCRUAL DATE                                         ACCRETED VALUE
- ---------------------------------------------------------------  --------------
<S>                                                              <C>
                , 1996.........................................   $
                , 1997.........................................
                , 1997.........................................
                , 1998.........................................
                , 1998.........................................
                , 1999.........................................
                , 1999.........................................
                , 2000.........................................
                , 2000.........................................
                , 2001.........................................
                , 2001.........................................   $   1,000.00
</TABLE>
 
       (ii)if  the Specified  Date occurs  before the  first Semi-Annual Accrual
           Date, the sum of (A) the original issue price and (B) an amount equal
    to the product of (1) the  Accreted Value for the first Semi-Annual  Accrual
    Date  less the  original issue  price and (2)  a fraction,  the numerator of
    which is the number of days from the Issue Date to the Specified Date, using
    a 360-day year of twelve 30-day months, and the denominator of which is  the
    number  of days elapsed from the issue date  of the Notes to the first Semi-
    Annual Accrual Date, using a 360-day year of twelve 30-day months;
 
       (iii)
           if the Specified Date occurs  between two Semi-Annual Accrual  Dates,
           the  sum of (A)  the Accreted Value for  the Semi-Annual Accrual Date
    immediately preceding the  Specified Date  and (B)  an amount  equal to  the
    product  of (1) the Accreted Value for the immediately following Semi-Annual
    Accrual  Date  less  the  Accreted  Value  for  the  immediately   preceding
    Semi-Annual  Accrual Date and (2) a fraction,  the numerator of which is the
    number of days from  the immediately preceding  Semi-Annual Accrual Date  to
    the  Specified Date, using a  360-day year of twelve  30-day months, and the
    denominator of which is 180; or
 
       (iv)if the Specified Date occurs after the last Semi-Annual Accrual Date,
           $1,000.
 
    "ACQUIRED  DEBT"  means,   with  respect  to   any  specified  Person,   (i)
Indebtedness  of any  other Person  existing at  the time  such other  Person is
merged with or into or became a Subsidiary of such specified Person,  including,
without   limitation,   Indebtedness  incurred   in   connection  with,   or  in
contemplation of,  such  other  Person  merging  with  or  into  or  becoming  a
Subsidiary  of such  specified Person, and  (ii) Indebtedness secured  by a Lien
encumbering any asset acquired by such specified Person.
 
    "ADJUSTED CONSOLIDATED NET INCOME" means, for any period, the aggregate  net
income  (or loss) of the Company and its Restricted Subsidiaries for such period
determined in conformity with GAAP; PROVIDED  that the following items shall  be
excluded  in computing  Adjusted Consolidated Net  Income (without duplication):
(i) the  net income  of any  Person (other  than net  income attributable  to  a
Restricted Subsidiary) in which any Person (other than the Company or any of its
Restricted  Subsidiaries)  has  a  joint  interest and  the  net  income  of any
Unrestricted Subsidiary, except  to the  extent of  the amount  of dividends  or
other  distributions  actually paid  to  the Company  or  any of  its Restricted
Subsidiaries  by   such  other   Person  (including,   without  limitation,   an
Unrestricted  Subsidiary) during  such period; (ii)  solely for  the purposes of
calculating the  amount of  Restricted Payments  that may  be made  pursuant  to
clause  (C) of  the first paragraph  of the "Limitation  on Restricted Payments"
covenant described above  (and in  such case,  except to  the extent  includable
pursuant  to clause (i) above),  the net income (or  loss) of any Person accrued
prior to  the date  it becomes  a Restricted  Subsidiary or  is merged  into  or
consolidated  with the Company or  any of its Restricted  Subsidiaries or all or
substantially all of the property and assets of such Person are acquired by  the
Company  or any  of its  Restricted Subsidiaries;  (iii) the  net income  of any
Restricted Subsidiary to the extent that the declaration or payment of dividends
or similar distributions by such Restricted Subsidiary of such net income is not
at the time permitted by the operation of
 
                                       96
<PAGE>
the terms of its charter or any agreement, instrument, judgment, decree,  order,
statute,   rule  or  governmental  regulation   applicable  to  such  Restricted
Subsidiary; (iv) any  gains or losses  (on an after-tax  basis) attributable  to
Asset  Sales; (v)  except for purposes  of calculating the  amount of Restricted
Payments that may be made pursuant to  clause (C) of the first paragraph of  the
"Limitation  on Restricted Payments"  covenant described above,  any amount paid
as, or accrued  for, cash dividends  on Preferred  Stock of the  Company or  any
Restricted  Subsidiary owned by  Persons other than  the Company and  any of its
Restricted Subsidiaries; and  (vi) all extraordinary  or nonrecurring gains  and
losses.
 
    "ADJUSTED CONSOLIDATED NET TANGIBLE ASSETS" means the total amount of assets
of  the Company and  its Restricted Subsidiaries  (less applicable depreciation,
amortization and other valuation reserves), except to the extent resulting  from
write-ups  of capital assets (excluding  write-ups in connection with accounting
for acquisitions in  conformity with  GAAP), after deducting  therefrom (i)  all
current  liabilities of the  Company and its  Restricted Subsidiaries (excluding
intercompany items) and  (ii) all  goodwill, trade  names, trademarks,  patents,
unamortized  debt discount  and expense and  other like  intangibles (other than
licenses issued  by the  FCC),  all as  set forth  on  the quarterly  or  annual
consolidated  balance  sheet of  the  Company and  its  Restricted Subsidiaries,
prepared in conformity  with GAAP and  most recently filed  with the  Commission
pursuant  to the  "Reports" covenant;  PROVIDED that  the value  of any licenses
issued by the FCC  shall, in the  event of an auction  for similar licenses,  be
equal  to the fair market value ascribed thereto  in good faith by the Board and
evidenced by a resolution of the Board. As used in the Indenture, references  to
financial  statements of  the Company and  its Restricted  Subsidiaries shall be
adjusted to exclude Unrestricted Subsidiaries if the context requires.
 
    "AFFILIATE" of  any specified  Person  means any  other Person  directly  or
indirectly  controlling  or controlled  by or  under  direct or  indirect common
control with such specified Person.  For purposes of this definition,  "control"
(including,  with correlative meanings, the terms "controlling," "controlled by"
and "under common control with"), as used with respect to any Person, shall mean
the possession, directly  or indirectly,  of the power  to direct  or cause  the
direction  of the  management or  policies of  such Person,  whether through the
ownership of  voting  securities,  by  agreement  or  otherwise;  PROVIDED  that
beneficial  ownership of 10% or more of  the voting securities of a Person shall
be deemed to  be control. For  purposes of the  Indenture, the term  "Affiliate"
shall  at all times include Laurence S. Zimmerman, Landover Holdings Corporation
and their respective Affiliates.
 
    "ART LICENSING"  means ART  Licensing Corp.,  a Delaware  corporation and  a
wholly  owned subsidiary of the Company, or any successor thereto, or such other
Subsidiary or  Subsidiaries  of  the  Company formed  for  the  purpose  of  the
application for, acquisition of or ownership of FCC licenses and authorizations.
 
    "ART WEST" means ART West Joint Venture, a Delaware partnership owned by the
Company and Extended Communications, Inc.
 
    "ASSET  ACQUISITION" means (i)  an Investment by  the Company or  any of its
Restricted Subsidiaries in any other Person pursuant to which such Person  shall
become  a  Restricted Subsidiary  of  the Company  or  shall be  merged  into or
consolidated with the Company or any  of its Restricted Subsidiaries or (ii)  an
acquisition by the Company or any of its Restricted Subsidiaries of the property
and  assets  of any  Person  other than  the Company  or  any of  its Restricted
Subsidiaries that constitute substantially all of a division or line of business
of such Person.
 
    "ASSET SALE" means any sale, transfer or other disposition (including by way
of merger, consolidation or sale-leaseback transaction) in one transaction or  a
series  of  related  transactions  by  the  Company  or  any  of  its Restricted
Subsidiaries to  any Person  other than  the Company  or any  of its  Restricted
Subsidiaries  of  (i)  all  or  any  of  the  Capital  Stock  of  any Restricted
Subsidiary, (ii)  all or  substantially all  of the  property and  assets of  an
operating  unit or business of the Company or any of its Restricted Subsidiaries
or (iii) any other property  or assets of the Company  or any of its  Restricted
Subsidiaries  (including Capital Stock of any Unrestricted Subsidiaries) outside
the ordinary course of  business of the Company  or such Restricted  Subsidiary;
PROVIDED  that the following shall not be  included within the meaning of "Asset
Sale": (A)  sales or  other  dispositions of  inventory, receivables  and  other
current assets;
 
                                       97
<PAGE>
(B) sales or other dispositions of equipment that has become worn out, obsolete,
damaged  or otherwise unsuitable for use in  connection with the business of the
Company or its Restricted  Subsidiaries; (C) Permitted  Asset Swaps; (D)  sales,
transfers  or  other  dispositions  otherwise  constituting  Asset  Sales  in an
aggregate amount not to exceed $500,000 during the relevant twelve-month  period
referred  to in the "Disposition  of Proceeds of Asset  Sales" covenant; (E) any
Restricted  Payment  permitted  by  the  "Limitation  on  Restricted   Payments"
covenant;  (F) any  Lien permitted  to be Incurred  by the  "Limitation on Liens
Securing Certain Indebtedness" covenant; (G) any transaction that is governed by
the provisions of the  "Consolidation, Merger, Sale  of Assets, Etc."  covenant;
(H)  any  sale,  transfer  or  other disposition  of  the  Capital  Stock  of an
Unrestricted  Subsidiary;  and  (I)  any  disposition  pursuant  to  the  Option
Agreement, dated as of July 3, 1996, between the Company and Commco, L.L.C.
 
    "AVERAGE  LIFE" means, at any date of determination with respect to any debt
security, the quotient obtained by dividing (i)  the sum of the products of  (A)
the  number  of years  from  such date  of determination  to  the dates  of each
successive scheduled principal payment of such debt security and (B) the  amount
such principal payment by (ii) the sum of all such principal payments.
 
    "BOARD" means the Board of Directors of the Company.
 
    "CAPITAL  STOCK" means  (i) in the  case of a  corporation, corporate stock,
(ii) in the  case of  an association  or business  entity, any  and all  shares,
interests,  participations, rights or other  equivalents (however designated) of
corporate stock,  (iii) in  the  case of  a partnership,  partnership  interests
(whether  general or limited) and (iv)  any other interest or participation that
confers on a Person the right to receive  a share of the profits and losses  of,
or distributions of assets of, the issuing Person.
 
    "CAPITALIZED  LEASE"  means, as  applied  to any  Person,  any lease  of any
property (whether real, personal or mixed) of which the discounted present value
of the rental obligations of such Person as lessee, in conformity with GAAP,  is
required to be capitalized on the balance sheet of such Person; and "Capitalized
Lease  Obligations" means the discounted present value of the rental obligations
under such lease.
 
    "CHANGE IN CONTROL" means such time as (i) a "person" or "group" (within the
meaning of Sections 13(d) and 14(d)(2) of the Exchange Act) becomes the ultimate
"beneficial owner" (as defined in Rule  13d-3 under the Exchange Act) of  Voting
Stock  representing more than 50% of the  total voting power of the Voting Stock
of the Company on a fully diluted basis, (ii) individuals who on the Issue  Date
constitute  the Board  (together with  any new  directors whose  election by the
Board or  whose  nomination  for  election by  the  Company's  stockholders  was
approved  by a vote of at  least two-thirds of the members  of the Board then in
office who either were members of the Board on the Issue Date or whose  election
or  nomination for election was previously so  approved) cease for any reason to
constitute a majority of the members of  the Board then in office and (iii)  the
merger  or consolidation of the Company with or into another corporation, or the
merger or consolidation of another corporation  with and into the Company,  with
the  effect that,  immediately after such  transaction, the  stockholders of the
Company immediately prior to such transaction  hold less than 50% of the  Voting
Stock of the Person surviving such merger or consolidation.
 
    "COMMON  STOCK" means the  common stock, par  value $.001 per  share, of the
Company.
 
    "CONSOLIDATED EBITDA" means, for any period, the sum of the amounts for such
period of  (i)  Adjusted Consolidated  Net  Income, (ii)  Consolidated  Interest
Expense,  to  the  extent  such  amount  was  deducted  in  calculating Adjusted
Consolidated Net  Income, (iii)  income taxes,  to the  extent such  amount  was
deducted  in  calculating Adjusted  Consolidated Net  Income (other  than income
taxes  (either  positive   or  negative)  attributable   to  extraordinary   and
non-recurring gains or losses or sales of assets), (iv) depreciation expense, to
the  extent such  amount was deducted  in calculating  Adjusted Consolidated Net
Income, (v) amortization  expense, to  the extent  such amount  was deducted  in
calculating  Adjusted  Consolidated Net  Income, (vi)  all other  non-cash items
reducing Adjusted Consolidated Net  Income (other than  items that will  require
cash  payments and for which an accrual or reserve is, or is required by GAAP to
be,  made),  less  all  non-cash  items  increasing  Adjusted  Consolidated  Net
 
                                       98
<PAGE>
Income  and (vii) all cash dividend  payments (and non-cash dividend payments in
the case of a Person that is a Restricted Subsidiary) on any series of preferred
stock of such Person, all as determined on a consolidated basis for the  Company
and  its Restricted Subsidiaries in conformity  with GAAP; PROVIDED that, if any
Restricted Subsidiary is not a Wholly Owned Restricted Subsidiary,  Consolidated
EBITDA  shall be reduced (to the extent not otherwise reduced in accordance with
GAAP) by an  amount equal to  (A) the  amount of the  Adjusted Consolidated  Net
Income attributable to such Restricted Subsidiary MULTIPLIED BY (B) the quotient
of  (1) the  number of  shares of  outstanding Common  Stock of  such Restricted
Subsidiary not owned on the last day of such period by the Company or any of its
Restricted Subsidiaries DIVIDED BY (2) the total number of shares of outstanding
Common Stock  of such  Restricted Subsidiary  on the  last day  of such  period.
Notwithstanding  the foregoing, the  provision for taxes based  on the income or
profits of, and the depreciation and amortization and other non-cash charges of,
a Restricted Subsidiary of a Person shall be added to Adjusted Consolidated  Net
Income  to  compute Consolidated  EBITDA only  to  the extent  (and in  the same
proportion) that the net  income of such Restricted  Subsidiary was included  in
calculating  the Adjusted Consolidated Net  Income of such Person  and only if a
corresponding amount  would be  permitted at  the date  of determination  to  be
dividended  to the Company by such  Restricted Subsidiary without prior approval
(that has not  been obtained),  pursuant to  the terms  of its  charter and  all
agreements,   instruments,  judgments,  decrees,  orders,  statutes,  rules  and
governmental  regulations  applicable  to  that  Restricted  Subsidiary  or  its
stockholders.
 
    "CONSOLIDATED  INTEREST EXPENSE" means, for any period, the aggregate amount
of interest in respect of Indebtedness (including amortization of original issue
discount on any Indebtedness  and the interest portion  of any deferred  payment
obligation,  calculated  in accordance  with  the effective  interest  method of
accounting; all  commissions, discounts  and other  fees and  charges owed  with
respect  to letters of credit and bankers' acceptance financing and net payments
(if any) pursuant to Hedging Obligations; and Indebtedness that is Guaranteed or
secured by the Company or  any of its Restricted  Subsidiaries) and all but  the
principal component of rentals in respect of Capitalized Lease Obligations paid,
accrued  or  scheduled to  be  paid or  to  be accrued  by  the Company  and its
Restricted Subsidiaries during such period;  EXCLUDING, HOWEVER, (i) any  amount
of  such  interest  of any  Restricted  Subsidiary  if the  net  income  of such
Restricted Subsidiary is excluded from the calculation of Adjusted  Consolidated
Net  Income pursuant to clause (iii) of  the definition thereof (but only in the
same proportion as the net income of such Restricted Subsidiary is excluded from
the calculation of Adjusted Consolidated Note Income pursuant to clause (iii) of
the definition  thereof) and  (ii)  any premiums,  fees  and expenses  (and  any
amortization  thereof) payable in connection with the offering of the Notes, all
as determined on a consolidated basis (without taking into account  Unrestricted
Subsidiaries) in conformity with GAAP.
 
    "CREDIT FACILITY" means a bank credit facility, to be entered into among the
Company,  Canadian Imperial Bank of Commerce,  Inc., as agent (the "Agent"), and
certain lenders to be party thereto, on substantially the terms set forth in the
Summary of Terms and Conditions of the Agent, dated as of June 23, 1996, and any
amendment, extension, restatement,  refinancing or  refunding thereof;  PROVIDED
that  the Company and the Agent shall have (A) executed a commitment letter with
respect to such facility  not later than  January 1, 1997  and (B) entered  into
such  facility not later than June 30, 1997; PROVIDED FURTHER that, in the event
that the Company and the Agent shall have failed to execute a commitment  letter
or  enter into  such facility  within the time  periods specified  in the second
provision of this definition, clauses (xiii)  and (xiv) of the second  paragraph
of  the "Limitation on Indebtedness"  covenant shall be of  no further force and
effect.
 
    "DEFAULT" means any event that is, or with the passage of time or the giving
of notice or both would be, an Event of Default.
 
    "DEFAULT AMOUNT" means (i) as of any date prior to              , 2001,  the
Accreted  Value of the  Notes (plus any  applicable premium thereon)  as of such
date and (ii) as  of any date  on or after                 ,  2001, 100% of  the
principal amount at maturity of the Notes (plus any applicable premium thereon).
 
                                       99
<PAGE>
    "DIRECTED  INVESTMENT" means any Investment in a Telecommunications Business
that is made  by investing the  net proceeds  of the issuance  of Capital  Stock
(other  than Redeemable  Stock) by  the Company  (or options,  warrants or other
rights to purchase such Capital Stock) after the Issue Date; PROVIDED that  such
Investment  shall be  made with such  net proceeds  in the form  received by the
Company and shall be limited to an amount equal to (A) 50% of such net  proceeds
to  the extent that such net proceeds consist  of cash, and (B) 100% of such net
proceeds  to  the  extent  such  net  proceeds  consist  of  Capital  Stock   or
Telecommunications  Assets; PROVIDED FURTHER that such Investment is made within
180 days of such issuance of Capital Stock.
 
    "EQUITY OFFERING"  means an  underwritten public  offering or  flotation  of
Common  Stock of the Company which has  been registered under the Securities Act
and/or admitted to listing on a national securities exchange.
 
    "FAIR MARKET VALUE" means the  price that would be  paid in an arm's  length
transaction  between an informed and willing  seller under no compulsion to sell
and an informed and willing buyer under  no compulsion to buy, as determined  in
good  faith by the Board (whose determination shall be conclusive) and evidenced
by a resolution of the Board.
 
    "FCC" means  the United  States Federal  Communications Commission  and  any
state  or local  telecommunications authority, department,  commission or agency
(and any successors thereto).
 
    "GAAP" means generally accepted accounting  principles in the United  States
of  America as in effect from time to time, including, without limitation, those
set forth in the opinions and pronouncements of the Accounting Principles  Board
of  the American  Institute of Certified  Public Accountants  and statements and
pronouncements of  the Financial  Accounting Standards  Board or  in such  other
statements  by such  other entity  as approved by  a significant  segment of the
accounting profession. All  ratios and computations  contained in the  Indenture
shall  be computed in conformity with GAAP applied on a consistent basis, except
that calculations made for purposes of determining compliance with the terms  of
the  covenants and with other provisions of  the Indenture shall be made without
giving effect to  (i) the amortization  of any expenses  incurred in  connection
with  the  offering of  the Notes  and  (ii) except  as otherwise  provided, the
amortization of any amounts required or permitted by Accounting Principles Board
Opinion Nos. 16 and 17.
 
    "GUARANTEE" means any  obligation, contingent  or otherwise,  of any  Person
directly  or indirectly guaranteeing any Indebtedness or other obligation of any
other Person  and,  without  limiting  the  generality  of  the  foregoing,  any
obligation,  direct or indirect, contingent or  otherwise, of such Person (i) to
purchase or pay (or advance or supply funds for the purchase or payment of) such
Indebtedness or other obligation of such other Person (whether arising by virtue
of partnership arrangements, or by agreements to keep-well, to purchase  assets,
goods,  securities  or  services,  to  take-or-pay,  or  to  maintain  financial
statement conditions or otherwise) or (ii) entered into for purposes of assuring
in any other manner the obligee of such Indebtedness or other obligation of  the
payment  thereof or to protect such obligee  against loss in respect thereof (in
whole or  in  part);  PROVIDED  that the  term  "Guarantee"  shall  not  include
endorsements  for collection or deposit in  the ordinary course of business. The
term "Guarantee" used as a verb has a corresponding meaning.
 
    "HEDGING OBLIGATIONS" means, with respect to any Person, the obligations  of
such  Person  under  (i)  interest  rate  swap  agreements,  interest  rate  cap
agreements and  interest rate  collar agreements  and (ii)  other agreements  or
arrangements  designed to protect  such Person against  fluctuations in interest
rates.
 
    "INCUR" means, with respect  to any Indebtedness,  to incur, create,  issue,
assume,  Guarantee or otherwise become liable for  or with respect to, or become
responsible for, the payment of,  contingently or otherwise, such  Indebtedness,
including,  with  respect to  the Company  and  its Restricted  Subsidiaries, an
"incurrence" of  Indebtedness  by  reason  of a  Person  becoming  a  Restricted
Subsidiary of the Company; PROVIDED that neither the accrual of interest nor the
accretion  of  original  issue discount  shall  be considered  an  Incurrence of
Indebtedness.
 
                                      100
<PAGE>
    "INDEBTEDNESS"  means,  with  respect   to  any  Person   at  any  date   of
determination  (without duplication),  (i) all  indebtedness of  such person for
borrowed money,  (ii)  all  obligations  of  such  Person  evidenced  by  bonds,
debentures,   notes  or   other  similar  instruments   (whether  negotiable  or
non-negotiable), (iii) all obligations of such  Person in respect of letters  of
credit  or other  similar instruments (including  reimbursement obligations with
respect thereto), (iv) all  obligations of such Person  to pay the deferred  and
unpaid  purchase price of property or services, which purchase price is due more
than six months after  the date of  placing such property  in service or  taking
delivery  and title  thereto or  the completion  of such  services, except trade
payables  and  escrows,   holdbacks  and  comparable   arrangements  to   secure
indemnification obligations under acquisition agreements, (v) all obligations of
such  Person as lessee under Capitalized  Leases, (vi) all indebtedness of other
Persons secured by  a Lien  on any  asset of such  Person, whether  or not  such
indebtedness  is  assumed  by such  Person,  PROVIDED  that the  amount  of such
indebtedness shall be the lesser of (A)  the fair market value of such asset  at
such  date of determination and  (B) the amount of  such indebtedness, (vii) the
balance  deferred  and  unpaid  of  the  purchase  price  of  any  property   or
representing  any Hedging Obligations, except  any such balance that constitutes
an accrued expense or trade payable and (viii) all indebtedness of other Persons
Guaranteed by such Person to the extent such indebtedness is Guaranteed by  such
Person.  The  amount of  Indebtedness of  any Person  at any  date shall  be the
outstanding balance at such date  of all unconditional obligations as  described
above  and, with respect to  contingent obligations that are  included in any of
clauses (i) through (viii) above, the  maximum liability upon the occurrence  of
the  contingency giving  rise to  the obligation,  PROVIDED (A)  that the amount
outstanding at any time of any Indebtedness issued with original issue  discount
is  the face  amount of  such Indebtedness and  (B) that  Indebtedness shall not
include any liability for federal, state, local or other taxes.
 
    "INDEBTEDNESS TO EBITDA RATIO" means, as  at any date of determination,  the
ratio  of  (i) the  aggregate  amount of  Indebtedness  of the  Company  and its
Restricted Subsidiaries on a consolidated basis ("Consolidated Indebtedness") as
at the date of determination (the  "Transaction Date") to (ii) the  Consolidated
EBITDA  of the Company  for the then  most recent four  full fiscal quarters for
which reports have been filed pursuant to the "Reports" covenant described above
(such four full  fiscal quarter  period being referred  to herein  as the  "Four
Quarter  Period"); PROVIDED  that (x)  pro forma  effect shall  be given  to any
Indebtedness Incurred from the beginning of the Four Quarter Period through  the
Transaction  Date (including any Indebtedness Incurred on the Transaction Date),
to the extent  outstanding on  the Transaction Date,  (y) if  during the  period
commencing  on the first day of such Four Quarter Period through the Transaction
Date (the "Reference Period"), the Company or any of the Restricted Subsidiaries
shall have engaged in any Asset Sale, Consolidated EBITDA for such period  shall
be  reduced by an amount  equal to the EBITDA (if  positive), or increased by an
amount equal to the  EBITDA (if negative), directly  attributable to the  assets
which  are the subject of such Asset Sale any related retirement of Indebtedness
as if such Asset Sale and related retirement of Indebtedness had occurred on the
first day of such Reference  Period or (z) if  during such Reference Period  the
Company  or  any  of  the  Restricted Subsidiaries  shall  have  made  any Asset
Acquisition, Consolidated EBITDA  of the Company  shall be calculated  on a  pro
forma  basis as if such Asset Acquisition  and any Incurrence of Indebtedness to
finance such  Asset  Acquisition  had taken  place  on  the first  day  of  such
Reference Period.
 
    "INDEBTEDNESS  TO TOTAL MARKET  CAPITALIZATION RATIO" means,  at any date of
determination, the ratio  of (i)  the aggregate  amount of  Indebtedness of  the
Company  and Restricted Subsidiaries on a consolidated basis outstanding to (ii)
the Total Market Capitalization of the Company.
 
    "INVESTMENT" in any  Person means any  direct or indirect  advance, loan  or
extension  of  credit (including,  without limitation,  by  way of  Guarantee or
similar arrangement; but excluding advances to customers in the ordinary  course
of  business that are, in conformity  with GAAP, recorded as accounts receivable
on the balance sheet of the  Company or its Restricted Subsidiaries) or  capital
contribution to (by means of any transfer of cash or other property to others or
any  payment for property or services for the  account or use of others), or any
purchase or  acquisition of  Capital Stock,  bonds, notes,  debentures or  other
similar instruments issued by, such Person and shall include (i) the designation
of  a  Restricted Subsidiary  as an  Unrestricted Subsidiary  and (ii)  the fair
market value of the Capital Stock held by the
 
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Company and the Restricted Subsidiaries  of any Person that  has ceased to be  a
Restricted  Subsidiary by reason of any transaction permitted by clause (iii) of
the "Limitation  on  the  Issuance  and Sale  of  Capital  Stock  of  Restricted
Subsidiaries"   covenant.  For  purposes  of  the  definition  of  "Unrestricted
Subsidiary"  and  the   "Limitation  on  Restricted   Payments"  covenant,   (i)
"Investment"  shall  include  the  fair  market  value  of  the  assets  (net of
liabilities) of any Restricted Subsidiary of  the Company at the time that  such
Restricted Subsidiary is designated an Unrestricted Subsidiary and shall exclude
the  fair market value  of the assets  (net of liabilities)  of any Unrestricted
Subsidiary at  the  time  that  such Unrestricted  Subsidiary  is  designated  a
Restricted  Subsidiary of  the Company and  (ii) any property  transferred to or
from an Unrestricted Subsidiary shall be valued at its fair market value at  the
time of such transfer, in each case as determined by the Board in good faith.
 
    "ISSUE DATE" means the date of original issuance of the Notes.
 
    "LIEN" means, with respect to any asset, any mortgage, lien, pledge, charge,
security  interest or encumbrance of any kind  in respect of such asset, whether
or not filed, recorded  or otherwise perfected  under applicable law  (including
any conditional sale or other title retention agreement, any lease in the nature
thereof,  any option or other  agreement to sell or  give a security interest in
and any filing of or agreement to give any financing statement under the Uniform
Commercial Code (or equivalent statutes) of any jurisdiction).
 
    "NET CASH PROCEEDS" means (a) with  respect to any Asset Sale, the  proceeds
of  such Asset Sale in the form  of cash or cash equivalents, including payments
in respect of deferred payment obligations  (to the extent corresponding to  the
principal,  but not  interest, component thereof)  when received in  the form of
cash or cash equivalents (except to the extent such obligations are financed  or
sold  with recourse to the Company or  any Restricted Subsidiary of the Company)
and proceeds from the  conversion of other property  received when converted  to
cash  or cash equivalents, net  of (i) brokerage commissions  and other fees and
expenses (including fees and expenses of counsel and investment bankers) related
to such Asset Sale,  (ii) provisions for  all taxes (whether  or not such  taxes
will  actually be paid  or are payable) as  a result of  such Asset Sale without
regard to  the  consolidated  results  of operations  of  the  Company  and  its
Restricted  Subsidiaries,  taken  as  a  whole,  (iii)  payments  made  to repay
Indebtedness or any other obligation outstanding at the time of such Asset  Sale
that  either (A) is secured by  a Lien on the property  or assets sold or (B) is
required to be paid as a result of such sale and (iv) appropriate amounts to  be
provided by the Company or any Restricted Subsidiary of the Company as a reserve
against  any  liabilities associated  with such  Asset Sale,  including, without
limitation, pension and other  post-employment benefit liabilities,  liabilities
related  to  environmental  matters and  liabilities  under  any indemnification
obligations associated with  such Asset  Sale, all as  determined in  conformity
with  GAAP and (b)  with respect to any  issuance or sale  of Capital Stock, the
proceeds of such  issuance or  sale in  the form  of cash  or cash  equivalents,
including  payments in  respect of deferred  payment obligations  (to the extent
corresponding to  the  principal,  but not  interest,  component  thereof)  when
received  in the  form of cash  or cash  equivalents (except to  the extent such
obligations are financed or sold with recourse to the Company or any  Restricted
Subsidiary  of the Company)  and proceeds from the  conversion of other property
received when converted  to cash or  cash equivalents, net  of attorney's  fees,
underwriters' or placement agents' fees, discounts or commissions and brokerage,
consultant  and other fees incurred in connection with such issuance or sale and
net of taxes paid or payable as a result thereof.
 
    "NON-RECOURSE DEBT" means Indebtedness (a)  as to which neither the  Company
nor  any of its Restricted Subsidiaries (i)  provides credit support of any kind
(including any  undertaking,  agreement  or  instrument  that  would  constitute
Indebtedness)  or  (ii) is  directly  or indirectly  liable  (as a  guarantor or
otherwise); (b) no default with respect to which (including any rights that  the
holders  thereof may  have to  take enforcement  action against  an Unrestricted
Subsidiary) would permit (upon notice, lapse of time or both) any holder of  any
other  Indebtedness  (other  than  the  Notes) of  the  Company  or  any  of its
Restricted Subsidiaries to declare a default on such other Indebtedness or cause
the payment thereof to be accelerated  or payable prior to its stated  maturity;
and (c) as to which the lender of any indebtedness
 
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for  borrowed money in  an aggregate amount  in excess of  $5.0 million has been
notified in writing that such lender will not have any recourse to the stock  or
assets of the Company or any of its Restricted Subsidiaries.
 
    "OFFER TO PURCHASE" means an offer to purchase Notes by the Company from the
holders  that is  required by  the "Disposition of  Proceeds of  Asset Sales" or
"Change in Control" covenants of the Indenture and which is commenced by mailing
a notice to the Trustee  and each holder stating:  (i) the covenant pursuant  to
which  the  offer is  being made  and that  all Notes  validly tendered  will be
accepted for payment on a pro rata  basis; (ii) the purchase price and the  date
of  purchase (which shall  be a business day  no earlier than  30 days nor later
than 60 days from the  date such notice is  mailed) (the "Payment Date");  (iii)
that  any Note  not tendered  will continue to  accrue interest  pursuant to its
terms; (iv) that,  unless the Company  defaults in the  payment of the  purchase
price,  any Note accepted  for payment pursuant  to the Offer  to Purchase shall
cease to  accrue  interest on  and  after the  Payment  Date; (v)  that  holders
electing  to have  a Note purchased  pursuant to  the Offer to  Purchase will be
required to surrender the  Note together with the  form entitled "Option of  the
Holder  to Elect Purchase" on the reverse  side thereof completed, to the Paying
Agent at the address specified in the  notice prior to the close of business  on
the  business day immediately preceding the Payment Date; (vi) that holders will
be entitled to withdraw their election if the Payment Agent receives, not  later
than  the close of business on the  third business day immediately preceding the
Payment Date, a  telegram, facsimile  transmission or letter  setting forth  the
name  of such holder, the principal amount of Notes delivered for purchase and a
statement that  such holder  is  withdrawing his  election  to have  such  Notes
purchased;  and (vii) that holders whose Notes  are being purchased only in part
will be issued new  Notes equal in principal  amount to the unpurchased  portion
thereof;  PROVIDED that each Note purchased and each new Note issued shall be in
a principal amount of $1,000 or integral multiples thereof. On the Payment Date,
the Company shall (i) accept for payment  on a pro rata basis Notes or  portions
thereof  tendered pursuant to an Offer to Purchase, (ii) deposit with the Paying
Agent money  sufficient to  pay the  purchase  price of  all Notes  or  portions
thereof  so accepted and (iii) deliver, or cause to be delivered, to the Trustee
all Notes or portions thereof so accepted together with an Officers' Certificate
specifying the Notes or portions thereof so accepted for payment by the Company.
The Paying Agent shall  promptly mail to  the holders of  Notes so accepted  for
payment in an amount equal to the purchase price, and the Trustee shall promptly
authenticate  and mail to such  holders a new Note  equal in principal amount to
any unpurchased  portion  of  the  Note surrendered;  PROVIDED  that  each  Note
purchased  and each new Note issued shall be  in a principal amount of $1,000 or
integral multiples thereof. The Company will publicly announce the results of an
Offer to Purchase  as soon as  practicable after the  Payment Date. The  Trustee
shall  act as the Paying Agent for an Offer to Purchase. The Company will comply
with Rule  14e-1  under the  Exchange  Act and  any  other securities  laws  and
regulations  thereunder to the extent such  laws and regulations are applicable,
in the event that  the Company is  required to repurchase  Notes pursuant to  an
Offer to Purchase.
 
    "PERMITTED  ASSET SWAP" means any  disposition by the Company  or any of its
Restricted Subsidiaries of Telecommunications Assets or a majority of the Voting
Stock of a Restricted Subsidiary  in exchange for comparable  Telecommunications
Assets  or a majority of the Voting Stock of a comparable Restricted Subsidiary;
PROVIDED that the Board  shall have approved such  disposition and exchange  and
determined  the fair market value  of the assets subject  to such transaction as
evidenced by  a resolution  of the  Board or  such fair  market value  has  been
determined  by  a written  opinion  of an  investment  banking firm  of national
standing or other recognized independent  expert with experience appraising  the
terms and conditions of the type of transaction contemplated thereby.
 
    "PERMITTED INVESTMENTS" MEANS:
 
         (i)  an Investment in  a Restricted Subsidiary or  a Person which will,
    upon the making  of such Investment,  become a Restricted  Subsidiary or  be
    merged   or  consolidated  with  or  into  or  transfer  or  convey  all  or
    substantially all its assets to, the Company or a Restricted Subsidiary;
 
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        (ii) Temporary Cash Investments;
 
        (iii) payroll, travel  and similar  advances to cover  matters that  are
    expected  at the time of such advances  ultimately to be treated as expenses
    in accordance with GAAP;
 
        (iv) loans or advances  to employees (other  than executive officers  of
    the  Company) in an aggregate principal amount not to exceed $1.0 million at
    any one time outstanding;
 
        (v)  stock,  obligations  or  securities  received  in  satisfaction  of
    judgments;
 
        (vi)  Investments, to the extent that  the consideration provided by the
    Company or any  of its  Restricted Subsidiaries consists  solely of  Capital
    Stock (other than Redeemable Stock) of the Company;
 
       (vii)  notes payable to the  Company that are received  by the Company as
    payment of  the purchase  price  for Capital  Stock (other  than  Redeemable
    Stock) of the Company;
 
       (viii)  Investments in an aggregate amount not to exceed $20.0 million at
    any one time outstanding;
 
        (ix) Investments in an  aggregate amount not to  exceed $1.0 million  at
    any   time  outstanding   in  Unrestricted   Subsidiaries  engaged   in  the
    Telecommunications Business outside of the United States;
 
        (x) Investments  in entities  (other than  ART West)  that own  licenses
    granted  by the FCC; PROVIDED that (A) such Investments are made pursuant to
    a senior promissory note, in an amount equal to such Investment, that by its
    terms is payable in full at or before any required repayment of principal on
    the Notes, (B) such promissory note is secured equally and ratably with  (or
    prior to) any other secured Indebtedness of such entity, (C) such Investment
    is  made and  used for  the purpose  of effecting,  and does  not exceed the
    amount reasonably required to effect, the minimum build-out with respect  to
    such  licenses that is required by the FCC as a prerequisite to the transfer
    of a majority equity interest  in such entity to the  Company or one of  its
    Restricted  Subsidiaries, as determined  in good faith by  the Board and (D)
    the Company, at the  time such Investment is  made, had a contractual  right
    to,  and intends  (subject in  all cases  to compliance  with applicable FCC
    rules and regulations) to, acquire such majority equity interest;
 
        (xi) Investments existing on the Issue Date;
 
       (xii) the acquisition of all equity  interests of ART West not  otherwise
    owned by the Company; and
 
      (xiii) Directed Investments.
 
        "PERMITTED LIENS" MEANS:
 
         (i)  Liens for taxes, assessments,  governmental charges or claims that
    are being contested in  good faith by  appropriate legal proceedings  timely
    instituted  and  diligently  conducted  and for  which  a  reserve  or other
    appropriate provision, if any, as shall be required in conformity with  GAAP
    shall have been made;
 
        (ii)   statutory  or  common  law   Liens  of  landlords  and  carriers,
    warehousemen, mechanics, suppliers, materialmen, repairmen or other  similar
    Liens arising in the ordinary course of business and with respect to amounts
    not  yet delinquent  or being contested  in good faith  by appropriate legal
    proceedings timely  instituted  and diligently  conducted  and for  which  a
    reserve  or other  appropriate provision,  if any,  as shall  be required in
    conformity with GAAP shall have been made;
 
        (iii) Liens incurred or deposits made in the ordinary course of business
    in connection with workers'  compensation, unemployment insurance and  other
    types of social security;
 
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        (iv)  Liens  incurred  or deposits  made  to secure  the  performance of
    tenders,  bids,  leases,  statutory  or  regulatory  obligations,   bankers'
    acceptances,  surety and appeal bonds, government contracts, performance and
    return- of-money bonds and other obligations of a similar nature incurred in
    the ordinary course of business (exclusive of obligations for the payment of
    borrowed money) and a  bank's unexercised right of  set-off with respect  to
    deposits made in the ordinary course;
 
        (v)  easements,  rights-of-way,  municipal  and  zoning  ordinances  and
    similar charges, encumbrances, title defects or other irregularities that do
    not materially interfere with the ordinary course of business of the Company
    or any of its other irregularities that do not materially interfere with the
    ordinary course of business of the Company or any of its Subsidiaries;
 
        (vi) Liens  (including extensions  and renewals  thereof) upon  real  or
    personal property acquired after the Issue Date; PROVIDED that (A) such Lien
    is  created  solely for  the purpose  of  securing Indebtedness  Incurred in
    accordance with the  "Limitation on Indebtedness"  covenant, (1) to  finance
    the  cost (including the cost of improvement or construction) of the item of
    property or assets subject thereto and such Lien is created prior to, at the
    time of  or  within six  months  after the  later  of the  acquisition,  the
    completion  of construction  or the commencement  of full  operation of such
    property or (2) to refinance any Indebtedness previously so secured, (B) the
    principal amount of the  Indebtedness secured by such  Lien does not  exceed
    100%  of such cost  and (C) any such  Lien shall not extend  to or cover any
    property or  assets other  than such  item  of property  or assets  and  any
    improvements on such item;
 
       (vii)  leases  or  subleases granted  to  others that  do  not materially
    interfere with  the ordinary  course  of business  of  the Company  and  its
    Restricted Subsidiaries, taken as a whole;
 
       (viii)  Liens encumbering  property or assets  under construction arising
    from progress  or partial  payments by  a  customer of  the Company  or  its
    Restricted Subsidiaries relating to such property or assets;
 
        (ix)  any interest or title  of a lessor in  the property subject to any
    Capitalized Lease or operating lease;
 
        (x)  Liens  arising  from  filing  Uniform  Commercial  Code   financing
    statements regarding leases;
 
        (xi) Liens on property of, or on shares of stock or Indebtedness of, any
    corporation existing at the time such corporation becomes, or becomes a part
    of,  any Restricted Subsidiary; PROVIDED that such Liens do not extend to or
    cover any property  or assets of  the Company or  any Restricted  Subsidiary
    other than the property or assets acquired;
 
       (xii) Liens in favor of the Company or any Restricted Subsidiary;
 
      (xiii)  Liens  arising from  the rendering  of a  final judgment  or order
    against the Company or  any Restricted Subsidiary of  the Company that  does
    not give rise to an Event of Default;
 
       (xiv) Liens securing reimbursement obligations with respect to letters of
    credit  that encumber documents and the property relating to such letters of
    credit and the products and proceeds thereof;
 
       (xv) Liens  in favor  of customs  and revenue  authorities arising  as  a
    matter  of law to  secure payment of  customs duties in  connection with the
    importation of goods;
 
       (xvi) Liens arising out of conditional sale, title retention, consignment
    or similar arrangements for the sale of goods entered into by the Company or
    any of its  Restricted Subsidiaries in  the ordinary course  of business  in
    accordance  with  the  past  practices of  the  Company  and  its Restricted
    Subsidiaries prior to the Issue Date;
 
      (xvii) Liens on or sales of receivables;
 
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     (xviii) Liens securing  other Indebtedness  in an aggregate  amount not  to
    exceed $250,000 at any one time;
 
      (xix)   Liens  on   assets  of   Unrestricted  Subsidiaries   that  secure
    Non-Recourse Debt of Unrestricted Subsidiaries;
 
       (xx) Liens existing on the Issue Date;
 
      (xxi) Liens granted after the Issue Date on any assets or Capital Stock of
    the Company or its Restricted Subsidiaries  created in favor of the  holders
    of the Notes;
 
      (xxii) Liens with respect to the assets of a Restricted Subsidiary granted
    by  such Restricted Subsidiary  to the Company or  a Wholly Owned Restricted
    Subsidiary to secure Indebtedness owing to the Company or such other  Wholly
    Owned Restricted Subsidiary;
 
     (xxiii)  Liens securing Indebtedness which is Incurred to refinance secured
    Indebtedness which is  permitted to be  Incurred under clause  (iii) of  the
    second paragraph of the "Limitation on Indebtedness" covenant; PROVIDED that
    such  Liens do not extend to or cover  any property or assets of the Company
    or any Restricted Subsidiary other than the property or assets securing  the
    Indebtedness being refinanced;
 
     (xxiv) purchase money Liens upon equipment, software or systems acquired or
    held  by the Company or any of its Restricted Subsidiaries taken or retained
    by the seller (or a financing institution acting on behalf of the seller) of
    such equipment, software or systems to secure all or a part of the  purchase
    price  therefor; PROVIDED  that such  Liens do  not extend  to or  cover any
    property or assets of  the Company or any  Restricted Subsidiary other  than
    the equipment so acquired; and
 
      (xxv)  Liens securing Indebtedness which is permitted to be Incurred under
    clause (xiii)  or  (xiv) of  the  second  paragraph of  the  "Limitation  on
    Indebtedness" covenant.
 
    "PERSON"  means  any  individual,  corporation,  limited  liability company,
partnership,   joint   venture,   association,   joint-stock   company,   trust,
unincorporated organization or government or any agency or political subdivision
thereof.
 
    "PREFERRED  STOCK" means,  with respect to  any Person, any  and all shares,
interests, participations  or other  equivalents  (however designated)  of  such
Person's  preferred or preference stock, whether now outstanding or issued after
the Issue Date,  and including, without  limitation, all classes  and series  of
preferred or preference stock of such Person.
 
    "REDEEMABLE  STOCK" means any class or series of Capital Stock of any Person
that by its  terms or  otherwise is  (i) required to  be redeemed  prior to  the
Stated  Maturity of the  Notes, (ii) redeemable  at the option  of the holder of
such class or series of Capital Stock  at any time prior to the Stated  Maturity
of  the Notes (unless the redemption price  is, at the Company's option, without
conditions precedent,  payable solely  is Common  Stock (other  than  Redeemable
Stock)  of the  Company) or (iii)  convertible into or  exchangeable for Capital
Stock referred to in clause (i) or (ii) above or Indebtedness having a scheduled
maturity prior to the  Stated Maturity of the  Notes; PROVIDED that any  Capital
Stock  that would  not constitute  Redeemable Stock  but for  provisions thereof
giving holders thereof the right to require such Person to repurchase or  redeem
such Capital Stock upon the occurrence of an "asset sale" or "change of control"
occurring  prior  to  the Stated  Maturity  of  the Notes  shall  not constitute
Redeemable  Stock  if  the  "asset  sale"  or  "change  of  control"  provisions
applicable  to such Capital Stock  are no more favorable  to the holders of such
Capital Stock than the provisions contained in "Disposition of Proceeds of Asset
Sales" and "Change in Control" covenants described above and such Capital  Stock
specifically  provides that such  Person will not repurchase  or redeem any such
stock pursuant to such provision prior to the Company's repurchase of such Notes
as are required to  be repurchased pursuant to  the "Disposition of Proceeds  of
Asset Sales" and "Change in Control" covenants described above.
 
    "RESTRICTED  SUBSIDIARY" of  a Person means  any Subsidiary  of the referent
Person that is not an Unrestricted Subsidiary.
 
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    "SIGNIFICANT SUBSIDIARY" means, at any date of determination, any Restricted
Subsidiary of the Company that, together with its Subsidiaries, (i) for the most
recent fiscal  year  of  the  Company,  accounted  for  more  than  10%  of  the
consolidated  revenues of the Company and its Restricted Subsidiaries or (ii) as
of the end of such fiscal year, had  assets accounting for more than 10% of  the
consolidated  assets of the Company and  its Restricted Subsidiaries, all as set
forth on the most  recently available consolidated  financial statements of  the
Company for such fiscal year.
 
    "SPECIFIED  DATE" means any  redemption date, any date  of purchase of Notes
pursuant to the "Disposition of Proceeds of Asset Sales" or "Change in  Control"
covenants  described above, or any  date on which the  Notes are due and payable
after an Event of Default.
 
    "STATED MATURITY" means,  (i) with respect  to any debt  security, the  date
specified in such debt security as the fixed date on which the final installment
of  principal of such debt security is due  and payable and (ii) with respect to
any scheduled installment of principal of or interest on any debt security,  the
date specified in such debt security as the fixed date on which such installment
is due and payable.
 
    "STRATEGIC  EQUITY INVESTOR"  means any  company which  is (or  a controlled
Affiliate of any company which is or a controlled Affiliate of which is) engaged
principally in a cable or telecommunications  business which has a total  market
capitalization of at least $1.0 billion.
 
    "SUBSIDIARY"  means,  with  respect  to  any  Person,  (i)  any corporation,
association or other business entity of which more than 50% of the total  voting
power  of shares of Capital Stock entitled  (without regard to the occurrence of
any contingency) to  vote in  the election  of directors,  managers or  trustees
thereof  is at  the time  owned or controlled,  directly or  indirectly, by such
Person or one or more of the other Subsidiaries of that Person (or a combination
thereof) and (ii) any partnership (a)  the sole general partner or the  managing
general  partner of which is  such Person or a Subsidiary  of such Person or (b)
the only  general  partners  of  which  are  such  Person  or  of  one  or  more
Subsidiaries of such Person (or any combination thereof).
 
    "TELECOMMUNICATIONS ASSETS" means all assets (including, without limitation,
assets  consisting  of  subscribers),  rights  (contractual  or  otherwise)  and
properties,  whether  tangible  or  intangible,   used  in  connection  with   a
Telecommunications Business.
 
    "TELECOMMUNICATIONS  BUSINESS" means, when used  in reference to any Person,
that such Person is  engaged primarily in the  business of (i) providing  voice,
video  or data communications services,  (ii) creating, developing, marketing or
selling communications related  equipment, software and  other devices or  (iii)
evaluating,  participating in or pursuing any other activity or opportunity that
is related or incidental to those identified in clauses (i) or (ii) above.
 
    "TEMPORARY  CASH  INVESTMENT"  means  any  of  the  following:  (i)   direct
obligations  of the United States or any agency thereof or obligations fully and
unconditionally guaranteed by the United States or any agency thereof; (ii) time
deposit accounts, certificates  of deposit  and money  market deposits  maturing
within  six months of the date of acquisition  thereof issued by a bank or trust
company which  is organized  under the  laws  of the  United States,  any  state
thereof  or any foreign country recognized by  the United States, and which bank
or trust  company has  capital,  surplus and  undivided profits  aggregating  in
excess  of $50.0  million (or the  foreign currency equivalent  thereof) and has
outstanding debt  which is  rated "A"  (or such  similar equivalent  rating)  or
higher by at least one nationally recognized statistical rating organization (as
defined in Rule 436 under the Securities Act) or any money-market fund sponsored
by  a  registered broker  dealer or  mutual  fund distributor;  (iii) repurchase
obligations with a term of  not more than 30  days for underlying securities  of
the  types described in  clause (i) above  entered into with  a bank meeting the
qualifications described in clause (ii)  above; (iv) commercial paper,  maturing
not  more than six months after the date of acquisition, issued by a corporation
other than an  Affiliate of the  Company) organized and  in existence under  the
laws  of the United States, any state  thereof or any foreign country recognized
by the United States with rating at the time as of which any investment  therein
is  made of "P-1"  (or higher) according  to Moody's Investors  Service, Inc. or
"A-1" (or  higher)  according  to  Standard &  Poor's  Ratings  Group;  and  (v)
securities with maturities of six months
 
                                      107
<PAGE>
or  less  from  the date  of  acquisition  issued or  fully  and unconditionally
guaranteed by any state, commonwealth or  territory of the United States, or  by
any political subdivision or taxing authority thereof, and rated at least "A" by
Standard  & Poor's  Ratings Group or  Moody's Investors  Service, Inc.; PROVIDED
that, notwithstanding the foregoing, the maturity  of any of the foregoing  that
is  applied to  provide security  in favor  of the  Indebtedness referred  to in
clause (xxiv) of the definition  of "Permitted Liens" may  occur as late as  the
earliest  date  that such  Indebtedness may  be  redeemed at  the option  of the
obligor with respect to such Indebtedness and provided further that the  Company
shall cause such Liens referred to in such clause (xxiv) to be incurred no later
than the first anniversary of the Issue Date.
 
    "TOTAL  MARKET  CAPITALIZATION"  of  any  Person means,  as  of  any  day of
determination, the sum of (a) the  consolidated Indebtedness of such Person  and
its  Restricted  Subsidiaries on  such  day, PLUS  (b)  the product  of  (i) the
aggregate number of outstanding  shares of Common Stock  of such Person on  such
day  (which  shall  not  include  any  options  or  warrants  on,  or securities
convertible or exchangeable  into, shares of  Common Stock of  such Person)  and
(ii)  the average  Closing Price  of such Common  Stock over  the 10 consecutive
Trading Days ending not earlier than  10 Trading Days immediately prior to  such
date  of determination, PLUS (c) the liquidation value of any outstanding shares
of Preferred Stock of such Person on  such day. If no such Closing Price  exists
with  respect to shares of any such class, the value of such shares for purposes
of clause (b) of the preceding sentence shall be determined by the Board in good
faith and  evidenced  by a  resolution  of the  Board  filed with  the  Trustee.
Notwithstanding  the foregoing, unless  the Company's Common  Stock is listed on
any national securities exchange  or on the Nasdaq  National Market, the  "Total
Market   Capitalization"  of  the   Company  shall  mean,  as   of  any  day  of
determination, the enterprise value (without duplication) of the Company and its
Restricted Subsidiaries  (including the  fair  market value  of their  debt  and
equity,  but  excluding  the  enterprise  value  of  the  Company's Unrestricted
Subsidiaries), as determined by an independent banking firm of national standing
with experience  in  such valuations  and  evidenced  by a  written  opinion  in
customary  form filed with the  Trustee; PROVIDED that for  purposes of any such
determination, the enterprise value of the Company shall be calculated as if the
Company were a publicly held corporation without a controlling stockholder.  For
purposes  of any  such determination,  such banking  firm's written  opinion may
state that such fair market  value is no less than  a specified amount and  such
opinion  may be as of a  date no earlier than 90 days  prior to the date of such
determination.
 
    "TRADING DAY" with respect to  a securities exchange or automated  quotation
system  means a day on which  such exchange or system is  open for a full day of
trading.
 
    "UNRESTRICTED SUBSIDIARY" means  any Subsidiary  that is  designated by  the
Board  as an Unrestricted Subsidiary pursuant to  a resolution of the Board; but
only to  the extent  that such  Subsidiary (i)  has no  Indebtedness other  than
Non-Recourse  Debt; (ii) is not party to any agreement, contract, arrangement or
understanding with  the Company  or  any Restricted  Subsidiary of  the  Company
unless  the terms of any such  agreement, contract, arrangement or understanding
are no less favorable  to the Company or  such Restricted Subsidiary than  those
that  might be obtained at  the time from Persons who  are not Affiliates of the
Company; (iii) is a Person with respect to which neither the Company nor any  of
its  Restricted  Subsidiaries  has  any direct  or  indirect  obligation  (A) to
subscribe for  additional  equity interests,  except  to the  extent  that  such
obligation  complies with the  "Limitation on Restricted  Payments" covenant, or
(B) to maintain or preserve such  Person's financial condition or to cause  such
Person  to achieve  any specified  levels of  operating results;  (iv) is  not a
guarantor of or otherwise directly or indirectly provides credit support for any
Indebtedness of the Company or any of its Restricted Subsidiaries; and (v)  has,
immediately  prior to the commencement of material business operations, at least
one director on  its board  of directors  that is  not a  director or  executive
officer  of the Company or  any of its Restricted  Subsidiaries and has at least
one executive officer that is not a director or executive officer of the Company
or any of its Restricted Subsidiaries.  Any such designation by the Board  shall
be  evidenced to the Trustee by filing with  the Trustee a certified copy of the
resolution of  the Board  giving effect  to such  designation and  an  Officers'
Certificate  certifying  that  such  designation  complied  with  the  foregoing
conditions and was permitted by the  covenant described above under the  caption
"Limitation   on  Restricted  Payments."  If,  at  any  time,  any  Unrestricted
Subsidiary would fail to meet the foregoing
 
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requirements as an Unrestricted Subsidiary, it  shall thereafter cease to be  an
Unrestricted  Subsidiary for purposes  of the Indenture  and any Indebtedness of
such Subsidiary shall be deemed to be Incurred by a Restricted Subsidiary of the
Company as  of such  date (and,  if such  Indebtedness is  not permitted  to  be
Incurred  as  of  such  date  under the  covenant  described  under  the caption
"Limitation on Indebtedness," the Company shall be in default of such covenant).
The Board  may  at  any time  designate  any  Unrestricted Subsidiary  to  be  a
Restricted  Subsidiary; PROVIDED that such designation  shall be deemed to be an
Incurrence of Indebtedness  by a  Restricted Subsidiary  of the  Company of  any
outstanding  Indebtedness of  such Unrestricted Subsidiary  and such designation
shall only be permitted if (i) such Indebtedness is permitted under the covenant
described under the caption "Limitation on Indebtedness" and (ii) no Default  or
Event of Default would be in existence following such designation.
 
    "VOTING STOCK" means, with respect to any Person, Capital Stock of any class
or  kind ordinarily  having the  power to  vote for  the election  of directors,
managers or other voting members of the governing body of such Person.
 
    "VOTING TRUST AGREEMENT"  means that  certain Voting  Trust and  Irrevocable
Proxy Agreement, to be entered into on or prior to the Issue Date.
 
    "WHOLLY  OWNED" means,  with respect to  any Subsidiary of  any Person, such
Subsidiary if all  of the outstanding  Capital Stock in  such Subsidiary  (other
than  any  director's  qualifying  shares or  Investments  by  foreign nationals
mandated by applicable law) is owned by such Person or one or more Wholly  Owned
Subsidiaries of such Person.
 
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                            DESCRIPTION OF WARRANTS
 
    The  Warrants will be  issued pursuant to a  warrant agreement (the "Warrant
Agreement") by and between the Company and Continental Stock Transfer and  Trust
Company,  as  warrant  agent (the  "Warrant  Agent"). The  following  summary of
certain provisions of the Warrant Agreement and the Warrants does not purport to
be complete  and  is qualified  in  its entirety  by  reference to  the  Warrant
Agreement  and the Warrants, including the definitions therein of certain terms.
The Warrant Agreement will be substantially in the form of the Warrant Agreement
filed as an exhibit to the Registration Statement of which this Prospectus is  a
part.
 
GENERAL
 
    Each  Warrant, when  exercised, will entitle  the holder  thereof to receive
       shares of Common Stock (such shares, the "Warrant Shares") at an exercise
price of $      per share  (the "Exercise  Price"). The Exercise  Price and  the
number  of Warrant Shares issuable on exercise  of a Warrant are both subject to
adjustment in certain cases referred to  below. The Warrants are exercisable  at
any  time on or after  the Separation Date. Unless  exercised, the Warrants will
automatically expire on             , 2006 (the "Expiration Date"). The Warrants
will entitle  the  holders thereof  to  purchase in  the  aggregate   %  of  the
outstanding  Common Stock of the Company on a fully diluted basis as of the date
of issuance  of the  Warrants after  giving effect  to the  consummation of  the
Offerings.
 
    The Warrants may be exercised at any time on or after the Separation Date by
surrendering  to the  Company at  the office  of the  Warrant Agent  the Warrant
certificates evidencing such Warrants with the accompanying form of election  to
purchase  properly completed and executed, together with payment of the Exercise
Price. Payment of  the Exercise  Price may  be made  in the  form of  cash or  a
certified  or official  bank check  payable to  the order  of the  Company. Upon
surrender of the  Warrant certificate  and payment  of the  Exercise Price,  the
Warrant  Agent will  deliver or cause  to be  delivered, to or  upon the written
order of  such holder,  a stock  certificate representing  the number  of  whole
Warrant  Shares or other securities or property to which such holder is entitled
under the Warrant Agreement and the Warrants, including, without limitation, any
cash payment to adjust for fractional interests in Warrant Shares issuable  upon
such  exercise.  If  less  than  all of  the  Warrants  evidenced  by  a Warrant
certificate are to be  exercised, a new Warrant  certificate will be issued  for
the  remaining number  of Warrants.  The Warrant  Shares to  be issued  upon the
exercise of the Warrants will be registered under the Securities Act.
 
    No fractional Warrant Share will be issued upon exercise of the Warrants. If
any fraction of a  Warrant Share would, except  for the foregoing provision,  be
issuable  on the exercise of any Warrants  (or a specified portion thereof), the
Company shall  pay an  amount in  cash equal  to the  current market  price  per
Warrant  Share,  as determined  on the  day immediately  preceding the  date the
Warrant is presented for exercise, multiplied by such fraction, computed to  the
nearest whole U.S. cent.
 
    Certificates  for Warrants  will be issued  in registered form  only, and no
service charge  will be  made  for registration  of  transfer or  exchange  upon
surrender  of  any  Warrant  certificate  at the  office  of  the  Warrant Agent
maintained for that purpose. The Company may require payment of a sum sufficient
to cover any tax or other governmental charge that may be imposed in  connection
with any registration, transfer or exchange of Warrant certificates.
 
    The  holders of the Warrants  have no right to  vote on matters submitted to
the stockholders of  the Company  and have no  right to  receive dividends.  The
holders  of the  Warrants are  not be  entitled to  share in  the assets  of the
Company in the event of liquidation, dissolution or winding up of the  Company's
affairs.
 
    In  the  event of  taxable  distribution to  holders  of Common  Stock which
results in an adjustment to the number of Warrant Shares or other  consideration
for  which  a Warrant  may be  exercised, the  holders of  the Warrants  may, in
certain circumstances,  be deemed  to have  received a  distribution subject  to
United  States federal income tax as a dividend. See "Certain Federal Income Tax
Considerations".
 
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<PAGE>
REGISTRATION OF WARRANT SHARES
 
    Holders of  Warrants will  be able  to  exercise their  Warrants only  if  a
registration  statement relating to the Warrant Shares is then in effect, or the
exercise of such Warrants  is exempt from the  registration requirements of  the
Securities  Act,  and such  securities  are qualified  for  sale or  exempt from
qualification under the applicable  securities laws of the  states in which  the
various holders of the Warrants or other persons to whom it is proposed that the
Warrant  Shares be  issued on  exercise of the  Warrants reside.  The Company is
required under the  terms of  the Warrant  Agreement to  file and  use its  best
efforts  to make  effective, by the  earlier of  the Separation Date  or 45 days
after the occurrence of a Change in Control, and (subject to certain "black-out"
periods not to exceed 45 days in any calendar year) maintain effective until the
expiration or exercise  of all  Warrants a  shelf registration  statement on  an
appropriate  form under the Securities Act  covering the issuance of the Warrant
Shares upon the exercise  of the Warrants.  There can be  no assurance that  the
Company  will  be  able  to file,  cause  to  be declared  effective  or  keep a
registration statement continuously  effective until  all of  the Warrants  have
been exercised or have expired.
 
ADJUSTMENTS
 
    The  number of shares of  Common Stock purchasable upon  the exercise of the
Warrants and the Exercise  Price both will be  subject to adjustment in  certain
events  (subject to certain exceptions) including (i) the payment by the Company
of dividends (and other distributions) on  Common Stock payable in Common  Stock
or  other shares of the Company's capital stock, (ii) subdivisions, combinations
and reclassifications of  Common Stock,  (iii) the  issuance to  all holders  of
Common  Stock of  rights, options  or warrants  entitling them  to subscribe for
Common Stock or of securities convertible into or exchangeable for Common Stock,
for a consideration per  share of Common  Stock which is  less than the  current
market  price per share of Common Stock and (iv) the distribution to all holders
of Common Stock of any of the Company's assets, debt securities or any rights or
warrants to purchase securities (excluding those rights and warrants referred to
in clause  (iii)  above and  excluding  cash  dividends less  than  a  specified
amount).  In  addition,  the Exercise  Price  may  be reduced  in  the  event of
purchases of Common Stock  pursuant to a  tender or exchange  offer made by  the
Company  of any subsidiary thereof at a price greater than the sale price of the
Common Stock at the time such tender or exchange offer expires.
 
    No adjustment in the Exercise Price will be required unless such  adjustment
would  require  an increase  or decrease  of at  least one  percent (1%)  in the
Exercise Price; PROVIDED, HOWEVER, that any adjustment which is not made will be
carried forward and taken into account in any subsequent adjustment.
 
    In the case of certain consolidations or mergers of the Company, or the sale
of all or substantially all of the assets of the Company to another corporation,
each Warrant shall thereafter be exercisable  for the right to receive the  kind
and  amount of  shares of stock  or other  securities or property  to which such
holder would have  been entitled as  a result of  such consolidation, merger  or
sale had the Warrants been exercised immediately prior thereto.
 
AUTHORIZED SHARES
 
    The  Company has  authorized for  issuance such  number of  shares of Common
Stock as shall be  issuable upon the due  exercise of all outstanding  Warrants.
Such  shares of Common Stock, when paid for and issued, will be duly and validly
issued, fully paid and non-assessable, free  of preemptive rights and free  from
all  taxes,  liens, charges  and security  interests with  respect to  the issue
thereof (other than any such tax, lien, charge or security interest imposed upon
or granted by the holder of the Common Stock).
 
AMENDMENT
 
    From time to time, the Company and the Warrant Agent, without the consent of
the holders of the Warrants, may  amend or supplement the Warrant Agreement  for
certain purposes, including curing
 
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<PAGE>
defects  or inconsistencies or  making changes that  do not materially adversely
affect the rights  of any  holder. Any amendment  or supplement  to the  Warrant
Agreement  that has a material adverse effect on the interests of the holders of
the Warrants shall require the written consent  of the holders of a majority  of
the  then outstanding Warrants (excluding Warrants held by the Company or any of
its Affiliates). The consent  of each holder of  the Warrants affected shall  be
required  for  any  amendment pursuant  to  which  the Exercise  Price  would be
increased or the number of Warrant Shares purchasable upon exercise of  Warrants
would  be decreased (other than pursuant  to adjustments provided in the Warrant
Agreement).
 
GOVERNING LAW
 
    The Warrant Agreement and the Warrants will be governed by, and construed in
accordance with,  the laws  of  the State  of New  York  without regard  to  the
principles of conflicts of law thereof.
 
REPORTS
 
    Whether  or not the Company is subject  to the reporting requirements of the
Exchange Act, the  Company shall  cause copies  of the  reports described  under
"Description  of Notes  -- Certain  Covenants -- Reports"  to be  filed with the
Commission (to the  extent permitted) and  the Warrant Agent  and mailed to  the
holders  at their addresses appearing in  the register of Warrants maintained by
the Warrant  Agent to  the same  extent as  such reports  are furnished  to  the
holders of Notes in accordance with the Indenture.
 
                                      112
<PAGE>
                          DESCRIPTION OF CAPITAL STOCK
 
    The   authorized  capital  stock  of   the  Company  currently  consists  of
100,000,000 shares of Common Stock, $0.001  par value, and 10,000,000 shares  of
Serial Preferred Stock, $0.001 par value (the "Preferred Stock").
 
COMMON STOCK
 
    As  of  June  28,  1996,  there  were  10,013,055  shares  of  Common  Stock
outstanding held of  record by  11 stockholders  (without giving  effect to  the
Merger  or  any exercise  of outstanding  warrants or  options). The  holders of
Common Stock are entitled to one vote per share on all matters to be voted on by
the  stockholders.  Subject  to  preferences  that  may  be  applicable  to  the
outstanding  share of Preferred Stock, the  holders of Common Stock are entitled
to receive ratably such dividends  as may be declared from  time to time by  the
Board  of Directors out of funds legally available therefor. In the event of the
liquidation, dissolution or  winding up of  the Company, the  holders of  Common
Stock  are entitled to  share ratably in  all assets remaining  after payment of
liabilities, subject  to  prior  liquidation  rights  of  Preferred  Stock  then
outstanding.  The  Common Stock  has no  preemptive  conversion rights  or other
subscription  rights.  There  are  no  redemption  or  sinking  fund  provisions
applicable to the Common Stock. All outstanding shares of Common Stock are fully
paid  and non-assessable, and the shares of  Common Stock to be outstanding upon
consummation of the Common Stock Offering will be fully paid and non-assessable.
 
PREFERRED STOCK
 
    As of June 28,  1996, there was  one share of ART  Series A Preferred  Stock
outstanding  held of record by Telecom. Upon  the completion of the Merger, such
Preferred Stock will automatically be surrendered. See "Certain Transactions  --
Merger." The Board of Directors will have the authority to issue Preferred Stock
in  one  or more  series  and to  fix  the rights,  preferences,  privileges and
restrictions granted to or imposed upon any wholly unissued shares of  Preferred
Stock  and  to  fix  the  number  of  shares  constituting  any  series  in  the
designations of  such  series,  without  any  further  vote  or  action  by  the
stockholders.  The Board of  Directors, without stockholder  approval, can issue
Preferred Stock with voting and  conversion rights which could adversely  affect
the voting power of the holders of Common Stock. The issuance of Preferred Stock
may  have the effect of delaying, deferring or preventing a change in control of
the Company. The Company does not presently intend to issue Preferred Stock.  In
addition, the terms of the Indenture will restrict the ability of the Company to
issue Preferred Stock. See "Description of Notes -- Certain Covenants."
 
CHANGE IN CONTROL PROVISIONS
 
    Certain  provisions of the Company's Certificate of Incorporation and Bylaws
may have the effect  of preventing, discouraging or  delaying any change in  the
control of the Company any may maintain the incumbency of the Board of Directors
and  management. The authorization of Preferred  Stock makes it possible for the
Board of  Directors to  issue Preferred  Stock with  voting or  other rights  or
preferences  that could impede the success of  any attempt to effect a change in
control of the  Company. In  addition, on  the effectiveness  of the  Offerings,
certain provisions of the Certificate of Incorporation will create three classes
of directors serving for staggered three-year terms and prevent any amendment to
such  provisions without the  consent of holders  of at least  two-thirds of the
then outstanding shares of Common Stock. These provisions could also impede  the
success of any attempt to effect a change in control of the Company.
 
    The  Company is subject  to Section 203 of  the Delaware General Corporation
Law ("Section 203"). Section 203 prohibits a publicly-held Delaware  corporation
from engaging in a "business combination" with an "interested stockholder" for a
period  of three  years after the  date of  the transaction in  which the person
became an interested stockholder,  unless (i) prior to  such date, the board  of
directors  of the  corporation approves either  the business  combination or the
transaction  which   resulted  in   the  stockholder   becoming  an   interested
stockholder,  (ii)  upon  consummation  of  the  transaction  which  resulted in
 
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<PAGE>
the stockholder becoming an  interested stockholder, the interested  stockholder
owns at least 85% of the outstanding voting stock (excluding certain shares held
by  persons who are both  directors and officers of  the corporation and certain
employee stock plans), or (iii) on or after the consummation date, the  business
combination is approved by the board of directors and by the affirmative vote of
at  least 66  2/3% of  the outstanding  voting stock  that is  not owned  by the
interested stockholder. For  purposes of Section  203, a "business  combination"
includes,  among  other  things,  a  merger,  asset  sale  or  other transaction
resulting  in  a  financial  benefit  to  the  interested  stockholder,  and  an
"interested stockholder" is generally a person who, together with affiliates and
associates, owns (or within three years, owned) 15% or more of the corporation's
voting stock.
 
TRANSFER AGENT AND REGISTRAR
 
    The  Transfer Agent and Registrar for  the Common Stock is Continental Stock
Transfer & Trust Company.
 
LISTING
 
    The Common Stock  has been  approved for  quotation on  the Nasdaq  National
Market under the symbol "ARTT."
 
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<PAGE>
                      DESCRIPTION OF CERTAIN INDEBTEDNESS
 
EMI NOTE
 
    In  connection with  the acquisition by  Telecom of the  EMI Assets, Telecom
issued  to   EMI   a   $1.5  million   principal   amount   non-negotiable   and
non-transferable,  unsecured promissory note  (the "EMI Note").  Interest on the
EMI Note accrues  at a  rate equal to  the prime  rate plus 2%.  The Company  is
obligated to make quarterly principal repayments of $187,500, commencing January
1,  1997. The EMI Note matures on November 14, 1998. See "Business -- Agreements
Relating to Licenses and Acquisitions -- EMI Acquisition."
 
EQUIPMENT FINANCING
 
    On April 1, 1996, CRA, Inc. ("CRA") entered into secured Equipment Financing
with the Company  for the  purchase from  P-Com of  38 GHz  radio equipment.  To
evidence  its obligations under  the Equipment Financing,  the Company issued in
favor of  CRA  a $2,445,000  Equipment  Note,  payable in  twenty  four  monthly
installments  of $92,694  with a  final payment equal  to $642,305  due April 1,
1998.
 
BRIDGE FINANCING
 
    On March 8, 1996, the Company issued $5.0 million principal amount of Bridge
Notes in  connection with  the Bridge  Financing. See  "Certain Transactions  --
Bridge  Financing." The Bridge Notes are subordinated in right of payment to the
EMI Note  and will  be repaid  with proceeds  from the  Offerings. See  "Use  of
Proceeds."
 
COMMCOCCC FINANCING
 
    On  June  27  and  July  3, 1996,  the  Company  issued  to  stockholders of
CommcoCCC, in connection  with the  CommcoCCC Agreement  $3.0 million  principal
amount  of subordinated bridge notes (the "CommcoCCC Notes") bearing interest at
the prime rate, and payable 90 days  after the date of the CommcoCCC  Agreement.
The  CommcoCCC Notes are secured by a security  interest in all of the assets of
the Company, including a pledge of the Company's stock in Telecom. See  "Certain
Transactions  -- CommcoCCC Acquisition." The CommcoCCC Notes are subordinated in
right of payment to the  EMI Note and the Bridge  Notes and will be repaid  with
proceeds from the Offerings. See "Use of Proceeds."
 
CREDIT FACILITY
 
    Canadian  Imperial  Bank of  Commerce ("CIBC")  has  provided the  Company a
Summary of Terms and Conditions on which it and other banks might extend  credit
pursuant  to  a  Senior  Secured  Revolving  Credit  Facility  converting  to an
Amortizing Term Loan (the "Credit Facility").  Under the Credit Facility, up  to
$100,000,000   in  revolving  loans  would  be  available  based  on  incurrence
provisions which will be determined but would include measures of total debt  to
operating  cash flow, numbers of  links, numbers of links  per pop or market and
amount of  revenue  per  link.  The  proceeds  could  be  used  to  finance  the
construction   of  the   Company's  systems,   capital  expenditures,  permitted
acquisitions, operating losses and working capital. The Credit Facility would be
secured by all of  the assets of  the Company and  its subsidiaries including  a
pledge  of stock of  subsidiaries, and would be  guaranteed by all subsidiaries,
excluding unrestricted subsidiaries  to be determined.  The interest rate  would
initially  be at 2.50% over the bank's base  rate or 3.50% over LIBOR subject to
reduction. Mandatory prepayment will be required with respect to a percentage of
excess cash flow and proceeds of equity offerings. The revolving credit facility
will convert to a term loan after a period, for a term and with an  amortization
to be determined.
 
    In  addition, the  Credit Facility  will include  financial covenants  to be
determined relating to ratios of total  debt to annualized operating cash  flow,
operating  cash  flow to  cash interest  expense, cash  flow available  for debt
service to pro forma fixed charges and total debt per total links as well as  to
minimum  revenues, operating  cash flow (or  maximum loss),  minimum revenue per
link and minimum number of links. The Credit Facility will prohibit the  Company
from   making  restricted   payments  and  acquisitions   other  than  permitted
acquisitions, from  incurring indebtedness  except with  certain limitations  or
liens,
 
                                      115
<PAGE>
or merging, and will limit investments and asset sales. The Credit Facility will
contain  a provision relating  to change of  control of the  Company. The Credit
Facility will  also  contain customary  events  of default,  including  but  not
limited  to  nonpayment  of  principal  or  interest  when  due,  violations  of
covenants, falsity of  representations and warranties  in any material  respect,
actual  or asserted invalidity of security  documents and security interests and
the occurrence of certain events with  respect to the Company or any  subsidiary
including  cross-default and cross-acceleration, bankruptcy, material judgments,
ERISA violations,  change in  control and  loss or  material impairment  of  FCC
licenses.
 
    The Company will be required to pay a structuring fee which has not yet been
determined,  a facility fee of  3.5% payable at closing  and a commitment fee of
0.5% per annum on the  unused portion of the  facility. Execution of the  Credit
Facility  will be dependant upon, among other things, satisfactory due diligence
review by the banks, consummation of the Offerings on terms satisfactory to  the
banks  and  negotiation and  execution  of mutually  satisfactory documentation.
There is no assurance that the Credit Facility will be executed, what the  terms
of the Credit Facility will be, or if executed, that the Company will be able to
borrow under the Credit Facility.
 
                                      116
<PAGE>
                   CERTAIN FEDERAL INCOME TAX CONSIDERATIONS
 
    The  following discussion is a summary of the material United States federal
income tax considerations relevant to the purchase, ownership and disposition of
the Units, Notes and Warrants by  holders acquiring Units on original issue  for
cash,  but  does not  purport to  be a  complete analysis  of all  potential tax
effects. The discussion  is based  upon the Internal  Revenue Code  of 1986,  as
amended  (the "Code"),  Treasury regulations,  Internal Revenue  Service ("IRS")
rulings and pronouncements and judicial decisions  all in effect as of the  date
hereof,  all of which are subject to change at any time, and any such change may
be applied retroactively in a manner that could adversely affect a holder of the
Units, Notes or  Warrants. The discussion  does not address  all of the  federal
income  tax  consequences that  may be  relevant to  a holder  in light  of such
holder's particular circumstances or to  holders subject to special rules,  such
as  certain financial institutions, insurance  companies, dealers in securities,
foreign corporations,  nonresident alien  individuals  and persons  holding  the
Units,  Notes  or  Warrants as  part  of  a "straddle,"  "hedge"  or "conversion
transaction." Moreover, the effect of any applicable state, local or foreign tax
laws is not discussed. The discussion deals only with Units, Notes and  Warrants
held as "capital assets" within the meaning of section 1221 of the Code.
 
    The  Company has not sought and will not  seek any rulings from the IRS with
respect to  the  position  of the  Company  discussed  below. There  can  be  no
assurance  that the IRS  will not take  a different position  concerning the tax
consequences of the purchase,  ownership or disposition of  the Units, Notes  or
Warrants or that any such position would not be sustained.
 
    PROSPECTIVE  INVESTORS SHOULD CONSULT THEIR OWN  TAX ADVISORS WITH REGARD TO
THE APPLICATION OF THE  TAX CONSIDERATIONS DISCUSSED  BELOW TO THEIR  PARTICULAR
SITUATIONS  AS WELL AS THE APPLICATION OF ANY STATE, LOCAL, FOREIGN OR OTHER TAX
LAWS.
 
THE UNITS
 
    Because the original  purchasers of  the Notes also  will acquire  Warrants,
each  Note will be treated for federal income tax purposes as having been issued
as part of an "investment unit" consisting of the Note and associated  Warrants.
The  issue price  of an  investment unit consisting  of the  Note and associated
Warrants will be the first price at which a substantial amount of Units are sold
to the public  for money (excluding  sales to bond  houses, brokers, or  similar
persons  or  organizations acting  in  the capacity  of  underwriters, placement
agents or wholesalers).  The "issue price"  of an investment  unit is  allocated
between  its component  parts based  on their  relative fair  market values. The
Company will  allocate the  issue  price of  a Unit  between  the Note  and  the
associated  Warrants  in accordance  with the  Company's determination  of their
relative fair  market  values on  the  issue date.  The  Company will  use  that
allocation  to determine the issue price of the Notes and the holder's tax basis
in the Warrants. Although the Company's allocation is not binding on the IRS,  a
holder  of a Unit must use the  Company's allocation unless the holder discloses
on its federal  income tax return  that it plans  to use an  allocation that  is
inconsistent with the Company's allocation.
 
THE NOTES
 
    The  Notes will be issued with  "original issue discount" for federal income
tax purposes. A holder generally is required to include original issue  discount
in  gross income as it accrues, regardless  of the holder's method of accounting
for federal income tax  purposes. Accordingly, each holder  will be required  to
include  amounts in gross income in advance of  the receipt of the cash to which
such income is attributable.
 
    The amount of original issue discount with respect to each Note is an amount
equal to the excess of  the "stated redemption price  at maturity" of such  Note
over  its issue price. The stated redemption price at maturity of each Note will
include all  cash payments,  including principal  and interest,  required to  be
 
                                      117
<PAGE>
made  thereunder until maturity. The issue price of a Note will be equal to that
portion of the issue price of the Unit allocable to the Note as described above.
It is  expected that  each Note  will be  issued with  a substantial  amount  of
original issue discount.
 
    TAXATION OF ORIGINAL ISSUE DISCOUNT.  Each holder of a Note will be required
to include in gross income an amount equal to the sum of the "daily portions" of
the original issue discount of the Note for all days during each taxable year in
which  the holder holds the Note. The  daily portions of original issue discount
will be determined on a constant interest  rate basis by allocating to each  day
during the taxable year in which the holder holds the Note a pro rata portion of
the  original issue discount thereon that  is attributable to the accrual period
in which  such  day is  included.  The amount  of  the original  issue  discount
attributable  to each full accrual  period will be the  product of the "adjusted
issue price" of the Note at the beginning of such accrual period and the  "yield
to maturity" of the Note (adjusted to reflect the length of the accrual period).
The  adjusted issue price of a Note at the beginning of an accrual period is the
original issue price  of the Note  plus the aggregate  amount of original  issue
discount  that has accrued in all prior  accrual periods, less any cash payments
on the Note  on or before  the first day  of such accrual  period. The yield  to
maturity  is the discount rate that, when used in computing the present value of
all principal and interest payments to be  made on the Note, produces an  amount
equal  to  the issue  price. Under  these  rules, holders  will have  to include
increasingly greater  amounts  of original  issue  discount in  each  successive
accrual period.
 
    The  accrual period generally is  the six-month period ending  on the day in
each calendar year corresponding to the day before the maturity date of the Note
or the date six months before such date. The initial accrual period of a note is
the short period beginning on  the issue date and ending  on the day before  the
first  day  of the  first  full accrual  period.  The amount  of  original issue
discount attributable to an initial short  accrual period may be computed  under
any reasonable method.
 
    The  Company is required to furnish certain information to the IRS, and will
furnish annually  to record  holders  of a  Note,  information with  respect  to
original issue discount accruing during the calendar year. That information will
be  based upon the  adjusted issue price of  the Note as if  the holder were the
original holder of the Note.
 
    SALE OR RETIREMENT OF A NOTE.  In general, a holder of a Note will recognize
gain or loss upon the sale, retirement or other taxable disposition of such Note
in an amount equal to the difference between (a) the amount of cash and the fair
market value of  property received  in exchange  therefor and  (b) the  holder's
adjusted tax basis in such Note.
 
    A holder's tax basis in a Note generally will be equal to the price paid for
such  Note,  increased  by  the  amount  of  original  issue  discount,  if any,
includable in gross income  prior to the date  of disposition, and decreased  by
the amount of any payment on such Note prior to disposition.
 
    Any  gain  or loss  recognized  on the  sale,  retirement, or  other taxable
disposition of a Note generally will be capital gain or loss. Such capital  gain
or  loss generally will be  long-term capital gain or loss  if the Note has been
held for more than one year.
 
THE WARRANTS
 
    Upon the sale or  exchange of a  Warrant (including the  receipt of cash  in
lieu  of a fractional interest in a Warrant Share upon exercise of a Warrant), a
holder will recognize gain or loss in an amount equal to the difference  between
the  amount of cash and the fair  market value of property received therefor and
the holder's tax basis in the Warrant. A holder's initial tax basis in a Warrant
acquired in the Unit  Offering will be  that portion of the  issue price of  the
Units allocable to the Warrant, as described above, subject to adjustment in the
events  described below. Such gain  or loss will be capital  gain or loss if the
Warrant Shares to  which the Warrants  relate would  be a capital  asset in  the
hands  of the Warrant  holder. Any such  capital gain or  loss will be long-term
capital gain or loss if the Warrant was held for more than one year.
 
                                      118
<PAGE>
    The exercise of a Warrant for cash will not result in a taxable event to the
holder of the Warrant (except to the extent of cash, if any, received in lieu of
fractional interest in a  Warrant Share). Upon such  exercise, the holder's  tax
basis  in the Warrant Shares obtained will be  equal to the sum of such holder's
tax basis  in  the Warrant  (described  above) and  the  exercise price  of  the
Warrant;  the holder's holding  period with respect to  such Warrant Shares will
commence on the day after the date of exercise. The holder will realize  capital
gain  or loss on the sale or exchange of a Warrant Share if the Warrant Share is
a capital asset in the hands of the  holder, and such capital gain or loss  will
be  long-term if the Warrant Share was held for more than one year. If a Warrant
expires without being exercised, the holder  will recognize a loss in an  amount
equal  to its tax basis in the Warrant. Such  loss will be a capital loss if the
Warrant Shares to which the Warrants relate  would have been a capital asset  in
the  hands of  the Warrant  holder, and  such capital  loss will  be a long-term
capital loss is the Warrant was held for more than one year.
 
    Adjustments to the conversion ratio of the Warrants, or the failure to  make
adjustments,  may  in certain  circumstances result  in  the receipt  of taxable
constructive dividends by the holder, in  which event the holder's tax basis  in
the Warrants would be increased by an amount equal to the constructive dividend.
 
BACKUP WITHHOLDING
 
    A  holder of a  Note may be subject  to backup withholding at  a rate of 31%
with respect to interest and original issue discount on, and gross proceeds upon
sale or retirement of, a Note unless  such holder (i) is a corporation or  other
exempt  recipient and, when required, demonstrates that fact, or (ii) provides a
correct taxpayer  identification number,  certifies,  when required,  that  such
holder  is  not  subject  to backup  withholding,  and  otherwise  complies with
applicable requirements of the backup  withholding rules. Backup withholding  is
not  an  additional tax;  any  amounts so  withheld  are creditable  against the
holder's federal income tax,  provided the required  information is provided  to
the IRS.
 
DEDUCTIBILITY OF ORIGINAL ISSUE DISCOUNT AND INTEREST PAYMENTS
 
    The  deduction by  the Company  in respect  of interest  (including original
issue discount) accrued with respect  to the Notes will  be limited in part  and
deferred  in part if the Notes are "applicable high yield discount obligations."
The Company anticipates  that the Notes  may be applicable  high yield  discount
obligations  because,  among other  things,  it is  expected  that the  yield to
maturity of the  Notes may exceed  the sum of  the applicable federal  long-term
rate  (a  rate  published by  the  IRS  each month  for  application  during the
following calendar month) in effect  at the time of  issuance of the Notes  (the
"AFR")  plus  five percentage  points. If  the Notes  are applicable  high yield
discount obligations, then (i) if the yield to maturity of the Notes exceeds the
sum of the AFR plus six percentage points (such excess referred to below as  the
"Disqualified  Yield"),  the deduction  for  interest (including  original issue
discount) accrued on the Notes will be permanently disallowed to the extent such
interest or original issue discount  is attributable to the Disqualified  Yield,
and  such  interest  (including original  issue  discount) would  be  treated as
dividends to  corporate holders  of the  Notes for  purposes of  the  dividends-
received  deduction (to the extent that such  amounts would have been treated as
dividends had they been  distributions made by the  Company with respect to  its
stock)  and (ii) the remainder of the original issue discount on the Notes would
not be deductible by the Company until paid.
 
                                      119
<PAGE>
                                  UNDERWRITING
 
    Subject to the terms and conditions  set forth in a purchase agreement  (the
"Purchase  Agreement"), among the Company, Merrill Lynch, Pierce, Fenner & Smith
Incorporated ("Merrill  Lynch"), Montgomery  Securities  and Smith  Barney  Inc.
("Smith  Barney" and, together with Merrill Lynch and Montgomery Securities, the
"Underwriters"), the Company has  agreed to sell to  the Underwriters, and  each
Underwriter  has agreed to purchase from the Company, severally but not jointly,
the number of Units  set forth opposite its  name below. The Purchase  Agreement
provides  that,  subject to  the  terms and  conditions  set forth  therein, the
Underwriters will be obligated to  purchase all of the  Units if any such  Units
are purchased.
 
<TABLE>
<CAPTION>
                                                                    NUMBER
              UNDERWRITERS                                         OF UNITS
                                                                   ---------
 
<S>                                                                <C>
Merrill Lynch, Pierce, Fenner & Smith
           Incorporated..........................................
Montgomery Securities............................................
Smith Barney Inc.................................................
                                                                   ---------
           Total.................................................
                                                                   ---------
                                                                   ---------
</TABLE>
 
    The  Underwriters propose to offer  the Units directly to  the public at the
offering price set forth on  the cover page of this  Prospectus, and in part  to
certain  selected dealers at such price less a concession not in excess of     %
per Unit. The several  Underwriters may allow, and  such dealers may reallow,  a
discount  not in excess of       % per Unit to  certain other dealers. After the
initial public offering, the public offering price, concession and discount  may
be changed. The Underwriters do not intend to confirm sales to any accounts over
which they exercise discretionary authority.
 
    There  is  currently  no public  market  for  the Units,  the  Notes  or the
Warrants, and the Company does not intend to apply for listing of the Units, the
Notes or  the  Warrants  on  any securities  exchange  or  on  any  inter-dealer
quotation  system.  The Common  Stock (including  the  Warrant Shares)  has been
approved for  quotation on  the Nasdaq  National Market.  The Company  has  been
advised by the Underwriters that, following the completion of the initial public
offering of the Notes, the Underwriters presently intend to make a market in the
Units,  the  Notes  and  the  Warrants  as  permitted  by  applicable  laws  and
regulations; however, they are not obligated to do so and any such market-making
may be discontinued at any  time without notice at  the sole discretion of  each
Underwriter.  Accordingly, there  can be  no assurance  as to  whether an active
public market for the  Units, the Notes  or the Warrants will  develop or, if  a
public  market does develop, as  to the liquidity of  the trading market for the
Units, the Notes or the Warrants. If  an active public market does not  develop,
the  market price and liquidity for the Units,  the Notes or the Warrants may be
adversely affected.  See "Risk  Factors --  Absence of  Public Market;  Possible
Volatility of Stock Price."
 
    The  Company  has  agreed  to  indemnify  the  Underwriters  against certain
liabilities, including liabilities under the Securities Act of 1933, as  amended
(the  "Securities  Act"), and,  under  certain circumstances,  to  contribute to
payments the Underwriters may be required to make in respect thereof.
 
    The Company has agreed that it will not,  for a period of 180 days from  the
date  of this Prospectus, without the prior written consent of the Underwriters,
directly or indirectly, offer, sell, grant  any option to purchase or  otherwise
dispose  of, any debt security of the  Company which is publicly offered or sold
pursuant to Rule 144A under the Securities Act.
 
    Montgomery Securities  and  Merrill  Lynch are  acting  as  underwriters  in
connection   with  the  Common   Stock  Offering  and   will  receive  customary
compensation  in  connection  therewith.   In  connection  with  the   CommcoCCC
Acquisition,  Montgomery  Securities has  been retained  by  the Company  as its
financial advisor for  which it will  receive fees of  up to approximately  $2.7
million  and the reimbursement of  reasonable out-of-pocket expenses incurred in
connection therewith.
 
                                      120
<PAGE>
                                 LEGAL MATTERS
 
    The validity of the Units, the Notes and the Warrants offered hereby will be
passed upon for the Company  by Hahn & Hessen LLP,  New York, New York.  Certain
legal  matters in connection with the Unit  Offering will be passed upon for the
Underwriters by  Latham &  Watkins, Washington,  D.C.  As of  the date  of  this
Prospectus,  a member of Hahn & Hessen LLP  owns $25,000 of the Bridge Notes and
5,500 Bridge  Warrants and  beneficially  owns 13,627  shares of  Common  Stock.
Latham  &  Watkins,  Washington,  D.C., currently  represents  the  Company with
respect to certain FCC matters.
 
                                    EXPERTS
 
    The  historical  financial   statements  of   Advanced  Radio   Technologies
Corporation  as of December 31, 1995 and 1994, for the years then ended, and for
the period from August 23, 1993 (date of inception) to December 31, 1993 and  of
Advanced  Radio Telecom Corp.  as of December  31, 1995 and  for the period from
March 28,  1995  (date of  inception)  to December  31,  1995 included  in  this
Prospectus,  have been included herein in reliance on the reports, each of which
includes an explanatory paragraph regarding  the substantial doubt which  exists
about the respective entity's ability to continue as a going concern, of Coopers
&  Lybrand L.L.P., independent accountants, given  on the authority of that firm
as experts in accounting and auditing.
 
                             AVAILABLE INFORMATION
 
    The Company has filed with the  Commission a registration statement on  Form
S-1  (together with all amendments, exhibits, schedules and supplements thereto,
the "Registration  Statement") under  the  Securities Act  with respect  to  the
securities   offered  hereby.  This  Prospectus,  which  forms  a  part  of  the
Registration Statement, does not contain all of the information set forth in the
Registration Statement, certain parts of  which have been omitted in  accordance
with  the rules and regulations of  the Commission. For further information with
respect to the Company and the  securities offered hereby, reference is made  to
the  Registration Statement and  to the schedules  and exhibits filed therewith.
Statements contained in this Prospectus as to the contents of certain  documents
are  not necessarily complete, and,  in each instance, reference  is made to the
copy of the  document filed  as an exhibit  to the  Registration Statement.  The
Registration  Statement, including  the exhibits  and schedules  thereto, can be
inspected and  copied  at the  public  reference facilities  maintained  by  the
Commission  at Room 1024,  Judiciary Plaza, 450  Fifth Street, N.W., Washington,
D.C. 20549, and at  the following regional offices  of the Commission: New  York
Regional  Office, 7 World  Trade Center, New  York, New York  10007; and Chicago
Regional Office,  Suite  1400,  Northwestern Atrium  Center,  500  West  Madison
Street,  Chicago, Illinois 60661.  Copies of such material  can also be obtained
from the Commission at prescribed rates through its Public Reference Section  at
450 Fifth Street, N.W., Washington, D.C. 20549.
 
    Immediately  following the  Offerings, the  Company will  be subject  to the
informational requirements of the  Securities Exchange Act  of 1934, as  amended
(the  "Exchange  Act"), and  in accordance  therewith will  be required  to file
reports and other information with the Commission. Such reports may be inspected
and copied at the public reference  facilities at the addresses set forth  above
and  at the Public Reference Section of  the Commission at the address set forth
above. In addition,  the Indenture and  the Warrant Agreement  provide that  the
Company, to the extent that it is not required to file such information pursuant
to  the Exchange  Act, shall provide  the Trustee  and holders of  the Notes and
Warrants with audited year-end financial  statements of the Company prepared  in
accordance  with GAAP and substantially in  the form of the Financial Statements
included in this Prospectus, and unaudited quarterly financial statements of the
Company prepared in accordance  with GAAP and substantially  in the form of  the
Financial Statements included in this Prospectus.
 
                                      121
<PAGE>
                                    GLOSSARY
 
    ACCESS  CHARGES  -- The  fees paid  by  long distance  carriers to  LECs for
originating and terminating long distance calls on their local networks.
 
    BANDWIDTH -- At any  given level of compression,  the amount of  information
transportable  over  a link  per unit  of time.  A DS-1,  or Digital  Service 1,
circuit will carry up to 1,544,000 bits (or 1.544 megabits) per second.
 
    BPS -- Bits per second. A bit  is the basic unit of information,  yes-or-no,
on-or-off,  1-or-0 in the binary  (base 2) system which  is the basis of digital
computing. In contrast, a voice telephone  signal over a copper wire is  analog,
reflecting a continuous range of vocal tone (frequency) and volume (amplitude).
 
    BROADBAND  -- Data streams of at  least 1.544 megabits per second. Broadband
communications systems can transmit large quantities of voice, data and video by
way of digital or  analog signals. Examples  of broadband communication  systems
include  DS-3 systems, which can  transmit 672 simultaneous voice conversations,
or a broadcast television  station signal that  transmits high resolution  audio
and  video signals into the home. Broadband connectivity is an essential element
for interactive multimedia applications.
 
    BTA (BASIC  TRADING AREA)  -- An  area erected  by Rand  McNally based  upon
various  business  demographics to  establish a  contiguous urban  area, without
reference to political or similar boundaries.  The FCC has proposed to use  BTAs
to auction 38 GHz authorizations.
 
    CAP  (COMPETITIVE ACCESS PROVIDER) -- A  company that provides its customers
with an alternative  to the  local telephone  company for  local and  interstate
transport of private line, special access and switched access telecommunications
services.  CAPs  are  also referred  to  in  the industry  as  competitive local
exchange  carriers   (CLECs),  alternative   local  telecommunications   service
providers  (ALTs)  and  metropolitan  area  network  providers  (MANs)  and were
formerly referred to as alternative access vendors (AAVs).
 
    CELLULAR -- Characterized by "cells," the area accessible by  transceiver(s)
typically  located at one site. A cellular  phone connects to the transceiver in
its current cell, then the connection is  handed-off as and when the user  moves
to any other cell.
 
    COMPRESSION  -- Any process that transforms a  signal to a more compact form
(fewer bits) for easier transfer, and then restores the signal after transfer.
 
    CMRS -- Commercial mobile radio services.
 
    COPPER WIRE -- A  shorthand reference to  traditional telephone lines  using
electric current to carry signals over copper wire.
 
    DIGITAL  --  A method  of storing,  processing and  transmitting information
through the use  of distinct  electronic or  optical pulses  that represent  the
binary  code digits  0 and  1. Digital  transmission and  switching technologies
employ a sequence  of these  pulses to represent  infomation as  opposed to  the
continously   variable  analog   signal.  Digital   transmission  and  switching
technologies offer a  threefold improvement  in speed and  capacity over  analog
techniques,  allowing  much more  efficient  and cost-effective  transmission of
voice, video, and data.
 
    DIALING PARITY -- Dialing parity is one of the changes intended to level the
competitive playing  field, that  are required  by the  Telecommunications  Act.
Dialing parity when implemented will enable customers to have dial only 1+ or 0+
service no matter which local or long distance carrier they choose.
 
    DS-0,  DS-1,  DS-3 --  Standard  telecommunications industry  digital signal
formats, which are distinguishable by bit  rate (the number of binary digits  (0
and  1) transmitted per second). DS-0 service has  a bit rate of 64 kilobits per
second. DS-1  service has  a bit  rate of  1.544 megabits  per second  and  DS-3
service has a bit rate of 45 megabits per second.
 
                                      122
<PAGE>
    ESMR  (ENHANCED SPECIALIZED MOBILE RADIO) --  A recent mobile radio services
category involving technical  and service enhancements  to traditional "push  to
talk" dispatch services.
 
    FCC -- Federal Communications Commission.
 
    FIBER  OPTICS -- Fiber optic cable largely immune to electrical interference
and environmental factors that affect copper wiring and satellite  transmission.
Fiber  optic technology involves sending laser light pulses across glass strands
in order to transmit digital information.
 
    GHZ (GIGAHERTZ) -- Billions of  cycles or hertz per  second. A hertz is  one
full cycle (an s-shaped sine curve with one peak and one valley).
 
    INTER-LATA  LONG DISTANCE --  Inter-LATA long distance  calls are calls that
pass from one LATA to another. Typically, these calls are simply referred to  as
"long distance" calls although IntraLATA calls also can be long distance calls.
 
    INTERNET  --  An array  of  interconnected networks  using  a common  set of
protocols defining the information coding  and processing requirements that  can
communicate  across hardware  platforms and  over many  links now  operated by a
consortium of telecommunications service providers and others.
 
    ISP -- Internet service provider.
 
    ITC (INDEPENDENT TELEPHONE COMPANY) -- A telephone company not associated or
formerly associated with the Bell Telephone system.
 
    IXC (INTER-EXCHANGE  CARRIERS)  --  Usually referred  to  as  long  distance
providers.  There are many facilities-based IXCs, including AT&T, MCI, WorldCom,
Sprint and Frontier.
 
    KILOBIT --  One  thousand  bits  of  information.  The  information-carrying
capacity  (i.e.,  bandwidth  of  a  circuit may  be  measured  in  "kilobits per
second").
 
    KBPS -- Kilobits per second.
 
    LANS (LOCAL  AREA NETWORKS)  --  The interconnection  of computers  for  the
purpose  of sharing files,  programs and various devices  such as work stations,
printers and high-speed  modems. LANs  may include dedicated  computers or  file
servers  that provide  a centralized source  of shared files  and programs. Most
office computer networks use  a LAN to share  files, printers, modems and  other
items.  Where computers are separated by  greater distances, a Metropolitan Area
Net (MAN) or other Wide Area Net (WAN) may be used.
 
    LAST  MILE   --  A   shorthand  reference   to  the   last  section   of   a
telecommunications  path to  the ultimate  end user  which may  be less  than or
greater than a mile.
 
    LATAS (LOCAL ACCESS AND TRANSPORT AREAS) -- The geographically defined areas
in which RBOCs were  authorized by the MFJ  to provide local exchange  services.
These  LATAs roughly reflect  the population density  of their respective states
(California has 11 LATAs while Wyoming has only one). There are 164 LATAs in the
United States. LATAs have one or more area codes and may cross state lines.
 
    LEC (LOCAL EXCHANGE CARRIER) -- A company providing local exchange services.
The traditional  local  telephone  companies  (also  known  as  incumbent  local
exchange carriers), such as the RBOCs, which until recently were monopolies.
 
    LINE  OF SIGHT -- An unobstructed view between two transceivers comprising a
link.
 
    LINK -- A transmission link between two transceivers.
 
    MAN -- Metropolitan Area Network.
 
    MARKET -- The  potential and  actual customers  within the  boundaries of  a
wireless  license.  For  simplicity,  the  definition  of  the  market  in  this
Prospectus has been  based on Basic  Trading Areas, though  each application  as
granted defines its own actual boundaries.
 
                                      123
<PAGE>
    MEGABIT  --  One  million  bits  of  information.  The  information-carrying
capacity (i.e.,  bandwidth)  of a  circuit  may  be measured  in  "megabits  per
second."
 
    MFJ  (MODIFIED FINAL  JUDGMENT) --  The MFJ  was an  agreement made  in 1982
between AT&T and the Department of Justice  which forced the breakup of the  old
Bell  System. This judgment, also known  as the Divestiture of AT&T, established
seven separate RBOCs and enhanced the establishment of two distinct segments  of
telecommunications  service: local and  long distance. This  laid the groundwork
for intense  competition  in  the  long distance  industry.  The  MFJ  has  been
superseded by the Telecommunications Act of 1996.
 
    MICROWAVE  -- A portion  of the radio  spectrum having radio  waves that are
physically very short,  ranging in length  between about  30 cm and  0.3 cm  and
generally used to refer to frequencies above 2 GHz.
 
    MILLIMETRIC  MICROWAVE OR MILLIMETER WAVE -- Those portions of the microwave
radio spectrum having wave lengths measured in millimeter lengths and  generally
used to refer to frequencies above 20 GHz.  A shorter wave length means a higher
frequency and vice versa.
 
    MHZ (MEGAHERTZ) -- Millions of cycles or hertz per second.
 
    MBPS -- Megabits per second.
 
    NARROWBAND -- Data streams less than 64 kilobits per second.
 
    NPRM  (NOTICE  OF  PROPOSED  RULEMAKING) --  A  term  used  in governmental,
principally FCC, rulemaking proceedings to refer to initiation of the process.
 
    NUMBER PORTABILITY -- The  ability of an end  user to change local  exchange
carriers  while retaining the same telephone  number. If number portability does
not exist, customers will  have to change phone  numbers when they change  local
exchange carriers.
 
    OFF-NET  CUSTOMERS -- A customer that is not physically connected to a CAP's
network but who  is accessed through  interconnection with a  LEC network or  an
alternative provider such as a 38 GHz licensee.
 
    ON-NET  CUSTOMERS  -- A  customer that  is physically  connected to  a CAP's
network.
 
    PCS (PERSONAL COMMUNICATIONS SERVICE) -- Cellular-like services provided  at
the  2 GHz band  of the radio spectrum  rather than 800 MHz.  A type of wireless
telephone system that uses light, inexpensive handheld sets and communicates via
low power antennas.
 
    PIPE -- A  generic term for  telecommunications transmission media,  whether
wired  or wireless, used to carry signals between the signal generating unit and
the user.
 
    POPS (POINTS  OF  PRESENCE)  --  Locations where  a  carrier  has  installed
transmission  equipment in a service area that  serves as, or relays calls to, a
network switching center of that carrier.
 
    PSTN (PUBLIC  SWITCHED TELECOMMUNICATIONS  NETWORK) --  The traditional  LEC
networks that switch calls between different customers.
 
    RBOCS  (REGIONAL BELL OPERATING  COMPANIES) -- The  holding companies owning
LEC affiliates of the old AT&T or Bell system.
 
    REPEATER -- An intermediate  transceiver between two transceivers  connected
to  end  users and  established to  circumvent  obstacles in  the line  of sight
between communications ports,  such as  buildings in  urban areas  and hills  in
rural areas.
 
    RESELLERS  -- Companies which purchase telecommunications services wholesale
from underlying carriers and resell them to end users at retail rates.
 
    ROOF RIGHTS --  The legal right  to locate, maintain  and operate  equipment
(most  commonly transceivers)  on the roofs  of buildings, on  special towers or
even on utility poles or pylons.
 
                                      124
<PAGE>
    WIDEBAND -- Data streams between 64 kilobits and 1.544 megabits per second.
 
    10-13 BIT ERROR RATE -- The measurement of a transmission path's ability  to
pass  data in an  uncorrupted format. Bit  error rate ("BER")  is defined as the
number of  erroneous bits  ("errors"), divided  by  the number  of bits  over  a
stipulated  period of time. In the  example of a BER of  10-13 , a BER tester (a
test and measurement  instrument), placed  in line to  measure the  transmission
path  (in real time)  would have to  measure, and analyze,  ten trillion bits of
data before it detected one bit of erroneous data.
 
                                      125
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                            ---------
<S>                                                                                                         <C>
Advanced Radio Technologies Corporation
  Unaudited Pro Forma:
    Unaudited Pro Forma Condensed Balance Sheets as of December 31, 1995 and March 31, 1996...............     F-3
    Unaudited Pro Forma Condensed Balance Sheets -- Supplementary Combining Balance Sheet Data as of
     December 31, 1995 and March 31, 1996.................................................................     F-4
    Unaudited Pro Forma Condensed Statement of Operations for the three months ended March 31, 1996 and
     for the year ended December 31, 1995.................................................................     F-5
    Notes to Unaudited Pro Forma Condensed Financial Statements...........................................     F-6
  Historical:
    Report of Independent Accountants.....................................................................     F-8
    Balance Sheets as of December 31, 1995 and 1994.......................................................     F-9
    Statements of Operations for the years ended December 31, 1995 and 1994, for the period from August
     23, 1993 (date of inception) to December 31, 1993 and cumulative for the period from August 23, 1993
     (date of inception) to December 31, 1995.............................................................    F-10
    Statements of Stockholders' Equity (Deficit) for the years ended December 31, 1995 and 1994, for the
     period from August 23, 1993 (date of inception) to December 31, 1993 and cumulative for the period
     from August 23, 1993 (date of inception) to December 31, 1995........................................    F-11
    Statements of Cash Flows for the years ended December 31, 1995 and 1994, for the period from August
     23, 1993 (date of inception) to December 31, 1993 and cumulative for the period from August 23, 1993
     (date of inception) to December 31, 1995.............................................................    F-12
    Notes to Financial Statements.........................................................................    F-13
    Unaudited Interim Condensed Balance Sheets as of March 31, 1996 and 1995..............................    F-24
    Unaudited Interim Condensed Statements of Operations for the three months ended March 31, 1996 and
     1995.................................................................................................    F-25
    Unaudited Interim Condensed Statements of Cash Flows for the three months ended March 31, 1996 and
     1995.................................................................................................    F-26
    Notes to Unaudited Interim Condensed Financial Statements.............................................    F-27
 
Advanced Radio Telecom Corp.
 
  Historical:
    Report of Independent Accountants.....................................................................    F-30
    Balance Sheet as of December 31, 1995.................................................................    F-31
    Statement of Operations for the period from March 28, 1995 (date of inception) to December 31, 1995...    F-32
    Statement of Stockholders' Deficit for the period from March 28, 1995 (date of inception) to December
     31, 1995.............................................................................................    F-33
    Statement of Cash Flows for the period from March 28, 1995 (date of inception) to December 31, 1995...    F-34
    Notes to Financial Statements.........................................................................    F-35
    Unaudited Interim Condensed Balance Sheet as of March 31, 1996........................................    F-47
    Unaudited Interim Condensed Statement of Operations for the three months ended March 31, 1996.........    F-48
    Unaudited Interim Condensed Statement of Stockholders' Equity (Deficit) for the three months ended
     March 31, 1996.......................................................................................    F-49
    Unaudited Interim Condensed Statement of Cash Flows for the three months ended March 31, 1996.........    F-50
    Notes to Unaudited Interim Condensed Financial Statements.............................................    F-51
</TABLE>
 
                                      F-1
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
               UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS
 
    The  following  unaudited  pro  forma  condensed  financial  statements  are
presented as if all of the following transactions had occurred: (i) the March 8,
1996 issuance of the Bridge Notes in connection with the Bridge Financing;  (ii)
the  receipt of $2,220,000 in  cash proceeds from the  issuance of the Equipment
Note and Indemnity Warrants  in connection with  the Equipment Financing,  after
deducting  related expenses of $225,000; (iii) the receipt of $3,000,000 in cash
proceeds from the issuance of the CommcoCCC Notes and the CommcoCCC Warrants  in
connection  with  the  CommcoCCC Financing;  (iv)  the Conversion;  and  (v) the
Merger, including the issuance of ART  Common Stock to Telecom stockholders  and
the cancellation of all outstanding Telecom common stock.
 
    The following unaudited pro forma as adjusted condensed financial statements
reflect  further adjustments assuming  (i) the sale by  the Company of 7,500,000
shares of Common Stock offered in the Common Stock Offering based on an  assumed
initial  public offering price of  $9.00 per share and  the Units offered in the
Unit Offering  assuming $175,000,000  in  gross proceeds,  in each  case,  after
deducting  the estimated underwriting  discount and offering  expenses; (ii) the
receipt and application of the net proceeds therefrom to repay the Bridge  Notes
and  the CommcoCCC Notes and  to acquire the 50%  ownership interest of ART West
held by Extended for $6.0 million in cash and the DCT Assets for $3.6 million in
cash; and  (iii) the  consummation of  the  acquisition by  the Company  of  the
CommcoCCC Assets in exchange for 16,500,000 shares of Common Stock at an assumed
value of $9.00 per share.
 
    All  such  transactions are  reflected as  if  they had  occurred as  of the
beginning of  the  respective periods  for  the unaudited  pro  forma  condensed
statements  of  operations and  at  the respective  balance  sheet date  for the
unaudited pro forma condensed balance sheet.
 
    These unaudited pro forma condensed  financial statements were derived  from
and  should  be  read in  conjunction  with  the audited  and  unaudited interim
condensed financial statements of ART and Telecom and the related notes thereto,
included elsewhere herein. In management's opinion, all adjustments necessary to
reflect the foregoing and related transactions have been made.
 
    The unaudited pro forma condensed  financial statements are not  necessarily
indicative  of what the actual financial position or results of operations would
have been assuming that the  transactions described in the preceding  paragraphs
had occurred on the dates indicated, nor does it purport to represent the future
financial position or results of operations of the Company.
 
                                      F-2
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                  UNAUDITED PRO FORMA CONDENSED BALANCE SHEETS
 
                                     ASSETS
<TABLE>
<CAPTION>
                         AS OF
                      DECEMBER 31,  AS OF MARCH
                          1995        31, 1996
                      ------------  ------------
                       HISTORICAL    HISTORICAL
                      COMBINED (A)  COMBINED (A)
                      ------------  ------------
<S>                   <C>           <C>
Current assets:
  Cash and cash
   equivalents......  $ 633,654     $ 3,024,161
  Other current
   assets...........     52,325          61,226
                      ------------  ------------
    Total current
     assets.........    685,979       3,085,387
Property and
 equipment, net.....  3,581,561       6,380,895
Equity
 investments........    285,000         285,000
FCC licenses........  4,235,734       4,235,734
Deferred financing
 costs..............    778,897         681,692
Equipment and other
 deposits...........    284,012         344,417
Other assets........     25,376          23,212
                      ------------  ------------
                      $9,876,559    $15,036,337
                      ------------  ------------
                      ------------  ------------
 
      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable
   and accrued
   liabilities......  $3,694,489    $ 4,213,517
  CommcoCCC Notes...                    --
                      ------------  ------------
    Total current
     liabilities....  3,694,489       4,213,517
Convertible notes
 payable............  4,950,000
Note payable to
 EMI................  1,500,000       1,500,000
Bridge notes
 payable............     --           3,983,082
Equipment financing
 note payable.......     --             --
Senior discount
 notes..............     --             --
Deferred tax
 liability..........     --             --
                      ------------  ------------
    Total
     liabilities....  10,144,489      9,696,599
                      ------------  ------------
Redeemable Preferred
 Stock..............     44,930         --
                      ------------  ------------
Stockholders'
 equity:
  Preferred stock,
   par..............        488             921
  Common stock,
   par..............     25,304          28,127
  Additional paid-in
   capital..........  3,031,405      19,375,335
  Accumulated
   deficit..........  (3,370,057  ) (14,064,645)
                      ------------  ------------
    Total
     stockholders'
     equity.........   (312,860   )   5,339,738
                      ------------  ------------
                      $9,876,559    $15,036,337
                      ------------  ------------
                      ------------  ------------
 
<CAPTION>
 
                         PRO FORMA                      OFFERING       PRO FORMA
                      ADJUSTMENTS (B)    PRO FORMA    ADJUSTMENTS (C) AS ADJUSTED
                      ---------------   ------------  -------------   -----------
<S>                   <C>               <C>           <C>             <C>
Current assets:
  Cash and cash
   equivalents......    $3,000,000(2)
                        $2,220,000(3)   $  8,244,161  62,35$7,474(1)
                                                      168,667,526(2)
                                                      (8,000,000)(3)
                                                      (6,000,000)(5)
                                                      (3,600,000)(6)
                                                      (3,000,000)(4)  218$,669,161
  Other current
   assets...........                          61,226                       61,226
                      ---------------   ------------  -------------   -----------
    Total current
     assets.........     5,220,000         8,305,387  210,425,000     218,730,387
Property and
 equipment, net.....                       6,380,895                    6,380,895
Equity
 investments........                         285,000    (285,000)(5)      --
FCC licenses........                       4,235,734  201,990,000(4)
                                                       6,285,000(5)
                                                       3,600,000(6)   216,110,734
Deferred financing
 costs..............       175,899(3)        857,591    (189,749)(1)
                                                       6,332,474(2)     7,000,316
Equipment and other
 deposits...........                         344,417                      344,417
Other assets........                          23,212                       23,212
                      ---------------   ------------  -------------   -----------
                        $5,395,899      $ 20,432,236  428,1$57,725    448$,589,961
                      ---------------   ------------  -------------   -----------
                      ---------------   ------------  -------------   -----------
      LIABILITIES AN
Current liabilities:
  Accounts payable
   and accrued
   liabilities......    $               $  4,213,517       $            4$,213,517
  CommcoCCC Notes...     2,975,000(2)      2,975,000  (2,975,000)(3)      --
                      ---------------   ------------  -------------   -----------
    Total current
     liabilities....     2,975,000         7,188,517  (2,975,000)       4,213,517
Convertible notes
 payable............       --                --                           --
Note payable to
 EMI................                       1,500,000                    1,500,000
Bridge notes
 payable............                       3,983,082  (3,983,082)(3)
Equipment financing
 note payable.......     1,911,439(3)      1,911,439                    1,911,439
Senior discount
 notes..............                         --       159,800,000(2)  159,800,000
Deferred tax
 liability..........                                  50,490,000(4)    50,490,000
                      ---------------   ------------  -------------   -----------
    Total
     liabilities....     4,886,439        14,583,038  203,331,918     217,914,956
                      ---------------   ------------  -------------   -----------
Redeemable Preferred
 Stock..............                         --           --              --
                      ---------------   ------------  -------------   -----------
Stockholders'
 equity:
  Preferred stock,
   par..............          (921)(1)       --
  Common stock,
   par..............         1,959(1)         30,086       7,500(1)       --
                                                          16,500(4)        54,086
  Additional paid-in
   capital..........        (1,038)(1)
                            25,000(2)
                           484,460(3)     19,883,757  62,160,225(1)
                                                      15,200,000(2)
                                                      148,483,500(4)  245,727,482
  Accumulated
   deficit..........                     (14,064,645) (1,041,918)(3)  (15,106,563)
                      ---------------   ------------  -------------   -----------
    Total
     stockholders'
     equity.........       509,460         5,849,198  224,825,807     230,675,005
                      ---------------   ------------  -------------   -----------
                        $5,395,899      $ 20,432,236  428,1$57,725    448$,589,961
                      ---------------   ------------  -------------   -----------
                      ---------------   ------------  -------------   -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                      F-3
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                  UNAUDITED PRO FORMA CONDENSED BALANCE SHEETS
                  SUPPLEMENTARY COMBINING BALANCE SHEET DATA:
<TABLE>
<CAPTION>
                                           AS OF DECEMBER 31, 1995
                      -----------------------------------------------------------------
                                                 HISTORICAL
                      -----------------------------------------------------------------
                      ADVANCED RADIO   ADVANCED RADIO
                       TECHNOLOGIES       TELECOM                           HISTORICAL
                      CORPORATION (D)    CORP. (E)      ELIMINATIONS (F)     COMBINED
                      --------------   --------------   ----------------   ------------
<S>                   <C>              <C>              <C>                <C>
Current assets:
  Cash and cash
   equivalents......   $     6,069      $    627,585                       $    633,654
  Due from ART......       --                738,680      $  (738,680)          --
  Other current
   assets...........       --                 52,325                             52,325
                      --------------   --------------   ----------------   ------------
    Total current
     assets.........         6,069         1,418,590         (738,680)          685,979
Note receivable from
 Telecom............     5,000,000          --             (5,000,000)          --
Property and
 equipment, net.....         1,723         3,579,838                          3,581,561
Equity investments..       285,000          --                                  285,000
FCC licenses........         8,913         4,226,821                          4,235,734
Deferred financing
 costs, net.........       457,543           321,354                            778,897
Equipment and other
 deposits...........       --                284,012                            284,012
Investment in ART...       --               --                                  --
Other assets........        25,376          --                                   25,376
                      --------------   --------------   ----------------   ------------
                       $ 5,784,624      $  9,830,615      $(5,738,680)     $  9,876,559
                      --------------   --------------   ----------------   ------------
                      --------------   --------------   ----------------   ------------
                    LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable
   and accrued
   liabilities......   $   243,952      $  3,450,537                       $  3,694,489
  Due to Telecom....       738,680          --            $  (738,680)          --
  Commco Notes......       --               --                                  --
                      --------------   --------------   ----------------   ------------
    Total current
     liabilities....       982,632         3,450,537         (738,680)        3,694,489
Convertible notes
 payable............     4,950,000          --                                4,950,000
Losses in excess of
 equity investment..       211,543          --               (211,543)          --
Note payable to
 ART................       --              5,000,000       (5,000,000)          --
Note payable to
 EMI................       --              1,500,000                          1,500,000
Bridge notes
 payable............       --               --                                  --
Equipment financing
 note payable.......       --               --                                  --
Senior discount
 notes..............       --               --                                  --
                      --------------   --------------   ----------------   ------------
    Total
     liabilities....     6,144,175         9,950,537       (5,950,223)       10,144,489
                      --------------   --------------   ----------------   ------------
Redeemable Preferred
 Stock..............        44,930          --                                   44,930
                      --------------   --------------   ----------------   ------------
Stockholders'
 equity:
  Preferred stock,
   par..............       --                    488                                488
  Common stock,
   par..............        10,013            15,291                             25,304
  Additional paid-in
   capital..........       988,375         2,845,372         (802,002)
                                                                 (340)        3,031,405
  Accumulated
   deficit..........    (1,402,869)       (2,981,073)       1,013,885        (3,370,057)
                      --------------   --------------   ----------------   ------------
    Total
     stockholders'
     equity
     (deficit)......      (404,481)         (119,922)         211,543          (312,860)
                      --------------   --------------   ----------------   ------------
                       $ 5,784,624      $  9,830,615      $(5,738,680)     $  9,876,559
                      --------------   --------------   ----------------   ------------
                      --------------   --------------   ----------------   ------------
 
<CAPTION>
                                          AS OF MARCH 31, 1996
                      -------------------------------------------------------------
 
                                               HISTORICAL
                      -------------------------------------------------------------
                                          ADVANCED
                      ADVANCED RADIO       RADIO
                       TECHNOLOGIES       TELECOM                       HISTORICAL
                      CORPORATION (D)    CORP. (E)    ELIMINATIONS (F)   COMBINED
                      ---------------   ------------  ---------------   -----------
<S>                   <C>               <C>           <C>               <C>
Current assets:
  Cash and cash
   equivalents......    $    5,970      $3,018,191                        3$,024,161
  Due from ART......       --              498,100      (49$8,100)          --
  Other current
   assets...........       --               61,226                           61,226
                      ---------------   ------------  ---------------   -----------
    Total current
     assets.........         5,970       3,577,517      (498,100)         3,085,387
Note receivable from
 Telecom............       --               --                              --
Property and
 equipment, net.....         1,292       6,379,603                        6,380,895
Equity investments..     3,242,401          --        (2,957,401)           285,000
FCC licenses........         8,913       4,226,821                        4,235,734
Deferred financing
 costs, net.........       --              681,692                          681,692
Equipment and other
 deposits...........       --              344,417                          344,417
Investment in ART...       --               44,930       (44,930)           --
Other assets........        23,212          --                               23,212
                      ---------------   ------------  ---------------   -----------
                        $3,281,788      $15,254,980   (3,50$0,431)       15$,036,337
                      ---------------   ------------  ---------------   -----------
                      ---------------   ------------  ---------------   -----------
 
Current liabilities:
  Accounts payable
   and accrued
   liabilities......         2,500      $4,211,017                        4$,213,517
  Due to Telecom....       498,100          --          (49$8,100)          --
  Commco Notes......       --               --                              --
                      ---------------   ------------  ---------------   -----------
    Total current
     liabilities....       500,600       4,211,017      (498,100)         4,213,517
Convertible notes
 payable............       --               --                              --
Losses in excess of
 equity investment..                        --                              --
Note payable to
 ART................                        --                              --
Note payable to
 EMI................       --            1,500,000                        1,500,000
Bridge notes
 payable............       --            3,983,082                        3,983,082
Equipment financing
 note payable.......       --               --                              --
Senior discount
 notes..............       --               --                              --
                      ---------------   ------------  ---------------   -----------
    Total
     liabilities....       500,600       9,694,099      (498,100)         9,696,599
                      ---------------   ------------  ---------------   -----------
Redeemable Preferred
 Stock..............        44,930          --           (44,930)           --
                      ---------------   ------------  ---------------   -----------
Stockholders'
 equity:
  Preferred stock,
   par..............       --                  921                              921
  Common stock,
   par..............        10,013          18,114                           28,127
  Additional paid-in
   capital..........     7,783,889      19,189,302    (7,597,856)        19,375,335
 
  Accumulated
   deficit..........    (5,057,644)     (13,647,456 )  4,640,455        (14,064,645)
                      ---------------   ------------  ---------------   -----------
    Total
     stockholders'
     equity
     (deficit)......     2,736,258       5,560,881    (2,957,401)         5,339,738
                      ---------------   ------------  ---------------   -----------
                        $3,281,788      $15,254,980   (3,50$0,431)       15$,036,337
                      ---------------   ------------  ---------------   -----------
                      ---------------   ------------  ---------------   -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                      F-4
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
             UNAUDITED PRO FORMA CONDENSED STATEMENT OF OPERATIONS
<TABLE>
<CAPTION>
                                                      THREE MONTHS ENDED MARCH 31, 1996
                         --------------------------------------------------------------------------------------------
                                                   HISTORICAL
                         --------------------------------------------------------------
                          ADVANCED RADIO   ADVANCED RADIO
                           TECHNOLOGIES       TELECOM                                       PRO FORMA
                         CORPORATION (D)     CORP. (E)     ELIMINATIONS (F)  COMBINED    ADJUSTMENTS (B)   PRO FORMA
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
<S>                      <C>               <C>             <C>              <C>          <C>              <C>
Operating revenue......    $                $      9,620                    $     9,620                   $     9,620
                         ----------------  --------------                   -----------                   -----------
Expenses:
  General and
   administrative
   (H).................          24,939        8,889,364                      8,914,303                     8,914,303
  Market development
   (I).................         --             1,150,063                      1,150,063                     1,150,063
  Research &
   development.........         --               419,418                        419,418                       419,418
Depreciation and
 amortization..........           2,595           86,684                         89,279                        89,279
  Interest, net........             671          130,474                        131,145     $ 198,425(4)
                                                                                              157,316(5)
                                                                                               86,360(6)
                                                                                              (44,507)(7)     528,739
                         ----------------  --------------                   -----------  ---------------  -----------
    Total expenses.....          28,205       10,676,003                     10,704,208       397,594      11,101,802
Equity loss in
 Telecom...............       3,626,570          --          $(3,626,570)       --                            --
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
Pretax loss............       3,654,775       10,666,383      (3,626,570)    10,694,588       397,594      11,092,182
Deferred tax benefit...         --               --                             --                            --
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
      Net loss.........    $  3,654,775     $ 10,666,383     ($3,626,570)   $10,694,588     $ 397,594     $11,092,182
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
Pro forma net loss per
 share of common stock
 (G)...................    $       0.12                                                                   $      0.35
                         ----------------                                                                 -----------
                         ----------------                                                                 -----------
Pro forma weighted
 average number of
 shares of Common Stock
 outstanding (G).......      31,651,605                                                                    31,651,605
                         ----------------                                                                 -----------
                         ----------------                                                                 -----------
 
<CAPTION>
 
                             OFFERING       PRO FORMA
                         ADJUSTMENTS (C)   AS ADJUSTED
                         ----------------  ------------
<S>                      <C>               <C>
Operating revenue......                     $    9,620
                                           ------------
Expenses:
  General and
   administrative
   (H).................                      8,914,303
  Market development
   (I).................                      1,150,063
  Research &
   development.........                        419,418
Depreciation and
 amortization..........    $  1,350,692(8)   1,439,971
  Interest, net........
 
                               (264,658)(3)
                                (86,360)(3)
                              5,811,579(7)   5,989,300
                         ----------------  ------------
    Total expenses.....       6,811,253     17,913,055
Equity loss in
 Telecom...............                         --
                         ----------------  ------------
Pretax loss............       6,811,253     17,903,435
Deferred tax benefit...        (459,236)(8)    (459,236)
                         ----------------  ------------
      Net loss.........    $  6,352,017     $17,444,199
                         ----------------  ------------
                         ----------------  ------------
Pro forma net loss per
 share of common stock
 (G)...................                     $     0.31
                                           ------------
                                           ------------
Pro forma weighted
 average number of
 shares of Common Stock
 outstanding (G).......                     55,651,605
                                           ------------
                                           ------------
</TABLE>
<TABLE>
<CAPTION>
                                       YEAR ENDED DECEMBER 31, 1995
                      --------------------------------------------------------------
                                                HISTORICAL
                      --------------------------------------------------------------
                      ADVANCED RADIO     ADVANCED
                       TECHNOLOGIES    RADIO TELECOM
                      CORPORATION (D)    CORP. (E)     ELIMINATIONS (F)    COMBINED
                      --------------   -------------   ----------------   ----------
<S>                   <C>              <C>             <C>                <C>
Operating revenue...    $  --           $     5,793                       $   5,793
                      --------------   -------------                      ----------
Expenses:
  General and
   administrative
   (G)..............       204,937        2,706,336                       2,911,273
  Market
   development......       --               191,693                         191,693
  Depreciation and
   amortization.....        10,378            5,306                          15,684
  Interest, net.....        38,455           83,531                         121,986
                      --------------   -------------                      ----------
    Total
     expenses.......       253,770        2,986,866                       3,240,636
Equity loss in
 Telecom............     1,013,885                       $(1,013,885)        --
                      --------------   -------------   ----------------   ----------
Pretax Loss.........     1,267,655        2,981,073       (1,013,885)     3,234,843
Deferred tax
 benefit............       --               --                               --
                      --------------   -------------   ----------------   ----------
      Net loss......    $1,267,655      $ 2,981,073      $(1,013,885)     $3,234,843
                      --------------   -------------   ----------------   ----------
                      --------------   -------------   ----------------   ----------
Pro forma net loss
 per share of Common
 Stock (G)..........    $     0.04
                      --------------
                      --------------
Pro forma weighted
 average number of
 shares of Common
 Stock outstanding
 (G)................    31,651,605
                      --------------
                      --------------
 
<CAPTION>
 
                         PRO FORMA                     OFFERING        PRO FORMA
                      ADJUSTMENTS (B)   PRO FORMA   ADJUSTMENTS (C)   AS ADJUSTED
                      ---------------   ----------  ---------------   -----------
<S>                   <C>               <C>         <C>               <C>
Operating revenue...                    $   5,793       $               $5,793
                                        ----------  ---------------   -----------
Expenses:
  General and
   administrative
   (G)..............                    2,911,273                     2,911,273
  Market
   development......                      191,693                      191,693
  Depreciation and
   amortization.....                       15,684    5,402,768(8)     5,418,452
  Interest, net.....  $1,019,145(4)
                         673,534(5)
                         270,438(6)
                        (110,828)(7)    1,974,275   (1,019,145)(3)
                                                      (270,438)(3)
                                                    23,246,316(7)     23,931,008
                      ---------------   ----------  ---------------   -----------
    Total
     expenses.......   1,852,289        5,092,925   27,359,501        32,452,426
Equity loss in
 Telecom............                       --                            --
                      ---------------   ----------  ---------------   -----------
Pretax Loss.........   1,852,289        5,087,132   27,359,501        32,446,633
Deferred tax
 benefit............      --                        (1,836,941)(8)    (1,836,941)
                      ---------------   ----------  ---------------   -----------
      Net loss......  $1,852,289        $5,087,132  25,5$22,560       30$,609,692
                      ---------------   ----------  ---------------   -----------
                      ---------------   ----------  ---------------   -----------
Pro forma net loss
 per share of Common
 Stock (G)..........                    $    0.16                       $ 0.55
                                        ----------                    -----------
                                        ----------                    -----------
Pro forma weighted
 average number of
 shares of Common
 Stock outstanding
 (G)................                    31,651,605                    55,651,605
                                        ----------                    -----------
                                        ----------                    -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                      F-5
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
          NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS
 
(A)  Represents the historical  combined balance sheets of  ART and Telecom. See
    supplementary combining balance sheet data on page F-4.
 
(B) Pro forma adjustments:
 
    (1) Conversion of Telecom serial preferred stock into Telecom common  stock,
       issuance of ART Common Stock to Telecom stockholders, and cancellation of
       the  outstanding Telecom  common stock  and the  ART Redeemable Preferred
       Stock in connection with the Merger.
 
    (2) Proceeds of $3,000,000 in cash from the CommcoCCC Financing in  exchange
       for the CommcoCCC Notes and CommcoCCC Warrants. The value ascribed to the
       CommcoCCC Warrants totaled $25,000.
 
    (3) Proceeds of $2,220,000 in cash from the Equipment Financing and issuance
       of  the  Indemnity  Warrants,  net  of  the  related  financing  costs of
       $225,000. The value ascribed to the Indemnity Warrants totaled $484,460.
 
    (4) Interest expense from the  Bridge Financing provided by stockholders  of
       Telecom  at the effective interest rate  after giving effect to the value
       ascribed to the Bridge Warrants, as if the Bridge Notes were issued as of
       the beginning of the respective periods.
 
    (5) Interest expense from the Equipment Financing at the effective  interest
       rate after giving effect to the value ascribed to the Indemnity Warrants,
       as  if  the  Equipment Notes  were  issued  as of  the  beginning  of the
       respective periods.
 
    (6) Interest expense from the CommcoCCC Financing, at the effective interest
       rate after giving effect to the value ascribed to the CommcoCCC Warrants,
       as if  the  CommcoCCC  Notes were  issued  as  of the  beginning  of  the
       respective periods.
 
    (7)  Elimination  of  interest  expense  from  the  Advent  Notes  that were
       converted into shares of Telecom stock on February 2, 1996.
 
(C) Offering adjustments:
 
    (1) Issuance of 7,500,000 shares of Common Stock offered in the Common Stock
       Offering based on an assumed initial  public offering price of $9.00  per
       share,  after  deducting  the  estimated  offering  discount  and related
       expenses of $5,332,275.
 
    (2) Assumed gross proceeds  of $175,000,000 from the  issuance of the  Notes
       and  Warrants  in  the  Unit  Offering,  and  related  estimated offering
       discount and related expenses  of $6,824,417. The  value ascribed to  the
       Unit Warrants totaled $15,200,000.
 
    (3) Repayment of the Bridge Financing and CommcoCCC Financing out of the net
       proceeds  from the  Offerings and  the reversal  of the  related interest
       expense. The  unamortized offering  discount and  deferred finance  costs
       associated  with the Bridge Financing and CommcoCCC Financing will result
       in an  extraordinary  loss of  approximately  $1,000,000 which  has  been
       excluded from the pro forma as adjusted presentation.
 
    (4)  The  acquisition of  the CommcoCCC  Assets  in exchange  for 16,500,000
       shares of Common Stock of the Company based on an assumed value of  $9.00
       per share, the related deferred tax liabilities and the estimated related
       expenses of $3,000,000.
 
    (5)  The  acquisition of  the 50%  ownership  interest of  ART West  held by
       Extended for $6 million in cash, to be paid out of the net proceeds  from
       the Offerings..
 
    (6)  The acquisition of the DCT assets for  $3.6 million in cash, to be paid
       out of the net proceeds from the Offerings.
 
    (7) Interest  expense on  the Notes,  at  an assumed  coupon rate  of  13.5%
       (resulting in an effective interest rate of 15.2% on the Notes, including
       the  amortization of debt issuance costs and original issue discount), as
       if the Notes were issued as  of the beginning of the respective  periods.
       If the interest rate on the Notes changed by 0.5%, interest expense would
       change by approximately $765,000 and $191,250 for the year ended December
       31, 1995 and three months ended March 31, 1996, respectively.
 
                                      F-6
<PAGE>
    (8)  Depreciation and amortization expense related to the acquisition of the
       CommcoCCC Assets, the 50% ownership interest in ART West, the DCT  Assets
       and the related deferred taxes.
 
(D)  Represents the  historical amounts of  ART as  of and for  the three months
    ended March 31, 1996 and as of and for the year ended December 31, 1995.
 
(E) Represents the historical amounts of Telecom as of and for the three  months
    ended  March 31, 1996, as of December 31, 1995 and for the period from March
    28, 1995 (date of inception) to December 31, 1995.
 
(F)  Represents  the  elimination  of  inter-entity  transactions  and  balances
    consisting  of  (i)  receivables  and  payables,  (ii)  ART's  investment in
    Telecom,  Telecom's  corresponding  stockholder   equity  amounts  and   the
    recognition  by ART of its  equity in losses of  Telecom and (iii) Telecom's
    investment in ART Redeemable Preferred Stock.
 
(G) Pro forma net loss  per share and the weighted  average number of shares  of
    Common  Stock reflect  (i) the  conversion of  all shares  of Telecom serial
    preferred stock to Telecom common stock;  (ii) issuance of ART Common  Stock
    to  Telecom stockholders, (iii) the  cancellation of the outstanding Telecom
    common stock and the ART Series  A Redeemable Preferred Stock; and (iv)  the
    issuance of potentially dilutive instruments issued within one year prior to
    a  proposed initial  public offering  at exercise  prices below  the assumed
    initial public offering price of $9.00 per share as if they were outstanding
    as of the beginning of the respective periods.
 
<TABLE>
<S>                                                                   <C>
Pro Forma:
  Weighted average number of shares of Common Stock outstanding for
   primary computation..............................................      10,013,055(1)
  Issuances of shares of Telecom serial preferred stock as converted
   into shares of ART Common Stock..................................      10,916,807
  Issuances of shares of Telecom common stock as converted into
   shares of ART Common Stock.......................................       8,100,807(2)
  Options and warrants issued and outstanding.......................       2,620,936
                                                                      --------------
  Pro forma weighted average number of shares of Common Stock.......      31,651,605(3)
                                                                      --------------
                                                                      --------------
Pro Forma As Adjusted:
  Pro forma weighted average number of shares of Common Stock.......      31,651,605
  Common Stock issued in connection with the Common Stock Offering
   and the acquisition of the CommcoCCC Assets......................      24,000,000
                                                                      --------------
  Pro forma as adjusted weighted average number of shares of Common
   Stock............................................................      55,651,605(3)
                                                                      --------------
                                                                      --------------
</TABLE>
 
    (1) The  weighted average  number  of shares  of  Common Stock  for  primary
       computation   exclude   all   common   stock   equivalents,   which   are
       anti-dilutive.
 
    (2) Excludes shares of Telecom common stock owned by ART.
 
    (3)  The  Securities  and  Exchange  Commission  requires  that  potentially
       dilutive  instruments issued within one year  prior to a proposed initial
       public offering  at exercise  prices below  the expected  initial  public
       offering price be treated as outstanding for the entire period presented.
       The  weighted average number of shares of Common Stock on a pro forma and
       a pro  forma  as  adjusted  basis  reflects  those  potentially  dilutive
       instruments  assuming the sale  of shares of Common  Stock offered in the
       Common Stock Offering based on  an assumed initial public offering  price
       of  $9.00 per share. In measuring the dilutive effect, the treasury stock
       method was used.
 
(H) General  and  administrative  expense  includes  a  non-recurring,  non-cash
    compensation  expense of $802,002 and $6,795,514 for the year ended December
    31, 1995  and for  the  three months  ended  March 31,  1996,  respectively,
    associated  with the release of Escrow Shares in 1995 and the termination of
    the Escrow Shares arrangement in 1996.
 
(I) Market  development  expense for  the  three  months ended  March  31,  1996
    includes  $1,053,000,  representing  the  value  ascribed  to  the Strategic
    Distribution Agreement in  connection with the  February 1996 investment  in
    Telecom by Ameritech.
 
                                      F-7
<PAGE>
                       REPORT OF INDEPENDENT ACCOUNTANTS
 
To the Stockholders of
Advanced Radio Technologies Corporation:
 
    We   have  audited  the  accompanying   balance  sheets  of  Advanced  Radio
Technologies Corporation (a development stage  company) as of December 31,  1995
and  1994, and the  related statements of  operations, stockholders' deficit and
cash flows for the years ended December  31, 1995 and 1994, for the period  from
August  23, 1993 (date of inception) to December 31, 1993 and for the cumulative
period from August  23, 1993  (date of inception)  to December  31, 1995.  These
financial  statements are  the responsibility  of the  Company's management. Our
responsibility is to express an opinion  on these financial statements based  on
our audits.
 
    We  conducted  our audits  in  accordance with  generally  accepted auditing
standards. Those standards require that we plan and perform the audits to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence  supporting
the  amounts and disclosures in the financial statements. An audit also includes
assessing the  accounting  principles used  and  significant estimates  made  by
management,  as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
    In our opinion, the financial  statements referred to above present  fairly,
in  all material respects, the financial position of Advanced Radio Technologies
Corporation as of December 31, 1995 and 1994, and the results of its  operations
and  its cash flows for the years ended  December 31, 1995 and 1994, and for the
period from  August  23, 1993  (date  of inception)  to  December 31,  1993,  in
conformity with generally accepted accounting principles.
 
    The  accompanying  financial  statements  have been  prepared  on  the going
concern basis  of  accounting,  which contemplates  realization  of  assets  and
liquidation  of liabilities in the ordinary  course of business. As described in
Note 1, the Company  has a substantial working  capital deficit at December  31,
1995,  has  incurred operating  losses since  inception and  does not  expect to
generate significant operating revenues until fiscal 1996. The Company estimates
that revenues  in  1996 will  not  be sufficient  to  fund its  initial  capital
requirements,  operating expenses and other  working capital needs. In addition,
as set forth in  Notes 5, 7,  8, and 11, the  Company has significant  financial
commitments.   The   Company's  continued   funding   of  its   initial  capital
requirements,  operating  expenses,  working   capital  needs  and   contractual
commitments  is  dependent  upon  its  ability  to  raise  additional financing.
Management's plans in  this regard  are discussed  in Note  1. These  conditions
raise  substantial  doubt about  the Company's  ability to  continue as  a going
concern. The  financial statements  do not  include any  adjustments that  might
result from the outcome of these uncertainties.
 
                                          COOPERS & LYBRAND L.L.P.
 
New York, New York
April 26, 1996, except for Note 2C, Note 5B and
  the second paragraph of Note 9
  as to which the date is June 26, 1996
 
                                      F-8
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                                 BALANCE SHEETS
                           DECEMBER 31, 1995 AND 1994
 
<TABLE>
<CAPTION>
                                                                                           1995           1994
                                                                                      --------------  ------------
<S>                                                                                   <C>             <C>
                                                      ASSETS
Current assets:
  Cash..............................................................................  $        6,069  $      5,133
                                                                                      --------------  ------------
      Total current assets..........................................................           6,069         5,133
Note receivable from Telecom (Note 4)...............................................       5,000,000
Equity investments (Note 5).........................................................         285,000
Deferred financing costs, net.......................................................         457,543
FCC licenses........................................................................           8,913
Property and equipment, net.........................................................           1,723         3,448
Other assets........................................................................          25,376        34,030
                                                                                      --------------  ------------
      Total assets..................................................................  $    5,784,624  $     42,611
                                                                                      --------------  ------------
                                                                                      --------------  ------------
 
                                      LIABILITIES AND STOCKHOLDERS' DEFICIT
Current liabilities:
  Accounts payable and accrued liabilities..........................................  $      243,952  $     11,689
  Due to Telecom (Note 11)..........................................................         738,680
  Note payable to related party (Note 11)...........................................                        70,000
                                                                                      --------------  ------------
      Total current liabilities.....................................................         982,632        81,689
Equity loss in excess of investment (Note 5)........................................         211,543
Convertible note payable (Note 4)...................................................       4,950,000
                                                                                      --------------  ------------
      Total liabilities.............................................................       6,144,175        81,689
                                                                                      --------------  ------------
Redeemable Preferred Stock, $.01 par value; 1,000 shares authorized; 1 share issued
 and outstanding at December 31,
 1995 (Note 4)......................................................................          44,930
                                                                                      --------------  ------------
Commitments and contingencies (Notes 1, 5, 7, 8, 11 and 12).........................
 
Stockholders' deficit (Note 9):
  Common Stock, $.001 par value; 58,900,320 shares authorized; 10,013,055 and
   5,890,032 shares issued and outstanding..........................................          10,013         5,890
  Additional paid-in capital........................................................         988,375        90,246
  Deficit accumulated during the development stage..................................      (1,402,869)     (135,214)
                                                                                      --------------  ------------
      Total stockholders' deficit...................................................        (404,481)      (39,078)
                                                                                      --------------  ------------
        Total liabilities and stockholders' deficit.................................  $    5,784,624  $     42,611
                                                                                      --------------  ------------
                                                                                      --------------  ------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-9
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENTS OF OPERATIONS
                FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1994,
            FOR THE PERIOD FROM AUGUST 23, 1993 (DATE OF INCEPTION)
               TO DECEMBER 31, 1993 AND CUMULATIVE FOR THE PERIOD
         FROM AUGUST 23, 1993 (DATE OF INCEPTION) TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                                                                        CUMULATIVE
                                                                                         PERIOD FROM    FROM AUGUST
                                                                                         AUGUST 23,      23, 1993
                                                                   YEARS ENDED          1993 (DATE OF    (DATE OF
                                                                   DECEMBER 31,         INCEPTION) TO  INCEPTION) TO
                                                            --------------------------  DECEMBER 31,   DECEMBER 31,
                                                                1995          1994          1993           1995
                                                            -------------  -----------  -------------  -------------
<S>                                                         <C>            <C>          <C>            <C>
Consulting income.........................................  $    --        $   137,489    $  --         $   137,489
                                                            -------------  -----------  -------------  -------------
Expenses:
  General and administrative expenses.....................        204,937      253,453        5,906         464,296
  Depreciation and amortization...........................         10,378        8,281          688          19,347
  Interest expense, net (Note 11).........................         38,455        4,375                       42,830
                                                            -------------  -----------  -------------  -------------
      Total expenses......................................        253,770      266,109        6,594         526,473
Equity loss on investment in Telecom (Note 5).............      1,013,885                                 1,013,885
                                                            -------------  -----------  -------------  -------------
      Net loss............................................  $   1,267,655  $   128,620    $   6,594     $ 1,402,869
                                                            -------------  -----------  -------------  -------------
                                                            -------------  -----------  -------------  -------------
Pro forma net loss per share (unaudited)..................  $        0.04
                                                            -------------
                                                            -------------
Pro forma weighted average number of shares of Common
 Stock outstanding (unaudited)............................     31,651,605
                                                            -------------
                                                            -------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-10
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                  STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)
                FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1994,
            FOR THE PERIOD FROM AUGUST 23, 1993 (DATE OF INCEPTION)
               TO DECEMBER 31, 1993 AND CUMULATIVE FOR THE PERIOD
         FROM AUGUST 23, 1993 (DATE OF INCEPTION) TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                                                         DEFICIT
                                                                                       ACCUMULATED
                                                                         ADDITIONAL       DURING
                                                               COMMON      PAID-IN     DEVELOPMENT
                                                                STOCK      CAPITAL        STAGE           TOTAL
                                                              ---------  -----------  --------------  --------------
<S>                                                           <C>        <C>          <C>             <C>
Net issuance of 2,945,016 shares of Common Stock for cash...  $   2,945  $    58,191                  $       61,136
Net loss....................................................                          $       (6,594)         (6,594)
                                                              ---------  -----------  --------------  --------------
Balance, December 31, 1993..................................      2,945       58,191          (6,594)         54,542
Issuance of 2,945,016 shares of Common Stock for cash.......      2,945       32,055                          35,000
Net loss....................................................                                (128,620)       (128,620)
                                                              ---------  -----------  --------------  --------------
Balance, December 31, 1994..................................      5,890       90,246        (135,214)        (39,078)
Issuance of 73,625 shares of Common Stock to ART West.......         74       24,926                          25,000
Issuance of 4,049,398 shares of Common Stock to existing
 shareholders...............................................      4,049       (4,049)
Conversion of note payable and interest to paid-in
 capital....................................................                  75,250                          75,250
Investment in Telecom as a result of the release of escrow
 shares.....................................................                 802,002                         802,002
Net loss....................................................                              (1,267,655)     (1,267,655)
                                                              ---------  -----------  --------------  --------------
Balance, December 31, 1995..................................  $  10,013  $   988,375  $   (1,402,869) $     (404,481)
                                                              ---------  -----------  --------------  --------------
                                                              ---------  -----------  --------------  --------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-11
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENTS OF CASH FLOWS
                FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1994,
            FOR THE PERIOD FROM AUGUST 23, 1993 (DATE OF INCEPTION)
               TO DECEMBER 31, 1993 AND CUMULATIVE FOR THE PERIOD
         FROM AUGUST 23, 1993 (DATE OF INCEPTION) TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                                                            PERIOD FROM     CUMULATIVE
                                                                                            AUGUST 23,     FROM AUGUST
                                                                     YEARS ENDED           1993 (DATE OF  23, 1993 (DATE
                                                                    DECEMBER 31,           INCEPTION) TO  OF INCEPTION)
                                                            -----------------------------  DECEMBER 31,    TO DECEMBER
                                                                 1995           1994           1993          31, 1995
                                                            --------------  -------------  -------------  --------------
<S>                                                         <C>             <C>            <C>            <C>
Cash flows from operating activities:
  Net loss................................................  $   (1,267,655) $    (128,620)  $    (6,594)  $   (1,402,869)
  Adjustments to reconcile net loss to net cash used in
   operating activities:
    Non-cash interest expense.............................         110,828                                       110,828
    Depreciation and amortization.........................          10,378          8,281           688           19,347
    Equity loss on investment in Telecom..................       1,013,885                                     1,013,885
  Changes in operating assets and liabilities:
    Accounts payable and accrued liabilities..............          (3,939)        (8,282)       19,971            7,750
                                                            --------------  -------------  -------------  --------------
      Net cash (used in) provided by operating
       activities.........................................        (136,503)      (128,621)       14,065         (251,059)
                                                            --------------  -------------  -------------  --------------
Cash flows from investing activities:
  Additions to property and equipment.....................                         (5,175)                        (5,175)
  Investment in ART West and Telecom......................        (255,340)                                     (255,340)
  Note receivable from Telecom............................      (5,000,000)                                   (5,000,000)
  Acquisition of FCC Licenses.............................         (13,912)                                      (13,912)
  Increase in other assets................................                                      (41,272)         (41,272)
                                                            --------------  -------------  -------------  --------------
      Net cash used in investing activities...............      (5,269,252)        (5,175)      (41,272)      (5,315,699)
                                                            --------------  -------------  -------------  --------------
Cash flows from financing activities:
  Proceeds from issuance of Common Stock..................                         35,000        61,136           96,136
  Proceeds from loan and note payable.....................           8,500         70,000                         78,500
  Proceeds from issuance of Preferred Stock...............          50,000                                        50,000
  Preferred Stock issuance costs..........................          (5,070)                                       (5,070)
  Repayment of loan.......................................          (8,500)                                       (8,500)
  Proceeds from convertible note payable..................       4,950,000                                     4,950,000
  Deferred financing costs................................        (326,919)                                     (326,919)
  Due to Telecom..........................................         738,680                                       738,680
                                                            --------------  -------------  -------------  --------------
      Net cash provided by financing activities...........       5,406,691        105,000        61,136        5,572,827
                                                            --------------  -------------  -------------  --------------
      Net increase (decrease) in cash.....................             936        (28,796)       33,929            6,069
Cash, beginning of period.................................           5,133         33,929
                                                            --------------  -------------  -------------  --------------
Cash, end of period.......................................  $        6,069  $       5,133   $    33,929   $        6,069
                                                            --------------  -------------  -------------  --------------
                                                            --------------  -------------  -------------  --------------
Supplemental cash flow information:
Non-cash investing and financing activities:
  Release of escrow shares and increase in the investment
   in Telecom.............................................  $      802,002                                $      802,002
  Issuance of stock and contribution of licenses to ART
   West...................................................  $       30,000                                $       30,000
  Conversion of note payable and interest to Common
   Stock..................................................  $       75,250                                $       75,250
  Accrued deferred financing costs........................  $      175,000                                $      175,000
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-12
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                         NOTES TO FINANCIAL STATEMENTS
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION:
 
THE COMPANY
 
    Advanced  Radio  Technologies  Corporation  ("ART"  or  the  "Company")  was
organized as a  Delaware corporation on  August 23, 1993,  to provide  broadband
wireless  digital telecommunications services to the domestic telecommunications
market. The  Company's  operations  to  date include  the  application  for  and
acquisition  of certain  38 GHz licenses  granted by  the Federal Communications
Commission ("FCC") and costs incurred for the deployment of such services.
 
    During 1995,  The Company  established a  strategic alliance  with  Extended
Communications,  Inc. ("Extended") to form the  ART West joint venture. ART West
was formed on April 4, 1995 to develop and expand the Company's wireless digital
telecommunications services  in various  markets throughout  the western  United
States (see Note 5).
 
    During  1995, Advanced Radio Telecom Corp.  ("Telecom") was organized by the
Company and Landover Holdings Corporation  ("Landover") with one of its  initial
objectives  to acquire certain 38 GHz licenses in the northeastern United States
from EMI Communications, Corp. ("EMI"). Under the terms of a purchase  agreement
between  the Company, Landover, and Telecom dated April 21, 1995, (the "Purchase
Agreement") Landover  was  obligated to  purchase  $7,000,000 of  securities  of
Telecom.  Pursuant  to  the  Purchase Agreement  and  a  stockholders' agreement
between the Company, Telecom and their respective shareholders dated May 8, 1995
(the "Stockholders'  Agreement"), the  Company and  Telecom were  to merge  once
approval from the FCC had been granted. (See Note 2).
 
INITIAL CAPITALIZATION
 
    The  Company was  formed on August  23, 1993  by two of  its executives (the
"Founding Stockholders") by issuing 2,945,016 shares of Common Stock in exchange
for $1,136. During November 1993, ART redeemed 1,178,006 shares of Common  Stock
from  the Founding Stockholders and through a private placement issued 1,178,006
shares of Common Stock to High Sky Limited Partnership ("High Sky") in  exchange
for $60,000. During March 1994, High Sky II Limited Partnership ("High Sky II"),
an   affiliate  of  High  Sky  (collectively   referred  to  as  the  "High  Sky
Partnerships") contributed  $100,000  to the  Company  in exchange  for  589,003
shares  of Common Stock  and a $70,000  Promissory Note. In  connection with the
High Sky II financing, ART issued an additional aggregate of 2,356,013 shares to
the Founding Stockholders and High Sky whereby the Founding Stockholders and the
High Sky Partnerships would each own a 50% interest in ART. Additionally, during
1994, one  of the  Founding Stockholders  contributed an  additional $5,000  for
which contribution there were no shares issued.
 
    Pursuant  to an agreement dated March 1,  1995, High Sky II agreed to assign
the $70,000 Promissory Note, plus accrued interest, to the Founding Stockholders
in exchange for two new promissory notes executed by the Founding  Stockholders.
Concurrent  with the exchange of the promissory notes, the Founding Stockholders
contributed the $70,000 Promissory Note plus  accrued interest of $5,250 to  the
Company, for which contribution there were no additional shares issued.
 
BASIS OF PRESENTATION
 
    The  financial statements have  been prepared on the  going concern basis of
accounting,  which  contemplates  realization  of  assets  and  liquidation   of
liabilities  in the ordinary  course of business. The  Company has a substantial
working capital deficit, has incurred operating losses since inception and  does
not expect to recognize significant operating revenues until the commencement of
its  commercial  services, which  is anticipated  to occur  in fiscal  1996. The
Company estimates  that revenues  in 1996  will not  be sufficient  to fund  its
initial   operating  expenses   and  other  working   capital  needs,  including
 
                                      F-13
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION, CONTINUED:
consulting, service and purchase commitments set forth in Notes 5, 7, 8 and  11.
The  Company's  continued funding  of  its initial  operating  expenses, working
capital needs and contractual commitments is dependent upon its ability to raise
additional financing. The  Company and Telecom  have engaged various  investment
bankers  to assist them  in raising financing  through a public  equity and debt
offering. There  can  be no  assurance  that the  Company  and Telecom  will  be
successful in their effort to raise additional financing through these offerings
or,  if available,  that the Company  and Telecom will  be able to  obtain it on
acceptable terms. These conditions raise  substantial doubt about the  Company's
ability  to continue as a going concern. The financial statements do not include
any adjustments that might result from the outcome of these uncertainties.
 
2.  PURCHASE AGREEMENT:
 
A -- INITIAL CAPITALIZATION OF TELECOM
 
    Pursuant to  the  Purchase  Agreement, as  its  initial  capitalization,  an
aggregate of 8,580,000 shares of Class B and Class A common stock were issued by
Telecom  to Landover and consultants to Landover, respectively, for an aggregate
cash consideration of $1,020. Such  shares of Class B  and Class A common  stock
represented  64% and  2%, respectively,  of the  total number  shares of capital
stock of Telecom then outstanding. Concurrently, the Company received  4,420,000
shares  of Class A common stock, representing  34% of the total number of shares
of capital stock of Telecom  then outstanding in exchange  for $340. All of  the
above  references to  shares of  common stock of  Telecom have  been adjusted to
reflect a 13 for 1 stock split which occurred in February 1996, but are prior to
the issuance of anti-dilutive shares described below.
 
    Under the  Purchase Agreement,  Landover agreed  to invest  or cause  to  be
invested  $7,000,000 in ART, Telecom and their affiliates (the "Landover Funding
Commitment"). In consideration for this $7,000,000 investment, Telecom agreed to
issue preferred stock,  the number  of shares of  which would  be designated  by
Landover.  Under the  anti-dilution provisions of  the Class A  common stock, in
respect of each such preferred stock  issuance, Telecom agreed to issue, for  no
consideration,  additional shares of Class A common stock in number necessary to
maintain the 36% ownership interest in Telecom of the holders of Class A  common
stock.
 
    Under  the Purchase  Agreement, the  individual shareholders  of the Company
were required to place 5,153,778 shares of Common Stock in the Company in escrow
(the "Escrow Shares") to be released upon the completion of the then pending EMI
Asset acquisition  (see  Note 8),  Telecom's  attainment of  specific  operating
income  levels for the years 1997 through  1999 and the acquisition of interests
in a specified  number of FCC  license authorizations  by April 30,  2000. As  a
result  of  the consummation  of the  EMI Asset  acquisition, in  November 1995,
1,873,030 of the  Escrow Shares  of ART  were released.  The fair  value of  the
Escrow Shares released in 1995, amounting to $802,002, has been accounted for as
an  equity investment  in Telecom,  the effect of  which has  been recognized as
additional paid-in capital  in the  Company. Pursuant  to the  February 2,  1996
Reorganization,  the Escrow  Shares arrangement  was terminated  and all  of the
remaining Escrow Shares were  released to the stockholders  of the Company.  The
fair   value  of  the  remaining  Escrow  Shares  released,  in  the  amount  of
approximately $6.8 million,  will be  accounted for  in the  same manner  during
1996.
 
B -- MERGER
 
    Under the terms of the Purchase Agreement, the Company and Telecom intend to
operate  both companies as a single enterprise and are committed to merge if and
when permitted by the FCC.
 
                                      F-14
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
2.  PURCHASE AGREEMENT, CONTINUED:
Concurrent with the Purchase Agreement, the Company and Telecom entered into  an
exclusive   20-year  services  agreement  (the  "Services  Agreement")  for  the
construction, development and operation of systems in the Company's markets (see
Note 6).
 
    On February 2, 1996, the Company, Telecom and their respective  shareholders
agreed  to an amendment and restatement of the Stockholders' Agreement providing
for (i) termination effective  on the closing of  a public share offering,  (ii)
amendment and restatement of the Certificate of Incorporation and reorganization
of  the capital structure of Telecom; (iii) the exchange of the Advent Notes and
one share of  ART Series A  Redeemable Preferred  Stock for shares  of Series  E
preferred  stock  of  Telecom (see  Note  4);  (iv) revision  of  provisions for
election of  directors;  (v) amendment  and  restatement of  ART's  registration
rights  agreements;  (vi)  release of  shares  escrowed in  connection  with the
original Stockholders' Agreement; and (vii)  approval of a definitive  agreement
to merge the Company and Telecom (the "Reorganization").
 
C -- AMENDED MERGER
 
    The  definitive merger  agreement, as entered  into on February  2, 1996 and
subsequently restated and  amended on  June 26, 1996,  (the "Merger  Agreement")
provides for the merger of a newly-formed wholly owned subsidiary of the Company
("Merger  Sub")  into  Telecom  (the "Merger")  subject  to  certain conditions,
including the receipt  of FCC approval.  Prior to the  Merger, each  outstanding
share  of Telecom's serial preferred  stock will be converted  into 13 shares of
Telecom's common stock. In the Merger, each outstanding share of common stock of
Telecom will be exchanged for the right to receive an equal number of shares  of
Common  Stock of the  Company. As a  result, Telecom will  become a wholly owned
subsidiary of the Company. The Merger  Agreement provides that if the Merger  is
not  consummated by May 13, 1997, the  shares of Telecom's common stock owned by
the Company will be surrendered to Telecom, and the Services Agreements is to be
revised to, among other revisions, extend the term to 40 years and provide for a
proportionate participation by the Company's stockholders in any dividends  paid
by  Telecom or the proceeds from any  sale of Telecom. The Merger Agreement also
provides for the  assignment of Telecom's  interests in all  of its  agreements,
including  the  various  services agreements,  employment  agreements, equipment
purchase agreements and  purchase option  agreements, to  the Company.  Further,
upon  the Merger, the holders of warrants  to purchase an aggregate of 2,302,136
shares of Telecom common stock will be entitled to purchase an equivalent number
of shares of Common Stock on the same terms. Employee stock options to  purchase
1,664,732  shares of Telecom's common stock will be converted into similar stock
options of the Company.
 
3.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
 
DEVELOPMENT STAGE ENTERPRISE
 
    The Company is  a development stage  enterprise as defined  in Statement  of
Financial  Accounting Standards No. 7,  "Accounting and Reporting by Development
Stage Enterprises." The  financial statements  have been prepared  on the  going
concern basis of accounting.
 
PROPERTY AND EQUIPMENT
 
    Property  and equipment is stated at  cost. Depreciation and amortization is
computed using the straight-line method over the estimated useful lives of three
years.
 
                                      F-15
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
3.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, CONTINUED:
INVESTMENTS
 
    The Company accounts for its 50% interest in the ART West joint venture  and
its 34% interest in Telecom under the equity method.
 
FCC LICENSES
 
    The   Company  has   obtained  radio   spectrum  rights   under  FCC  issued
authorizations and licenses throughout the United States by petitioning the  FCC
directly  and through the purchase of such  rights held by others. Such licenses
are issued for an initial term of six years and are renewable subject to  review
by  the FCC.  The costs  associated with  the acquisition  of such  licenses are
capitalized and  amortized  on  a  straight-line basis  over  a  40-year  period
beginning  upon commencement  of operations in  the related  market. The 40-year
period is based upon management's license renewal expectations.
 
RECOVERABILITY OF LONG-LIVED ASSETS
 
    The  recoverability   of  property   and  equipment   and  capitalized   FCC
authorizations  and  licenses is  dependent upon  the successful  development of
systems in  each of  the respective  markets, or  through sale  of such  assets.
Management  estimates that  it will recover  the carrying amount  of those costs
from cash flow generated by the systems once they have been developed.  However,
it  is reasonably  possible that such  estimate will  change as a  result of the
failure to develop the FCC authorizations  on a timely basis, or  technological,
regulatory or other changes.
 
    The  Company's policy  is to assess  annually any impairment  in value based
upon a comparison of  projected operating cash flows  from each market over  its
expected  period of operation, on an  undiscounted basis, to the carrying amount
of the property and equipment, licenses  and other capitalized costs related  to
the market.
 
FINANCING COSTS
 
    Direct  costs  associated with  obtaining  debt financing  are  deferred and
charged to interest expense  using the effective interest  rate method over  the
term  of the debt.  Direct costs associated with  obtaining equity financing are
deferred and charged  to additional  paid-in capital  as the  related funds  are
raised.  Deferred costs associated  with unsuccessful financings  are charged to
expense.
 
    Accumulated amortization  of deferred  financing  costs totaled  $44,376  at
December 31, 1995.
 
REVENUE RECOGNITION
 
    Revenue  from telecommunications  services are  recognized ratably  over the
period such services are provided.
 
    During 1994, the Company recognized  income from consulting fees  associated
with  the  application of  FCC licenses  on behalf  of third  parties, including
consulting fees of approximately $80,000 from Extended.
 
INCOME TAXES
 
    The Company  accounts  for  income  taxes  under  the  liability  method  of
accounting.  Under the liability method, deferred  taxes are determined based on
the differences between  the financial  statement and  tax bases  of assets  and
liabilities  at enacted tax rates in effect in the year in which the differences
are expected to reverse. Valuation  allowances are established, when  necessary,
to reduce deferred tax assets to the amounts expected to be realized.
 
                                      F-16
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
3.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, CONTINUED:
NET LOSS PER SHARE
 
    Historical  net loss per share is computed  based on the loss for the period
divided by the  weighted average number  of shares of  Common Stock  outstanding
during the period. Historical net loss per share and the weighted average number
of shares of Common Stock outstanding are as follows:
 
<TABLE>
<CAPTION>
                                                                                       FOR THE PERIOD
                                                           FOR THE YEARS ENDED        FROM AUGUST 23,
                                                              DECEMBER 31,             1993 (DATE OF
                                                      -----------------------------    INCEPTION) TO
                                                           1995           1994       DECEMBER 31, 1993
                                                      --------------  -------------  ------------------
<S>                                                   <C>             <C>            <C>
Net loss per share..................................  $         0.13  $        0.01    $     --
                                                      --------------  -------------  ------------------
                                                      --------------  -------------  ------------------
Weighted average number shares of Common Stock
 outstanding........................................      10,013,055      9,178,633         5,006,527
                                                      --------------  -------------  ------------------
                                                      --------------  -------------  ------------------
</TABLE>
 
    The  Securities and  Exchange Commission requires  that potentially dilutive
instruments issued within one year prior  to a proposed initial public  offering
at  exercise prices below the expected  initial public offering price be treated
as outstanding for all periods presented. Accordingly, an additional  21,638,550
shares  are reflected in the  weighted average number of  shares of Common Stock
outstanding in computing the unaudited pro forma net loss per share for the year
ended December 31, 1995.
 
USE OF ESTIMATES
 
    The  preparation  of  financial  statements  in  conformity  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions that  affect the  reported  amounts of  assets and  liabilities  and
disclosure  of contingent assets and liabilities as of the date of the financial
statements and  the  reported  amounts  of  revenues  and  expenses  during  the
reporting period. Actual results could differ from those estimates.
 
4.  NOTE RECEIVABLE FROM TELECOM AND CONVERTIBLE NOTES PAYABLE TO ADVENT:
    The   Company,  Telecom   and  several   entities  affiliated   with  Advent
International Corp. (collectively, "Advent"), entered into a securities purchase
agreement (the "Advent Purchase Agreement") dated November 13, 1995 under  which
Advent agreed to acquire a 10% interest in the combined entities of the Company,
Telecom  and certain specified affiliates. Pending  the merger of these entities
(see Note 2), the Company issued  promissory notes (the "Advent Notes") with  an
aggregate principal amount of $4,950,000 and one share of the Company's Series A
Redeemable Preferred Stock in exchange for $5,000,000 in cash.
 
    The  Advent  Notes carried  interest at  a rate  of 10%  per annum  and were
payable on demand at any  time on or after May  13, 1997. The Advent Notes  were
collateralized  by certain assets  of the Company and  Telecom. The Advent Notes
were convertible into that number of shares of preferred stock which represented
in the aggregate at least 10% of the fully diluted capital stock of the combined
entities described  above, as  defined  in the  Advent Purchase  Agreement.  The
Advent  Notes were convertible either (i) immediately prior to an initial public
offering with  aggregate gross  proceeds  of at  least  $10,000,000 or  (ii)  at
Advent's election.
 
    At December 31, 1995, the Company accrued interest expense of $66,542 on the
Advent   Notes,  which  has  been  included  in  accounts  payable  and  accrued
liabilities.
 
    On November  13, 1995,  the gross  proceeds of  $5,000,000 received  by  the
Company  from Advent  were transferred  to Telecom in  exchange for  a note with
terms equivalent to  the terms of  the Advent  Notes. On February  2, 1996,  the
Company,    Telecom   and   Advent   entered    into   an   exchange   agreement
 
                                      F-17
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
4.  NOTE RECEIVABLE FROM TELECOM AND CONVERTIBLE NOTES PAYABLE TO
ADVENT, CONTINUED:
under which the Advent Notes, including  accrued interest, and the one share  of
ART  Series  A Redeemable  Preferred  Stock held  by  Advent were  exchanged for
232,826 shares  of  Series  E preferred  stock  of  Telecom, and  the  note  was
canceled.  As a result,  the Advent Notes  were canceled and  Telecom became the
owner of the one share of the ART Series A Redeemable Preferred Stock.
 
5.  EQUITY INVESTMENTS:
 
A -- INVESTMENT IN ART WEST JOINT VENTURE
 
    On April 4,  1995, the Company  entered into an  agreement with Extended  to
form  ART West, a jointly controlled general partnership established to acquire,
develop, and operate  radio systems  using 38  GHz licenses  in certain  western
states  of the U.S. The ART West  joint venture will continue until December 31,
2055, unless  terminated earlier.  The  Company's initial  capital  contribution
consisted  of $255,000 in cash, FCC licenses  and related assets with a carrying
value of  approximately  $5,000, and  73,625  shares  of Common  Stock  of  ART.
Extended's  initial capital  contribution consisted  of $5,000  in cash  and FCC
licenses. The combined  systems are  collectively referred  to as  the ART  West
Systems.  Additionally, Extended received distributions  of $250,000 in cash and
the 73,625 shares of Common Stock contributed  by the Company to ART West. As  a
result  of these contributions and distributions, the Company and Extended share
equally in  the partnership  interests of  ART West.  The Company  recorded  its
investment  in ART West in  the amount of $285,000.  The excess of the Company's
share of  the underlying  net assets  of ART  West over  the Company's  recorded
investment will be amortized over the life of the ART West Systems.
 
    On  October 1, 1994,  ART entered into an  exclusive services agreement with
Extended, whereby  ART  is  responsible  for  the  construction,  operation  and
management  of Extended's telecommunications systems.  The term of the Agreement
is for  five years.  In connection  with  the formation  of ART  West,  Extended
assigned  its interest in the services agreement to ART West. Under the terms of
the services  agreement,  ART will  incur  all  costs and  expenses  related  to
construction, operation and management of the systems. As compensation, ART will
receive  all revenues generated  by the systems  after deducting certain related
direct expenses, less 45%  which is to  be paid to ART  West. ART's interest  in
this service agreement was subsequently assigned to Telecom (Note 6). An officer
of ART is also the President and a shareholder of Extended.
 
B -- ART WEST JOINT VENTURE ACQUISITION AND MANAGEMENT AGREEMENTS
 
    In  June  1996,  the  Company agreed  to  acquire  Extended's  50% ownership
interest in ART West for $6,000,000  in cash upon consummation of public  equity
and  debt offerings with aggregate net proceeds of $125.0 million to the Company
and receipt of FCC  approval. In addition, the  Company entered into a  ten-year
management  agreement  which,  effective  June 1,  1996,  replaces  the services
agreement referred to above  with an arrangement whereby  the Company agrees  to
construct, operate and manage the ART West Systems in exchange for a license fee
equal to 10% of recurring operating revenues.
 
C -- INVESTMENT IN TELECOM
 
    The Company acquired 4,420,000 shares of Class A common stock of Telecom, or
34%  of the outstanding  and issued shares, for  cash of $340  (see Note 2). The
Company also recorded $802,002 as an  investment in Telecom based upon the  fair
value  of  Escrow  Shares released  in  1995 (see  Note  2). The  excess  of the
Company's share  of the  underlying net  assets of  Telecom over  the  Company's
recorded  investment  will  be  amortized  over  the  estimated  useful  life of
Telecom's FCC licenses.
 
                                      F-18
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
5.  EQUITY INVESTMENTS, CONTINUED:
    The Company recognizes its proportionate share  of the losses of Telecom  in
excess of its investment to the extent of its funding and financial commitments.
During 1995, the Company recognized its proportionate share of Telecom's loss in
the  amount of  $1,013,885. Summarized financial  information for  Telecom as of
December 31, 1995 and for the period from March 28, 1995 (date of inception)  to
December 31, 1995 is as follows:
<TABLE>
<CAPTION>
                                                                                          DECEMBER 31,
                                                                                              1995
                                                                                         ---------------
<S>                                                                                      <C>
Total current assets...................................................................   $   1,418,590
Property and equipment, net............................................................       3,579,838
FCC licenses...........................................................................       4,226,821
Other assets...........................................................................         605,366
                                                                                         ---------------
  Total assets.........................................................................   $   9,830,615
                                                                                         ---------------
                                                                                         ---------------
Total current liabilities..............................................................   $   3,450,537
Note payable to EMI....................................................................       1,500,000
Note payable to ART....................................................................       5,000,000
Total stockholders' deficit............................................................        (119,922)
                                                                                         ---------------
  Total liabilities and stockholders' deficit..........................................   $   9,830,615
                                                                                         ---------------
                                                                                         ---------------
 
<CAPTION>
 
                                                                                         MARCH 28, 1995
                                                                                            (DATE OF
                                                                                          INCEPTION) TO
                                                                                          DECEMBER 31,
                                                                                              1995
                                                                                         ---------------
<S>                                                                                      <C>
Operating revenue......................................................................   $       5,793
Expenses...............................................................................       2,986,866
                                                                                         ---------------
Net loss...............................................................................   $   2,981,073
                                                                                         ---------------
                                                                                         ---------------
</TABLE>
 
6.  TELECOM SERVICES AGREEMENT:
    The  Company entered into an exclusive  Services Agreement with Telecom, for
the construction,  operation and  management  of the  FCC licenses  and  related
telecommunications  systems that are owned by ART  or for which ART has existing
services agreements. Under the Services Agreement, Telecom will incur all  costs
and  expenses related to construction, operation  and management of the systems.
As compensation,  Telecom will  receive all  revenues generated  by the  systems
after deducting certain related direct expenses, less 25% which is to be paid to
the Company. The Services Agreement is for a period of 20 years.
 
    Through  this Services Agreement, the Company  has assigned its interests in
other similar services agreements with ART West  (see Note 5) and DCT (see  Note
7). There have been no services provided through December 31, 1995 on any of the
services agreements.
 
7.  DCT AGREEMENTS:
 
SYSTEM PURCHASE AGREEMENT
 
    On  September  1,  1994, the  Company  entered  into an  agreement  with DCT
Communications, Inc.  ("DCT"),  in which  the  Company obtained  the  option  to
purchase  certain FCC licenses (the "Systems")  from DCT for $500,000 and shares
of ART Common Stock that represent 5% of its fully diluted equity as of the date
of transfer. The option is exercisable at  any time after December 31, 1995  and
up to the date
 
                                      F-19
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
7.  DCT AGREEMENTS, CONTINUED:
that  is three years after the FCC issues DCT's first license. At any time after
December 31, 1995,  DCT may require  that the Company  purchase the Systems  for
$50,000, plus reimbursement of certain costs defined in the agreement.
 
SERVICES AGREEMENT
 
    On  September  1,  1994,  the Company  entered  into  an  exclusive services
agreement with  DCT whereby  the Company  is responsible  for the  construction,
operation and management of DCT's Systems. The term of the Agreement is for five
years.  Under the terms  of the services  agreement, the Company  will incur all
costs and  expenses related  to construction,  operation and  management of  the
systems. As compensation, the Company will receive all revenues generated by the
systems after deducting certain related direct expenses, less 45% which is to be
paid to DCT.
 
CONSULTING AND LOAN AGREEMENT
 
    On  March 13, 1995, the Company entered into a consulting and loan agreement
(the "Consulting and  Loan Agreement"). Under  the terms of  the Consulting  and
Loan  Agreement, DCT agreed to  loan the Company $8,500,  bearing interest at 9%
per annum. The loan, including interest of $431, was due and paid on August  31,
1995.
 
DCT PRELIMINARY AGREEMENT
 
    On  April  25, 1996,  the  Company and  Telecom  entered into  a preliminary
agreement with DCT to acquire DCT's  interest in certain FCC authorizations  and
licenses  in exchange for $3.6  million in cash, subject  to the completion of a
definitive purchase agreement  and services agreement.  The definitive  purchase
agreement  will supersede and replace all  other existing agreements between DCT
and the Company. The  definitive purchase agreement must  be signed by June  28,
1996 and the closing of the transaction is subject to FCC approval.
 
8.  COMMITMENTS:
 
ACQUISITION OF ASSETS OF EMI
 
    On  April 4, 1995, the Company entered into a purchase option agreement with
EMI to acquire  EMI's interest  in certain 38  GHz radio  spectrum licenses  and
related  assets in the northeastern United States (the "EMI Assets") in exchange
for $3,000,000 in cash  and a three year  non-negotiable promissory note in  the
amount  of  $1,500,000. Pursuant  to  the Purchase  Agreement  (see Note  1), in
November, 1995,  the  Company assigned  its  rights and  obligations  under  the
purchase option agreement to Telecom. The FCC subsequently approved the transfer
of  the EMI licenses  and Telecom directly  acquired the EMI  Assets in November
1995. The Company  has also  issued a  guarantee to  EMI of  the obligations  of
Telecom under the promissory note.
 
TELECOM ONE OPTION
 
    On  May 25,  1995, the  Company entered into  an agreement  with TeleCom One
Incorporated ("TeleCom One") whereby the Company agreed to assist TeleCom One in
its applications for certain FCC  licenses (the "TeleCom One Agreement").  Under
the  terms  of the  TeleCom One  Agreement,  in exchange  for its  services, the
Company acquired options to purchase a 49% interest in each of the FCC  licenses
obtained  by TeleCom One at a purchase price of $.0133 per person covered by the
geographic license area. The  term of the TeleCom  One Agreement is five  years.
The Company has not exercised any of its options.
 
                                      F-20
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
8.  COMMITMENTS, CONTINUED:
EMPLOYMENT AND CONSULTING AGREEMENTS
 
    On  May 8,  1995, the  Company and  Telecom jointly  entered into consulting
agreements with two executive officers of the Company and Telecom, effective  as
of  January  1, 1995  and continuing  for a  term of  three years,  with minimum
payments aggregating approximately $170,000 annually. The costs associated  with
these  contracts have been recorded by Telecom  and no amounts have been charged
to the Company.
 
    On December  16, 1995,  one of  the executive  officers of  the Company  and
Telecom, previously a party to one of the consulting agreements described above,
entered into a full-time employment agreement. The employment agreement is for a
three-year term with an annual salary of $250,000 in the first year, $275,000 in
the  second year  and $300,000  in the  third year.  In addition,  the agreement
provides for a cash bonus of up to $100,000 for each year based upon achievement
of specific performance objectives. The costs associated with this contract have
been recorded by Telecom and no amounts have been charged to the Company.
 
    On July  11,  1995, the  Company  and  Telecom entered  into  an  employment
agreement,  as  amended January  8, 1996,  with  an officer  of the  Company and
Telecom. The  term of  the  agreement is  three years  at  an annual  salary  of
$160,000  in the  first year, $200,000  in the  second year and  $240,000 in the
third year. Options to purchase shares  of Telecom common stock were awarded  to
this officer equivalent to 2.5% of the outstanding capital stock of Telecom. The
agreement also provides for an engagement bonus of $17,000 upon execution of the
agreement  and  a  cash  bonus  of  up to  $100,000  for  each  year  based upon
achievement of specific performance objectives.  The costs associated with  this
contract  have been recorded by Telecom and  no amounts have been charged to the
Company.
 
    The Company and Telecom  have also entered  into employment agreements  with
other executives that provide for annual base salaries and cash bonuses based on
achievement  of specific performance goals. These contracts may be terminated at
any time by management.
 
FINANCING AGREEMENT
 
    During 1994, the Company entered  into an agreement with Southeast  Research
Partners  ("SERP"), a subsidiary  of Josephthal, Lyons &  Ross, a Florida broker
dealer, to procure additional financing for the Company in exchange for cash and
options to purchase capital stock of the Company. Pursuant to a letter agreement
dated July  12,  1995,  the Company  and  Telecom  paid SERP  $245,000  and  the
shareholders  of the Company granted SERP  options to purchase 313,612 shares of
the Company's  Common  Stock directly  from  the Founding  Stockholders  for  an
aggregate consideration of $210,000.
 
    As  of December 31, 1995, the Company and Telecom have accounted for the fee
of $245,000 as  part of  the financing  provided by  Landover and,  accordingly,
$175,000  has been recorded as deferred  financing costs related to the issuance
of the Advent Notes (See Note 4) and the balance of $70,000 has been  recognized
as  an offset  against the  proceeds from the  issuance of  the serial preferred
stock of Telecom.
 
9.  COMMON STOCK:
    On April 5, 1994, the Board of  Directors authorized a 5 for 1 stock  split.
Subsequently,  on April  5, 1995, the  Board of  Directors authorized a  1 for 5
reverse stock split and simultaneously issued an additional 4,049,398 shares  of
Common Stock.
 
    On  May 30, 1996, the Board of  Directors authorized a 29,450.16 for 1 stock
split, increased the number of authorized  shares of Preferred Stock and  Common
Stock to 10,000,000 and 100,000,000,
 
                                      F-21
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
9.  COMMON STOCK, CONTINUED:
respectively,  and  changed the  par value  per  share from  $.01 to  $.001. All
references to the number of shares and per share amounts of the Company's Common
Stock in the accompanying financial statements have been restated to reflect the
five for one stock split, the one for five reverse stock split and the 29,450.16
for 1 stock split, unless otherwise  indicated. All par value amounts have  been
restated to reflect the change in par value to $.001 per share.
 
10. INCOME TAXES:
    As  of  December 31,  1995  and 1994,  the  Company has  net  operating loss
carry-forwards for income tax purposes  of approximately $390,000 and  $134,000,
respectively,  which will expire  between 2008 and 2010.  Deferred tax assets of
approximately $130,000 and $46,000 at December 31, 1995 and 1994,  respectively,
principally  comprised of such net operating  tax loss carry-forwards, have been
offset in full by a valuation allowance.
 
11. RELATED PARTY TRANSACTIONS:
    On May 8, 1995, the Company and Telecom entered into a consulting  agreement
with  Landover as  a strategic and  financial consultant.  Telecom paid Landover
$70,000 for services under this agreement during 1995. The consulting  agreement
was terminated on November 13, 1995.
 
    On  November 13,  1995, the  Company and  Telecom entered  into a management
consulting agreement  with Landover  to  provide strategic  planning,  corporate
development and general management. Under the agreement, the Company and Telecom
will  pay Landover $35,000 per month for  an initial one year term, renewable by
the Company and Telecom for two additional one year terms. The aggregate expense
recognized by  Telecom under  this agreement  during 1995  amounted to  $70,000.
These  expenses have been recorded by Telecom  and no portion of such costs have
been charged  to the  Company. The  agreement also  provides that  in the  event
Landover  arranges financing, acquisitions or certain other transactions for the
Company and Telecom,  Landover will be  paid a fee  in accordance with  industry
standards.
 
    Pursuant  to the Purchase  Agreement, the Company  and Telecom paid Landover
$391,750 for expenses  in connection  with the Landover  Funding Commitment,  of
which  $250,000 has been capitalized as  deferred financing costs by the Company
and the balance of $141,750 has been charged to paid-in capital of Telecom.
 
    Telecom  has  funded  certain  expenses  and  investments  of  the  Company,
including  the Company's  investment in ART  West and payments  of financing and
other operating costs. The amounts funded by Telecom to date totaling  $805,803,
offset by accrued interest income of $67,123 related to the note receivable from
Telecom (see Note 4) have been included in the amount due to Telecom.
 
    In  1994,  the  Company shared  office  space with  a  law firm  in  which a
principal of the law firm was also one of the Founding Stockholders. The Company
paid rent in the amount of  $6,353 to the law firm  for the use of their  office
space.  The  law firm  also regularly  provides legal  services to  the Company.
During 1995  and  1994,  the  Company incurred  fees  of  $34,770  and  $74,550,
respectively, for such services.
 
                                      F-22
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
12. FAIR VALUES OF FINANCIAL INSTRUMENTS
    The  carrying amounts and fair values of the Company's financial instruments
at December 31 were as follows:
 
<TABLE>
<CAPTION>
                                                                          1995                      1994
                                                              ----------------------------  --------------------
                                                                CARRYING                    CARRYING     FAIR
                                                                 AMOUNT       FAIR VALUE     AMOUNT      VALUE
                                                              -------------  -------------  ---------  ---------
<S>                                                           <C>            <C>            <C>        <C>
Note receivable from Telecom................................  $   5,000,000  $   5,000,000     --         --
Notes payable...............................................      4,950,000      4,950,000  $  70,000  $  70,000
</TABLE>
 
    Note receivable from Telecom: The  carrying amounts reported in the  balance
sheet are a reasonable estimate of fair values.
 
    Notes   payable:  The  carrying  amounts   reported  in  the  balance  sheet
approximate fair values based upon  interest rates that are currently  available
to the Company for issuance of similar debt with similar terms and maturities.
 
                                      F-23
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                   UNAUDITED INTERIM CONDENSED BALANCE SHEETS
                         AS OF MARCH 31, 1996 AND 1995
 
<TABLE>
<CAPTION>
                                                                                           1996           1995
                                                                                      --------------  ------------
<S>                                                                                   <C>             <C>
                                                      ASSETS
Current assets:
  Cash..............................................................................  $        5,970  $        255
                                                                                      --------------  ------------
      Total current assets..........................................................           5,970           255
Equity investments..................................................................       3,242,401
FCC licenses........................................................................           8,913
Property and equipment, net.........................................................           1,292         3,448
Other assets........................................................................          23,212        34,030
                                                                                      --------------  ------------
      Total assets..................................................................  $    3,281,788  $     37,733
                                                                                      --------------  ------------
                                                                                      --------------  ------------
 
                                  LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable and accrued liabilities..........................................  $        2,500  $      4,230
  Due to Telecom....................................................................         498,100
  Notes payable.....................................................................                       114,334
                                                                                      --------------  ------------
      Total current liabilities.....................................................         500,600       118,564
Redeemable Preferred Stock, $.01 par value; 1,000 shares authorized; 1 share issued
 and outstanding at March 31, 1996..................................................          44,930
                                                                                      --------------  ------------
Commitments and contingencies
 
Stockholders' equity (deficit):
  Common Stock, $.001 par value; 58,900,320 shares authorized; 10,013,055 and
   5,890,032 shares issued and outstanding..........................................          10,013         5,890
  Additional paid-in capital........................................................       7,783,889        90,246
  Deficit accumulated during the development stage..................................      (5,057,644)     (176,967)
                                                                                      --------------  ------------
      Total stockholders' equity (deficit)..........................................       2,736,258       (80,831)
                                                                                      --------------  ------------
        Total liabilities and stockholders' equity (deficit)........................  $    3,281,788  $     37,733
                                                                                      --------------  ------------
                                                                                      --------------  ------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-24
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
              UNAUDITED INTERIM CONDENSED STATEMENTS OF OPERATIONS
               FOR THE THREE MONTHS ENDED MARCH 31, 1996 AND 1995
 
<TABLE>
<CAPTION>
                                                                                               1996         1995
                                                                                           -------------  ---------
<S>                                                                                        <C>            <C>
Expenses:
  General and administrative.............................................................  $      24,939  $  40,878
  Depreciation and amortization..........................................................          2,595
  Interest expense, net..................................................................            671        875
                                                                                           -------------  ---------
      Total expenses.....................................................................         28,205     41,753
Equity loss on investment in Telecom.....................................................      3,626,570
                                                                                           -------------  ---------
      Net loss...........................................................................  $   3,654,775  $  41,753
                                                                                           -------------  ---------
                                                                                           -------------  ---------
Pro forma net loss per share.............................................................  $        0.12
                                                                                           -------------
                                                                                           -------------
Pro forma weighted average number of shares of Common Stock outstanding (unaudited)......     31,651,605
                                                                                           -------------
                                                                                           -------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-25
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
              UNAUDITED INTERIM CONDENSED STATEMENTS OF CASH FLOWS
               FOR THE THREE MONTHS ENDED MARCH 31, 1996 AND 1995
 
<TABLE>
<CAPTION>
                                                                                                1996          1995
                                                                                           --------------  ----------
<S>                                                                                        <C>             <C>
Cash flows from operating activities:
  Net loss...............................................................................  $   (3,654,775) $  (41,753)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Non-cash interest expense............................................................          69,347
    Depreciation and amortization........................................................           2,595
    Equity loss on investment in Telecom.................................................       3,626,570
  Changes in operating assets and liabilities:
    Accounts payable and accrued liabilities.............................................         (43,836)     (7,459)
                                                                                           --------------  ----------
      Net cash used in operating activities..............................................             (99)    (49,212)
                                                                                           --------------  ----------
Cash flows from financing activities:
  Proceeds from loan and note payable....................................................                      44,334
                                                                                           --------------  ----------
      Net cash provided by financing activities..........................................        --            44,334
                                                                                           --------------  ----------
      Net decrease in cash...............................................................             (99)     (4,878)
Cash, beginning of period................................................................           6,069       5,133
                                                                                           --------------  ----------
Cash, end of period......................................................................  $        5,970  $      255
                                                                                           --------------  ----------
                                                                                           --------------  ----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-26
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
           NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION:
 
THE COMPANY
 
    Advanced  Radio  Technologies  Corporation  ("ART"  or  the  "Company")  was
organized as a  Delaware corporation on  August 23, 1993,  to provide  broadband
wireless  digital telecommunications services to the domestic telecommunications
market.
 
BASIS OF PRESENTATION
 
    The unaudited interim  condensed financial statements  included herein  have
been  prepared by the Company. The  foregoing statements contain all adjustments
(consisting only of normal recurring adjustments)  which are, in the opinion  of
the  Company's management, necessary to present fairly the financial position of
the Company as of March 31, 1996 and 1995, and the results of its operations and
its cash flows for the three months ended March 31, 1996 and 1995.
 
    Certain information and footnote disclosures normally included in  financial
statements  have been condensed or omitted pursuant to the rules and regulations
of the Securities and Exchange Commission. These condensed financial  statements
should  be  read in  conjunction with  the Company's  December 31,  1995 audited
financial statements and notes thereto.
 
    The financial statements have  been prepared on the  going concern basis  of
accounting,   which  contemplates  realization  of  assets  and  liquidation  of
liabilities in  the  ordinary  course  of  business.  The  Company  has  limited
financial  resources,  incurred operating  losses since  inception and  does not
expect to recognize material  operating revenues until  the commencement of  its
commercial  services, which is anticipated to  occur in fiscal 1996. The Company
estimates that  revenues in  1996 will  not be  sufficient to  fund its  initial
operating  expenses  and  other  working  capital  needs,  including consulting,
service and purchase commitments. The Company's continued funding of its initial
operating  expenses,  working  capital  needs  and  contractual  commitments  is
dependent  upon  its  ability to  raise  additional financing.  The  Company and
Advanced Radio  Telecom Corp.  ("Telecom")  (see Note  2) have  engaged  various
investment  bankers to assist them in  raising financing through a public equity
and debt offering. There can be no  assurance that the Company and Telecom  will
be  successful in their effort to raise additional financing through this public
offering or, if available, that the Company  and Telecom will be able to  obtain
it  on  acceptable terms.  These conditions  raise  substantial doubt  about the
Company's ability to continue  as a going concern.  The financial statements  do
not  include  any  adjustments  that  might result  from  the  outcome  of these
uncertainties.
 
2.  STOCKHOLDERS' AGREEMENT:
    On February 2, 1996, the Company, Telecom and their respective  shareholders
agreed  to an amendment and restatement of the Stockholders' Agreement providing
for (i) termination effective  on the closing of  a public share offering,  (ii)
amendment and restatement of the Certificate of Incorporation and reorganization
of  the capital structure of Telecom; (iii) the exchange of the Advent Notes and
one share of  ART Series A  Redeemable Preferred  Stock for shares  of Series  E
preferred  stock  of  Telecom;  (iv)  revision  of  provisions  for  election of
directors;  (v)  amendment   and  restatement  of   ART's  registration   rights
agreements;  (vi) release  of shares  escrowed in  connection with  the original
Stockholders' Agreement; and (vii) approval of the definitive merger agreement.
 
    The definitive merger  agreement, as entered  into on February  2, 1996  and
subsequently  restated and  amended on June  26, 1996  (the "Merger Agreement"),
provides for the merger of a newly-formed wholly owned subsidiary of the Company
("Merger Sub")  into  Telecom  (the "Merger")  subject  to  certain  conditions,
including  the receipt  of FCC approval.  Prior to the  Merger, each outstanding
share of
 
                                      F-27
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
      NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS, CONTINUED
 
2.  STOCKHOLDERS' AGREEMENT: (CONTINUED)
Telecom's serial preferred stock will be  converted into 13 shares of  Telecom's
common  stock. In the Merger  each outstanding share of  common stock of Telecom
will be exchanged for the right to  receive an equal number of shares of  Common
Stock of the Company. As a result, Telecom will become a wholly owned subsidiary
of  the  Company.  The Merger  Agreement  provides  that if  the  Merger  is not
consummated by May 13, 1997, the shares  of Telecom's common stock owned by  the
Company  will be  surrendered to  Telecom and  the Services  Agreement is  to be
revised to, among other revisions, extend the term to 40 years and provide for a
proportionate participation by the Company's stockholders in any dividends  paid
by  Telecom or the proceeds from any  sale of Telecom. The Merger Agreement also
provides for the  assignment of Telecom's  interests in all  of its  agreements,
including  the  various  services agreements,  employment  agreements, equipment
purchase agreements and  purchase option  agreements, to  the Company.  Further,
upon  the Merger, the holders of warrants  to purchase an aggregate of 2,302,136
shares of Telecom common stock will be entitled to purchase an equivalent number
of shares of Common Stock on the same terms. Employee stock options to  purchase
1,664,732  shares of Telecom's common stock will be converted into similar stock
options of the Company.
 
3.  NET LOSS PER SHARE
    Historical net loss per share is computed  based on the loss for the  period
divided  by the  weighted average number  of shares of  Common Stock outstanding
during the period. Historical net loss per share and the weighted average number
of shares of Common Stock outstanding are as follows:
 
<TABLE>
<CAPTION>
                                                                   FOR THE THREE MONTHS ENDED
                                                                           MARCH 31,
                                                                  ----------------------------
                                                                      1996           1995
                                                                  -------------  -------------
<S>                                                               <C>            <C>
Net loss per share..............................................  $         .37  $    --
                                                                  -------------  -------------
                                                                  -------------  -------------
Weighted average number shares of Common Stock outstanding......     10,013,055     10,013,055
                                                                  -------------  -------------
                                                                  -------------  -------------
</TABLE>
 
    The Securities and  Exchange Commission requires  that potentially  dilutive
instruments  issued within one year prior  to a proposed initial public offering
at exercise prices below the expected  initial public offering price be  treated
as  outstanding for all periods presented. Accordingly, an additional 21,638,550
shares are reflected in  the weighted average number  of shares of Common  Stock
outstanding  in computing  the unaudited  pro forma net  loss per  share for the
three months ended March 31, 1996.
 
4.  NOTES RECEIVABLE FROM TELECOM AND CONVERTIBLE NOTE PAYABLE TO ADVENT:
    On February  2,  1996, the  Company,  Telecom  and Advent  entered  into  an
exchange agreement under which the Advent Notes, including accrued interest, and
the  one share of ART's Series A  Redeemable Preferred Stock held by Advent were
exchanged for 232,826  shares of Series  E preferred stock  of Telecom, and  the
notes  payable  by the  Company to  Advent and  by Telecom  to the  Company were
canceled, the related interest forgiven, and Telecom became the owner of the one
share of ART Series A Redeemable Preferred Stock.
 
5.  INVESTMENTS:
    The Company accounts for its 50% interest in the ART West joint venture  and
its 34% interest in Telecom under the equity method.
 
    In  June  1996,  the  Company agreed  to  acquire  Extended's  50% ownership
interest in ART West for $6 million  in cash upon consummation of public  equity
and  debt offerings with aggregate  net proceeds of $125  million to the Company
and  receipt  of  FCC  approval.  In  addition,  the  Company  entered  into   a
 
                                      F-28
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
      NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS, CONTINUED
 
5.  INVESTMENTS: (CONTINUED)
ten-year  management  agreement  which,  effective June  1,  1996,  replaced the
services agreement with ART West with an arrangement whereby the Company  agrees
to construct, operate, and manage the ART West systems in exchange for a license
fee equal to 10% of recurring operating revenues.
 
    During 1995, the Company recorded $802,002 as an investment in Telecom based
upon  the fair value of Escrow Shares released  in 1995, the effect of which was
recognized as additional paid-in  capital in the Company.  On February 2,  1996,
the  Company recorded an  additional $6,795,514 based  on the fair  value of the
remaining Escrow Shares released, which was accounted for in the same manner.
 
    The Company recognizes its proportionate share  of the losses of Telecom  to
the  extent of its  investment, funding and  financial commitments. During 1996,
the Company has recognized its proportionate  share of the losses of Telecom  in
the amount of $3,626,570.
 
6.  COMMCOCCC ASSET ACQUISITION
    During July 1996, the Company entered into an agreement with CommcoCCC, Inc.
("CommcoCCC")   to  acquire  CommcoCCC's   interests  in  certain   38  GHz  FCC
authorizations (the "CommcoCCC Assets") in  exchange for 16.5 million shares  of
Common  Stock. The  acquisition of  the CommcoCCC  Assets is  subject to various
conditions including (i)  minimum population coverage  of the authorizations  of
the  Company and CommcoCCC, (ii) receipt of final FCC and other approvals, (iii)
receipt by CommcoCCC of an opinion as to the tax-free nature of the  transaction
(iv)  the accuracy of representations and warranties except for breaches that do
not have  in  the  aggregate  a  material adverse  effect,  (v)  no  pending  or
threatened  material  litigation, (vi)  consummation of  public equity  and debt
offerings  on  terms  reasonably  satisfactory  to  CommcoCCC  and  (vii)  other
customary  closing conditions.  Pending the  completion of  the acquisition, the
Company has agreed to construct, manage and operate the CommcoCCC Assets.
 
    The Company has given  a stockholder ("Commco LLC")  of CommcoCCC an  option
(the "Option") to purchase FCC authorizations in specified market areas in which
the  Company will  have more than  one authorization. The  Option is exercisable
only in the event that the  CommcoCCC Acquisition is consummated and Commco  LLC
receives  authorizations  pursuant to  pending  applications covering  a minimum
specified population  and expires  nine  months after  the consummation  of  the
Common  Stock Offering.  The price of  authorizations to be  purchased under the
Option is based upon a formula that  considers the market price of Common  Stock
on the date of exercise.
 
    In  connection with the  agreement to acquire  the CommcoCCC Assets, certain
stockholders of CommcoCCC loaned the Company $3 million in cash in exchange  for
notes  due September 30, 1996 (the "CommcoCCC Notes") with interest at the prime
rate and received three year warrants to purchase 50,000 shares of Common  Stock
at  a price of $15  per share. The CommcoCCC Notes  are collateralized by all of
the assets of the Company and, if not paid in full when due, the unpaid  balance
is  convertible into Common Stock,  at the option of  each holder, at stipulated
per share prices based upon the timing of exercise.
 
7.  RELATED PARTY TRANSACTIONS
    Telecom has funded the payment of certain expenses of the Company, including
financing costs. The amounts  funded by Telecom during  the quarter ended  March
31,  1996 totaled $175,000.  The balance resulting  from the funding activities,
offset by  the  net  effect of  the  conversion  of the  Advent  Notes  and  the
cancellation  of the note receivable  from Telecom (Note 3),  is shown as due to
Telecom in the accompanying balance sheet.
 
                                      F-29
<PAGE>
                       REPORT OF INDEPENDENT ACCOUNTANTS
 
To the Board of Directors and Stockholders of
Advanced Radio Telecom Corp.:
 
    We  have audited  the accompanying balance  sheet of  Advanced Radio Telecom
Corp. (a development  stage company) as  of December 31,  1995, and the  related
statements  of operations, stockholders'  deficit and cash  flows for the period
from March 28, 1995  (date of inception) to  December 31, 1995. These  financial
statements   are   the   responsibility  of   the   Company's   management.  Our
responsibility is to express an opinion  on these financial statements based  on
our audit.
 
    We  conducted  our  audit  in accordance  with  generally  accepted auditing
standards. Those standards require that we plan and perform the audit to  obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also  includes
assessing  the  accounting principles  used  and significant  estimates  made by
management, as well as evaluating the overall financial statement  presentation.
We believe that our audit provides a reasonable basis for our opinion.
 
    In  our opinion, the financial statements  referred to above present fairly,
in all material respects, the financial position of Advanced Radio Telecom Corp.
as of December 31, 1995,  and the results of its  operations and its cash  flows
for  the period from March 28, 1995 (date of inception) to December 31, 1995, in
conformity with generally accepted accounting principles.
 
    The accompanying  financial  statements  have been  prepared  on  the  going
concern  basis  of  accounting,  which contemplates  realization  of  assets and
liquidation of liabilities in the ordinary  course of business. As described  in
Note  1, the Company has  a substantial working capital  deficit at December 31,
1995, has  incurred operating  losses since  inception and  does not  expect  to
generate significant operating revenues until fiscal 1996. The Company estimates
that  revenues  in 1996  will  not be  sufficient  to fund  its  initial capital
requirements, operating expenses and other  working capital needs. In  addition,
as  set  forth  in  Notes  8  and  2,  the  Company  has  significant  financial
commitments.  The   Company's  continued   funding   of  its   initial   capital
requirements,   operating  expenses,  working   capital  needs  and  contractual
commitments is  dependent  upon  its  ability  to  raise  additional  financing.
Management's  plans in  this regard  are discussed  in Note  1. These conditions
raise substantial  doubt about  the Company's  ability to  continue as  a  going
concern.  The financial  statements do  not include  any adjustments  that might
result from the outcome of these uncertainties.
 
                                          COOPERS & LYBRAND L.L.P.
 
New York, New York
April 26, 1996, except for Note 2B
as to which the date is June 26, 1996
 
                                      F-30
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                                 BALANCE SHEET
                               DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                           ASSETS
<S>                                                                              <C>
Current assets:
  Cash and cash equivalents....................................................  $   627,585
  Due from ART (Note 12).......................................................      738,680
  Other current assets.........................................................       52,325
                                                                                 -----------
    Total current assets.......................................................    1,418,590
Property and equipment, net (Note 5)...........................................    3,579,838
FCC licenses (Note 4)..........................................................    4,226,821
Equipment and other deposits (Note 8)..........................................      284,012
Deferred financing costs.......................................................      321,354
                                                                                 -----------
      Total assets.............................................................  $ 9,830,615
                                                                                 -----------
                                                                                 -----------
 
                           LIABILITIES AND STOCKHOLDERS' DEFICIT
Current liabilities:
  Accounts payable and accrued liabilities (Note 6)............................  $ 3,450,537
                                                                                 -----------
      Total current liabilities................................................    3,450,537
Note payable to ART (Note 7)...................................................    5,000,000
Note payable to EMI (Note 4)...................................................    1,500,000
                                                                                 -----------
      Total liabilities........................................................    9,950,537
                                                                                 -----------
Commitments and contingencies (Notes 1, 8, 12 and 14)
Stockholders' deficit (Note 9):
  Serial preferred stock, $.001 par value, 488,492 shares issued and
   outstanding.................................................................          488
  Class A common stock, $.001 par value, 7,779,135 shares issued and
   outstanding.................................................................        7,779
  Class B common stock, $.001 par value, 7,512,076 shares issued and
   outstanding.................................................................        7,512
  Additional paid-in capital...................................................    2,845,372
  Deficit accumulated during the development stage.............................   (2,981,073)
                                                                                 -----------
      Total stockholders' deficit..............................................     (119,922)
                                                                                 -----------
        Total liabilities and stockholders' deficit............................  $ 9,830,615
                                                                                 -----------
                                                                                 -----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-31
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENT OF OPERATIONS
             FOR THE PERIOD FROM MARCH 28, 1995 (DATE OF INCEPTION)
                              TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
Operating revenue..............................................................  $    5,793
<S>                                                                              <C>
                                                                                 ----------
Expenses:
  General and administrative expenses (Notes 8, 9 and 10)......................   2,706,336
  Market development expenses..................................................     191,693
  Depreciation and amortization................................................       5,306
  Interest expense, net (Notes 4 and 7)........................................      83,531
                                                                                 ----------
    Total expenses.............................................................   2,986,866
                                                                                 ----------
      Net loss.................................................................  $2,981,073
                                                                                 ----------
                                                                                 ----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-32
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                       STATEMENT OF STOCKHOLDERS' DEFICIT
             FOR THE PERIOD FROM MARCH 28, 1995 (DATE OF INCEPTION)
                              TO DECEMBER 31, 1995
<TABLE>
<CAPTION>
                                        COMMON STOCK                             PREFERRED STOCK
                                    --------------------  -------------------------------------------------------------
SHARES                               CLASS A    CLASS B    SERIES A     SERIES B     SERIES C     SERIES D      TOTAL
- ----------------------------------  ---------  ---------  -----------  -----------  -----------  -----------  ---------
<S>                                 <C>        <C>        <C>          <C>          <C>          <C>          <C>
Issuance of common stock to ART
 for cash.........................  4,420,000
Issuance of common stock to
 Landover and affiliates for
 cash.............................    260,000  8,320,000
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................                           332,091                                            332,091
  Series B........................                                         82,318                                82,318
  Series C........................                                                       5,402                    5,402
Issuance of Series D preferred
 stock for cash...................                                                                   61,640      61,640
Shares issued to reflect
 anti-dilution adjustments........  3,099,135                  2,852        4,189                                 7,041
Redemption of common stock from
 Landover.........................              (807,924)
                                    ---------  ---------  -----------  -----------       -----   -----------  ---------
Balance at December 31, 1995......  7,779,135  7,512,076     334,943       86,507        5,402       61,640     488,492
                                    ---------  ---------  -----------  -----------       -----   -----------  ---------
                                    ---------  ---------  -----------  -----------       -----   -----------  ---------
 
<CAPTION>
SHARES
- ----------------------------------
<S>                                 <C>            <C>              <C>
Issuance of common stock to ART
 for cash.........................
Issuance of common stock to
 Landover and affiliates for
 cash.............................
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................
  Series B........................
  Series C........................
Issuance of Series D preferred
 stock for cash...................
Shares issued to reflect
 anti-dilution adjustments........
Redemption of common stock from
 Landover.........................
Balance at December 31, 1995......
</TABLE>
<TABLE>
<CAPTION>
                                                                               PAR VALUE
                                    -----------------------------------------------------------------------------------------------
                                          COMMON STOCK                                   PREFERRED STOCK
                                    ------------------------  ---------------------------------------------------------------------
AMOUNTS                               CLASS A      CLASS B     SERIES A      SERIES B       SERIES C       SERIES D        TOTAL
- ----------------------------------  -----------  -----------  -----------  -------------  -------------  -------------  -----------
<S>                                 <C>          <C>          <C>          <C>            <C>            <C>            <C>
Issuance of common stock to ART
 for cash.........................   $   4,420
Issuance of common stock to
 Landover and affiliates for
 cash.............................         260    $   8,320
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................                             $     332                                                 $     332
  Series B........................                                           $      82                                          82
  Series C........................                                                          $       5                            5
Issuance of Series D preferred
 stock for cash...................                                                                         $      62            62
Shares issued to reflect
 anti-dilution adjustments........       3,099                         3             4                                           7
Serial preferred stock issuance
 costs............................
Redemption of common stock from
 Landover.........................                     (808)
Investment by ART as a result of
 the release of escrow shares.....
Accrued stock option
 compensation.....................
Net loss..........................
                                                                                                   --
                                    -----------  -----------       -----           ---                           ---         -----
Balance at December 31, 1995......   $   7,779    $   7,512    $     335     $      86      $       5      $      62     $     488
                                                                                                   --
                                                                                                   --
                                    -----------  -----------       -----           ---                           ---         -----
                                    -----------  -----------       -----           ---                           ---         -----
 
<CAPTION>
 
                                    ADDITIONAL
                                      PAID-IN     ACCUMULATED
AMOUNTS                               CAPITAL       DEFICIT        TOTAL
- ----------------------------------  -----------  -------------  -----------
<S>                                 <C>          <C>            <C>
Issuance of common stock to ART
 for cash.........................  $    (4,080)                $       340
Issuance of common stock to
 Landover and affiliates for
 cash.............................       (7,560)                      1,020
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................    1,006,268                   1,006,600
  Series B........................      880,618                     880,700
  Series C........................      112,695                     112,700
Issuance of Series D preferred
 stock for cash...................    1,999,938                   2,000,000
Shares issued to reflect
 anti-dilution adjustments........       (3,106)
Serial preferred stock issuance
 costs............................     (229,814)                   (229,814)
Redemption of common stock from
 Landover.........................   (1,999,192)                 (2,000,000)
Investment by ART as a result of
 the release of escrow shares.....      802,002                     802,002
Accrued stock option
 compensation.....................      287,603                     287,603
Net loss..........................                $(2,981,073)   (2,981,073)
 
                                    -----------  -------------  -----------
Balance at December 31, 1995......  $ 2,845,372   $(2,981,073)  $  (119,922)
 
                                    -----------  -------------  -----------
                                    -----------  -------------  -----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-33
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENT OF CASH FLOWS
             FOR THE PERIOD FROM MARCH 28, 1995 (DATE OF INCEPTION)
                              TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
Cash flows from operating activities:
<S>                                                                              <C>
  Net loss.....................................................................  $(2,981,073)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Depreciation and amortization..............................................        5,306
    Non-cash compensation expense..............................................    1,089,605
    Changes in operating assets and liabilities:
      Deposits.................................................................       (4,012)
      Accounts payable and accrued liabilities.................................      567,290
      Other current assets.....................................................      (52,325)
                                                                                 -----------
        Net cash used in operating activities..................................   (1,375,209)
                                                                                 -----------
Cash flows from investing activities:
  Acquisition of EMI licenses and property and equipment.......................   (3,023,971)
  Additions to property and equipment..........................................     (621,364)
  Advances to ART..............................................................     (738,680)
  Deposits on equipment........................................................     (280,000)
                                                                                 -----------
        Net cash used in investing activities..................................   (4,664,015)
                                                                                 -----------
Cash flows from financing activities:
  Proceeds from issuance of common stock.......................................        1,360
  Proceeds from issuance of serial preferred stock.............................    4,000,000
  Stock issuance costs.........................................................     (208,814)
  Proceeds from issuance of note payable to ART................................    5,000,000
  Advances from Landover and affiliates........................................      175,000
  Payments on advances from Landover and affiliates............................     (175,000)
  Redemption of common stock...................................................   (2,000,000)
  Additions to deferred financing costs........................................     (125,737)
                                                                                 -----------
        Net cash provided by financing activities..............................    6,666,809
                                                                                 -----------
          Net increase in cash and cash equivalents and balance at end of
           period..............................................................  $   627,585
                                                                                 -----------
                                                                                 -----------
Supplemental cash flow information:
  Non-cash financing and investing activities:
    Additions to property and equipment........................................  $ 2,666,630
    Issuance of promissory note payable to EMI.................................    1,500,000
    Accrued stock issuance costs...............................................       21,000
    Accrued deferred financing costs...........................................      195,617
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-34
<PAGE>
                              [INSIDE BACK COVER]
 
                     [MAP OF U.S. DISPLAYING ADVANCED RADIO
                     TELECOM CORP.'S 38 GHz SERVICE AREAS.]
<PAGE>
- -------------------------------------------
                                     -------------------------------------------
- -------------------------------------------
                                     -------------------------------------------
 
    NO  DEALER, SALESPERSON, OR OTHER INDIVIDUAL HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS,  OTHER THAN THOSE CONTAINED IN  THIS
PROSPECTUS  IN CONNECTION WITH THE OFFERING COVERED BY THIS PROSPECTUS. IF GIVEN
OR MADE, SUCH INFORMATION OR REPRESENTATIONS  MUST NOT BE RELIED UPON AS  HAVING
BEEN  AUTHORIZED BY  THE COMPANY OR  THE UNDERWRITERS. THIS  PROSPECTUS DOES NOT
CONSTITUTE AN  OFFER  TO  SELL, OR  A  SOLICITATION  OF AN  OFFER  TO  BUY,  THE
SECURITIES  OFFERED HEREBY IN ANY JURISDICTION WHERE,  OR TO ANY PERSON TO WHOM,
IT IS UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION. NEITHER THE DELIVERY OF  THIS
PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE AN
IMPLICATION  THAT THERE HAS NOT  BEEN ANY CHANGE IN THE  FACTS SET FORTH IN THIS
PROSPECTUS OR IN THE AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF.
                            ------------------------
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                   PAGE
                                                                   ----
<S>                                                                <C>
Prospectus Summary...............................................    3
Risk Factors.....................................................   11
The Company......................................................   24
Use of Proceeds..................................................   25
Dividend Policy..................................................   25
Capitalization...................................................   26
Selected Historical Combined and Pro Forma Financial Data........   27
Management's Discussion and Analysis of Financial Condition and
 Results of Operations...........................................   31
Business.........................................................   37
Management.......................................................   63
Principal Stockholders...........................................   74
Certain Transactions.............................................   76
Description of Units.............................................   81
Description of Notes.............................................   81
Description of Warrants..........................................  110
Description of Capital Stock.....................................  113
Description of Certain Indebtedness..............................  115
Certain Federal Income Tax Considerations........................  117
Underwriting.....................................................  120
Legal Matters....................................................  121
Experts..........................................................  121
Available Information............................................  121
Glossary.........................................................  122
Index to Financial Statements....................................  F-1
</TABLE>
 
                            ------------------------
 
    UNTIL        , 1996 (90 DAYS AFTER THE DATE OF THIS PROSPECTUS), ALL DEALERS
EFFECTING  TRANSACTIONS  IN  THE  UNITS,  NOTES  OR  WARRANTS,  WHETHER  OR  NOT
PARTICIPATING  IN THIS  DISTRIBUTION, MAY BE  REQUIRED TO  DELIVER A PROSPECTUS.
THIS DELIVERY REQUIREMENT IS IN ADDITION TO THE OBLIGATION OF DEALERS TO DELIVER
A PROSPECTUS  WHEN ACTING  AS  UNDERWRITERS AND  WITH  RESPECT TO  THEIR  UNSOLD
ALLOTMENTS OR SUBSCRIPTIONS.
 
                                  $175,000,000
                                 GROSS PROCEEDS
 
                                     [LOGO]
 
                          ADVANCED RADIO TELECOM CORP.
 
                                 UNITS CONSISTING OF
                             SENIOR DISCOUNT NOTES
                                  DUE 2006 AND
                              WARRANTS TO PURCHASE
                             SHARES OF COMMON STOCK
 
                             ---------------------
 
                                   PROSPECTUS
                             ---------------------
 
                              MERRILL LYNCH & CO.
 
                             MONTGOMERY SECURITIES
 
                               SMITH BARNEY INC.
 
                                        , 1996
 
- -------------------------------------------
                                     -------------------------------------------
- -------------------------------------------
                                     -------------------------------------------
<PAGE>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 13.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
 
    The  following table sets forth the  various expenses in connection with the
sale and  distribution of  the securities  being registered,  not including  the
Representative's   non-accountable  expense   allowance.  Except   for  the  SEC
registration fee and the NASD filing fee, all of the amounts in the table  below
are estimated.
 
<TABLE>
<CAPTION>
Securities and Exchange Commission registration fee...................  $  60,345
<S>                                                                     <C>        <C>
NASD filing fee.......................................................     18,500
Accounting fees and expenses..........................................      *
Printing..............................................................      *
Blue Sky fees and expenses (including counsel fees)...................     20,000
Legal fees and expenses...............................................      *
Transfer Agent and Registrar fees and expenses........................      *
Miscellaneous expenses................................................      *
                                                                        ---------
TOTAL (estimated).....................................................  $
                                                                        ---------
                                                                        ---------
</TABLE>
 
- ------------------------
*To be completed by amendment.
 
                                      II-1
<PAGE>
ITEM 14.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
    Section  145  of the  General Corporation  Law of  Delaware provides  that a
corporation has the power to indemnify a director, officer, employee or agent of
the corporation  and  certain  other  persons serving  at  the  request  of  the
corporation  in related capacities against amounts paid and expenses incurred in
connection with an action or  proceeding to which he is  or is threatened to  be
made a party be reason of such position. If such person shall have acted in good
faith and in a manner he reasonable believed to be in or not opposed to the best
interests  of the corporation,  and, in any criminal  proceeding, if such person
had no reasonable cause to believe  his conduct was unlawful; provided that,  in
the  case  of  actions  brought  by  or in  the  right  of  the  corporation, no
indemnification shall be made with respect to any matter as to which such person
shall have been adjudged to be liable to the corporation unless and only to  the
extent  that  the adjudicating  court  determines that  such  indemnification is
proper under the circumstances.
 
    Reference is made to  Article Ninth of the  Certificate of Incorporation  of
the  Registrant,  Section 6.4  of the  By-laws and  each of  the Indemnification
Agreements filed as Exhibits  10-5, 10-6, 10-7 and  10-8, respectively, to  this
Registration  Statement for  information regarding  indemnification of directors
and officers under certain circumstances.
 
    The  Registrant  has  agreed  to   indemnify  the  Underwriters  and   their
controlling   persons,  and  the  Underwriters  have  agreed  to  indemnify  the
Registrant and its controlling  persons, against certain liabilities,  including
liabilities  under the Securities Act of 1933, as amended (the "Act"). Reference
is made to the Purchase Agreement filed as part of Exhibit 1-1 hereto.
 
    For  information  regarding  the  Registrant's  undertaking  to  submit   to
adjudication  the issue of indemnification for violation of the Act, see Item 17
hereof.
 
    The Registrant's Certificate of Incorporation provides that every  director,
officer  or agent of the Company shall be  entitled to be indemnified out of the
assets of the  Company against all  losses or  liabilities which he  or she  may
sustain or incur in or about the execution of the duties of his or her office or
otherwise in relation thereto, including any liability incurred by him or her in
defending any proceedings, whether civil or criminal, in which judgment is given
in his or her favor or in which he or she is acquitted, and no director or other
officer  shall be liable for any loss,  damage or misfortune which may happen to
or be incurred  by the  Company in the  execution of  the duties of  his or  her
office or in relation thereto.
 
ITEM 15.  RECENT SALES OF UNREGISTERED SECURITIES.
 
    TELECOM CLASS A AND B COMMON STOCK PRIVATE PLACEMENT
 
    In  April  1995,  the  Company  and  Landover  Holdings  Corporation ("LHC")
subscribed 340,000 shares of Telecom Class A common stock and 640,000 shares  of
Telecom  Class B common stock, respectively,  for $0.001 per share, which, after
giving effect to anti-dilution adjustments and the February 1996 Reorganization,
currently are equivalent upon  conversion prior to  the Offerings to  10,013,055
shares  and  7,512,076  shares,  respectively,  of  Common  Stock.  In addition,
Hedgerow Corporation of  Maine ("Hedgerow")  and Toro  Financial Corp.  ("Toro")
subscribed  15,000 shares  and 5,000  shares, respectively,  of Telecom  Class A
common stock at the  price of $0.001  per share, which,  after giving effect  to
anti-dilution  adjustments and  the February  1996 Reorganization  currently are
equivalent upon conversion prior to the Offerings to 441,753 shares and  147,251
shares  of the  Common Stock, respectively.  The securities issued  in the above
transactions  were  offered  and  sold  in  reliance  upon  the  exemption  from
registration  under  Section  4(2)  of  the  Act.  The  recipients  made certain
representations as to the nature of their investments and had adequacy of access
to information about the Registrant.
 
    PREFERRED STOCK PRIVATE PLACEMENTS
 
    Between May 8,  1995 and November  13, 1995,  the LHC Stock  was diluted  by
purchases  of series of  Telecom preferred stock  by E2-2, E2,  E1 Holdings L.P.
("E1") and E2-3 Holdings,  L.P. ("E2-3" and collectively  with E1, E2 and  E2-2,
the  "Landover Partnerships"), each a  limited partnership whose general partner
is controlled by LHC, in separate  private placements. E2-2, which committed  to
 
                                      II-2
<PAGE>
purchase  up to $3,500,000  of Telecom preferred  stock matching other investors
under the LHC Purchase Agreement, purchased  405,880 shares of Telecom Series  A
preferred  stock  (which converts  into 5,276,440  shares  of Common  Stock upon
completion of this  offering) for an  aggregate of $946,600,  and LHC  purchased
35,873  shares of such Telecom Series A preferred stock from E2-2 for $1,050,000
pursuant to an option.  E2 purchased an aggregate  of 105,823 shares of  Telecom
Series  B preferred stock (which converts  into 1,375,699 shares of Common Stock
upon completion of  this offering) for  an aggregate of  $842,400. E1  purchased
13,797  shares of Telecom Series A  preferred stock (which converts into 179,361
shares of Common  Stock upon completion  of this offering)  for an aggregate  of
$60,000  and 8,856  shares of Telecom  Series B preferred  stock (which converts
into 115,128 shares  of Common Stock  upon completion of  this offering) for  an
aggregate  of $38,300.  E2-3 purchased an  aggregate of 7,363  shares of Telecom
Series C preferred stock (which converts into 95,719 shares of Common Stock upon
completion of this offering) for an  aggregate of $112,700. All of the  Landover
Partnerships  will liquidate  upon completion  of this  offering. The securities
issued in each of the foregoing  transactions were offered and sold in  reliance
on an exemption from registration under Regulation D promulgated under the Act.
 
    On  November  9,  1995,  Telecom  sold 61,640  shares  of  Telecom  Series D
preferred stock  (which  convert  into  801,320  shares  of  Common  Stock  upon
completion  of this  offering) for  $2,000,000 in  a private  placement. Telecom
simultaneously redeemed  807,924 shares  of Telecom  common stock  from LHC  for
$2,000,000. In connection with the February 1996 Reorganization described below,
LHC  granted to  the holders  of Telecom Series  D preferred  stock a contingent
option to purchase  400,634 shares of  Telecom common stock  at a nominal  price
(the  "Series  D/LHC  Option"), which  option  expires upon  completion  of this
offering.
 
    On November  13,  1995, Global  Private  Equity II,  L.P.,  Advent  Partners
Limited  Partnership and Advent  International Investors II  L.P. each a limited
partnership  controlled  by  Advent  International  Corporation,  (collectively,
"Advent")  purchased  for an  aggregate of  $5,000,000, (i)  one share  of ART's
Series A Redeemable Preferred Stock for a purchase price of $50,000 and (ii) the
Company's 10%  Secured  Convertible Demand  Promissory  Notes in  the  aggregate
principal   amount  of  $4,950,000.   In  connection  with   the  February  1996
Reorganization, Advent  exchanged  such Preferred  Stock  and Note  for  232,826
shares of Telecom Series E preferred stock (which converts into 3,026,738 shares
of  Common Stock upon completion of this  offering), $0.001 par value per share.
The securities issued  in each of  the foregoing transactions  were offered  and
sold   in  reliance  on  an  exemption  from  registration  under  Regulation  D
promulgated under the Act. Advent made certain representations as to the  nature
of its investment and had adequate access to information about the Registrant.
 
    On February 2, 1996, Ameritech Development Corp. ("Ameritech") purchased for
an  aggregate of $2,500,000  48,893 shares of Telecom  Series F preferred stock,
par value $0.001 per share, (the "Ameritech Financing") convertible into 635,609
shares of Common Stock  upon completion of this  offering. In addition,  Telecom
entered  into the Ameritech  Strategic Distribution Agreement  and in connection
therewith granted to Ameritech a ten-year warrant to purchase 877,136 shares  of
Telecom  common stock exercisable at  a price of $.01  per share (the "Ameritech
Warrant"). The  securities issued  in each  of the  foregoing transactions  were
offered  and sold in reliance on an exemption from registration under Regulation
D promulgated under the  Act. Ameritech made certain  representations as to  the
nature  of  its investment  and  had adequate  access  to information  about the
Registrant.
 
BRIDGE NOTES
 
    On March 8, 1996, Telecom issued in a private placement $5,000,000 principal
amount of  two year,  10% unsecured  notes (the  "Bridge Notes")  and  five-year
warrants  to purchase up to  an aggregate of 1,100,000  shares of Telecom common
stock at  a  price of  $6.25  per share  (the  "Bridge Warrants")  to  investors
including:  (i) affiliates of J.C. Demetree, Jr. and Mark Demetree, directors of
the Company; (ii)  the Advent  Partnerships; and (iii)  Ameritech, who  invested
$700,000,  $725,000  and  $750,000  in the  Bridge  Notes  and  Bridge Warrants,
respectively.
 
                                      II-3
<PAGE>
EQUIPMENT FINANCING
 
    On April  1,  1996, CRA,  Inc.  ("CRA")  entered into  a  secured  equipment
financing  with Telecom (the "Equipment Financing")  for the purchase from P-Com
of 38  GHz  radio equipment.  To  evidence  its obligations  and  the  Equipment
Financing,  Telecom issued in favor of CRA a $2,445,000 promissory note, payable
in 24 monthly installments of $92,694 with a final payment equal to $642,305 due
April 1, 1998. The securities issued  in the foregoing transaction were  offered
and  sold  in reliance  on  an exemption  from  registration under  Regulation D
promulgated under the Act.
 
COMMCOCCC ACQUISITION
 
    On July 3, 1996, the Company entered into the CommcoCCC Agreement to acquire
129 38 GHz wireless  broadband authorizations from  CommcoCCC, Inc. in  exchange
for   16,500,000  shares  of   Common  Stock.  The   stockholders  of  CommcoCCC
simultaneously loaned  $3.0 million  on a  secured, subordinated  basis  bearing
interest  at  the  prime rate  and  payable  on September  30,  1996  and issued
three-year warrants to acquire 50,000 shares  of Common Stock at $15 per  share.
The  securities to be  issued in the  foregoing transaction will  be offered and
sold in reliance on a exemption from registration under Regulation D promulgated
under the Act.
 
ITEM 16.  EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.
 
    (a) Exhibits
 
    The following exhibits were delivered  with this Registration Statement,  or
will be delivered by amendment, for filing:
 
<TABLE>
<CAPTION>
      1-1  Purchase Agreement.**
<C>        <S>                                                                              <C>
      2-1  (a)Amended   and  Restated   Certificate  of   Incorporation  and   By-laws  of
              Registrant.(2)
           (b)Amendment to Amended and Restated Certificate of Incorporation.(2)
           (c)Amended and Restated Certificate of Incorporation (to be effective prior to
            the consummation of the Offerings) and Restated and Amended Bylaws (effective
              on the date of the Prospectus) of Registrant.(2)
      4-1  Specimen of Common Stock Certificate.(3)
      4-2  (a) Indenture.
           (b) Specimen of Senior Discount Note (See Exhibit 4-2(a)).**
      4-3  Form of Lock-Up Agreement.(2)
      4-4  (a) Form of Warrant Agreement.**
           (b) Specimen of Warrant Certificate (See Exhibit 4-3(a)).**
      5-1  Opinion and Consent of Hahn & Hessen LLP, counsel for the Registrant, with
            respect to the Registrant's Common Stock and the Notes.*
      9-1  (a) Voting Trust Agreement.(3)
           (b) Form of Trustee Indemnification Agreement.(3)
           (c) Voting Agreement.(3)
           (d) Confidentiality Agreement.(3)
     10-1  Employment and Consulting Agreements.
           (a) Vernon L. Fotheringham, dated December 16, 1995.(1)
           (b) Steven D. Comrie, dated February 2, 1996.(1)
           (c) W. Theodore Pierson, Jr., dated May 8, 1995 and effective January 1,
            1995.(1)
           (d) I. Don Brown, dated February 16, 1996.(1)
           (e) Charles Menatti, dated March 8, 1996.(1)
           (f) James D. Miller, dated February 1, 1996.(1)
           (g) Thomas A. Grina, dated April 26, 1996.**
     10-2  (a) Second Amended and Restated Certificate of Incorporation and By-laws of
               Telecom (filed as Exhibit 2-1 to the Registration on Form S-1 of the
               Company dated May 2, 1996).(1)
           (b) Certificate of Incorporation of ART Merger Corporation (to become the
               Certificate of Incorporation of Telecom upon the completion of the
               Merger).(2)
     10-3  Form of Director Indemnification Agreement.(1)
     10-4  (a) Registrant's Equity Incentive Plan, as amended.(2)
</TABLE>
 
                                      II-4
<PAGE>
<TABLE>
<C>        <S>                                                                              <C>
           (b) Form of Stock Option Agreement.(3)
     10-5  (a) Registrant's 1996 Non-Employee Directors Automatic Stock Option Plan.(1)
           (b) Form of Non-Employee Directors Stock Option Agreement.(2)
     10-6  Stock Option Agreements.
           (a) Comrie Non-Qualified Stock Option Agreement.(1)
           (b) Comrie Incentive Stock Option Agreement.(1)
     10-7  Management Consulting Agreement with Landover Holdings Corporation, dated
            November 13, 1995.(1)
     10-8  (a) ART West Joint Venture Agreement dated April 4, 1995, with Extended
               Communications, Inc.(1)
           (b) Put/Call Agreement dated October 1, 1994, with Extended Communications,
               Inc.(1)
           (c) Services Agreement dated October 1, 1994, with Extended Communications,
               Inc.(1)
           (d) Amendment dated April 4, 1995 to the Put/Call Agreement dated October 1,
               1994, with Extended Communications, Inc.(1)
           (e)Asset Purchase Agreement dated June 24, 1996 with Extended Communications,
              Inc.(2)
           (f) Management Agreement dated June 1, 1996 with ART West Partnership.(2)
     10-9  (a) Put/Call Agreement dated September 1, 1994 with DCT Communications, Inc.(1)
           (b) Services Agreement dated September 1, 1994 with DCT Communications, Inc.(1)
           (c) Terms Sheet dated April 26, 1996 with DCT.(1)
           (d) Purchase Agreement with DCT dated July 1, 1996.(2)
           (e) Amendment to Services Agreement dated June 1996 with DCT.(2)
    10-10  (a) Asset Purchase Agreement dated April 4, 1995 with EMI Communications
               Corporation.(1)
           (b) $1,500,000 Nonnegotiable and Nontransferable Promissory Note.(1)
           (c) Maintenance Agreement dated November 14, 1995 with EMI Communications
               Corporation.(1)
           (d) Agreement dated November 14, 1995 with EMI Communications Corporations.(1)
    10-11  38 GHz Radio Links Purchase Agreement dated August 11, 1995 with P-Com,
            Inc.(1)+
    10-12  (a) Agreement dated May 25, 1995 with Telecom One.(1)+
           (b) Services Agreement dated April 24, 1996 with Telecom One.(1)
           (c) Asset Purchase Agreement and Management Agreement with Telecom One dated
               June 27, 1996.(2)
    10-13  Agreement dated April 25, 1996 with GTE.(1)
    10-14  Software License Agreement dated March 29, 1996 with GTE.(1)
    10-15  Agreement dated July 12, 1995 with Southeast Research Partners, Inc.(1)
    10-16  Agreement dated March 1, 1995 with High Sky Limited Partnership, High Sky II
            Limited Partnership, Vernon L. Fotheringham, W. Theodore Pierson, Jr., and F.
            Thomas Tuttle.(1)
    10-17  Stock Purchase Agreement dated May 8, 1995 with Vernon L. Fotheringham, W.
            Theodore Pierson, Jr., High Sky Limited Partnership, High Sky II Limited
            Partnership, and Extended Communications, Inc.(1)
    10-18  (a) Purchase Agreement dated April 21, 1995 with Landover Holdings
               Corporation.(1)
           (b) Letter Agreement dated May 8, 1995 with the Demetrees, Telecom, and
            Landover Holdings Corporation.(1)
           (c) Letter Agreement dated November 13, 1995 with Telecom, E2-2 Holdings, L.P.
               and the Demetrees.(1)
    10-19  Restated and Amended Stockholders' Agreement dated February 2, 1996 with
            Telecom and the stockholders of each of Telecom and the Company.(1)
    10-20  Second Restated and Amended Registration Rights Agreement dated July 3, 1996
            with Telecom and the stockholders of each of Telecom and the Company.(2)
</TABLE>
 
                                      II-5
<PAGE>
<TABLE>
<C>        <S>                                                                              <C>
    10-21  Services Agreement dated May 8, 1995 with Telecom.(1)
    10-22  Option Agreement dated February 2, 1996 with Telecom.(1)
    10-23  (a) Securities Purchase Agreement dated November 13, 1995 with Telecom, Vernon
               Fotheringham, W. Theodore Pierson, Jr., the stockholders of the Telecom
               named therein and the Advent Partnerships.(1)
           (b) Exchange Agreement dated February 2, 1996 with Telecom and the Advent
               Partnerships.(1)
    10-24  (a) Securities Purchase Agreement dated February 2, 1996 with Telecom and
               Ameritech Development Corporation ("Ameritech"), including letter of
               intent.(1)
           (b) Warrant issued on February 2, 1996 to Ameritech.(1)
           (c) Put/Call Agreement dated February 2, 1996 with Ameritech.(1)
    10-25  Strategic Distribution Agreement dated April 29, 1996 with Ameritech.(1)
    10-26  Restated and Amended Merger Agreement and Plan of Reorganization dated June 26,
            1996 between the Company and Telecom.(2)
    10-27  (a) $2,445,000 Promissory Note in favor of CRA, Inc. ("CRA")(1)
           (b) Security Agreement with CRA(1)
           (c) Indemnity Agreement(1)
           (d) Form of Indemnity Warrant.(1)
    10-28  Memorandum of Terms of Development and Procurement Agreement with American
            Wireless with Extension Agreement dated April 25, 1996.(3)
    10-29  (a) Purchase Agreement dated April 26, 1996 with Harris Corporation Farinon
            Division ("Harris") (confidential treatment requested for certain terms).**
           (b) PCS Marketing Agreement dated April 26, 1996 with Harris (confidential
            treatment requested for certain terms).**
    10-30  Form of Subscription Agreement dated March 8, 1996, including forms of Bridge
            Note and Bridge Warrant.(2)
    10-31  (a) Asset Acquisition Agreement and Plan of Reorganization dated July 3, 1996
            with CommcoCCC, Inc.(2)
           (b) Form of Note issued to Commco, L.L.C.(2)
           (c) Form of Note issued to Columbia Capital Corporation.(2)
           (d) Form of Warrant issued to Commco, L.L.C.(2)
           (e) Form of Warrant issued to Columbia Capital Corporation.(2)
           (f) Option Agreement dated July 3, 1996 with Commco, L.L.C.(2)
           (g) Security Agreement dated June 27, 1996 with Columbia Capital
            Corporation.(2)
           (h) Form of Noncompetition Agreement with CommcoCCC.(2)
           (i) CommcoCCC Management Agreement dated July 3, 1996.(2)
           (j) Right of First Offer Agreement dated July 3, 1996.**
           (k) Engagement Letter with Montgomery Securities dated May 23, 1996.(2)
    10-32  Letter of Intent dated April 29, 1996 with Helioss Communications Inc.(2)
    10-33  Letter of Intent dated March 26, 1996 with Advantage Telecom, Inc.(3)
    10-34  Consulting Agreement dated March 1, 1996 with Trond Johannesen.(3)
       11  Computation of Pro Forma Net Loss Per Share of Common Stock.**
       12  Computation of Ratio of Earnings to Fixed Charges.**
       21  Subsidiaries of the Registrant.(1)
    23(a)  Consent of the Registrant's Independent Accountants.
    23(b)  Consent of the Registrant's Counsel.*
       25  Form T-1 Statement of Eligibility of The Bank of New York under the Trust
            Indenture Act of 1939.
</TABLE>
 
- ------------------------
 * To be filed by amendment.
 
** Previously filed.
 
 + Confidential treatment requested for the deleted portions of this document.
(1) Filed with the Registration Statement on  Form S-1 of the Company dated  May
2, 1996 (SEC Reg. No. 333-04388) ("Equity Registration Statement").
 
(2)  Filed with Amendment No.  1 to Equity Registration  Statement dated July 3,
1996.
(3) Filed with Amendment No. 2 to Equity Registration Statement.
 
                                      II-6
<PAGE>
ITEM 17.  UNDERTAKINGS.
 
    Insofar as indemnification for liabilities under the Act may be permitted to
directors, officers and  controlling person  of the Registrant  pursuant to  the
foregoing  provisions, or otherwise, the Registrant has been advised that in the
opinion of  the Commission  such  indemnification is  against public  policy  as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for  indemnification against  such liabilities  (other than  the payment  by the
Registrant of expenses incurred  or paid by a  director, officer or  controlling
person  of  the Registrant  in the  successful  defense of  any action,  suit or
proceeding) is  asserted by  such  director, officer  or controlling  person  in
connection  with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to  a  court  of  appropriate  jurisdiction  the  question  whether  such
indemnification  by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.
 
    The undersigned Registrant hereby undertakes to provide the Underwriters  at
the  closing  specified  in  the  Underwriting  Agreement  certificates  in such
denomination and registered  in such names  as required by  the Underwriters  to
permit prompt delivery to each purchaser.
 
    The undersigned Registrant hereby undertakes that:
 
        (1)  For  purposes  of  determining any  liability  under  the  Act, the
    information omitted  from the  form  of prospectus  filed  as part  of  this
    Registration Statement in reliance upon Rule 430A and contained in a form of
    prospectus  filed by  the Registrant pursuant  to Rule 424(b)(1)  or (4), or
    497(h) under  the  Act shall  be  deemed to  be  part of  this  Registration
    Statement as of the time it was declared effective.
 
        (2)  For the purposes  of determining any liability  under the Act, each
    post-effective amendment that contains a form of prospectus shall be  deemed
    to  be  a  new Registration  Statement  relating to  the  securities offered
    therein, and the offering of such securities at that time shall be deemed to
    be the initial bona fide offering thereof.
 
    The undersigned Registrant hereby undertakes:
 
        (1) To file, during any period in which offers or sales are being  made,
    a post-effective amendment to this Registration Statement;
 
            (i)  To include any  prospectus required by  Section 10(a)(3) of the
       Act;
 
           (ii) To reflect in the prospectus  any facts or events arising  after
       the  effective date  of the  Registration Statement  (or the  most recent
       post-effective  amendment  thereof)   which,  individually   or  in   the
       aggregate, represent a fundamental change in the information set forth in
       the Registration Statement;
 
           (iii) To include any material information with respect to the plan of
       distribution  not previously  disclosed in the  Registration Statement or
       any material change to such information in the Registration Statement;
 
        (2) That, for the  purpose of determining any  liability under the  Act,
    each  such post-effective amendment shall be deemed to be a new registration
    statement relating to the  securities offered therein,  and the offering  of
    such  securities at that  time shall be  deemed to be  the initial bona fide
    offering thereof.
 
        (3) To remove from registration  by means of a post-effective  amendment
    any   of  the  securities  being  registered  which  remain  unsold  at  the
    termination of the offering.
 
                                      II-7
<PAGE>
                                   SIGNATURES
 
    Pursuant  to the requirements of the  Securities Act of 1933, the Registrant
has duly caused this  Amendment to this Registration  Statement to be signed  on
its  behalf by  the undersigned,  thereunto duly authorized  in the  City of New
York, State of New York, on July   , 1996.
 
                                          Advanced Radio Technologies
                                          Corporation
 
                                          By:         /s/ THOMAS A. GRINA
 
                                             -----------------------------------
                                                       Thomas A. Grina
                                             EXECUTIVE VICE PRESIDENT AND CHIEF
                                                      FINANCIAL OFFICER
 
<TABLE>
<C>                                                     <S>                               <C>
                      SIGNATURES                                     TITLE                         DATE
- ------------------------------------------------------  --------------------------------  -----------------------
 
                 /s/ VERNON L. FOTHERINGHAM
     -------------------------------------------        Chairman, Chief Executive              July   , 1996
                Vernon L. Fotheringham                   Officer and Director
 
                   /s/ W. THEODORE PIERSON*
     -------------------------------------------        Executive Vice President,              July   , 1996
               W. Theodore Pierson, Jr.                  General Counsel and Director
 
                       /s/ MATHEW C. GOVE*
     -------------------------------------------        Director                               July   , 1996
                   Matthew C. Gove
 
                       /s/ THOMAS A. GRINA
     -------------------------------------------        Executive Vice President               July   , 1996
                   Thomas A. Grina                       and Chief Financial Officer
</TABLE>
 
- ------------------------
* By Thomas A. Grina, attorney-in-fact
 
                                      II-8
<PAGE>
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
 EXHIBIT NO.                                          DESCRIPTION                                             PAGE
- -------------  -----------------------------------------------------------------------------------------  -------------
<C>            <S>                                                                                        <C>
        1-1    Purchase Agreement.**
        2-1    (a)Amended and Restated Certificate of Incorporation and By-laws of Registrant.(2)
               (b)Amendment to Amended and Restated Certificate of Incorporation.(2)
               (c)Amended and Restated Certificate of Incorporation (to be effective prior to the
                  consummation of the Offerings) and Restated and Amended Bylaws (effective on the date
                  of the Prospectus) of Registrant.(2)
        4-1    Specimen of Common Stock Certificate.(3)
        4-2    (a) Indenture.
               (b) Specimen of Senior Discount Note (See Exhibit 4-2(a)).**
        4-3    Form of Lock-Up Agreement.(2)
        4-4    (a) Form of Warrant Agreement.**
               (b) Specimen of Warrant Certificate (See Exhibit 4-3(a))**
        5-1    Opinion and Consent of Hahn & Hessen LLP, counsel for the Registrant, with respect to the
                Registrant's Common Stock and the Notes.*
        9-1    (a) Voting Trust Agreement.(3)
               (b) Form of Trustee Indemnification Agreement.(3)
               (c) Voting Agreement.(3)
               (d) Confidentiality Agreement.(3)
       10-1    Employment and Consulting Agreements.
               (a) Vernon L. Fotheringham, dated December 16, 1995.(1)
               (b) Steven D. Comrie, dated February 2, 1996.(1)
               (c) W. Theodore Pierson, Jr., dated May 8, 1995 and effective January 1, 1995.(1)
               (d) I. Don Brown, dated February 16, 1996.(1)
               (e) Charles Menatti, dated March 8, 1996.(1)
               (f) James D. Miller, dated February 1, 1996.(1)
               (g) Thomas A. Grina, dated April 26, 1996.**
       10-2    (a) Second Amended and Restated Certificate of Incorporation and By-laws of Telecom
                   (filed as Exhibit 2-1 to the Registration on Form S-1 of the Company dated May 2,
                   1996).(1)
               (b) Certificate of Incorporation of ART Merger Corporation (to become the Certificate of
                   Incorporation of Telecom upon the completion of the Merger).(2)
       10-3    Form of Director Indemnification Agreement.(1)
       10-4    (a) Registrant's Equity Incentive Plan, as amended.(2)
               (b) Form of Stock Option Agreement.(3)
       10-5    (a) Registrant's 1996 Non-Employee Directors Automatic Stock Option Plan.(1)
               (b) Form of Non-Employee Directors Stock Option Agreement.(2)
       10-6    Stock Option Agreements.
               (a) Comrie Non-Qualified Stock Option Agreement.(1)
               (b) Comrie Incentive Stock Option Agreement.(1)
       10-7    Management Consulting Agreement with Landover Holdings Corporation, dated November 13,
                1995.(1)
       10-8    (a) ART West Joint Venture Agreement dated April 4, 1995, with Extended Communications,
                   Inc.(1)
               (b) Put/Call Agreement dated October 1, 1994, with Extended Communications, Inc.(1)
               (c) Services Agreement dated October 1, 1994, with Extended Communications, Inc.(1)
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT NO.                                          DESCRIPTION                                             PAGE
- -------------  -----------------------------------------------------------------------------------------  -------------
               (d) Amendment dated April 4, 1995 to the Put/Call Agreement dated October 1, 1994, with
                   Extended Communications, Inc.(1)
<C>            <S>                                                                                        <C>
               (e)Asset Purchase Agreement dated June 24, 1996 with Extended Communications, Inc.(2)
               (f) Management Agreement dated June 1, 1996 with ART West Partnership.(2)
       10-9    (a) Put/Call Agreement dated September 1, 1994 with DCT Communications, Inc.(1)
               (b) Services Agreement dated September 1, 1994 with DCT Communications, Inc.(1)
               (c) Terms Sheet dated April 26, 1996 with DCT.(1)
               (d) Purchase Agreement with DCT dated July 1, 1996.(2)
               (e) Amendment to Services Agreement dated June 1996 with DCT.(2)
      10-10    (a) Asset Purchase Agreement dated April 4, 1995 with EMI Communications Corporation.(1)
               (b) $1,500,000 Nonnegotiable and Nontransferable Promissory Note.(1)
               (c) Maintenance Agreement dated November 14, 1995 with EMI Communications Corporation.(1)
               (d) Agreement dated November 14, 1995 with EMI Communications Corporations.(1)
      10-11    38 GHz Radio Links Purchase Agreement dated August 11, 1995 with P-Com, Inc.(1)+
      10-12    (a) Agreement dated May 25, 1995 with Telecom One.(1)+
               (b) Services Agreement dated April 24, 1996 with Telecom One.(1)
               (c) Asset Purchase Agreement and Management Agreement with Telecom One dated June 27,
                   1996.(2)
      10-13    Agreement dated April 25, 1996 with GTE.(1)
      10-14    Software License Agreement dated March 29, 1996 with GTE.(1)
      10-15    Agreement dated July 12, 1995 with Southeast Research Partners, Inc.(1)
      10-16    Agreement dated March 1, 1995 with High Sky Limited Partnership, High Sky II Limited
                Partnership, Vernon L. Fotheringham, W. Theodore Pierson, Jr., and F. Thomas Tuttle.(1)
      10-17    Stock Purchase Agreement dated May 8, 1995 with Vernon L. Fotheringham, W. Theodore
                Pierson, Jr., High Sky Limited Partnership, High Sky II Limited Partnership, and
                Extended Communications, Inc.(1)
      10-18    (a) Purchase Agreement dated April 21, 1995 with Landover Holdings Corporation.(1)
               (b) Letter Agreement dated May 8, 1995 with the Demetrees, Telecom, and Landover Holdings
                   Corporation.(1)
               (c) Letter Agreement dated November 13, 1995 with Telecom, E2-2 Holdings, L.P. and the
                   Demetrees.(1)
      10-19    Restated and Amended Stockholders' Agreement dated February 2, 1996 with Telecom and the
                stockholders of each of Telecom and the Company.(1)
      10-20    Second Restated and Amended Registration Rights Agreement dated July 3, 1996 with Telecom
                and the stockholders of each of Telecom and the Company.(2)
      10-21    Services Agreement dated May 8, 1995 with Telecom.(1)
      10-22    Option Agreement dated February 2, 1996 with Telecom.(1)
      10-23    (a) Securities Purchase Agreement dated November 13, 1995 with Telecom, Vernon
                   Fotheringham, W. Theodore Pierson, Jr., the stockholders of the Telecom named therein
                   and the Advent Partnerships.(1)
               (b) Exchange Agreement dated February 2, 1996 with Telecom and the Advent
                   Partnerships.(1)
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT NO.                                          DESCRIPTION                                             PAGE
- -------------  -----------------------------------------------------------------------------------------  -------------
      10-24    (a) Securities Purchase Agreement dated February 2, 1996 with Telecom and Ameritech
                   Development Corporation ("Ameritech"), including letter of intent.(1)
<C>            <S>                                                                                        <C>
               (b) Warrant issued on February 2, 1996 to Ameritech.(1)
               (c) Put/Call Agreement dated February 2, 1996 with Ameritech.(1)
      10-25    Strategic Distribution Agreement dated April 29, 1996 with Ameritech.(1)
      10-26    Restated and Amended Merger Agreement and Plan of Reorganization dated June 26, 1996
                between the Company and Telecom.(2)
      10-27    (a) $2,445,000 Promissory Note in favor of CRA, Inc. ("CRA")(1)
               (b) Security Agreement with CRA(1)
               (c) Indemnity Agreement(1)
               (d) Form of Indemnity Warrant.(1)
      10-28    Memorandum of Terms of Development and Procurement Agreement with American Wireless with
                Extension Agreement dated April 25, 1996.(1)
      10-29    (a) Purchase Agreement dated April 26, 1996 with Harris Corporation Farinon Division
                ("Harris") (confidential treatment requested for certain terms).**
               (b) PCS Marketing Agreement dated April 26, 1996 with Harris (confidential treatment
                requested for certain terms).**
      10-30    Form of Subscription Agreement dated March 8, 1996, including forms of Bridge Note and
                Bridge Warrant.(2)
      10-31    (a) Asset Acquisition Agreement and Plan of Reorganization dated July 3, 1996 with
                CommcoCCC, Inc.(2)
               (b) Form of Note issued to Commco, L.L.C.(2)
               (c) Form of Note issued to Columbia Capital Corporation.(2)
               (d) Form of Warrant issued to Commco, L.L.C.(2)
               (e) Form of Warrant issued to Columbia Capital Corporation.(2)
               (f) Option Agreement dated July 3, 1996 with Commco, L.L.C.(2)
               (g) Security Agreement dated June 27, 1996 with Columbia Capital Corporation.(2)
               (h) Form of Noncompetition Agreement with CommcoCCC.(2)
               (i) CommcoCCC Management Agreement dated July 3, 1996.(2)
               (j) Right of First Offer Agreement dated July 3, 1996.(2)
               (k) Engagement Letter with Montgomery Securities dated May 23, 1996.(2)
      10-32    Letter of Intent dated April 29, 1996 with Helioss Communications Inc.(2)
      10-33    Letter of Intent dated March 26, 1996 with Advantage Telecom, Inc.(3)
      10-34    Consulting Agreement dated March 1, 1996 with Trond Johannesen(3)
         11    Computation of Pro Forma Net Loss Per Share of Common Stock.**
         12    Computation of Ratio of Earnings to Fixed Charges.**
         21    Subsidiaries of the Registrant.(1)
       23(a)   Consent of the Registrant's Independent Accountants.
       23(b)   Consent of the Registrant's Counsel.*
         25    Form T-1 Statement of Eligibility of The Bank of New York under the Trust Indenture Act
                of 1939.
</TABLE>
 
- ------------------------
 * To be filed by amendment.
 
** Previously filed.
 
 + Confidential treatment requested for the deleted portions of this document.
(1)  Filed with the Registration Statement on  Form S-1 of the Company dated May
2, 1996 (SEC Reg. No. 333-04388) ("Equity Registration Statement").
 
(2) Filed with Amendment No. 1 to Equity Registration Statement.
 
(3) Filed with Amendment No. 2 to Equity Registration Statement.

<PAGE>

                                                               L&W DRAFT 7/10/96




- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------




                          ADVANCED RADIO TELECOM CORP.



                               Units Consisting of
                  $_______________ Principal Amount at Maturity
                     of ___% Senior Discount Notes due 2006

                                       and

             Warrants to Purchase __________ Shares of Common Stock




                                    INDENTURE




                         Dated as of _____________, 1996




                              THE BANK OF NEW YORK

                                     Trustee




- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>

                             CROSS-REFERENCE TABLE*
Trust Indenture
  Act Section                                                  Indenture Section

310 (a)(1) . . . . . . . . . . . . . . . . . . . . . . . . . .             7.10
    (a)(2) . . . . . . . . . . . . . . . . . . . . . . . . . .             7.10
    (a)(3) . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
    (a)(4) . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
    (a)(5) . . . . . . . . . . . . . . . . . . . . . . . . . .             7.10
    (b)  . . . . . . . . . . . . . . . . . . . . . . . . . . .              7.10
    (c)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
311 (a)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             7.11
    (b)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             7.11
    (c)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
312 (a). . . . . . . . . . . . . . . . . . . . . . . . . . . .             2.05
    (b). . . . . . . . . . . . . . . . . . . . . . . . . . . .            10.03
    (c)  . . . . . . . . . . . . . . . . . . . . . . . . . . .
313 (a)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             7.06
    (b)(1) . . . . . . . . . . . . . . . . . . . . . . . . . .
    (b)(2) . . . . . . . . . . . . . . . . . . . . . . . . . .             7.06
    (c)  . . . . . . . . . . . . . . . . . . . . . . . . . . .       7.06; 10.02
    (d). . . . . . . . . . . . . . . . . . . . . . . . . . . .             7.06
314 (a)  . . . . . . . . . . . . . . . . . . . . . . . . . . .       4.03; 10.02
    (b)  . . . . . . . . . . . . . . . . . . . . . . . . . . .
    (c)(1) . . . . . . . . . . . . . . . . . . . . . . . . . .            10.04
    (c)(2) . . . . . . . . . . . . . . . . . . . . . . . . . .            10.04
    (c)(3) . . . . . . . . . . . . . . . . . . . . . . . . . .              N.A.
    (d). . . . . . . . . . . . . . . . . . . . . . . . . . . .
    (e)  . . . . . . . . . . . . . . . . . . . . . . . . . . .            10.05
    (f). . . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
315 (a). . . . . . . . . . . . . . . . . . . . . . . . . . . .             7.01
    (b). . . . . . . . . . . . . . . . . . . . . . . . . . . .       7.05, 10.02
    (c)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             7.01
    (d). . . . . . . . . . . . . . . . . . . . . . . . . . . .              7.01
    (e). . . . . . . . . . . . . . . . . . . . . . . . . . . .              6.11
316 (a)(last sentence) . . . . . . . . . . . . . . . . . . . .              2.09
    (a)(1)(A). . . . . . . . . . . . . . . . . . . . . . . . .              6.05
    (a)(1)(B)  . . . . . . . . . . . . . . . . . . . . . . . .              6.04
    (a)(2) . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
    (b)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             6.07
    (c)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             2.13
317 (a)(1) . . . . . . . . . . . . . . . . . . . . . . . . . .              6.08
    (a)(2) . . . . . . . . . . . . . . . . . . . . . . . . . .             6.09
    (b)  . . . . . . . . . . . . . . . . . . . . . . . . . . .             2.04
318 (a). . . . . . . . . . . . . . . . . . . . . . . . . . . .            10.01
    (b). . . . . . . . . . . . . . . . . . . . . . . . . . . .             N.A.
    (c). . . . . . . . . . . . . . . . . . . . . . . . . . . .            10.01
N.A. means not applicable.
*This Cross-Reference Table is not part of the Indenture.
<PAGE>

                                TABLE OF CONTENTS

                                                                            Page

                                    ARTICLE 1
                          DEFINITIONS AND INCORPORATION
                                  BY REFERENCE

Section 1.01.    Definitions . . . . . . . . . . . . . . . . . . . . . . . .   1
Section 1.02.    Other Definitions . . . . . . . . . . . . . . . . . . . . .  18
Section 1.03.    Incorporation by Reference of Trust Indenture Act . . . . .  18
Section 1.04.    Rules of Construction . . . . . . . . . . . . . . . . . . .  19

                                    ARTICLE 2
                                    THE NOTES

Section 2.01.    Form and Dating . . . . . . . . . . . . . . . . . . . . . .  19
Section 2.02.    Execution and Authentication. . . . . . . . . . . . . . . .  19
Section 2.03.    Registrar and Paying Agent. . . . . . . . . . . . . . . . .  20
Section 2.04.    Paying Agent to Hold Money in Trust . . . . . . . . . . . .  20
Section 2.05.    Lists of Holders of the Notes . . . . . . . . . . . . . . .  21
Section 2.06.    Transfer and Exchange . . . . . . . . . . . . . . . . . . .  21
Section 2.07.    Replacement Notes . . . . . . . . . . . . . . . . . . . . .  22
Section 2.08.    Outstanding Notes . . . . . . . . . . . . . . . . . . . . .  22
Section 2.09.    Treasury Notes. . . . . . . . . . . . . . . . . . . . . . .  22
Section 2.10.    Temporary Notes . . . . . . . . . . . . . . . . . . . . . .  22
Section 2.11.    Cancellation. . . . . . . . . . . . . . . . . . . . . . . .  23
Section 2.12.    Defaulted Interest. . . . . . . . . . . . . . . . . . . . .  23
Section 2.13.    Record Date . . . . . . . . . . . . . . . . . . . . . . . .  23
Section 2.14.    CUSIP Number. . . . . . . . . . . . . . . . . . . . . . . .  23

                                    ARTICLE 3
                                   REDEMPTION

Section 3.01.    Notices to Trustee. . . . . . . . . . . . . . . . . . . . .  24
Section 3.02.    Selection of Notes to Be Redeemed . . . . . . . . . . . . .  24
Section 3.03.    Notice of Redemption. . . . . . . . . . . . . . . . . . . .  24
Section 3.04.    Effect of Notice of Redemption. . . . . . . . . . . . . . .  25
Section 3.05.    Deposit of Redemption Price . . . . . . . . . . . . . . . .  25
Section 3.06.    Notes Redeemed in Part. . . . . . . . . . . . . . . . . . .  25
Section 3.07.    Optional Redemption . . . . . . . . . . . . . . . . . . . .  25
Section 3.08.    Mandatory Redemption. . . . . . . . . . . . . . . . . . . .  26

                                    ARTICLE 4
                                    COVENANTS

Section 4.01.    Payment of Notes. . . . . . . . . . . . . . . . . . . . . .  26
Section 4.02.    Maintenance of Office or Agency . . . . . . . . . . . . . .  27
Section 4.03.    Reports . . . . . . . . . . . . . . . . . . . . . . . . . .  27


                                        i
<PAGE>

Section 4.04.    Compliance Certificate. . . . . . . . . . . . . . . . . . .  27
Section 4.05.    Taxes . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
Section 4.06.    Stay, Extension and Usury Laws. . . . . . . . . . . . . . .  28
Section 4.07.    Limitation on Restricted Payments . . . . . . . . . . . . .  29
Section 4.08.    Limitation on Dividend and Other Payment Restrictions
                 Affecting Restricted Subsidiaries . . . . . . . . . . . . .  31
Section 4.09.    Limitation on Indebtedness. . . . . . . . . . . . . . . . .  33
Section 4.10.    Limitation on Issuances and Sales of Capital Stock of
                 Wholly Owned Restricted Subsidiaries. . . . . . . . . . . .  36
Section 4.11.    Disposition of Proceeds of Asset Sales. . . . . . . . . . .  36
Section 4.12.    Limitation on Transactions with Affiliates. . . . . . . . .  37
Section 4.13.    Limitation on Liens Securing Certain Indebtedness . . . . .  38
Section 4.14.    Corporate Existence . . . . . . . . . . . . . . . . . . . .  38
Section 4.15.    Change of Control . . . . . . . . . . . . . . . . . . . . .  38
Section 4.16.    Business Activities of the Company. . . . . . . . . . . . .  38
Section 4.17.    No Amendment to Agreement . . . . . . . . . . . . . . . . .  39


                                    ARTICLE 5
                                   SUCCESSORS

Section 5.01.    Consolidation, Merger, Sale of Assets, Etc. . . . . . . . .  39
Section 5.02.    Successor Corporation Substituted . . . . . . . . . . . . .  40

                                    ARTICLE 6
                              DEFAULTS AND REMEDIES

Section 6.01.    Events of Default . . . . . . . . . . . . . . . . . . . . .  40
Section 6.02.    Acceleration. . . . . . . . . . . . . . . . . . . . . . . .  41
Section 6.03.    Other Remedies. . . . . . . . . . . . . . . . . . . . . . .  42
Section 6.04.    Waiver of Past Defaults . . . . . . . . . . . . . . . . . .  42
Section 6.05.    Control by Majority . . . . . . . . . . . . . . . . . . . .  43
Section 6.06.    Limitation on Suits . . . . . . . . . . . . . . . . . . . .  43
Section 6.07.    Rights of Holders of Notes to Receive Payment . . . . . . .  43
Section 6.08.    Collection Suit by Trustee. . . . . . . . . . . . . . . . .  43
Section 6.09.    Trustee May File Proofs of Claim. . . . . . . . . . . . . .  44
Section 6.10.    Priorities. . . . . . . . . . . . . . . . . . . . . . . . .  44
Section 6.11.    Undertaking for Costs . . . . . . . . . . . . . . . . . . .  45

                                    ARTICLE 7
                                     TRUSTEE

Section 7.01.    Duties of Trustee . . . . . . . . . . . . . . . . . . . . .  45
Section 7.02.    Rights of Trustee . . . . . . . . . . . . . . . . . . . . .  46
Section 7.03.    Individual Rights of Trustee. . . . . . . . . . . . . . . .  46
Section 7.04.    Trustee's Disclaimer. . . . . . . . . . . . . . . . . . . .  46
Section 7.05.    Notice of Defaults. . . . . . . . . . . . . . . . . . . . .  47
Section 7.06.    Reports by Trustee to Holders of the Notes. . . . . . . . .  47
Section 7.07.    Compensation and Indemnity. . . . . . . . . . . . . . . . .  47


                                       ii
<PAGE>

Section 7.08.    Replacement of Trustee. . . . . . . . . . . . . . . . . . .  48
Section 7.09.    Successor Trustee by Merger, etc. . . . . . . . . . . . . .  49
Section 7.10.    Eligibility; Disqualification . . . . . . . . . . . . . . .  49
Section 7.11.    Preferential Collection of Claims Against Company . . . . .  49

                                    ARTICLE 8
                    LEGAL DEFEASANCE AND COVENANT DEFEASANCE

Section 8.01.    Option to Effect Legal Defeasance or Covenant Defeasance. .  49
Section 8.02.    Legal Defeasance and Discharge. . . . . . . . . . . . . . .  49
Section 8.03.    Covenant Defeasance . . . . . . . . . . . . . . . . . . . .  50
Section 8.04.    Conditions to Legal or Covenant Defeasance. . . . . . . . .  50
Section 8.05.    Deposited Money and Government Securities to be Held in
                 Trust; Other Miscellaneous Provisions.. . . . . . . . . . .  51
Section 8.06.    Repayment to Company. . . . . . . . . . . . . . . . . . . .  52
Section 8.07.    Reinstatement . . . . . . . . . . . . . . . . . . . . . . .  52

                                    ARTICLE 9
                        AMENDMENT, SUPPLEMENT AND WAIVER

Section 9.01.    Without Consent of Holders of Notes . . . . . . . . . . . .  52
Section 9.02.    With Consent of Holders of Notes. . . . . . . . . . . . . .  53
Section 9.03.    Compliance with Trust Indenture Act . . . . . . . . . . . .  54
Section 9.04.    Revocation and Effect of Consents . . . . . . . . . . . . .  54
Section 9.05.    Notation on or Exchange of Notes. . . . . . . . . . . . . .  55
Section 9.06.    Trustee to Sign Amendments, etc . . . . . . . . . . . . . .  55
Section 9.07.    Payment for Consents. . . . . . . . . . . . . . . . . . . .  55

                                   ARTICLE 10
                                  MISCELLANEOUS

Section 10.01.   Trust Indenture Act Controls. . . . . . . . . . . . . . . .  55
Section 10.02.   Notices . . . . . . . . . . . . . . . . . . . . . . . . . .  56
Section 10.03.   Communication by Holders of Notes with Other Holders of 
                 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
Section 10.04.   Certificate and Opinion as to Conditions Precedent. . . . .  57
Section 10.05.   Statements Required in Certificate or Opinion . . . . . . .  57
Section 10.06.   Rules by Trustee and Agents . . . . . . . . . . . . . . . .  57
Section 10.07.   No Personal Liability of Partners, Directors, Officers,
                 Employees and Stockholders. . . . . . . . . . . . . . . . .  58
Section 10.08.   Governing Law . . . . . . . . . . . . . . . . . . . . . . .  58
Section 10.09.   No Adverse Interpretation of Other Agreements . . . . . . .  58
Section 10.10.   Successors. . . . . . . . . . . . . . . . . . . . . . . . .  58
Section 10.11.   Severability. . . . . . . . . . . . . . . . . . . . . . . .  58
Section 10.12.   Counterpart Originals . . . . . . . . . . . . . . . . . . .  58
Section 10.13.   Table of Contents, Headings, etc. . . . . . . . . . . . . .  58


                                       iii
<PAGE>

                                    EXHIBITS

Exhibit A        Form of Note


                                       iv
<PAGE>

     INDENTURE dated as of July ___, 1996 between Advanced Radio Telecom Corp.,
f/k/a Advanced Radio Technologies Corporation, a Delaware corporation (the
"Company"), and The Bank of New York, as trustee (the "Trustee").

     The Company and the Trustee agree as follows for the benefit of each other
and for the equal and ratable benefit of the Holders of the ___% Senior Discount
Notes due 2006 (the "Notes"):

                                    ARTICLE 1
                          DEFINITIONS AND INCORPORATION
                                  BY REFERENCE

SECTION 1.01.  DEFINITIONS.

     "ACCRETED VALUE" as of any Specified Date, means with respect to each
$1,000 principal amount at maturity of Notes:

          (i)  if the Specified Date occurs on one of the following dates (each,
     a "Semi-Annual Accrual Date"), the amount set forth below opposite such
     date:

          Semi-Annual Accrual Date                          Accreted Value
          ------------------------                          --------------

              , 1996 . . . . . . . . . . . . . . . . . . .     $
              , 1997 . . . . . . . . . . . . . . . . . . .
              , 1997 . . . . . . . . . . . . . . . . . . .
              , 1998 . . . . . . . . . . . . . . . . . . .
              , 1998 . . . . . . . . . . . . . . . . . . .
              , 1999 . . . . . . . . . . . . . . . . . . .
              , 1999 . . . . . . . . . . . . . . . . . . .
              , 2000 . . . . . . . . . . . . . . . . . . .
              , 2000 . . . . . . . . . . . . . . . . . . .
              , 2001 . . . . . . . . . . . . . . . . . . .
              , 2001 . . . . . . . . . . . . . . . . . . .      $1,000.00

         (ii)  if the Specified Date occurs before the first Semi-Annual Accrual
     Date, the sum of (A) the original issue price and (B) an amount equal to
     the product of (1) the Accreted Value for the first Semi-Annual Accrual
     Date less the original issue price and (2) a fraction, the numerator of
     which is the number of days from the Issue Date to the Specified Date,
     using a 360-day year of twelve 30-day months, and the denominator of which
     is the number of days elapsed from the issue date of the Notes to the first
     Semi-Annual Accrual Date, using a 360-day year of twelve 30-day months;

        (iii)  if the Specified Date occurs between two Semi-Annual Accrual
     Dates, the sum of (A) the Accreted Value for the Semi-Annual Accrual Date
     immediately preceding the Specified Date and (B) an amount equal to the
     product of (1) the Accreted Value for the immediately following Semi-Annual
     Accrual Date less the Accreted Value for the immediately preceding Semi-
     Annual Accrual Date and (2) a fraction, the numerator of which is the
     number of days from the immediately preceding Semi-Annual Accrual Date to
     the Specified Date, using a 360-day year of twelve 30-day months, and the
     denominator of which is 180; or
<PAGE>

         (iv)  if the Specified Date occurs after the last Semi-Annual Accrual
     Date, $1,000.

     "ACQUIRED DEBT" means, with respect to any specified Person, (i)
Indebtedness of any other Person existing at the time such other Person is
merged with or into or became a Subsidiary of such specified Person, including,
without limitation, Indebtedness incurred in connection with, or in
contemplation of, such other Person merging with or into or becoming a
Subsidiary of such specified Person, and (ii) Indebtedness secured by a Lien
encumbering any asset acquired by such specified Person.

     "ADJUSTED CONSOLIDATED NET INCOME" means, for any period, the aggregate net
income (or loss) of the Company and its Restricted Subsidiaries for such period
determined in conformity with GAAP; PROVIDED that the following items shall be
excluded in computing Adjusted Consolidated Net Income (without duplication):
(i) the net income of any Person (other than net income attributable to a
Restricted Subsidiary) in which any Person (other than the Company or any of its
Restricted Subsidiaries) has a joint interest and the net income of any
Unrestricted Subsidiary, except to the extent of the amount of dividends or
other distributions actually paid to the Company or any of its Restricted
Subsidiaries by such other Person (including, without limitation, an
Unrestricted Subsidiary) during such period; (ii) solely for the purposes of
calculating the amount of Restricted Payments that may be made pursuant to
clause (C) of Section 4.07(a) hereof (and in such case, except to the extent
includable pursuant to clause (i) above), the net income (or loss) of any Person
accrued prior to the date it becomes a Restricted Subsidiary or is merged into
or consolidated with the Company or any of its Restricted Subsidiaries or all or
substantially all of the property and assets of such Person are acquired by the
Company or any of its Restricted Subsidiaries; (iii) the net income of any
Restricted Subsidiary to the extent that the declaration or payment of dividends
or similar distributions by such Restricted Subsidiary of such net income is not
at the time permitted by the operation of the terms of its charter or any
agreement, instrument, judgment, decree, order, statute, rule or governmental
regulation applicable to such Restricted Subsidiary; (iv) any gains or losses
(on an after-tax basis) attributable to Asset Sales; (v) except for purposes of
calculating the amount of Restricted Payments that may be made pursuant to
clause (C) of Section 4.07(a) hereof, any amount paid as, or accrued for, cash
dividends on Preferred Stock of the Company or any Restricted Subsidiary owned
by Persons other than the Company and any of its Restricted Subsidiaries; and
(vi) all extraordinary or nonrecurring gains and losses.

     "ADJUSTED CONSOLIDATED NET TANGIBLE ASSETS" means the total amount of
assets of the Company and its Restricted Subsidiaries (less applicable
depreciation, amortization and other valuation reserves), except to the extent
resulting from write-ups of capital assets (excluding write-ups in connection
with accounting for acquisitions in conformity with GAAP), after deducting
therefrom (i) all current liabilities of the Company and its Restricted
Subsidiaries (excluding intercompany items) and (ii) all goodwill, trade names,
trademarks, patents, unamortized debt discount and expense and other like
intangibles (other than licenses issued by the FCC), all as set forth on the
quarterly or annual consolidated balance sheet of the Company and its Restricted
Subsidiaries, prepared in conformity with GAAP and most recently filed with the
Commission pursuant to Section 4.03 hereof; PROVIDED that the value of any
licenses issued by the FCC shall, in the event of an auction for similar
licenses, be equal to the fair market value ascribed thereto in good faith by
the Board and evidenced by a resolution of the Board.  As used herein,
references to financial statements of the Company and its Restricted
Subsidiaries shall be adjusted to exclude Unrestricted Subsidiaries if the
context requires.

     "AFFILIATE" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person.  For purposes of


                                        2
<PAGE>

this definition, "control" (including, with correlative meanings, the terms
"controlling," "controlled by" and "under common control with"), as used with
respect to any Person, shall mean the possession, directly or indirectly, of the
power to direct or cause the direction of the management or policies of such
Person, whether through the ownership of voting securities, by agreement or
otherwise; PROVIDED that beneficial ownership of 10% or more of the voting
securities of a Person shall be deemed to be control.  For purposes hereof, the
term "Affiliate" shall at all times include Laurence S. Zimmerman, Landover
Holdings Corporation and their respective Affiliates.

     "AGENT" means any Registrar, Paying Agent or co-registrar.

     "ART LICENSING" means ART Licensing Corp., a Delaware corporation and a
wholly owned subsidiary of the Company, or any successor thereto, or such other
Subsidiary or Subsidiaries of the Company formed for the purpose of the
application for, acquisition of or ownership of FCC licenses and authorizations.

     "ART WEST" means ART West Joint Venture, a Delaware partnership owned by
the Company and Extended Communications, Inc.

     "ASSET ACQUISITION" means (i) an Investment by the Company or any of its
Restricted Subsidiaries in any other Person pursuant to which such Person shall
become a Restricted Subsidiary of the Company or shall be merged into or
consolidated with the Company or any of its Restricted Subsidiaries or (ii) an
acquisition by the Company or any of its Restricted Subsidiaries of the property
and assets of any Person other than the Company or any of its Restricted
Subsidiaries that constitute substantially all of a division or line of business
of such Person.

     "ASSET SALE" means any sale, transfer or other disposition (including by
way of merger, consolidation or sale-leaseback transaction) in one transaction
or a series of related transactions by the Company or any of its Restricted
Subsidiaries to any Person other than the Company or any of its Restricted
Subsidiaries of (i) all or any of the Capital Stock of any Restricted
Subsidiary, (ii) all or substantially all of the property and assets of an
operating unit or business of the Company or any of its Restricted Subsidiaries
or (iii) any other property or assets of the Company or any of its Restricted
Subsidiaries (including Capital Stock of any Unrestricted Subsidiaries) outside
the ordinary course of business of the Company or such Restricted Subsidiary;
PROVIDED that the following shall not be included within the meaning of "Asset
Sale": (A) sales or other dispositions of inventory, receivables and other
current assets; (B) sales or other dispositions of equipment that has become
worn out, obsolete, damaged or otherwise unsuitable for use in connection with
the business of the Company or its Restricted Subsidiaries; (C) Permitted Asset
Swaps; (D) sales, transfers or other dispositions otherwise constituting Asset
Sales in an aggregate amount not to exceed $500,000 during the relevant twelve-
month period referred to in Section 4.11 hereof; (E) any Restricted Payment
permitted by Section 4.07 hereof; (F) any Lien permitted to be Incurred by
Section 4.13 hereof; (G) any transaction that is governed by the provisions of
Article 5 hereof; (H) any sale, transfer or other disposition of the Capital
Stock of an Unrestricted Subsidiary; and (I) any disposition pursuant to the
Option Agreement, dated as of July 3, 1996, between the Company and Commco,
L.L.C.

     "AVERAGE LIFE" means, at any date of determination with respect to any debt
security, the quotient obtained by dividing (i) the sum of the products of
(A) the number of years from such date of


                                        3
<PAGE>

determination to the dates of each successive scheduled principal payment of
such debt security and (B) the amount such principal payment by (ii) the sum of
all such principal payments.

     "BOARD" means the Board of Directors of the Company.

     "BUSINESS DAY" means any day other than a Legal Holiday.

     "CAPITAL STOCK" means (i) in the case of a corporation, corporate stock,
(ii) in the case of an association or business entity, any and all shares,
interests, participations, rights or other equivalents (however designated) of
corporate stock, (iii) in the case of a partnership, partnership interests
(whether general or limited) and (iv) any other interest or participation that
confers on a Person the right to receive a share of the profits and losses of,
or distributions of assets of, the issuing Person.

     "CAPITALIZED LEASE" means, as applied to any Person, any lease of any
property (whether real, personal or mixed) of which the discounted present value
of the rental obligations of such Person as lessee, in conformity with GAAP, is
required to be capitalized on the balance sheet of such Person; and "Capitalized
Lease Obligations" means the discounted present value of the rental obligations
under such lease.

     "CHANGE IN CONTROL" means such time as (i) a "person" or "group" (within
the meaning of Sections 13(d) and 14(d)(2) of the Exchange Act) becomes the
ultimate "beneficial owner" (as defined in Rule 13d-3 under the Exchange Act) of
Voting Stock representing more than 50% of the total voting power of the Voting
Stock of the Company on a fully diluted basis, (ii) individuals who on the Issue
Date constitute the Board (together with any new directors whose election by the
Board or whose nomination for election by the Company's stockholders was
approved by a vote of at least two-thirds of the members of the Board then in
office who either were members of the Board on the Issue Date or whose election
or nomination for election was previously so approved) cease for any reason to
constitute a majority of the members of the Board then in office and (iii) the
merger or consolidation of the Company with or into another corporation, or the
merger or consolidation of another corporation with and into the Company, with
the effect that, immediately after such transaction, the stockholders of the
Company immediately prior to such transaction hold less than 50% of the Voting
Stock of the Person surviving such merger or consolidation.

     "COMMISSION" means the Securities and Exchange Commission.

     "COMMON STOCK" means the common stock, par value $.001 per share, of the
Company.

     "CONSOLIDATED EBITDA" means, for any period, the sum of the amounts for
such period of (i) Adjusted Consolidated Net Income, (ii) Consolidated Interest
Expense, to the extent such amount was deducted in calculating Adjusted
Consolidated Net Income, (iii) income taxes, to the extent such amount was
deducted in calculating Adjusted Consolidated Net Income (other than income
taxes (either positive or negative) attributable to extraordinary and non-
recurring gains or losses or sales of assets), (iv) depreciation expense, to the
extent such amount was deducted in calculating Adjusted Consolidated Net Income,
(v) amortization expense, to the extent such amount was deducted in calculating
Adjusted Consolidated Net Income, (vi) all other non-cash items reducing
Adjusted Consolidated Net Income (other than items that will require cash
payments and for which an accrual or reserve is, or is required by GAAP to be,
made), less all non-cash items increasing Adjusted Consolidated Net Income and
(vii) all


                                        4
<PAGE>

cash dividend payments (and non-cash dividend payments in the case of a Person
that is a Restricted Subsidiary) on any series of preferred stock of such
Person, all as determined on a consolidated basis for the Company and its
Restricted Subsidiaries in conformity with GAAP; PROVIDED that, if any
Restricted Subsidiary is not a Wholly Owned Restricted Subsidiary, Consolidated
EBITDA shall be reduced (to the extent not otherwise reduced in accordance with
GAAP) by an amount equal to (A) the amount of the Adjusted Consolidated Net
Income attributable to such Restricted Subsidiary MULTIPLIED BY (B) the quotient
of (1) the number of shares of outstanding Common Stock of such Restricted
Subsidiary not owned on the last day of such period by the Company or any of its
Restricted Subsidiaries DIVIDED BY (2) the total number of shares of outstanding
Common Stock of such Restricted Subsidiary on the last day of such period.
Notwithstanding the foregoing, the provision for taxes based on the income or
profits of, and the depreciation and amortization and other non-cash charges of,
a Restricted Subsidiary of a Person shall be added to Adjusted Consolidated Net
Income to compute Consolidated EBITDA only to the extent (and in the same
proportion) that the net income of such Restricted Subsidiary was included in
calculating the Adjusted Consolidated Net Income of such Person and only if a
corresponding amount would be permitted at the date of determination to be
dividended to the Company by such Restricted Subsidiary without prior approval
(that has not been obtained), pursuant to the terms of its charter and all
agreements, instruments, judgments, decrees, orders, statutes, rules and
governmental regulations applicable to that Restricted Subsidiary or its
stockholders.

     "CONSOLIDATED INTEREST EXPENSE" means, for any period, the aggregate amount
of interest in respect of Indebtedness (including amortization of original issue
discount on any Indebtedness and the interest portion of any deferred payment
obligation, calculated in accordance with the effective interest method of
accounting; all commissions, discounts and other fees and charges owed with
respect to letters of credit and bankers' acceptance financing and net payments
(if any) pursuant to Hedging Obligations; and Indebtedness that is Guaranteed or
secured by the Company or any of its Restricted Subsidiaries) and all but the
principal component of rentals in respect of Capitalized Lease Obligations paid,
accrued or scheduled to be paid or to be accrued by the Company and its
Restricted Subsidiaries during such period; EXCLUDING, HOWEVER, (i) any amount
of such interest of any Restricted Subsidiary if the net income of such
Restricted Subsidiary is excluded from the calculation of Adjusted Consolidated
Net Income pursuant to clause (iii) of the definition thereof (but only in the
same proportion as the net income of such Restricted Subsidiary is excluded from
the calculation of Adjusted Consolidated Note Income pursuant to clause (iii) of
the definition thereof) and (ii) any premiums, fees and expenses (and any
amortization thereof) payable in connection with the offering of the Notes, all
as determined on a consolidated basis (without taking into account Unrestricted
Subsidiaries) in conformity with GAAP.

     "CREDIT FACILITY" means a bank credit facility, to be entered into among
the Company, Canadian Imperial Bank of Commerce, Inc., as agent (the "Agent"),
and certain lenders to be party thereto, on substantially the terms set forth in
the Summary of Terms and Conditions of the Agent, dated as of June 23, 1996, and
any amendment, extension, restatement, refinancing or refunding thereof;
PROVIDED that the Company and the Agent shall have (A) executed a commitment
letter with respect to such facility not later than January 1, 1997 and (B)
entered into such facility not later than June 30, 1997; PROVIDED FURTHER that,
in the event that the Company and the Agent shall have failed to execute a
commitment letter or enter into such facility within the time periods specified
in the first proviso of this definition, Sections 4.09(b)(xiii) and (xiv) hereof
shall be of no further force and effect.


                                        5
<PAGE>

     "CORPORATE TRUST OFFICE OF THE TRUSTEE" shall be at the address of the
Trustee specified in Section 10.02 or such other address as to which the Trustee
may give notice to the Company.

     "DEFAULT" means any event that is, or with the passage of time or the
giving of notice or both would be, an Event of Default.

     "DEFAULT AMOUNT" means (i) as of any date prior to          , 2001, the
Accreted Value of the Notes (plus any applicable premium thereon) as of such
date and (ii) as of any date on or after          , 2001, 100% of the principal
amount at maturity of the Notes (plus any applicable premium thereon).

     "DIRECTED INVESTMENT" means any Investment in a Telecommunications Business
that is made by investing the net proceeds of the issuance of Capital Stock
(other than Redeemable Stock) by the Company (or options, warrants or other
rights to purchase such Capital Stock) after the Issue Date; PROVIDED that such
Investment shall be made with such net proceeds in the form received by the
Company and shall be limited to an amount equal to (A) 50% of such net proceeds
to the extent that such net proceeds consist of cash, and (B) 100% of such net
proceeds to the extent such net proceeds consist of Capital Stock or
Telecommunications Assets; PROVIDED FURTHER that such Investment is made within
180 days of such issuance of Capital Stock.

     "EQUITY OFFERING" means an underwritten public offering or flotation of
Common Stock of the Company which has been registered under the Securities Act
and/or admitted to listing on a national securities exchange.

     "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended (or
any successor act), and the rules and regulations thereunder.

     "FAIR MARKET VALUE" means the price that would be paid in an arm's length
transaction between an informed and willing seller under no compulsion to sell
and an informed and willing buyer under no compulsion to buy, as determined in
good faith by the Board (whose determination shall be conclusive) and evidenced
by a resolution of the Board.

     "FCC" means the United States Federal Communications Commission and any
state or local telecommunications authority, department, commission or agency
(and any successors thereto).

     "GAAP" means generally accepted accounting principles in the United States
of America as in effect from time to time, including, without limitation, those
set forth in the opinions and pronouncements of the Accounting Principles Board
of the American Institute of Certified Public Accountants and statements and
pronouncements of the Financial Accounting Standards Board or in such other
statements by such other entity as approved by a significant segment of the
accounting profession.  All ratios and computations contained herein shall be
computed in conformity with GAAP applied on a consistent basis, except that
calculations made for purposes of determining compliance with the terms of the
covenants and with other provisions hereof shall be made without giving effect
to (i) the amortization of any expenses incurred in connection with the offering
of the Notes and (ii) except as otherwise provided, the amortization of any
amounts required or permitted by Accounting Principles Board Opinion Nos. 16 and
17.


                                        6
<PAGE>

     "GOVERNMENT SECURITIES" means direct obligations of, or obligations
guaranteed by, the United States of America for the payment of which guarantee
or obligations the full faith and credit of the United States is pledged.

     "GUARANTEE" means any obligation, contingent or otherwise, of any Person
directly or indirectly guaranteeing any Indebtedness or other obligation of any
other Person and, without limiting the generality of the foregoing, any
obligation, direct or indirect, contingent or otherwise, of such Person (i) to
purchase or pay (or advance or supply funds for the purchase or payment of) such
Indebtedness or other obligation of such other Person (whether arising by virtue
of partnership arrangements, or by agreements to keep-well, to purchase assets,
goods, securities or services, to take-or-pay, or to maintain financial
statement conditions or otherwise) or (ii) entered into for purposes of assuring
in any other manner the obligee of such Indebtedness or other obligation of the
payment thereof or to protect such obligee against loss in respect thereof (in
whole or in part); PROVIDED that the term "Guarantee" shall not include
endorsements for collection or deposit in the ordinary course of business.  The
term "Guarantee" used as a verb has a corresponding meaning.

     "HEDGING OBLIGATIONS" means, with respect to any Person, the obligations of
such Person under (i) interest rate swap agreements, interest rate cap
agreements and interest rate collar agreements and (ii) other agreements or
arrangements designed to protect such Person against fluctuations in interest
rates.

     "HOLDER" means a Person in whose name a Note is registered.

     "INCUR" means, with respect to any Indebtedness, to incur, create, issue,
assume, Guarantee or otherwise become liable for or with respect to, or become
responsible for, the payment of, contingently or otherwise, such Indebtedness,
including, with respect to the Company and its Restricted Subsidiaries, an
"incurrence" of Indebtedness by reason of a Person becoming a Restricted
Subsidiary of the Company; PROVIDED that neither the accrual of interest nor the
accretion of original issue discount shall be considered an Incurrence of
Indebtedness.

     "INDEBTEDNESS" means, with respect to any Person at any date of
determination (without duplication), (i) all indebtedness of such person for
borrowed money, (ii) all obligations of such Person evidenced by bonds,
debentures, notes or other similar instruments (whether negotiable or non-
negotiable), (iii) all obligations of such Person in respect of letters of
credit or other similar instruments (including reimbursement obligations with
respect thereto), (iv) all obligations of such Person to pay the deferred and
unpaid purchase price of property or services, which purchase price is due more
than six months after the date of placing such property in service or taking
delivery and title thereto or the completion of such services, except trade
payables and escrows, holdbacks and comparable arrangements to secure
indemnification obligations under acquisition agreements, (v) all obligations of
such Person as lessee under Capitalized Leases, (vi) all indebtedness of other
Persons secured by a Lien on any asset of such Person, whether or not such
indebtedness is assumed by such Person, PROVIDED that the amount of such
indebtedness shall be the lesser of (A) the fair market value of such asset at
such date of determination and (B) the amount of such indebtedness, (vii) the
balance deferred and unpaid of the purchase price of any property or
representing any Hedging Obligations, except any such balance that constitutes
an accrued expense or trade payable and (viii) all indebtedness of other Persons
Guaranteed by such Person to the extent such indebtedness is Guaranteed by such
Person.  The amount of


                                        7
<PAGE>

Indebtedness of any Person at any date shall be the outstanding balance at such
date of all unconditional obligations as described above and, with respect to
contingent obligations that are included in any of clauses (i) through (viii)
above, the maximum liability upon the occurrence of the contingency giving rise
to the obligation, PROVIDED (A) that the amount outstanding at any time of any
Indebtedness issued with original issue discount is the face amount of such
Indebtedness and (B) that Indebtedness shall not include any liability for
federal, state, local or other taxes.

     "INDEBTEDNESS TO EBITDA RATIO" means, as at any date of determination, the
ratio of (i) the aggregate amount of Indebtedness of the Company and its
Restricted Subsidiaries on a consolidated basis ("Consolidated Indebtedness") as
at the date of determination (the "Transaction Date") to (ii) the Consolidated
EBITDA of the Company for the then most recent four full fiscal quarters for
which reports have been filed pursuant to Section 4.03 hereof (such four full
fiscal quarter period being referred to herein as the "Four Quarter Period");
PROVIDED that (x) pro forma effect shall be given to any Indebtedness Incurred
from the beginning of the Four Quarter Period through the Transaction Date
(including any Indebtedness Incurred on the Transaction Date), to the extent
outstanding on the Transaction Date, (y) if during the period commencing on the
first day of such Four Quarter Period through the Transaction Date (the
"Reference Period"), the Company or any of the Restricted Subsidiaries shall
have engaged in any Asset Sale, Consolidated EBITDA for such period shall be
reduced by an amount equal to the EBITDA (if positive), or increased by an
amount equal to the EBITDA (if negative), directly attributable to the assets
which are the subject of such Asset Sale any related retirement of Indebtedness
as if such Asset Sale and related retirement of Indebtedness had occurred on the
first day of such Reference Period or (z) if during such Reference Period the
Company or any of the Restricted Subsidiaries shall have made any Asset
Acquisition, Consolidated EBITDA of the Company shall be calculated on a pro
forma basis as if such Asset Acquisition and any Incurrence of Indebtedness to
finance such Asset Acquisition had taken place on the first day of such
Reference Period.

     "INDEBTEDNESS TO TOTAL MARKET CAPITALIZATION RATIO" means, at any date of
determination, the ratio of (i) the aggregate amount of Indebtedness of the
Company and its Restricted Subsidiaries on a consolidated basis outstanding to
(ii) the Total Market Capitalization of the Company.

     "INDENTURE" means this Indenture, as amended or supplemented from time to
time.

     "INVESTMENT" in any Person means any direct or indirect advance, loan or
extension of credit (including, without limitation, by way of Guarantee or
similar arrangement; but excluding advances to customers in the ordinary course
of business that are, in conformity with GAAP, recorded as accounts receivable
on the balance sheet of the Company or its Restricted Subsidiaries) or capital
contribution to (by means of any transfer of cash or other property to others or
any payment for property or services for the account or use of others), or any
purchase or acquisition of Capital Stock, bonds, notes, debentures or other
similar instruments issued by, such Person and shall include (i) the designation
of a Restricted Subsidiary as an Unrestricted Subsidiary and (ii) the fair
market value of the Capital Stock held by the Company and the Restricted
Subsidiaries of any Person that has ceased to be a Restricted Subsidiary by
reason of any transaction permitted by clause (iii) of Section 4.10 hereof.  For
purposes of the definition of "Unrestricted Subsidiary" and Section 4.07 hereof,
(i) "Investment" shall include the fair market value of the assets (net of
liabilities) of any Restricted Subsidiary of the Company at the time that such
Restricted Subsidiary is designated an Unrestricted Subsidiary and shall exclude
the fair market value of the assets (net of liabilities) of any Unrestricted
Subsidiary at the time that such Unrestricted Subsidiary is designated a
Restricted Subsidiary of the Company and (ii) any property transferred to or
from an


                                        8
<PAGE>

Unrestricted Subsidiary shall be valued at its fair market value at the time of
such transfer, in each case as determined by the Board in good faith.

     "ISSUE DATE" means the date of original issuance of the Notes.

     "LEGAL HOLIDAY" means a Saturday, a Sunday or a day on which banking
institutions in the City of New York or at a place of payment are authorized by
law, regulation or executive order to remain closed.  If a payment date is a
Legal Holiday at a place of payment, payment may be made at that place on the
next succeeding day that is not a Legal Holiday, and no interest shall accrue
for the intervening period.

     "LIEN" means, with respect to any asset, any mortgage, lien, pledge,
charge, security interest or encumbrance of any kind in respect of such asset,
whether or not filed, recorded or otherwise perfected under applicable law
(including any conditional sale or other title retention agreement, any lease in
the nature thereof, any option or other agreement to sell or give a security
interest in and any filing of or agreement to give any financing statement under
the Uniform Commercial Code (or equivalent statutes) of any jurisdiction).

     "NET CASH PROCEEDS" means (a) with respect to any Asset Sale, the proceeds
of such Asset Sale in the form of cash or cash equivalents, including payments
in respect of deferred payment obligations (to the extent corresponding to the
principal, but not interest, component thereof) when received in the form of
cash or cash equivalents (except to the extent such obligations are financed or
sold with recourse to the Company or any Restricted Subsidiary of the Company)
and proceeds from the conversion of other property received when converted to
cash or cash equivalents, net of (i) brokerage commissions and other fees and
expenses (including fees and expenses of counsel and investment bankers) related
to such Asset Sale, (ii) provisions for all taxes (whether or not such taxes
will actually be paid or are payable) as a result of such Asset Sale without
regard to the consolidated results of operations of the Company and its
Restricted Subsidiaries, taken as a whole, (iii) payments made to repay
Indebtedness or any other obligation outstanding at the time of such Asset Sale
that either (A) is secured by a Lien on the property or assets sold or (B) is
required to be paid as a result of such sale and (iv) appropriate amounts to be
provided by the Company or any Restricted Subsidiary of the Company as a reserve
against any liabilities associated with such Asset Sale, including, without
limitation, pension and other post-employment benefit liabilities, liabilities
related to environmental matters and liabilities under any indemnification
obligations associated with such Asset Sale, all as determined in conformity
with GAAP and (b) with respect to any issuance or sale of Capital Stock, the
proceeds of such issuance or sale in the form of cash or cash equivalents,
including payments in respect of deferred payment obligations (to the extent
corresponding to the principal, but not interest, component thereof) when
received in the form of cash or cash equivalents (except to the extent such
obligations are financed or sold with recourse to the Company or any Restricted
Subsidiary of the Company) and proceeds from the conversion of other property
received when converted to cash or cash equivalents, net of attorney's fees,
underwriters' or placement agents' fees, discounts or commissions and brokerage,
consultant and other fees incurred in connection with such issuance or sale and
net of taxes paid or payable as a result thereof.

     "NON-RECOURSE DEBT" means Indebtedness (a) as to which neither the Company
nor any of its Restricted Subsidiaries (i) provides credit support of any kind
(including any undertaking, agreement or instrument that would constitute
Indebtedness) or (ii) is directly or indirectly liable (as a guarantor or
otherwise); (b) no default with respect to which (including any rights that the
holders thereof may have


                                        9
<PAGE>

to take enforcement action against an Unrestricted Subsidiary) would permit
(upon notice, lapse of time or both) any holder of any other Indebtedness (other
than the Notes) of the Company or any of its Restricted Subsidiaries to declare
a default on such other Indebtedness or cause the payment thereof to be
accelerated or payable prior to its stated maturity; and (c) as to which the
lender of any indebtedness for borrowed money in an aggregate amount in excess
of $5.0 million has been notified in writing that such lender will not have any
recourse to the stock or assets of the Company or any of its Restricted
Subsidiaries.

     "NOTES" means the Notes described above issued under this Indenture.

     "OFFER TO PURCHASE" means an offer to purchase Notes by the Company from
the holders that is required by Section 4.11 or Section 4.15 hereof and which is
commenced by mailing a notice to the Trustee and each holder stating: (i) the
covenant pursuant to which the offer is being made and that all Notes validly
tendered will be accepted for payment on a pro rata basis; (ii) the purchase
price and the date of purchase (which shall be a business day no earlier than 30
days nor later than 60 days from the date such notice is mailed) (the "Payment
Date"); (iii) that any Note not tendered will continue to accrue interest
pursuant to its terms; (iv) that, unless the Company defaults in the payment of
the purchase price, any Note accepted for payment pursuant to the Offer to
Purchase shall cease to accrue interest on and after the Payment Date; (v) that
holders electing to have a Note purchased pursuant to the Offer to Purchase will
be required to surrender the Note together with the form entitled "Option of the
Holder to Elect Purchase" on the reverse side thereof completed, to the Paying
Agent at the address specified in the notice prior to the close of business on
the business day immediately preceding the Payment Date; (vi) that holders will
be entitled to withdraw their election if the Payment Agent receives, not later
than the close of business on the third business day immediately preceding the
Payment Date, a telegram, facsimile transmission or letter setting forth the
name of such holder, the principal amount of Notes delivered for purchase and a
statement that such holder is withdrawing his election to have such Notes
purchased; and (vii) that holders whose Notes are being purchased only in part
will be issued new Notes equal in principal amount to the unpurchased portion
thereof; PROVIDED that each Note purchased and each new Note issued shall be in
a principal amount of $1,000 or integral multiples thereof.  On the Payment
Date, the Company shall (i) accept for payment on a pro rata basis Notes or
portions thereof tendered pursuant to an Offer to Purchase, (ii) deposit with
the Paying Agent money sufficient to pay the purchase price of all Notes or
portions thereof so accepted and (iii) deliver, or cause to be delivered, to the
Trustee all Notes or portions thereof so accepted together with an Officers'
Certificate specifying the Notes or portions thereof so accepted for payment by
the Company.  The Paying Agent shall promptly mail to the holders of Notes so
accepted for payment in an amount equal to the purchase price, and the Trustee
shall promptly authenticate and mail to such holders a new Note equal in
principal amount to any unpurchased portion of the Note surrendered; PROVIDED
that each Note purchased and each new Note issued shall be in a principal amount
of $1,000 or integral multiples thereof.  The Company will publicly announce the
results of an Offer to Purchase as soon as practicable after the Payment Date.
The Trustee shall act as the Paying Agent for an Offer to Purchase.  The Company
will comply with Rule 14e-1 under the Exchange Act and any other securities laws
and regulations thereunder to the extent such laws and regulations are
applicable, in the event that the Company is required to repurchase Notes
pursuant to an Offer to Purchase.

     "OFFICER" means, with respect to any Person, the Chairman of the Board, the
Chief Executive Officer, the President, the Chief Operating Officer, the Chief
Financial Officer, the Treasurer, any Assistant Treasurer, Controller, Secretary
or any Vice-President of such Person.


                                       10
<PAGE>

     "OFFICERS' CERTIFICATE" means a certificate (a) signed by two Officers of
the Company, one of whom must be the principal executive officer, principal
financial officer, treasurer or principal accounting officer of the Company, and
(b) which complies with Sections 10.04 and 10.05 hereof.

     "OPINION OF COUNSEL" means an opinion (a) from legal counsel, who may be an
employee of or counsel to the Company, any Subsidiary of the Company or the
Trustee, and (b) which complies with Sections 10.04 and 10.05 hereof.

     "PERMITTED ASSET SWAP" means any disposition by the Company or any of its
Restricted Subsidiaries of Telecommunications Assets or a majority of the Voting
Stock of a Restricted Subsidiary in exchange for comparable Telecommunications
Assets or a majority of the Voting Stock of a comparable Restricted Subsidiary;
PROVIDED that the Board shall have approved such disposition and exchange and
determined the fair market value of the assets subject to such transaction as
evidenced by a resolution of the Board or such fair market value has been
determined by a written opinion of an investment banking firm of national
standing or other recognized independent expert with experience appraising the
terms and conditions of the type of transaction contemplated thereby.

     "PERMITTED INVESTMENTS" means:

          (i)  an Investment in a Restricted Subsidiary or a Person which will,
     upon the making of such Investment, become a Restricted Subsidiary or be
     merged or consolidated with or into or transfer or convey all or
     substantially all its assets to, the Company or a Restricted Subsidiary;

         (ii)  Temporary Cash Investments;

        (iii)  payroll, travel and similar advances to cover matters that are
     expected at the time of such advances ultimately to be treated as expenses
     in accordance with GAAP;

         (iv)  loans or advances to employees (other than executive officers of
     the Company) in an aggregate principal amount not to exceed $1.0 million at
     any one time outstanding;

          (v)  stock, obligations or securities received in satisfaction of
     judgments;

         (vi)  Investments, to the extent that the consideration provided by the
     Company or any of its Restricted Subsidiaries consists solely of Capital
     Stock (other than Redeemable Stock) of the Company;

        (vii)  notes payable to the Company that are received by the Company as
     payment of the purchase price for Capital Stock (other than Redeemable
     Stock) of the Company;

       (viii)  Investments in an aggregate amount not to exceed $20.0 million at
     any one time outstanding;

         (ix)  Investments in an aggregate amount not to exceed $1.0 million at
     any time outstanding in Unrestricted Subsidiaries engaged in the
     Telecommunications Business outside of the United States;


                                       11
<PAGE>

          (x)  Investments in entities (other than ART West) that own licenses
     granted by the FCC; PROVIDED that (A) such Investments are made pursuant to
     a senior promissory note, in an amount equal to such Investment, that by
     its terms is payable in full at or before any required repayment of
     principal on the Notes, (B) such promissory note is secured equally and
     ratably with (or prior to) any other secured Indebtedness of such entity,
     (C) such Investment is made and used for the purpose of effecting, and does
     not exceed the amount reasonably required to effect, the minimum build-out
     with respect to such licenses that is required by the FCC as a prerequisite
     to the transfer of a majority equity interest in such entity to the Company
     or one of its Restricted Subsidiaries, as determined in good faith by the
     Board and (D) the Company, at the time such Investment is made, had a
     contractual right to, and intends (subject in all cases to compliance with
     applicable FCC rules and regulations) to, acquire such majority equity
     interest;

         (xi)  Investments existing on the Issue Date;

        (xii)  the acquisition of all equity interests of ART West not otherwise
     owned by the Company; and

       (xiii)  Directed Investments.

     "PERMITTED LIENS" means:

          (i)  Liens for taxes, assessments, governmental charges or claims that
     are being contested in good faith by appropriate legal proceedings timely
     instituted and diligently conducted and for which a reserve or other
     appropriate provision, if any, as shall be required in conformity with GAAP
     shall have been made;

         (ii)  statutory or common law Liens of landlords and carriers,
     warehousemen, mechanics, suppliers, materialmen, repairmen or other similar
     Liens arising in the ordinary course of business and with respect to
     amounts not yet delinquent or being contested in good faith by appropriate
     legal proceedings timely instituted and diligently conducted and for which
     a reserve or other appropriate provision, if any, as shall be required in
     conformity with GAAP shall have been made;

        (iii)  Liens incurred or deposits made in the ordinary course of
     business in connection with workers' compensation, unemployment insurance
     and other types of social security;

         (iv)  Liens incurred or deposits made to secure the performance of
     tenders, bids, leases, statutory or regulatory obligations, bankers'
     acceptances, surety and appeal bonds, government contracts, performance and
     return-of-money bonds and other obligations of a similar nature incurred in
     the ordinary course of business (exclusive of obligations for the payment
     of borrowed money) and a bank's unexercised right of set-off with respect
     to deposits made in the ordinary course;

          (v)  easements, rights-of-way, municipal and zoning ordinances and
     similar charges, encumbrances, title defects or other irregularities that
     do not materially interfere with the ordinary course of business of the
     Company or any of its other irregularities that do not materially interfere
     with the ordinary course of business of the Company or any of its
     Subsidiaries;


                                       12
<PAGE>

         (vi)  Liens (including extensions and renewals thereof) upon real or
     personal property acquired after the Issue Date; PROVIDED that (A) such
     Lien is created solely for the purpose of securing Indebtedness Incurred in
     accordance with Section 4.09 hereof, (1) to finance the cost (including the
     cost of improvement or construction) of the item of property or assets
     subject thereto and such Lien is created prior to, at the time of or within
     six months after the later of the acquisition, the completion of
     construction or the commencement of full operation of such property or
     (2) to refinance any Indebtedness previously so secured, (B) the principal
     amount of the Indebtedness secured by such Lien does not exceed 100% of
     such cost and (C) any such Lien shall not extend to or cover any property
     or assets other than such item of property or assets and any improvements
     on such item;

        (vii)  leases or subleases granted to others that do not materially
     interfere with the ordinary course of business of the Company and its
     Restricted Subsidiaries, taken as a whole;

       (viii)  Liens encumbering property or assets under construction arising
     from progress or partial payments by a customer of the Company or its
     Restricted Subsidiaries relating to such property or assets;

         (ix)  any interest or title of a lessor in the property subject to any
     Capitalized Lease or operating lease;

          (x)  Liens arising from filing Uniform Commercial Code financing
     statements regarding leases;

         (xi)  Liens on property of, or on shares of stock or Indebtedness of,
     any corporation existing at the time such corporation becomes, or becomes a
     part of, any Restricted Subsidiary; PROVIDED that such Liens do not extend
     to or cover any property or assets of the Company or any Restricted
     Subsidiary other than the property or assets acquired;

        (xii)  Liens in favor of the Company or any Restricted Subsidiary;

       (xiii)  Liens arising from the rendering of a final judgment or order
     against the Company or any Restricted Subsidiary of the Company that does
     not give rise to an Event of Default;

        (xiv)  Liens securing reimbursement obligations with respect to letters
     of credit that encumber documents and the property relating to such letters
     of credit and the products and proceeds thereof;

         (xv)  Liens in favor of customs and revenue authorities arising as a
     matter of law to secure payment of customs duties in connection with the
     importation of goods;

        (xvi)  Liens arising out of conditional sale, title retention,
     consignment or similar arrangements for the sale of goods entered into by
     the Company or any of its Restricted Subsidiaries in the ordinary course of
     business in accordance with the past practices of the Company and its
     Restricted Subsidiaries prior to the Issue Date;


                                       13
<PAGE>

       (xvii)  Liens on or sales of receivables;

      (xviii)  Liens securing other Indebtedness in an aggregate amount not to
     exceed $250,000 at any one time;

        (xix)  Liens on assets of Unrestricted Subsidiaries that secure Non-
     Recourse Debt of Unrestricted Subsidiaries;

         (xx)  Liens existing on the Issue Date;

        (xxi)  Liens granted after the Issue Date on any assets or Capital Stock
     of the Company or its Restricted Subsidiaries created in favor of the
     holders of the Notes;

       (xxii)  Liens with respect to the assets of a Restricted Subsidiary
     granted by such Restricted Subsidiary to the Company or a Wholly Owned
     Restricted Subsidiary to secure Indebtedness owing to the Company or such
     other Wholly Owned Restricted Subsidiary;

      (xxiii)  Liens securing Indebtedness which is Incurred to refinance
     secured Indebtedness which is permitted to be Incurred under Section
     4.09(b)(iii) hereof; PROVIDED that such Liens do not extend to or cover any
     property or assets of the Company or any Restricted Subsidiary other than
     the property or assets securing the Indebtedness being refinanced;

       (xxiv)  purchase money Liens upon equipment, software or systems acquired
     or held by the Company or any of its Restricted Subsidiaries taken or
     retained by the seller (or a financing institution acting on behalf of the
     seller) of such equipment, software or systems to secure all or a part of
     the purchase price therefor; PROVIDED that such Liens do not extend to or
     cover any property or assets of the Company or any Restricted Subsidiary
     other than the equipment so acquired; and

        (xxv)  Liens securing Indebtedness which is permitted to be Incurred
     under Section 4.09(b)(xiii) or (xiv) hereof.

     "PERSON" means any individual, corporation, limited liability company,
partnership, joint venture, association, joint-stock company, trust,
unincorporated organization or government or any agency or political subdivision
thereof.

     "PREFERRED STOCK" means, with respect to any Person, any and all shares,
interests, participations or other equivalents (however designated) of such
Person's preferred or preference stock, whether now outstanding or issued after
the Issue Date, and including, without limitation, all classes and series of
preferred or preference stock of such Person.

     "REDEEMABLE STOCK" means any class or series of Capital Stock of any Person
that by its terms or otherwise is (i) required to be redeemed prior to the
Stated Maturity of the Notes, (ii) redeemable at the option of the holder of
such class or series of Capital Stock at any time prior to the Stated Maturity
of the Notes (unless the redemption price is, at the Company's option, without
conditions precedent, payable solely is Common Stock (other than Redeemable
Stock) of the Company) or (iii) convertible into or exchangeable for Capital
Stock referred to in clause (i) or (ii) above or Indebtedness having a


                                       14
<PAGE>

scheduled maturity prior to the Stated Maturity of the Notes; PROVIDED that any
Capital Stock that would not constitute Redeemable Stock but for provisions
thereof giving holders thereof the right to require such Person to repurchase or
redeem such Capital Stock upon the occurrence of an "asset sale" or "change of
control" occurring prior to the Stated Maturity of the Notes shall not
constitute Redeemable Stock if the "asset sale" or "change of control"
provisions applicable to such Capital Stock are no more favorable to the holders
of such Capital Stock than the provisions contained in Sections 4.11 and 4.15
hereof and such Capital Stock specifically provides that such Person will not
repurchase or redeem any such stock pursuant to such provision prior to the
Company's repurchase of such Notes as are required to be repurchased pursuant to
Sections 4.11 and 4.15 hereof.

     "RESPONSIBLE OFFICER," when used with respect to the Trustee, means any
officer within the Corporate Trust Administration of the Trustee (or any
successor group of the Trustee) or any other officer of the Trustee customarily
performing functions similar to those performed by any of the above designated
officers and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of his knowledge of
and familiarity with the particular subject.

     "RESTRICTED SUBSIDIARY" of a Person means any Subsidiary of the referent
Person that is not an Unrestricted Subsidiary.

     "SECURITIES ACT" means the Securities Act of 1933, as amended (or any
successor act), and the rules and regulations thereunder.

     "SIGNIFICANT SUBSIDIARY" means, at any date of determination, any
Restricted Subsidiary of the Company that, together with its Subsidiaries, (i)
for the most recent fiscal year of the Company, accounted for more than 10% of
the consolidated revenues of the Company and its Restricted Subsidiaries or (ii)
as of the end of such fiscal year, had assets accounting for more than 10% of
the consolidated assets of the Company and its Restricted Subsidiaries, all as
set forth on the most recently available consolidated financial statements of
the Company for such fiscal year.

     "SPECIFIED DATE" means any redemption date, any date of purchase of Notes
pursuant to Section 4.11 or Section 4.15 hereof, or any date on which the Notes
are due and payable after an Event of Default.

     "STATED MATURITY" means, (i) with respect to any debt security, the date
specified in such debt security as the fixed date on which the final installment
of principal of such debt security is due and payable and (ii) with respect to
any scheduled installment of principal of or interest on any debt security, the
date specified in such debt security as the fixed date on which such installment
is due and payable.

     "STRATEGIC EQUITY INVESTOR" means any company which is (or a controlled
Affiliate of any company which is or a controlled Affiliate of which is) engaged
principally in a cable or telecommunications business which has a total market
capitalization of at least $1.0 billion.

     "SUBSIDIARY" means, with respect to any Person, (i) any corporation,
association or other business entity of which more than 50% of the total voting
power of shares of Capital Stock entitled (without regard to the occurrence of
any contingency) to vote in the election of directors, managers or trustees
thereof is at the time owned or controlled, directly or indirectly, by such
Person or one or more of the


                                       15
<PAGE>

other Subsidiaries of that Person (or a combination thereof) and (ii) any
partnership (a) the sole general partner or the managing general partner of
which is such Person or a Subsidiary of such Person or (b) the only general
partners of which are such Person or of one or more Subsidiaries of such Person
(or any combination thereof).

     "TELECOMMUNICATIONS ASSETS" means all assets (including, without
limitation, assets consisting of subscribers), rights (contractual or otherwise)
and properties, whether tangible or intangible, used in connection with a
Telecommunications Business.

     "TELECOMMUNICATIONS BUSINESS" means, when used in reference to any Person,
that such Person is engaged primarily in the business of (i) providing voice,
video or data communications services, (ii) creating, developing, marketing or
selling communications related equipment, software and other devices or (iii)
evaluating, participating in or pursuing any other activity or opportunity that
is related or incidental to those identified in clauses (i) or (ii) above.

     "TEMPORARY CASH INVESTMENT" means any of the following:  (i) direct
obligations of the United States or any agency thereof or obligations fully and
unconditionally guaranteed by the United States or any agency thereof; (ii) time
deposit accounts, certificates of deposit and money market deposits maturing
within six months of the date of acquisition thereof issued by a bank or trust
company which is organized under the laws of the United States, any state
thereof or any foreign country recognized by the United States, and which bank
or trust company has capital, surplus and undivided profits aggregating in
excess of $50.0 million (or the foreign currency equivalent thereof) and has
outstanding debt which is rated "A" (or such similar equivalent rating) or
higher by at least one nationally recognized statistical rating organization (as
defined in Rule 436 under the Securities Act) or any money-market fund sponsored
by a registered broker dealer or mutual fund distributor; (iii) repurchase
obligations with a term of not more than 30 days for underlying securities of
the types described in clause (i) above entered into with a bank meeting the
qualifications described in clause (ii) above; (iv) commercial paper, maturing
not more than six months after the date of acquisition, issued by a corporation
other than an Affiliate of the Company) organized and in existence under the
laws of the United States, any state thereof or any foreign country recognized
by the United States with rating at the time as of which any investment therein
is made of "P-1" (or higher) according to Moody's Investors Service, Inc. or
"A-1" (or higher) according to Standard & Poor's Ratings Group; and
(v) securities with maturities of six months or less from the date of
acquisition issued or fully and unconditionally guaranteed by any state,
commonwealth or territory of the United States, or by any political subdivision
or taxing authority thereof, and rated at least "A" by Standard & Poor's Ratings
Group or Moody's Investors Service, Inc.; PROVIDED that, notwithstanding the
foregoing, the maturity of any of the foregoing that is applied to provide
security in favor of the Indebtedness referred to in clause (xxiv) of the
definition of "Permitted Liens" may occur as late as the earliest date that such
Indebtedness may be redeemed at the option of the obligor with respect to such
Indebtedness and PROVIDED FURTHER that the Company shall cause such Liens
referred to in such clause (xxiv) to be incurred no later than the first
anniversary of the Issue Date.

     "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. Sections 77aaa-
77bbbb) as in effect on the date on which this Indenture is qualified under the
TIA, except as provided in Section 9.03.

     "TOTAL MARKET CAPITALIZATION" of any Person means, as of any day of
determination, the sum of (a) the consolidated Indebtedness of such Person and
its Restricted Subsidiaries on such day, PLUS (b) the product of (i) the
aggregate number of outstanding shares of Common Stock of such Person on such
day


                                       16
<PAGE>

(which shall not include any options or warrants on, or securities convertible
or exchangeable into, shares of Common Stock of such Person) and (ii) the
average Closing Price of such Common Stock over the 10 consecutive Trading Days
ending not earlier than 10 Trading Days immediately prior to such date of
determination, PLUS (c) the liquidation value of any outstanding shares of
Preferred Stock of such Person on such day.  If no such Closing Price exists
with respect to shares of any such class, the value of such shares for purposes
of clause (b) of the preceding sentence shall be determined by the Board in good
faith and evidenced by a resolution of the Board filed with the Trustee.
Notwithstanding the foregoing, unless the Company's Common Stock is listed on
any national securities exchange or on the Nasdaq National Market, the "Total
Market Capitalization" of the Company shall mean, as of any date of
determination, the enterprise value (without duplication) of the Company and its
Restricted Subsidiaries (including the fair market value of their debt and
equity, but excluding the enterprise value of the Company's Unrestricted
Subsidiaries), as determined by an independent banking firm of national standing
with experience in such valuations and evidenced by a written opinion in
customary form filed with the Trustee; PROVIDED that for purposes of any such
determination, the enterprise value of the Company shall be calculated as if the
Company were a publicly held corporation without a controlling stockholder.  For
purposes of any such determination, such banking firm's written opinion may
state that such fair market value is no less than a specified amount and such
opinion may be as of a date no earlier than 90 days prior to the date of such
determination.

     "TRUSTEE" means the party named as such above until a successor replaces it
in accordance with the applicable provisions of this Indenture and thereafter
means the successor serving hereunder.

     "TRADING DAY" with respect to a securities exchange or automated quotation
system means a day on which such exchange or system is open for full day of
trading.

     "UNRESTRICTED SUBSIDIARY" means any Subsidiary that is designated by the
Board as an Unrestricted Subsidiary pursuant to a resolution of the Board; but
only to the extent that such Subsidiary (i) has no Indebtedness other than Non-
Recourse Debt; (ii) is not party to any agreement, contract, arrangement or
understanding with the Company or any Restricted Subsidiary of the Company
unless the terms of any such agreement, contract, arrangement or understanding
are no less favorable to the Company or such Restricted Subsidiary than those
that might be obtained at the time from Persons who are not Affiliates of the
Company; (iii) is a Person with respect to which neither the Company nor any of
its Restricted Subsidiaries has any direct or indirect obligation (A) to
subscribe for additional equity interests, except to the extent that such
obligation complies with Section 4.07 hereof, or (B) to maintain or preserve
such Person's financial condition or to cause such Person to achieve any
specified levels of operating results; (iv) is not a guarantor of or otherwise
directly or indirectly provides credit support for any Indebtedness of the
Company or any of its Restricted Subsidiaries; and (v) has, immediately prior to
the commencement of material business operations, at least one director on its
board of directors that is not a director or executive officer of the Company or
any of its Restricted Subsidiaries and has at least one executive officer that
is not a director or executive officer of the Company or any of its Restricted
Subsidiaries.  Any such designation by the Board shall be evidenced to the
Trustee by filing with the Trustee a certified copy of the resolution of the
Board giving effect to such designation and an Officers' Certificate certifying
that such designation complied with the foregoing conditions and was permitted
by Section 4.07 hereof.  If, at any time, any Unrestricted Subsidiary would fail
to meet the foregoing requirements as an Unrestricted Subsidiary, it shall
thereafter cease to be an Unrestricted Subsidiary for purposes of this Indenture
and any Indebtedness of such Subsidiary shall be deemed to be Incurred by a
Restricted Subsidiary of the Company as of such date (and, if such Indebtedness
is not permitted to be


                                       17
<PAGE>

Incurred as of such date under Section 4.09 hereof, the Company shall be in
default of such covenant).  The Board may at any time designate any Unrestricted
Subsidiary to be a Restricted Subsidiary; PROVIDED that such designation shall
be deemed to be an Incurrence of Indebtedness by a Restricted Subsidiary of the
Company of any outstanding Indebtedness of such Unrestricted Subsidiary and such
designation shall only be permitted if (i) such Indebtedness is permitted under
Section 4.09 hereof and (ii) no Default or Event of Default would be in
existence following such designation.

     "VOTING STOCK" means, with respect to any Person, Capital Stock of any
class or kind ordinarily having the power to vote for the election of directors,
managers or other voting members of the governing body of such Person.

     "VOTING TRUST AGREEMENT" means that certain Voting Trust and Irrevocable
Proxy Agreement, to be entered into on or prior to the Issue Date.

     "WHOLLY OWNED" means, with respect to any Subsidiary of any Person, such
Subsidiary if all of the outstanding Capital Stock in such Subsidiary (other
than any director's qualifying shares or Investments by foreign nationals
mandated by applicable law) is owned by such Person or one or more Wholly Owned
Subsidiaries of such Person.

SECTION 1.02.  OTHER DEFINITIONS.

                                                                 Defined in
         TERM                                                      Section

          "Affiliate Transaction". . . . . . . . . . . . . .         4.12
          "Bankruptcy Law" . . . . . . . . . . . . . . . . .         4.01
          "Covenant Defeasance". . . . . . . . . . . . . . .         8.03
          "Custodian". . . . . . . . . . . . . . . . . . . .         6.01
          "Event of Default" . . . . . . . . . . . . . . . .         6.01
          "Excess Proceeds". . . . . . . . . . . . . . . . .         4.11
          "Legal Defeasance" . . . . . . . . . . . . . . . .         8.02
          "Paying Agent" . . . . . . . . . . . . . . . . . .         2.03
          "Payment Default". . . . . . . . . . . . . . . . .         6.01
          "Registrar". . . . . . . . . . . . . . . . . . . .         2.03
          "Restricted Payments". . . . . . . . . . . . . . .         4.07

SECTION 1.03.  INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT.

     Whenever this Indenture refers to a provision of the TIA, the provision is
incorporated by reference in and made a part of this Indenture.

     The following TIA terms used in this Indenture have the following meanings:

          "INDENTURE SECURITIES" means the Notes;

          "INDENTURE SECURITY HOLDER" means a Holder of a Note;

          "INDENTURE TO BE QUALIFIED" means this Indenture;


                                       18
<PAGE>

          "INDENTURE TRUSTEE" or "INSTITUTIONAL TRUSTEE" means the Trustee;

          "OBLIGOR" on the Notes means the Company and any successor obligor
upon the Notes.

     All other terms used in this Indenture that are defined by the TIA, defined
by TIA reference to another statute or defined by Commission rule under the TIA
have the meanings so assigned to them.

SECTION 1.04.  RULES OF CONSTRUCTION.

     Unless the context otherwise requires:

          (1)  a term has the meaning assigned to it;

          (2)  an accounting term not otherwise defined has the meaning assigned
     to it in accordance with GAAP;

          (3)  "or" is not exclusive;

          (4)  words in the singular include the plural, and in the plural
     include the singular; and

          (5)  provisions apply to successive events and transactions.


                                    ARTICLE 2
                                    THE NOTES

SECTION 2.01.  FORM AND DATING.

     The Notes and the Trustee's certificate of authentication shall be
substantially in the form of Exhibit A hereto, the terms of which are
incorporated in and made a part of this Indenture.  The Notes may have
notations, legends or endorsements approved as to form by the Company and
required by law, stock exchange rule, agreements to which the Company is subject
or usage.  Each Note shall be dated the date of its authentication.  The Notes
shall be issuable only in denominations of $1,000 and integral multiples
thereof.

SECTION 2.02.  EXECUTION AND AUTHENTICATION.

     Two Officers of the Company shall sign the Notes for the Company by manual
or facsimile signature.  The Company's seal shall be reproduced on the Notes.

     If an Officer whose signature is on a Note no longer holds that office at
the time the Note is authenticated, the Note shall nevertheless be valid.

     A Note shall not be valid until authenticated by the manual signature of
the Trustee.  The signature of the Trustee shall be conclusive evidence that the
Note has been authenticated under this


                                       19
<PAGE>

Indenture.  The form of Trustee's certificate of authentication to be borne by
the Notes shall be substantially as set forth in Exhibit A hereto.

     The Trustee shall, upon a written order of the Company signed by two
Officers of the Company, authenticate Notes for original issue up to an
aggregate face amount (at maturity) stated in paragraph 4 of the Notes.  The
aggregate principal amount of Notes outstanding at any time shall not exceed the
amount set forth therein except as provided in Section 2.07.

     The Trustee may appoint an authenticating agent acceptable to the Company
to authenticate Notes.  Unless limited by the terms of such appointment, an
authenticating agent may authenticate Notes whenever the Trustee may do so.
Each reference in this Indenture to authentication by the Trustee includes
authentication by such agent.  An authenticating agent has the same rights as an
Agent to deal with the Company or an Affiliate of the Company.

SECTION 2.03.  REGISTRAR AND PAYING AGENT.

     The Company shall maintain (i) an office or agency where Notes may be
presented for registration of transfer or for exchange (including any co-
registrar, the "REGISTRAR") and (ii) an office or agency where Notes may be
presented for payment ("PAYING AGENT") and an office or agency in the Borough of
Manhattan, City and State of New York, where notices and demands upon the
Company in respect of the Notes and this Indenture may be served.  The Registrar
shall maintain an office or agency in the Borough of Manhattan, City and State
of New York, where Notes may be presented for registration of transfer or for
exchange, and the Paying Agent shall maintain an office or agency in the Borough
of Manhattan, City and State of New York, where Notes may be presented for
payment.  The Registrar shall keep a register of the Notes and of their transfer
and exchange.  The Company may appoint one or more co-registrars and one or more
additional paying agents.  The term "Paying Agent" includes any additional
paying agent.  The Company may change any Paying Agent, Registrar or
co-registrar without prior notice to any Holder of a Note.  The Company shall
notify the Trustee and the Trustee, at the Company's direction, shall notify the
Holders of the Notes of the name and address of any Agent not a party to this
Indenture.  The Company may act as Paying Agent, Registrar or co-registrar.  The
Company shall enter into an appropriate agency agreement with any Agent not a
party to this Indenture, which shall incorporate the provisions of the TIA.  The
agreement shall implement the provisions of this Indenture that relate to such
Agent.  The Company shall notify the Trustee of the name and address of any such
Agent.  If the Company fails to maintain a Registrar or Paying Agent, or fails
to give the foregoing notice, the Trustee shall act as such, and shall be
entitled to appropriate compensation in accordance with Section 7.07.

     The Company initially appoints the Trustee as Registrar, Paying Agent and
agent for service of notices and demands in connection with the Notes.

SECTION 2.04.  PAYING AGENT TO HOLD MONEY IN TRUST.

     The Company shall require each Paying Agent other than the Trustee to agree
in writing that the Paying Agent shall hold in trust for the benefit of the
Holders of the Notes or the Trustee all money held by the Paying Agent for the
payment of principal of, premium, if any, and interest on the Notes, and shall
notify the Trustee of any Default by the Company in making any such payment.
While any such Default continues, the Trustee may require a Paying Agent to pay
all money held by it to the Trustee.


                                       20
<PAGE>

The Company at any time may require a Paying Agent to pay all money held by it
to the Trustee.  Upon payment over to the Trustee, the Paying Agent (if other
than the Company) shall have no further liability for the money delivered to the
Trustee.  If the Company acts as Paying Agent, it shall segregate and hold in a
separate trust fund for the benefit of the Holders of the Notes all money held
by it as Paying Agent.

SECTION 2.05.  LISTS OF HOLDERS OF THE NOTES.

     The Trustee shall preserve in as current a form as is reasonably
practicable the most recent list available to it of the names and addresses of
Holders of the Notes and shall otherwise comply with TIA Section 312(a).  If the
Trustee is not the Registrar, the Company shall furnish to the Trustee at least
seven Business Days before each interest payment date and at such other times as
the Trustee may request in writing a list in such form and as of such date as
the Trustee may reasonably require of the names and addresses of Holders of the
Notes, including the aggregate principal amount of the Notes held by each
thereof, and the Company shall otherwise comply with TIA Section 312(a).

SECTION 2.06.  TRANSFER AND EXCHANGE.

     When Notes are presented to the Registrar with a request to register the
transfer of or to exchange them for an equal principal amount of Notes of other
denominations, the Registrar shall register the transfer of or make the exchange
if its requirements for such transactions are met; PROVIDED, HOWEVER, that any
Note presented or surrendered for registration of transfer or exchange shall be
duly endorsed or accompanied by a written instruction of transfer in form
satisfactory to the Registrar and the Trustee duly executed by the Holder
thereof or by his attorney duly authorized in writing.  To permit registrations
of transfer and exchanges, the Company shall issue and the Trustee shall
authenticate Notes at the Registrar's request, subject to such rules as the
Trustee may reasonably require.

     Neither the Company nor the Registrar shall be required to (i) issue,
register the transfer of or exchange Notes during a period beginning at the
opening of business on a Business Day 15 days before the day of any selection of
Notes for redemption under Section 3.02 or (ii) register the transfer of or
exchange any Note so selected for redemption in whole or in part, except the
unredeemed portion of any Note being redeemed in part.

     No service charge shall be made to any Holder of a Note for any
registration of transfer or exchange (except as otherwise expressly permitted
herein), but the Company may require payment of a sum sufficient to cover any
transfer tax or similar governmental charge payable in connection therewith
(other than such transfer tax or similar governmental charge payable upon
exchanges pursuant to Sections 2.10, 3.06 or 9.05, which shall be paid by the
Company).

     Prior to due presentment to the Trustee for registration of the transfer of
any Note, the Trustee, any Agent and the Company may deem and treat the Person
in whose name any Note is registered as the absolute owner of such Note for the
purpose of receiving payment of principal of, premium, if any, and interest on
such Note and for all other purposes whatsoever, whether or not such Note is
overdue, and neither the Trustee, any Agent nor the Company shall be affected by
notice to the contrary.


                                       21
<PAGE>

SECTION 2.07.  REPLACEMENT NOTES.

     If any mutilated Note is surrendered to the Trustee, or the Company and the
Trustee receive evidence to their satisfaction of the destruction, loss or theft
of any Note, the Company shall issue and the Trustee shall authenticate a
replacement Note if the Trustee's requirements for replacements of Notes are
met.  If required by the Trustee or the Company, an indemnity bond must be
supplied by the Holder that is sufficient in the judgment of the Trustee and the
Company to protect the Company, the Trustee, any Agent or any authenticating
agent from any loss which any of them may suffer if a Note is replaced.  Each of
the Company and the Trustee may charge for its expenses in replacing a Note.

     Every replacement Note is an additional obligation of the Company.

SECTION 2.08.  OUTSTANDING NOTES.

     The Notes outstanding at any time are all the Notes authenticated by the
Trustee except for those cancelled by it, those delivered to it for cancellation
and those described in this Section as not outstanding.

     If a Note is replaced pursuant to Section 2.07, it ceases to be outstanding
unless the Trustee receives proof satisfactory to it that the replaced Note is
held by a bona fide purchaser.

     If the principal amount of any Note is considered paid under Section 4.01,
it ceases to be outstanding and interest on it ceases to accrue.

     Subject to Section 2.09, a Note does not cease to be outstanding because
the Company, a Subsidiary of the Company or an Affiliate of the Company holds
the Note.

SECTION 2.09.  TREASURY NOTES.

     In determining whether the Holders of the required principal amount of
Notes have concurred in any direction, waiver or consent, Notes owned by the
Company, any Subsidiary of the Company or any Affiliate of the Company shall be
considered as though not outstanding, except that for purposes of determining
whether the Trustee shall be protected in relying on any such direction, waiver
or consent, only Notes which a Responsible Officer knows to be so owned shall be
so considered.  Notwithstanding the foregoing, Notes that are to be acquired by
the Company, any Subsidiary of the Company or an Affiliate of the Company
pursuant to an exchange offer, tender offer or other agreement shall not be
deemed to be owned by the Company, a Subsidiary of the Company or an Affiliate
of the Company until legal title to such Notes passes to the Company or such
Subsidiary or Affiliate, as the case may be.

SECTION 2.10.  TEMPORARY NOTES.

     Until definitive Notes are ready for delivery, the Company may prepare and
the Trustee shall authenticate temporary Notes.  Temporary Notes shall be
substantially in the form of definitive Notes but may have variations that the
Company and the Trustee consider appropriate for temporary Notes.  Without
unreasonable delay, the Company shall prepare and the Trustee, upon receipt of
the written order of the Company signed by two Officers of the Company, shall
authenticate definitive Notes in exchange


                                       22
<PAGE>

for temporary Notes.  Until such exchange, temporary Notes shall be entitled to
the same rights, benefits and privileges as definitive Notes.

SECTION 2.11.  CANCELLATION.

     The Company at any time may deliver Notes to the Trustee for cancellation.
The Registrar and Paying Agent shall forward to the Trustee any Notes
surrendered to them for registration of transfer, exchange or payment.  The
Trustee shall cancel all Notes surrendered for registration of transfer,
exchange, payment, replacement or cancellation and shall retain or destroy
cancelled Notes (subject to the record retention requirement of the Exchange
Act), unless the Company directs cancelled Notes to be returned to it.  The
Company may not issue new Notes to replace Notes that it has redeemed or paid or
that have been delivered to the Trustee for cancellation.  All cancelled Notes
held by the Trustee shall, at the direction of the Company, be destroyed and
certification of their destruction delivered to the Company, unless by a written
order, signed by two Officers of the Company, the Company shall direct that
cancelled Notes be returned to it.

SECTION 2.12.  DEFAULTED INTEREST.

     If the Company defaults in a payment of interest on the Notes, it shall pay
the defaulted interest in any lawful manner plus, to the extent lawful, interest
payable on the defaulted interest, to the Persons who are Holders of the Notes
on a subsequent special record date, which date shall be at the earliest
practicable date but in all events at least five Business Days prior to the
payment date, in each case at the rate provided in the Notes and in
Section 4.01.  The Company shall, with the consent of the Trustee, fix or cause
to be fixed each such special record date and payment date.  At least 15 days
before the special record date, the Company (or the Trustee, in the name of and
at the expense of the Company) shall mail to Holders of the Notes a notice that
states the special record date, the related payment date and the amount of such
interest to be paid.

SECTION 2.13.  RECORD DATE.

     The record date for purposes of determining the identity of Holders of the
Notes entitled to vote or consent to any action by vote or consent authorized or
permitted under this Indenture shall be determined as provided for in TIA
Section 316(c).

SECTION 2.14.  CUSIP NUMBER.

     The Company in issuing the Notes may use a "CUSIP" number and, if it does
so, the Trustee shall use the CUSIP number in notices of redemption or exchange
as a convenience to Holders; PROVIDED that any such notice may state that no
representation is made as to the correctness or accuracy of the CUSIP number
printed in the notice or on the Notes and that reliance may be placed only on
the other identification numbers printed on the Notes.  The Company will
promptly notify the Trustee of any change in the CUSIP number.


                                       23
<PAGE>

                                    ARTICLE 3
                                   REDEMPTION

SECTION 3.01.  NOTICES TO TRUSTEE.

     If the Company elects to redeem Notes pursuant to the optional redemption
provisions of Section 3.07, it shall furnish to the Trustee, at least 30 days
(unless a shorter period is acceptable to the Trustee) but not more than 60 days
before a redemption date, an Officers' Certificate setting forth (i) the
redemption date, (ii) the principal amount of Notes to be redeemed and (iii) the
redemption price.

SECTION 3.02.  SELECTION OF NOTES TO BE REDEEMED.

     If less than all of the Notes are to be redeemed, the Trustee shall select
the Notes to be redeemed among the Holders of the Notes in compliance with the
requirements of the principal national securities exchange, if any, on which the
Notes are listed, or, if the Notes are not so listed, on a PRO RATA basis, by
lot or in accordance with any other method the Trustee considers fair and
appropriate (and in such manner as complies with applicable legal and stock
exchange requirements, if any), PROVIDED that no Notes of $1,000 or less shall
be redeemed in part.  In the event of partial redemption by lot, the particular
Notes to be redeemed shall be selected, unless otherwise provided herein, not
less than 35 nor more than 60 days prior to the redemption date by the Trustee
from the outstanding Notes not previously called for redemption.

     The Trustee shall promptly notify the Company in writing of the Notes
selected for redemption and, in the case of any Note selected for partial
redemption, the principal amount thereof to be redeemed.  Notes and portions of
them selected shall be in amounts of $1,000 or whole multiples of $1,000; except
that if all of the Notes of a Holder are to be redeemed, the entire outstanding
amount of Notes held by such Holder, even if not a multiple of $1,000, shall be
redeemed.  Except as provided in the preceding sentence, provisions of this
Indenture that apply to Notes called for redemption also apply to portions of
Notes called for redemption.

SECTION 3.03.  NOTICE OF REDEMPTION.

     Subject to the provisions of Sections 4.11 and 4.15 hereof, at least
30 days but not more than 60 days before a redemption date, the Company shall
mail or cause to be mailed, by first class mail, a notice of redemption to each
Holder whose Notes are to be redeemed at its registered address; PROVIDED that
in the event of a redemption pursuant to Section 3.07(b) arising out of a sale
of the Company's Capital Stock (other than Disqualified Stock) to a Strategic
Equity Investor, such notice shall not be mailed prior to the consummation of
such sale.

     The notice shall identify the Notes to be redeemed and shall state: (a) the
redemption date; (b) the redemption price; (c) if any Note is being redeemed in
part, the portion of the principal amount of such Note to be redeemed and that,
after the redemption date upon surrender of such Note, a new Note or Notes in
principal amount equal to the unredeemed portion shall be issued; (d) the name
and address of the Paying Agent; (e) that Notes called for redemption must be
surrendered to the Paying Agent to collect the redemption price; (f) that,
unless the Company defaults in making such redemption payment, interest on Notes
called for redemption ceases to accrue on and after the redemption date; (g) the
paragraph of the Notes and/or Section of this Indenture pursuant to which the
Notes called for redemption


                                       24
<PAGE>

are being redeemed; and (h) that no representation is made as to the correctness
or accuracy of the CUSIP number, if any, listed in such notice or printed on the
Notes.

     At the Company's request, the Trustee shall give the notice of redemption
in the Company's name and at its expense; PROVIDED, HOWEVER, that the Company
shall have delivered to the Trustee, at least 45 days prior to the redemption
date, an Officers' Certificate requesting that the Trustee give such notice and
setting forth the information to be stated in such notice as provided in the
preceding paragraph.

SECTION 3.04.  EFFECT OF NOTICE OF REDEMPTION.

     Once notice of redemption is mailed in accordance with Section 3.03, Notes
called for redemption become due and payable on the redemption date at the
redemption price.  A notice of redemption may not be conditional.

SECTION 3.05.  DEPOSIT OF REDEMPTION PRICE.

     One Business Day prior to the redemption date, the Company shall deposit
with the Trustee or with the Paying Agent money sufficient to pay the redemption
price of and accrued interest on all Notes to be redeemed on that date.  The
Trustee or the Paying Agent shall promptly return to the Company any money
deposited with the Trustee or the Paying Agent by the Company in excess of the
amounts necessary to pay the redemption price of, and accrued interest on, all
Notes to be redeemed.

     If the Company complies with the provisions of the preceding paragraph, on
and after the redemption date, interest shall cease to accrue on the Notes or
the portions of Notes called for redemption.  If a Note is redeemed on or after
an interest record date but on or prior to the related interest payment date,
then any accrued and unpaid interest shall be paid to the Person in whose name
such Note was registered at the close of business on such record date.  If any
Note called for redemption shall not be so paid upon surrender for redemption
because of the failure of the Company to comply with the preceding paragraph,
interest shall be paid on the unpaid principal, from the redemption date until
such principal is paid, and to the extent lawful on any interest not paid on
such unpaid principal, in each case at the rate provided in the Notes and in
Section 4.01.

SECTION 3.06.  NOTES REDEEMED IN PART.

     Upon surrender of a Note that is redeemed in part, the Company shall issue
and the Trustee shall authenticate for the Holder of the Note at the expense of
the Company a new Note equal in principal amount to the unredeemed portion of
the Note surrendered.

SECTION 3.07.  OPTIONAL REDEMPTION.

     (a)  Except as set forth in Section 3.07(b) below, the Company shall not
have the option to redeem the Notes prior to _________ 2001.  Thereafter, the
Notes will be redeemable at the option of the Company, in whole or in part, at
any time on or after          , 2001, upon not less than 30 nor more than 60
days' notice, at the redemption prices (expressed as percentages of principal
amount at maturity)


                                       25
<PAGE>

set forth below, plus accrued and unpaid interest, if any, to the date of
redemption, if redeemed during the 12-month period beginning on           of the
years indicated below:

                                                                      Redemption
Year                                                                     Price
- ----                                                                  ----------
2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .           %
2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .           %
2003 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .           %
2004 and thereafter. . . . . . . . . . . . . . . . . . . . . . . . .    100.000%

     (b)  Notwithstanding the provisions of Section 3.07(a) above, in the event
a sale by the Company of its Common Stock in one or more Equity Offerings or
Investments by one or more Strategic Equity Investors for an aggregate purchase
price equal to or exceeding $70.0 million, on or prior to           , 1999, the
Company may, at its option, use all or a portion of the net proceeds thereof to
redeem up to a maximum of 33 1/3% of the initially outstanding aggregate
principal amount at maturity of the Notes at a redemption price equal to      %
of the Accreted Value of the Notes (determined as of the redemption date);
PROVIDED that not less than 66 2/3% of the initially outstanding aggregate
principal amount at maturity of the Notes remain outstanding following such
redemption.  Any such redemption must be effected upon not less than 30 nor more
than 60 days' notice given within 30 days after any such Equity Offering or sale
to a Strategic Equity Investor resulting in such gross proceeds, as the case may
be.

     (c)  Any redemption pursuant to this Section 3.07 shall be made pursuant to
the provisions of Sections 3.01 through 3.06 hereof.

SECTION 3.08.  MANDATORY REDEMPTION.

     Except as set forth under Sections 4.11 and 4.15 hereof, the Company shall
not be required to make mandatory redemption payments with respect to the Notes.
There are no sinking fund payments with respect to the Notes.


                                    ARTICLE 4
                                    COVENANTS

SECTION 4.01.  PAYMENT OF NOTES.

     The Company shall pay or cause to be paid the principal of, premium, if
any, and interest on the Notes on the dates and in the manner provided in the
Notes.  Principal, premium, if any, and interest shall be considered paid on the
date due if the Paying Agent, if other than the Company, holds as of 10:00 a.m.
Eastern Time on the due date money deposited by the Company in immediately
available funds and designated for and sufficient to pay all principal, premium,
if any, and interest then due.

     The Company shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue principal at the rate equal to
the then applicable interest rate on the Notes to the extent lawful; it shall
pay interest (including post-petition interest in any proceeding under any
Bankruptcy Law) on overdue installments of interest (without regard to any
applicable grace period) at the same rate to the extent lawful.


                                       26
<PAGE>

     The term "BANKRUPTCY LAW" means title 11, U.S. Code or any similar federal
or state law for the relief of debtors.

SECTION 4.02.  MAINTENANCE OF OFFICE OR AGENCY.

     The Company shall maintain an office or agency (which may be an office of
the Trustee or an affiliate of the Trustee, Paying Agent, Registrar or
co-registrar) where Notes may be surrendered for registration of transfer or
exchange and where notices and demands to or upon the Company in respect of the
Notes and this Indenture may be served.  The Company shall give prompt written
notice to the Trustee of the location, and any change in the location, of such
office or agency.  If at any time the Company shall fail to maintain any such
required office or agency or shall fail to furnish the Trustee with the address
thereof, such presentations, surrenders, notices and demands may be made or
served at the Corporate Trust Office of the Trustee.

     The Company may also from time to time designate one or more other offices
or agencies where the Notes may be presented or surrendered for any or all such
purposes and may from time to time rescind such designations; PROVIDED, HOWEVER,
that no such designation or rescission shall in any manner relieve the Company
of its obligation to maintain an office or agency for such purposes.  The
Company shall give prompt written notice to the Trustee of any such designation
or rescission and of any change in the location of any such other office or
agency.

     The Company hereby designates the Corporate Trust Office of the Trustee as
one such office or agency of the Company in accordance with Section 2.03.

SECTION 4.03.  REPORTS.

     (a)  Whether or not required by the rules and regulations of the Securities
and Exchange Commission (the "COMMISSION"), so long as any Notes are
outstanding, the Company will furnish to the Holders of Notes (i) all quarterly
and annual financial information that would be required to be contained in a
filing with the Commission on Forms 10-Q and 10-K if the Company were required
to file such Forms, including a "Management's Discussion and Analysis of
Financial Condition and Results of Operations" and, with respect to the annual
information only, a report thereon by the Company's certified independent
accountants and (ii) all current reports that would be required to be filed with
the Commission on Form 8-K if the Company were required to file such reports.
In addition, whether or not required by the rules and regulations of the
Commission, the Company will file a copy of all such information and reports
with the Commission for public availability (unless the Commission will not
accept such a filing) and make such information available to securities analysts
and prospective investors upon request.  The Company shall also comply with the
provisions of TIA Section 314(a).

     (b)  The Company shall provide the Trustee with a sufficient number of
copies of all SEC Reports that the Trustee may be required to deliver to the
Holders of the Notes under this Section 4.03.

SECTION 4.04.  COMPLIANCE CERTIFICATE.

     (a)  The Company shall deliver to the Trustee, within 120 days after the
end of each fiscal year, an Officers' Certificate stating that a review of the
activities of the Company and its Subsidiaries during the preceding fiscal year
has been made under the supervision of the signing Officers with a view


                                       27
<PAGE>

to determining whether the Company has kept, observed, performed and fulfilled,
and has caused each of its Subsidiaries to keep, observe, perform and fulfill,
its obligations under this Indenture, and further stating, as to each such
Officer signing such certificate, that to the best of his or her knowledge the
Company has kept, observed, performed and fulfilled, and has caused each of its
Subsidiaries to keep, observe, perform and fulfill, each and every covenant
contained in this Indenture and no such Person is in default in the performance
or observance of any of the terms, provisions and conditions of this Indenture
to be performed or observed by it (or, if a Default or Event of Default shall
have occurred, describing all such Defaults or Events of Default of which he or
she may have knowledge and what action each is taking or proposes to take with
respect thereto) and that to the best of his or her knowledge no event has
occurred and remains in existence by reason of which payments on account of the
principal of, premium, if any, or interest, if any, on the Notes are prohibited
or if such event has occurred, a description of the event and what action each
is taking or proposes to take with respect thereto.

     (b)  So long as not contrary to the then current recommendations of the
American Institute of Certified Public Accountants, the year-end financial
statements delivered pursuant to Section 4.03 above shall be accompanied by a
written statement of the Company's independent public accountants (who shall be
a firm of established national reputation) that in making the examination
necessary for certification of such financial statements, nothing has come to
their attention which would lead them to believe that the Company has violated
any provisions of Article Four or Article Five of this Indenture or, if any such
violation has occurred, specifying the nature and period of existence thereof,
it being understood that such accountants shall not be liable directly or
indirectly to any Person for any failure to obtain knowledge of any such
violation.

     (c)  The Company shall, so long as any of the Notes are outstanding,
deliver to the Trustee, forthwith upon any Officer becoming aware of (i) any
Default or Event of Default or (ii) any default under any Indebtedness referred
to in Section 6.01(e), an Officers' Certificate specifying such Default, Event
of Default or default and what action the Company is taking or proposes to take
with respect thereto.

     (d)  At the time of any Restricted Payment, the Company and its
Subsidiaries shall deliver to the Trustee an Officer's Certificate required by
Section 4.07(d).

SECTION 4.05.  TAXES.

     The Company shall pay, and shall cause each of its Subsidiaries to pay,
prior to delinquency, all material taxes, assessments, and governmental levies,
except as contested in good faith and by appropriate proceedings or where the
failure to effect such payment is not adverse in any material respect to the
Holders of the Notes.

SECTION 4.06.  STAY, EXTENSION AND USURY LAWS.

     The Company covenants (to the extent that it may lawfully do so) that it
shall not at any time insist upon, plead, or in any manner whatsoever claim or
take the benefit or advantage of, any stay, extension or usury law wherever
enacted, now or at any time hereafter in force, that may affect the covenants or
the performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such
law, and covenants that it shall not, by


                                       28
<PAGE>

resort to any such law, hinder, delay or impede the execution of any power
herein granted to the Trustee, but shall suffer and permit the execution of
every such power as though no such law has been enacted.

SECTION 4.07.  LIMITATION ON RESTRICTED PAYMENTS.

     (a)  The Company will not, and will not permit any Restricted Subsidiary
to, directly or indirectly, (i) declare or pay any dividend or make any
distribution on its or such Restricted Subsidiary's Capital Stock (other than
dividends or distributions payable solely in shares of its or such Restricted
Subsidiary's Capital Stock (other than Redeemable Stock) held by such holders or
in options, warrants or other rights to acquire such shares of Capital Stock)
other than such Capital Stock held by the Company or any of its Restricted
Subsidiaries (and other than pro rata dividends or distributions on Common Stock
of Restricted Subsidiaries), (ii) repurchase, redeem, retire or otherwise
acquire for value any shares of Capital Stock (including options, warrants or
other rights to acquire such shares of Capital Stock) of the Company (other than
any such Capital Stock held by the Company or any Wholly Owned Restricted
Subsidiary of the Company), (iii) make any voluntary or optional principal
payment, or voluntary or optional redemption, repurchase, defeasance, or other
acquisition or retirement for value, of Indebtedness of the Company that is
subordinated in right of payment to the Notes or (iv) make any Investment, other
than a Permitted Investment, in any Person (such payments or any other actions
described in clauses (i) through (iv) being collectively "RESTRICTED PAYMENTS")
if, at the time of, and after giving effect to, the proposed Restricted Payment:

          (A)  a Default or Event of Default shall have occurred and be
     continuing;

          (B)  except with respect to any Investment (other than an Investment
     consisting of the designation of a Restricted Subsidiary as an Unrestricted
     Subsidiary), the Company could not Incur at least $1.00 of Indebtedness
     under Section 4.09(a) hereof; and

          (C)  the aggregate amount expended for all Restricted Payments (the
     amount so expended, if other than in cash, to be determined in good faith
     by the Board, whose determination shall be conclusive and evidenced by a
     resolution of the Board) after the Issue Date shall exceed the sum of (1)
     50% of the aggregate amount of the Adjusted Consolidated Net Income (or, if
     the Adjusted Consolidated Net Income is a loss, MINUS 100% of such amount)
     (determined by excluding income resulting from transfers of assets by the
     Company or a Restricted Subsidiary to an Unrestricted Subsidiary) accrued
     on a cumulative basis during the period (taken as one accounting period)
     beginning on the first day of the fiscal quarter immediately following the
     Issue Date and ending on the last day of the last fiscal quarter preceding
     the date for which reports have been filed pursuant to Section 4.03 hereof,
     PLUS (2) the aggregate Net Cash Proceeds received by the Company after the
     Issue Date from the issuance and sale permitted by this Indenture of its
     Capital Stock (other than Redeemable Stock) to a Person who is not a
     Subsidiary of the Company, or from the issuance to a Person who is not a
     Subsidiary of the Company of any options, warrants or other rights to
     acquire Capital Stock of the Company (in each case, exclusive of any
     convertible Indebtedness, Redeemable Stock or any options, warrants or
     other rights that are redeemable at the option of the holder, or are
     required to be redeemed, prior to the Stated Maturity of the Notes), MINUS
     the actual amount of Net Cash Proceeds used to make such Directed
     Investments, PLUS (3) an amount equal to the net reduction in Investments
     (other than reductions in Permitted Investments) in any Person resulting
     from payments of interest on Indebtedness, dividends, repayments of loans
     or advances, or other


                                       29
<PAGE>

     transfers of assets, in each case to the Company or any Restricted
     Subsidiary (except to the extent any such payment is included in the
     calculation of Adjusted Consolidated Net Income), or from the redesignation
     of Unrestricted Subsidiaries as Restricted Subsidiaries (valued in each
     case as provided in the definition of "Investments"), not to exceed the
     amount of Investments previously made by the Company and its Restricted
     Subsidiaries in such Person.

     (b)  The foregoing provision shall not be violated by reason of:

          (i)  the payment of any dividend within 60 days after the date of
     declaration thereof if, at said date of declaration, such payment would
     comply with the foregoing paragraph;

         (ii)  the redemption, repurchase, defeasance or other acquisition or
     retirement for value of Indebtedness that is subordinated in right of
     payment to the Notes, including premium, if any, and accrued and unpaid
     interest, with the proceeds of, or in exchange for, Indebtedness Incurred
     under Section 4.09(b)(iii) hereof;

        (iii)  the repurchase, redemption or other acquisition of Capital Stock
     of the Company (or options, warrants or other rights to acquire such
     Capital Stock) in exchange for, or out of the proceeds of a substantially
     concurrent offering of, shares of Capital Stock or options, warrants or
     other rights to acquire such Capital Stock (in each case, other than
     Redeemable Stock) of the Company;

         (iv)  the making of any principal payment or repurchase, redemption,
     retirement, defeasance or other acquisition for value of Indebtedness of
     the Company which is subordinated in right of payment to the Notes in
     exchange for, or out of the proceeds of, a substantially concurrent
     offering of, shares of the Capital Stock of the Company (other than
     Redeemable Stock);

          (v)  payments or distributions, in the nature of satisfaction of
     dissenters' rights, pursuant to or in connection with a consolidation,
     merger or transfer of assets that complies with the provisions hereof
     applicable to mergers, consolidations and transfers of all or substantially
     all of the property and assets of the Company;

         (vi)  any purchase or acquisition from, or withholding on issuances to,
     any employee of the Company's Capital Stock in order to satisfy any
     applicable federal, state or local tax payments in respect of the receipt
     of shares of the Company's Capital Stock;

        (vii)  any purchase or acquisition from, or withholding on issuances to,
     any employee of the Company's Capital Stock in order to pay the purchase
     price of such Capital Stock or similar instrument pursuant to a stock
     option, equity incentive or other employee benefit plan or agreement of the
     Company or any of its Restricted Subsidiaries;

       (viii)  the repurchase of shares of, or options to purchase shares of,
     the Company's Capital Stock from employees of the Company in connection
     with the termination of their employment; PROVIDED that (A) the aggregate
     price paid for all such repurchased shares of Capital Stock made in any
     twelve-month period shall not exceed $250,000 PLUS the aggregate cash
     proceeds received by the Company during such twelve-month period from any
     reissuance of such


                                       30
<PAGE>

     Capital Stock by the Company to employees of the Company and its Restricted
     Subsidiaries and (B) no Default shall have occurred and be continuing
     immediately after such transaction;

         (ix)  payments and distributions pursuant to any tax sharing agreement
     between the Company and any other Person with which the Company files a
     consolidated tax return or with which the Company is part of a consolidated
     group, in each case, for federal income tax purposes;

          (x)  cash payments in lieu of the issuance of fractional shares of
     Common Stock of the Company upon conversion of any class of Preferred Stock
     of the Company; and

         (xi)  the issuance of shares of Common Stock upon exercise of warrants
     to purchase shares of common stock of ART Licensing existing on the Issue
     Date, including any contribution of such shares of Common Stock to ART
     Licensing, any payment by ART Licensing to the Company in consideration
     thereof and any contribution by the Company to ART Licensing in respect
     thereof.

PROVIDED that, except in the case of clauses (i) and (ii), no Default or Event
of Default shall have occurred and be continuing or occur as a consequence of
the actions or payments set forth herein.  Any Investments made other than in
cash shall be valued, in good faith, by the Board.

     (c)  Each Restricted Payment permitted pursuant to the preceding paragraph
(other than the Restricted Payment referred to in clause (ii) thereof) and the
Net Cash Proceeds from any issuance of Capital Stock referred to in clause (iii)
or (iv) shall be included in calculating whether the conditions of clause (C) of
Section 4.07(a) hereof have been met with respect to any subsequent Restricted
Payments.  In the event the proceeds of an issuance of Capital Stock of the
Company and are used for the redemption, repurchase or other acquisition of the
Notes or Indebtedness that is PARI PASSU with the Notes, then the Net Cash
Proceeds of such issuance shall be included in clause (C) of Section 4.07(a)
hereof only to the extent such proceeds are not used for such redemption,
repurchase or other acquisition of Indebtedness.

     (d)  The Board may designate any Restricted Subsidiary to be an
Unrestricted Subsidiary if such designation would not cause a Default.  For
purposes of making such determination, all outstanding Investments by the
Company and its Restricted Subsidiaries (except to the extent repaid in cash) in
the Subsidiary so designated will be deemed to be Restricted Payments at the
time of such designation and will reduce the amount available for Restricted
Payments under the first paragraph of this covenant.  All such outstanding
Investments will be deemed to constitute Investments in an amount valued in
accordance with the definition of "Investment."  Such designation will only be
permitted if such Restricted Payment would be permitted at such time and if such
Restricted Subsidiary otherwise meets the definition of an Unrestricted
Subsidiary.

SECTION 4.08.  LIMITATION ON DIVIDEND AND OTHER PAYMENT RESTRICTIONS AFFECTING
               RESTRICTED SUBSIDIARIES.

     (a)  The Company will not, and will not permit any Restricted Subsidiary
to, create or otherwise cause or suffer to exist or become effective any
consensual encumbrance or restriction of any kind on the ability of any
Restricted Subsidiary to (i) pay dividends or make other distributions permitted


                                       31
<PAGE>

by applicable law on any Capital Stock of such Restricted Subsidiary owned by
the Company or any other Restricted Subsidiary, (ii) pay any Indebtedness owed
to the Company or any other Restricted Subsidiary that owns, directly or
indirectly, any Capital Stock of such Restricted Subsidiary, (iii) make loans or
advances to the Company or any other Restricted Subsidiary that owns, directly
or indirectly, any Capital Stock of such Restricted Subsidiary or (iv) transfer
any of its property or assets to the Company or any other Restricted Subsidiary
that owns, directly or indirectly, any Capital Stock of such Restricted
Subsidiary.

     (b)  The foregoing provisions shall not prohibit any encumbrances or
restrictions:

          (i)  existing on the Issue Date in this Indenture or any other
     agreement in effect on the Issue Date, and any extension, refinancing,
     renewal or replacement of any such agreement; PROVIDED that the
     encumbrances and restrictions in any such extension, refinancing, renewal
     or replacement are no less favorable in any material respect to the holders
     than those encumbrances or restrictions that are then in effect and that
     are being extended, refinanced, renewed or replaced;

         (ii)  existing under or by reason of applicable law;

        (iii)  existing with respect to any Person or the property or assets of
     such Person acquired by the Company or any Restricted Subsidiary, at the
     time of such acquisition and not Incurred in contemplation thereof, which
     encumbrances or restrictions are not applicable to any Person or the
     property or assets of any Person other than such Person or the property or
     assets of such Person so acquired;

         (iv)  in the case of clause (iv) of Section 4.08(a) hereof, (A) that
     restrict in a customary manner the subletting, assignment or transfer of
     any property or asset that is a lease, license, conveyance or contract or
     similar property or asset, (B) existing by virtue of any transfer of,
     agreement to transfer, option or right with respect to, or Lien on, any
     property or assets of the Company or any Restricted Subsidiary, not
     otherwise prohibited hereby or (C) arising or agreed to in the ordinary
     course of business, not relating to any Indebtedness, and that do not,
     individually or in the aggregate, detract from the value of property or
     assets of the Company or any Restricted Subsidiary in any manner material
     to the Company or any Restricted Subsidiary; or

          (v)  imposed pursuant to an agreement that has been entered into for
     the sale or disposition of Capital Stock of, or property or assets of, the
     Company or a Restricted Subsidiary; PROVIDED that such encumbrance or
     restriction shall only remain in force during the pendency of such
     acquisition or disposition; or

         (vi)  imposed pursuant to agreements governing Indebtedness permitted
     to be Incurred under Sections 4.07(b)(xiii) and (xiv) hereof.

     (c)  Nothing contained in this Section 4.08 shall prevent the Company or
any Restricted Subsidiary from (a) creating, Incurring, assuming or suffering to
exist any Liens otherwise permitted in Section 4.13 hereof or (b) restricting
the sale or other disposition of property or assets of the Company


                                       32
<PAGE>

or any of its Restricted Subsidiaries that secure Indebtedness of the Company or
any of its Restricted Subsidiaries.

SECTION 4.09.  LIMITATION ON INDEBTEDNESS.

     (a)  The Company will not, and will not permit any of its Subsidiaries to,
Incur any Indebtedness (including Acquired Debt); PROVIDED that the Company may
Incur Indebtedness (including Acquired Debt) if, after giving effect to the
Incurrence of such Indebtedness and the receipt and application of the proceeds
therefrom, the Indebtedness to EBITDA Ratio would be greater than zero and less
than 5 to 1.

     (b)  The foregoing provisions will not apply to:

          (i)  Indebtedness of the Company outstanding at any time in an
     aggregate principal amount not to exceed $100.0 million, less any amount of
     Indebtedness permanently repaid as provided under Section 4.11 hereof;

         (ii)  Indebtedness of any of the Company's Restricted Subsidiaries
     owing to the Company; PROVIDED, HOWEVER, that (A) any subsequent issuance
     or transfer of Capital Stock that results in any such Indebtedness being
     held by a Person other than the Company and (B) any sale or other transfer
     of any such Indebtedness to a Person that is not the Company shall be
     deemed, in each case, to constitute an Incurrence of such Indebtedness by
     the Company;

        (iii)  Indebtedness issued in exchange for, or the net proceeds of which
     are used to refinance or refund, then outstanding Indebtedness, other than
     Indebtedness Incurred under clause (i), (ii), (v), (vi) or (viii) of this
     paragraph, and any refinancings thereof in an amount not to exceed the
     amount so refinanced or refunded (plus premiums, accrued interest, fees and
     expenses); PROVIDED that Indebtedness the proceeds of which are used to
     refinance or refund the Notes or Indebtedness that is PARI PASSU with, or
     subordinated in right of payment to, the Notes shall only be permitted
     under this clause (iii) if (A) in case the Notes are refinanced in part or
     the Indebtedness to be refinanced is PARI PASSU with the Notes, such new
     Indebtedness (by its terms or by the terms of any agreement or instrument
     pursuant to which such new Indebtedness is outstanding) is PARI PASSU with,
     or is expressly made subordinate in right of payment to, the remaining
     Notes, (B) in case the Indebtedness to be refinanced is subordinated in
     right of payment to the Notes, such new Indebtedness, by its terms or by
     the terms of any agreement or instrument pursuant to which such new
     Indebtedness is outstanding, is expressly made subordinate in right of
     payment to the Notes at least to the extent that the Indebtedness to be
     refinanced is subordinated to the Notes, and (C) such new Indebtedness,
     determined as of the date of Incurrence of such new Indebtedness, does not
     have a Stated Maturity prior to the Stated Maturity of the Indebtedness to
     be refinanced or refunded, and the Average Life of such new Indebtedness is
     at least equal to the remaining Average Life of the Indebtedness to be
     refinanced or refunded; and PROVIDED FURTHER that in no event may
     Indebtedness of the Company be refinanced by means of any Indebtedness of
     any Restricted Subsidiary of the Company pursuant to this clause (iii);

         (iv)  Indebtedness (A) in respect of performance, surety or appeal
     bonds provided in the ordinary course of business; and (B) arising from
     agreements providing for indemnification, adjustment of purchase price or
     similar obligations, or from Guarantees or letters of credit, surety


                                       33
<PAGE>

     bonds or performance bonds securing any obligations of the Company or any
     of the Restricted Subsidiaries pursuant to such agreements, in any case
     Incurred in connection with the disposition of any business, assets or
     Restricted Subsidiary of the Company (other than Guarantees of Indebtedness
     Incurred by any Person acquiring all or any portion of such business,
     assets or Restricted Subsidiary of the Company for the purpose of financing
     such acquisition), in a principal amount not to exceed the gross proceeds
     actually received by the Company or any Restricted Subsidiary in connection
     with such disposition;

          (v)  without duplication of clause (viii) hereof, Indebtedness of the
     Company not to exceed, at any one time outstanding, two TIMES an amount
     equal to (A) the aggregate proceeds (less appropriate fees and
     expenses)(which proceeds may consist of cash, Capital Stock of an entity
     that as a result of such transaction becomes a Restricted Subsidiary of the
     Company, or Telecommunications Assets which in connection with such
     transaction become held by the Company or a Restricted Subsidiary of the
     Company, and the value of which proceeds shall be the fair market value
     thereof as determined in good faith by the Board, which in all events shall
     make any appropriate adjustments on account of any Indebtedness associated
     with such Capital Stock or Telecommunications Assets in making such
     determination) received by the Company from the issuance and sale of its
     Capital Stock (other than Redeemable Stock and Preferred Stock that
     provides for the payment of dividends in cash) MINUS (B) the fair market
     value of any Directed Investments made with the proceeds of such issuances
     or sales; PROVIDED that such Indebtedness (x) does not have a Stated
     Maturity prior to the Stated Maturity of the Notes and has an Average Life
     longer than the Notes and (y) is unsecured and is expressly subordinated in
     right of payment to the Notes;

         (vi)  Indebtedness to the extent such Indebtedness is secured by Liens
     permitted under clause (xxiv) of the definition of "Permitted Liens;"

        (vii)  Indebtedness of the Company, to the extent the proceeds thereof
     are immediately used to purchase Notes tendered in an Offer to Purchase
     made as a result of a Change in Control;

       (viii)  without duplication of clause (v) hereof, Indebtedness of the
     Company Incurred in connection with the acquisition of (A) 38 GHz licenses
     or authorizations through auctions conducted by the FCC or (B) other
     licenses or authorizations through other spectrum auctions conducted by the
     FCC with respect to other frequencies approved for microwave point-to-point
     transmissions, in an amount not to exceed, at any one time outstanding, the
     greater of (1) $10.0 million and (2) an amount equal to the aggregate
     proceeds (less appropriate fees and expenses)(which proceeds may consist of
     cash, Capital Stock of an entity that as a result of such transaction
     becomes a Restricted Subsidiary of the Company, or Telecommunications
     Assets which in connection with such transaction become held by the Company
     or a Restricted Subsidiary of the Company, and the value of which proceeds
     shall be the fair market value thereof as determined in good faith by the
     Board, which in all events shall make any appropriate adjustments on
     account of any Indebtedness associated with such Capital Stock or
     Telecommunications Assets in making such determination) received by the
     Company from the issuance and sale of its Capital Stock (other than
     Redeemable Stock and Preferred Stock that provides for the payment of
     dividends in cash) MINUS the fair market value of any Directed Investments
     made with the proceeds of such issuances; PROVIDED that such Indebtedness
     (x) does not have a Stated Maturity prior to the Stated Maturity of the
     Notes and has an Average Life


                                       34
<PAGE>

     longer than the Notes and (y) is unsecured and is PARI PASSU or
     subordinated in right of payment with the Notes;

         (ix)  revolving credit Indebtedness of any Restricted Subsidiary
     Incurred pursuant to a credit facility in an aggregate amount not to
     exceed, at any one time outstanding, the greater of 62.5% and such greater
     percentage permitted pursuant to such credit facility of the accounts
     receivable net of reserves and allowances for doubtful accounts, determined
     in accordance with GAAP, of such Restricted Subsidiary and its Restricted
     Subsidiaries (without duplication); PROVIDED that such Indebtedness is not
     Guaranteed by the Company or any of its other Restricted Subsidiaries;

          (x)  the Incurrence by the Company or any of its Restricted
     Subsidiaries of Hedging Obligations that are Incurred for the purpose of
     fixing or hedging interest rate risk with respect to any floating rate
     Indebtedness of the Company or any Restricted Subsidiary, as the case may
     be, that is permitted by the terms hereof to be outstanding;

         (xi)  the Incurrence by the Company's Unrestricted Subsidiaries of Non-
     Recourse Debt, PROVIDED, HOWEVER, that if any such Indebtedness ceases to
     be Non-Recourse Debt of an Unrestricted Subsidiary, such event shall be
     deemed to constitute an Incurrence of Indebtedness by a Restricted
     Subsidiary of the Company;

        (xii)  the Incurrence by Unrestricted Subsidiaries of Indebtedness to
     the Company or any Restricted Subsidiary of the Company to the extent
     permitted by Section 4.07 hereof;

       (xiii)  Indebtedness of the Company in an aggregate amount not to exceed
     $100.0 million Incurred pursuant to the Credit Facility;

        (xiv)  Guarantees by the Company's Restricted Subsidiaries of the
     Indebtedness referred to in clause (xiii) above;

         (xv)  Indebtedness of the Company existing on the Issue Date; and

        (xvi)  Indebtedness of the Company represented by the Notes and this
     Indenture.

     (c)  For purposes of determining compliance with this Section 4.09, in the
event that an item of Indebtedness meets the criteria of more than one of the
types of Indebtedness described in the above clauses, the Company, in its sole
discretion, shall classify such item of Indebtedness and only be required to
include the amount and type of such Indebtedness in one of such clauses.

     (d)  The Company will not, and will not permit any Restricted Subsidiary
to, Incur any Guarantee of Indebtedness of any Unrestricted Subsidiary.

     (e)  Notwithstanding the foregoing, ART Licensing shall not Incur any
Indebtedness or issue any Preferred Stock; PROVIDED that ART Licensing may Incur
Indebtedness of the type and in the amount set forth in clause (xiv) of the
second paragraph of this Section_____.


                                       35
<PAGE>

SECTION 4.10.  LIMITATION ON ISSUANCES AND SALES OF CAPITAL STOCK OF WHOLLY
               OWNED RESTRICTED SUBSIDIARIES.

     The Company will not sell, and will not permit any Restricted Subsidiary,
directly or indirectly, to issue or sell any shares of Capital Stock of a
Restricted Subsidiary, other than ART Licensing (including options, warrants or
other rights to purchase shares of such Capital Stock), except (i) to the
Company or a Wholly Owned Restricted Subsidiary, (ii) issuances or sales to
foreign nationals of shares of Capital Stock of foreign Restricted Subsidiaries,
to the extent required by applicable law, (iii) if, immediately after giving
effect to such issuance or sale, such Restricted Subsidiary would no longer
constitute a Restricted Subsidiary or (iv) issuances or sales of Common Stock of
Restricted Subsidiaries, if within six months of each such issuance or sale, the
Company or such Restricted Subsidiary applies an amount not less than the Net
Cash Proceeds thereof (if any) in accordance with Section 4.11(a)(i)(A) or (B).

SECTION 4.11.  DISPOSITION OF PROCEEDS OF ASSET SALES.

     (a)  The Company will not, and will not permit any Restricted Subsidiary
to, consummate any Asset Sale, unless (a) the consideration received by the
Company or such Restricted Subsidiary is at least equal to the fair market value
of the assets sold or disposed of and (b) at least 85% of the consideration
received consists of cash or Temporary Cash Investments, PROVIDED that any notes
or other obligations received by the Company or any such Restricted Subsidiary
as consideration that are converted by the Company or such Restricted Subsidiary
into cash within 30 days of their receipt (to the extent of the cash received),
shall be deemed to be cash for purposes of this provision.  In the event and to
the extent that the Net Cash Proceeds received by the Company or its Restricted
Subsidiaries from one or more Asset Sales occurring on or after the Issue Date
in any period of 12 consecutive months exceed 10% of Adjusted Consolidated Net
Tangible Assets (determined as of the date closest to the commencement of such
12-month period for which a consolidated balance sheet of the Company and its
Restricted Subsidiaries has been prepared), then the Company shall, or shall
cause the relevant Restricted Subsidiary to, (i) within six months after the
date Net Cash Proceeds so received exceed 10% of Adjusted Consolidated Net
Tangible Assets (A) apply an amount equal to such excess Net Cash Proceeds to
permanently repay unsubordinated Indebtedness of the Company or any of its
Restricted Subsidiaries owing to a Person other than the Company or any of its
Restricted Subsidiaries or (B) invest an equal amount, or the amount not so
applied pursuant to clause (A) (or enter into a definitive agreement committing
to so invest within six months after the date of such agreement), in property or
assets of a nature or type or that are used in a business (or in a company
having property and assets of a nature or type, or engaged in a business)
similar or related to the nature or type of the property and assets of, or the
business of, the Company and its Restricted Subsidiaries existing on the date of
such Investment (as determined in good faith by the Board, whose determination
shall be conclusive and evidenced by a resolution of the Board and (ii) apply
(no later than the end of the six-month period referred to in clause (i)) such
excess Net Cash Proceeds (to the extent not applied pursuant to clause (i)) as
provided in the following paragraph of this Section 4.11.  The amount of such
excess Net Cash Proceeds required to be applied (or to be committed to be
applied) during such six-month period as set forth in clause (i) of the
preceding sentence and not applied as so required by the end of such period
shall constitute "Excess Proceeds."

     (b)  If, as of the first day of any calendar month, the aggregate amount of
Excess Proceeds not theretofore subject to an Offer to Purchase pursuant to this
Section 4.11 totals at least $5.0 million,


                                       36
<PAGE>

the Company must commence, not later than the fifteenth business day of such
month, and consummate an Offer to Purchase from the holders on a pro rata basis
an aggregate principal amount of Notes equal to the Excess Proceeds on such
date, at a purchase price equal to (i) 101% of the Accreted Value thereof
(determined at the date of purchase), if such purchase is prior to            ,
2001, or (ii) 101% of the principal amount at maturity thereof, plus accrued and
unpaid interest, if any, to the date of purchase, if such purchase is on or
after         , 2001.

SECTION 4.12.  LIMITATION ON TRANSACTIONS WITH AFFILIATES.

     The Company will not, and will not permit any of its Restricted
Subsidiaries to, sell, lease, transfer or otherwise dispose of any of its
properties or assets to, or purchase any property or assets from, or enter into
or make any contract, agreement, loan, advance or Guarantee with, or any
contract, agreement, loan, advance or Guarantee for the specific benefit of, any
Affiliate (each of the foregoing, an "AFFILIATE TRANSACTION"), unless (i) such
Affiliate Transaction is on terms that are no less favorable to the Company or
the relevant Restricted Subsidiary than those that would have been obtained in a
comparable transaction by the Company or such Restricted Subsidiary with an
unrelated Person and (ii) the Company delivers to the Trustee (A) with respect
to any Affiliate Transaction involving aggregate consideration in excess of $1.0
million, a resolution of the Board of Directors set forth in an Officers'
Certificate certifying that such Affiliate Transaction complies with clause (A)
above and that such Affiliate Transaction has been approved by a majority of the
disinterested members of the Board of Directors and (B) with respect to any
Affiliate Transaction involving aggregate consideration in excess of $5.0
million, a written opinion, appraisal or certification from a nationally
recognized professional experienced in evaluating similar types of transactions
stating that the terms of such transaction are fair to the Company or such
Restricted Subsidiary, as the case may be, from a financial point of view;
PROVIDED that the following shall not be deemed to constitute Affiliate
Transactions:

          (i)  the payment of reasonable fees to directors of the Company who
     are not employees of the Company;

         (ii)  agreements and arrangements existing on the date hereof;

        (iii)  any employment agreement entered into by the Company or any of
     its Restricted Subsidiaries in the ordinary course of business of the
     Company or such Restricted Subsidiary;

         (iv)  the adoption of employee benefit plans in the ordinary course of
     business and payments and other transactions thereunder; PROVIDED that any
     such adoption, payment or other transaction shall have been approved by a
     majority of the disinterested members of the Board;

          (v)  transactions between or among the Company and/or its Wholly Owned
     Restricted Subsidiaries;

         (vi)  any contract, agreement, loan, advance or Guarantee for the
     general benefit of the Company and its stockholders, including stockholders
     that are Affiliates of the Company; and

        (vii)  any Affiliate Transactions permitted by the provisions of Section
     4.07 hereof.


                                       37
<PAGE>

SECTION 4.13.  LIMITATION ON LIENS SECURING CERTAIN INDEBTEDNESS.

     The Company will not, and will not permit any Subsidiary to, create, Incur,
assume or suffer to exist any Lien, other than Permitted Liens, on any of its
assets or properties of any character, or any shares of Capital Stock or
Indebtedness of any Subsidiary, without making effective provision for all of
the Notes and all other amounts due hereunder to be directly secured equally and
ratably with (or, if the obligation or liability to be secured by such Lien is
subordinated in right of payment to the Notes prior to) the obligation or
liability secured by such Lien.

SECTION 4.14.  CORPORATE EXISTENCE.

     Subject to Article 5, the Company shall do or cause to be done all things
necessary to preserve and keep in full force and effect (i) its existence as a
corporation, and the corporate, partnership or other existence of any
Subsidiary, in accordance with the respective organizational documents (as the
same may be amended from time to time) of the Company or any such Subsidiary and
(ii) the rights (charter and statutory), licenses and franchises of the Company
and its Subsidiaries; PROVIDED, HOWEVER, that the Company shall not be required
to preserve any such right, license or franchise, or the corporate, partnership
or other existence of any of its Subsidiaries if the Board of Directors of the
Company shall determine that the preservation thereof is no longer desirable in
the conduct of the business of the Company and its Subsidiaries, taken as a
whole, and that the loss thereof is not adverse in any material respect to the
Holders of the Notes.

SECTION 4.15.  CHANGE OF CONTROL.

     In the event of a Change in Control, the Company must commence and
consummate an Offer to Purchase for all the Notes then outstanding, at a
purchase price equal to (i) 101% of the Accreted Value thereof, in the case of
any such purchase prior to           , 2001, or (ii) 101% of the principal
amount at maturity thereof, together with accrued and unpaid interest, if any,
to the date of purchase, in the case of any such purchase on or after
, 2001.  Not later than 20 days following any Change in Control, the Company
will mail a notice to each holder describing the transaction or transactions
that constitute the Change in Control and offering to repurchase Notes pursuant
to the procedures required by this Indenture and described in such notice.

SECTION 4.16.  BUSINESS ACTIVITIES OF THE COMPANY.

     (a)  The Company will not, and will not permit any Restricted Subsidiary
to, engage in (i) any business other than the Telecommunications Business and
such business activities as are incidental or related thereto and (ii) any
business, activities or services in which the Company and its Restricted
Subsidiaries were engaged on the Issue Date.  In addition, the Company will (i)
at such time and to the extent permitted by the FCC, transfer, or cause to be
transferred, all FCC licenses and authorizations of the Company and its
Restricted Subsidiaries to ART Licensing and (ii) cause ART Licensing to remain
a Wholly Owned Restricted Subsidiary of the Company.

     (b)  Notwithstanding the foregoing, to the extent permitted by the FCC, the
Company will not permit ART Licensing to engage in any business or activity,
other than the application for, acquisition of or ownership of FCC licenses and
authorizations.


                                       38
<PAGE>

SECTION 4.17.  NO AMENDMENT TO AGREEMENT.

     The Company will not amend, modify or alter the Voting Trust Agreement
without having obtained the consent of the holders of not less than a majority
in principal amount at maturity of the Notes then outstanding.


                                    ARTICLE 5
                                   SUCCESSORS

SECTION 5.01.  CONSOLIDATION, MERGER, SALE OF ASSETS, ETC.

     (a)  The Company shall not consolidate with, merge with or into, or sell,
convey, transfer, lease or otherwise dispose of all or substantially all of its
property and assets (as an entirety or substantially an entirety in one
transaction or a series of related transactions) to, any Person (other than a
consolidation or merger with or into a Wholly Owned Restricted Subsidiary with a
positive net worth; PROVIDED that, in connection with any such merger or
consolidation, no consideration (other than Common Stock in the surviving Person
or the Company) shall be issued or distributed to the stockholders of the
Company) or permit any Person to merge with or into the Company unless:  (i) the
Company shall be the continuing Person, or the Person (if other than the
Company) formed by such consolidation or into which the Company is merged or
that acquired or leased such property and assets of the Company shall be a
corporation organized and validly existing under the laws of the United States
of America or any jurisdiction thereof and shall expressly assume, by a
supplemental indenture, executed and delivered to the Trustee, all of the
obligations of the Company on all of the Notes and under this Indenture;
(ii) immediately after giving effect to such transaction, no Default or Event of
Default shall have occurred and be continuing; (iii) immediately after giving
effect to such transaction on a pro forma basis, the Indebtedness to Total
Market Capitalization Ratio (determined as of a date no earlier than 10 days
prior to such transaction) of the Company, or any person becoming the successor
obligor of the Notes, would be no greater than 130% of the Indebtedness to Total
Market Capitalization Ratio of the Company immediately prior to giving effect to
such transaction; PROVIDED that this clause (iii) shall not apply to any
transaction or series of transactions effected solely for the purpose of
creating a parent corporation of which the Company shall be a Wholly Owned
Subsidiary and whose stockholders shall be identical (without regard to the
exercise of options or warrants, or securities convertible or exchangeable into
shares of Common Stock) to those of the Company immediately prior thereto; and
(iv) the Company delivers to the Trustee an Officers' Certificate (attaching the
arithmetic computations to demonstrate compliance with clause (iii)) and an
Opinion of Counsel, in each case, stating that such consolidation, merger or
transfer and such supplemental indenture complies with this provision and that
all conditions precedent provided for herein relating to such transaction have
been complied with; PROVIDED, HOWEVER, that clause (iii) above does not apply
if, in the good faith determination of the Board, whose determination shall be
evidenced by a resolution of the Board, the principal purpose of such
transaction is to change the state of incorporation of the Company; and PROVIDED
FURTHER that any such transaction shall not have as one of its purposes the
evasion of the foregoing limitations.

     (b)  The Company shall deliver to the Trustee prior to such transaction an
Officers' Certificate covering clauses (i) through (v) of Section 5.01(a)
hereof, stating that such transaction and such supplemental indenture comply
with this Indenture, and an Opinion of Counsel covering paragraphs (i), (ii) and
(v) of the foregoing paragraph.


                                       39
<PAGE>

SECTION 5.02.  SUCCESSOR CORPORATION SUBSTITUTED.

     Upon any consolidation or merger, or any sale, lease, conveyance or other
disposition of all or substantially all of the assets of the Company in
accordance with Section 5.01, the successor corporation formed by such
consolidation or into or with which the Company is merged or to which such sale,
lease, conveyance or other disposition is made shall succeed to, and be
substituted for (so that from and after the date of such consolidation, merger,
sale, lease, conveyance or other disposition, the provisions of this Indenture
referring to the Company shall refer instead to the successor corporation and
not to the Company), and may exercise every right and power of the Company under
this Indenture with the same effect as if such successor Person has been named
as the Company, herein; PROVIDED, HOWEVER, that the predecessor Company shall
not be relieved from the obligations to pay the principal of and interest on the
Notes, except in the case of a sale of all of the Company's assets that meets
the requirements of Section 5.01 hereof.


                                    ARTICLE 6
                              DEFAULTS AND REMEDIES

SECTION 6.01.  EVENTS OF DEFAULT.

     Each of the following constitutes an "EVENT OF DEFAULT":

          (a)  default in the payment of interest on the Notes when it becomes
     due and payable, and continuance of such default for a period of 30 days or
     more; or

          (b)  default in the payment of principal of, or premium, if any, on
     the Notes when due; or

          (c)  default in the performance, or breach, of any covenant described
     under Sections 4.07, 4.08, 4.11 and 4.15 and Article 5 hereof; or

          (d)  default in the performance, or breach, of any covenant in this
     Indenture (other than defaults specified in clause (a), (b) or (c) above),
     and the continuance of such default or breach for a period of 30 days or
     more after written notice to the Company by the Trustee or to the Company
     and the Trustee by the holders of at least 25% in aggregate principal
     amount at maturity of the outstanding Notes (in each case, when such notice
     is deemed received in accordance with this Indenture); or

          (e)  default under any mortgage, indenture or instrument under which
     there may be issued or by which there may be secured or evidenced any
     Indebtedness for money borrowed by the Company or any of its Restricted
     Subsidiaries (or the payment of which is Guaranteed by the Company or any
     of its Restricted Subsidiaries) whether such Indebtedness or Guarantee now
     exists, or is created after the Issue Date, which default (i) is caused by
     a failure to pay principal of or premium, if any, or interest on such
     Indebtedness prior to the expiration of the grace period provided in such
     Indebtedness on the date of such default (a "PAYMENT DEFAULT") or
     (ii) results in the acceleration of such Indebtedness prior to its express
     maturity and, in each case, the principal amount of any such Indebtedness,
     together with the principal amount of any other such


                                       40
<PAGE>

     Indebtedness under which there has been a Payment Default, or the maturity
     of which has been so accelerated, aggregates $5.0 million or more; or

          (f)  any final judgment or order (not covered by insurance) for the
     payment of money in excess of $5.0 million in the aggregate for all such
     final judgments or orders against all such Persons (treating any
     deductibles, self-insurance or retention as not so covered) shall be
     rendered against the Company or any Significant Subsidiary and shall not be
     paid or discharged, and there shall be any period of 60 consecutive days
     following entry of the final judgment or order that causes the aggregate
     amount for all such final judgments or orders outstanding and not paid or
     discharged against all such Persons to exceed $5.0 million during which a
     stay of enforcement of such final judgment or order, by reason of a pending
     appeal or otherwise, shall not be in effect; or

          (g)  a court having jurisdiction in the premises enters a decree or
     order for (i) relief in respect of the Company or any Significant
     Subsidiary in an involuntary case under any applicable bankruptcy,
     insolvency or other similar law now or hereafter in effect, (ii) the
     appointment of a receiver, liquidator, assignee, custodian, trustee,
     sequestrator or similar official of the Company or any Significant
     Subsidiary or for all or substantially all of the property and assets of
     the Company or any Significant Subsidiary or (iii) the winding up or
     liquidation of the affairs of the Company or any Significant Subsidiary
     and, in each case, such decree or order shall remain unstayed and in effect
     for a period of 60 consecutive days; or

          (h)  the Company or any Significant Subsidiary (i) commences a
     voluntary case under any applicable bankruptcy, insolvency or other similar
     law now or hereafter in effect, or consents to the entry of an order for
     relief in an involuntary case under any such law, (ii) consents to the
     appointment of or taking possession by a receiver, liquidator, assignee,
     custodian, trustee, sequestrator or similar official of the Company or any
     Significant Subsidiary or for all or substantially all of the property and
     assets of the Company or any Significant Subsidiary or (iii) effects any
     general assignment for the benefit of creditors.

     The term "CUSTODIAN" means any receiver, trustee, assignee, liquidator or
similar official under any Bankruptcy Law.

SECTION 6.02.  ACCELERATION.

     If any Event of Default (other than an Event of Default specified in clause
(vii) or (viii) above with respect to the Company) occurs and is continuing,
then the Trustee or the holders of at least 25% in principal amount at maturity
of outstanding Notes may, by written notice, and the Trustee upon the request of
the holders of not less than 25% in principal amount at maturity of the
outstanding Notes shall, declare the Default Amount of, and any accrued and
unpaid interest on, all outstanding Notes to be immediately due and payable and
upon any such declaration such amounts shall become immediately due and payable.
If an Event of Default specified in clause (vii) or (viii) above with respect to
the Company occurs and is continuing, then the Default Amount of, and any
accrued and unpaid interest on, all outstanding Notes shall IPSO FACTO become
and be immediately due and payable without any declaration or other act on the
part of the Trustee or any holder.


                                       41
<PAGE>

     After a declaration of acceleration, the holders of a majority in aggregate
principal amount at maturity of outstanding Notes may, by notice to the Trustee,
rescind such declaration of acceleration if all existing Events of Default,
other than nonpayment of the Default Amount of, and any accrued and unpaid
interest on, the Notes that has become due solely as a result of such
acceleration, have been cured or waived and if the rescission of acceleration
would not conflict with any judgment or decree.  The holders of a majority in
principal amount at maturity of the outstanding Notes also have the right to
waive past defaults under this Indenture, except a default in the payment of the
Default Amount of, or any interest on, any outstanding Note, or in respect of a
covenant or a provision that cannot be modified or amended without the consent
of all holders of Notes.

     In the case of any Event of Default occurring by reason of any willful
action (or inaction) taken (or not taken) by or on behalf of the Company with
the intention of avoiding payment of the premium that the Company would have had
to pay if the Company then had elected to redeem the Notes pursuant to Section
3.07, an equivalent premium shall also become and be immediately due and payable
to the extent permitted by law.  If an Event of Default occurs prior to _______,
1999 by reason of any willful action (or inaction) taken (or not taken) by or on
behalf of the Company with the intention of avoiding the prohibition on
redemption of the Notes prior to such date pursuant to Section 3.07, then the
premium payable for purposes of this paragraph for each of the years beginning
on _______ of the years set forth below shall be as set forth in the following
table, expressed as a percentage of the amount that would otherwise be due but
for the provisions of this paragraph, plus accrued interest, if any, to the date
of payment:

          Year                                    Percentage
          ----                                    ----------

          1994 . . . . . . . . . . . . . . . . . . _______%
          1995 . . . . . . . . . . . . . . . . . . _______%
          1996 . . . . . . . . . . . . . . . . . . _______%
          1997 . . . . . . . . . . . . . . . . . . _______%
          1998 . . . . . . . . . . . . . . . . . . _______%

SECTION 6.03.  OTHER REMEDIES.

     If an Event of Default occurs and is continuing, the Trustee may pursue any
available remedy to collect the payment of principal, premium, if any, and
interest on the Notes or to enforce the performance of any provision of the
Notes or this Indenture.

     The Trustee may maintain a proceeding even if it does not possess any of
the Notes or does not produce any of them in the proceeding.  A delay or
omission by the Trustee or any Holder of a Note in exercising any right or
remedy accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default.  All remedies
are cumulative to the extent permitted by law.

SECTION 6.04.  WAIVER OF PAST DEFAULTS.

     Holders of not less than a majority in aggregate principal amount of the
then outstanding Notes by written notice to the Trustee may, on behalf of the
Holders of all of the Notes, waive an existing Default or Event of Default and
its consequences, except a continuing Default or Event of Default in the


                                       42
<PAGE>

payment of the principal of, premium, if any, or interest on, the Notes.  Upon
any such waiver, such Default shall cease to exist, and any Event of Default
arising therefrom shall be deemed to have been cured for every purpose of this
Indenture; but no such waiver shall extend to any subsequent or other Default or
impair any right consequent thereon.

SECTION 6.05.  CONTROL BY MAJORITY.

     Holders of a majority in principal amount of the then outstanding Notes may
direct the time, method and place of conducting any proceeding for exercising
any remedy available to the Trustee or exercising any trust or power conferred
on it.  However, the Trustee may refuse to follow any direction that conflicts
with the law or this Indenture or that the Trustee determines may be unduly
prejudicial to the rights of other Holders of Notes or that may involve the
Trustee in Personal liability.

SECTION 6.06.  LIMITATION ON SUITS.

     A Holder of a Note may pursue a remedy with respect to this Indenture or
the Notes only if: (a) the Holder of a Note gives to the Trustee written notice
of a continuing Event of Default; (b) the Holders of at least 25% in principal
amount of the then outstanding Notes make a written request to the Trustee to
pursue the remedy; (c) such Holder of a Note or Holders of Notes offer and, if
requested, provide to the Trustee indemnity satisfactory to the Trustee against
any loss, liability or expense; (d) the Trustee does not comply with the request
within 60 days after receipt of the request and the offer and, if requested, the
provision of indemnity; and (e) during such 60-day period the Holders of a
majority in principal amount of the then outstanding Notes do not give the
Trustee a direction inconsistent with the request.

     A Holder of a Note may not use this Indenture to prejudice the rights of
another Holder of a Note or to obtain a preference or priority over another
Holder of a Note.

SECTION 6.07.  RIGHTS OF HOLDERS OF NOTES TO RECEIVE PAYMENT.

     Notwithstanding any other provision of this Indenture, the right of any
Holder of a Note to receive payment of principal, premium, if any, and interest
on the Note, on or after the respective due dates expressed in the Note, or to
bring suit for the enforcement of any such payment on or after such respective
dates, shall not be impaired or affected without the consent of the Holder of
the Note.

SECTION 6.08.  COLLECTION SUIT BY TRUSTEE.

     Subject to Section 6.02 hereof, if an Event of Default specified in
Section 6.01(a) or (b) occurs and is continuing, the Trustee is authorized to
recover judgment in its own name and as trustee of an express trust against the
Company for the whole amount of principal of, premium, if any, and interest
remaining unpaid on the Notes and interest on overdue principal and, to the
extent lawful, interest and such further amount as shall be sufficient to cover
the costs and expenses of collection, including the reasonable compensation,
expenses, disbursements and advances of the Trustee, its agents and counsel.


                                       43
<PAGE>

SECTION 6.09.  TRUSTEE MAY FILE PROOFS OF CLAIM.

     The Trustee is authorized to file such proofs of claim and other papers or
documents as may be necessary or advisable in order to have the claims of the
Trustee (including any claim for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel) and the
Holders of the Notes allowed in any judicial proceedings relative to the Company
(or any other obligor upon the Notes), the Company's creditors or the Company's
property and shall be entitled and empowered to collect, receive and distribute
any money or other property payable or deliverable on any such claims and any
custodian in any such judicial proceeding is hereby authorized by each Holder of
a Note to make such payments to the Trustee, and in the event that the Trustee
shall consent to the making of such payments directly to the Holders of the
Notes, to pay to the Trustee any amount due to it for the reasonable
compensation, expenses, disbursements and advances of the Trustee, its agents
and counsel, and any other amounts due the Trustee under Section 7.07.  To the
extent that the payment of any such compensation, expenses, disbursements and
advances of the Trustee, its agents and counsel, and any other amounts due the
Trustee under Section 7.07 out of the estate in any such proceeding, shall be
denied for any reason, payment of the same shall be secured by a Lien on, and
shall be paid out of, any and all distributions, dividends, money, securities
and other properties which the Holders of the Notes may be entitled to receive
in such proceeding whether in liquidation or under any plan of reorganization or
arrangement or otherwise.  Nothing contained herein shall be deemed to authorize
the Trustee to authorize or consent to or accept or adopt on behalf of any
Holder of a Note any plan of reorganization, arrangement, adjustment or
composition affecting the Notes or the rights of any Holder of a Note thereof,
or to authorize the Trustee to vote in respect of the claim of any Holder of a
Note in any such proceeding.

SECTION 6.10.  PRIORITIES.

     If the Trustee collects any money pursuant to this Article, it shall pay
out the money in the following order:

          FIRST:  to the Trustee, its agents and attorneys for amounts due under
     Section 7.07, including payment of all compensation, expense and
     liabilities incurred, and all advances made, by the Trustee and the costs
     and expenses of collection;

          SECOND:  (i) first to Holders of Notes, for amounts due and unpaid on
     such Notes for principal, premium, if any, and interest, ratably, without
     preference or priority of any kind according to the amounts due and payable
     on the Notes for principal, premium, if any, and interest, respectively,
     and (ii) second, to the extent any other monies are available, to Holders
     of all Notes for amounts due and unpaid on all such Notes for principal,
     premium, if any, and interest, ratably, without preference or priority of
     any kind, according to the amounts due and payable on the Notes; and

          THIRD:  to the Company or to such party as a court of competent
     jurisdiction shall direct.

     The Trustee may fix a record date and payment date for any payment to
Holders of Notes.


                                       44
<PAGE>

SECTION 6.11.  UNDERTAKING FOR COSTS.

     In any suit for the enforcement of any right or remedy under this Indenture
or in any suit against the Trustee for any action taken or omitted by it as a
Trustee, a court in its discretion may require the filing by any party litigant
in the suit of an undertaking to pay the costs of the suit, and the court in its
discretion may assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in the suit, having due regard to the merits and good
faith of the claims or defenses made by the party litigant.  This Section does
not apply to a suit by the Trustee, a suit by a Holder of a Note pursuant to
Section 6.07, or a suit by Holders of more than 10% in principal amount of the
then outstanding Notes.


                                    ARTICLE 7
                                     TRUSTEE

SECTION 7.01.  DUTIES OF TRUSTEE.

     (a)  If an Event of Default has occurred and is continuing, the Trustee
shall exercise such of the rights and powers vested in it by this Indenture, and
use the same degree of care and skill in their exercise, as a prudent man would
exercise or use under the circumstances in the conduct of his own affairs.

     (b)  Except during the continuance of an Event of Default:

          (i)  the duties of the Trustee shall be determined solely by the
     express provisions of this Indenture and the Trustee need perform only
     those duties that are specifically set forth in this Indenture and no
     others, and no implied covenants or obligations shall be read into this
     Indenture against the Trustee, and

          (ii) in the absence of bad faith on its part, the Trustee may
     conclusively rely, as to the truth of the statements and the correctness of
     the opinions expressed therein, upon certificates or opinions furnished to
     the Trustee and conforming to the requirements of this Indenture.  However,
     the Trustee shall examine the certificates and opinions to determine
     whether or not they conform to the requirements of this Indenture.

     (c)  The Trustee may not be relieved from liabilities for its own negligent
action, its own negligent failure to act, or its own willful misconduct, except
that: (i) this paragraph does not limit the effect of paragraph (b) of this
Section; (ii) the Trustee shall not be liable for any error of judgment made in
good faith by a Responsible Officer, unless it is proved that the Trustee was
negligent in ascertaining the pertinent facts; and (iii) the Trustee shall not
be liable with respect to any action it takes or omits to take in good faith in
accordance with a direction received by it pursuant to Section 6.05.

     (d)  Whether or not therein expressly so provided, every provision of this
Indenture that in any way relates to the Trustee is subject to paragraphs (a),
(b), and (c) of this Section.

     (e)  No provision of this Indenture shall require the Trustee to expend or
risk its own funds or incur any liability.  The Trustee shall be under no
obligation to exercise any of its rights and powers


                                       45
<PAGE>

under this Indenture at the request of any Holder of Notes, unless such Holder
shall have offered to the Trustee security and indemnity satisfactory to the
Trustee against any loss, liability or expense.

     (f)  The Trustee shall not be liable for interest on any money received by
it except as the Trustee may agree in writing with the Company.  Money held in
trust by the Trustee need not be segregated from other funds except to the
extent required by law.

SECTION 7.02.  RIGHTS OF TRUSTEE.

     (a)  The Trustee may conclusively rely upon any document believed by it to
be genuine and to have been signed or presented by the proper Person.  The
Trustee need not investigate any fact or matter stated in the document.

     (b)  Before the Trustee acts or refrains from acting, it may require an
Officers' Certificate or an Opinion of Counsel or both.  The Trustee shall not
be liable for any action it takes or omits to take in good faith in reliance on
such Officers' Certificate or Opinion of Counsel.  The Trustee may consult with
counsel and the advice of such counsel or any Opinion of Counsel shall be full
and complete authorization and protection from liability in respect of any
action taken, suffered or omitted by it hereunder in good faith and in reliance
thereon.

     (c)  The Trustee may act through its attorneys and agents and shall not be
responsible for the misconduct or negligence of any agent appointed with due
care.

     (d)  The Trustee shall not be liable for any action it takes or omits to
take in good faith which it believes to be authorized or within its rights or
powers conferred upon it by this Indenture.

     (e)  Unless otherwise specifically provided in this Indenture, any demand,
request, direction or notice from the Company shall be sufficient if signed by
an Officer of the Company.

     (f)  The Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request or direction of any of
the Holders unless such Holders shall have offered to the Trustee reasonable
security or indemnity against the costs, expenses and liabilities that might be
incurred by it in compliance with such request or direction.

SECTION 7.03.  INDIVIDUAL RIGHTS OF TRUSTEE.

     The Trustee in its individual or any other capacity may become the owner or
pledgee of Notes and may otherwise deal with the Company or any Affiliate of the
Company with the same rights it would have if it were not Trustee.  However, in
the event that the Trustee acquires any conflicting interest it must eliminate
such conflict within 90 days, apply to the Commission for permission to continue
as trustee or resign.  Any Agent may do the same with like rights and duties.
The Trustee is also subject to Sections 7.10 and 7.11.

SECTION 7.04.  TRUSTEE'S DISCLAIMER.

     The Trustee shall not be responsible for and makes no representation as to
the validity or adequacy of this Indenture or the Notes, it shall not be
accountable for the Company's use of the proceeds


                                       46
<PAGE>

from the Notes or any money paid to the Company or upon the Company's direction
under any provision of this Indenture, it shall not be responsible for the use
or application of any money received by any Paying Agent other than the Trustee,
and it shall not be responsible for any statement or recital herein or any
statement in the Notes or any other document in connection with the sale of the
Notes or pursuant to this Indenture other than its certificate of
authentication.

SECTION 7.05.  NOTICE OF DEFAULTS.

     If a Default or Event of Default occurs and is continuing and if it is
known to a Responsible Officer of the Trustee, the Trustee shall mail to Holders
of Notes a notice of the Default or Event of Default within 90 days after it
occurs.  Except in the case of a Default or Event of Default in payment of
principal of, premium, if any, or interest on any Note, the Trustee may withhold
the notice if and so long as a committee of its Responsible Officers in good
faith determines that withholding the notice is in the interests of the Holders
of the Notes.

SECTION 7.06.  REPORTS BY TRUSTEE TO HOLDERS OF THE NOTES.

     Within 60 days after each May 15 beginning with the May 15 following the
date of this Indenture, the Trustee shall mail to the Holders of the Notes a
brief report dated as of such reporting date that complies with TIA Section
313(a) (but if no event described in TIA Section 313(a) has occurred within the
twelve months preceding the reporting date, no report need be transmitted).  The
Trustee also shall comply with TIA Section 313(b)(2).  The Trustee shall also
transmit by mail all reports as required by TIA Section 313(c).

     A copy of each report at the time of its mailing to the Holders of Notes
shall be mailed to the Company and filed with the Commission and each stock
exchange on which the Notes are listed.  The Company shall promptly notify the
Trustee when the Notes are listed on any stock exchange.

SECTION 7.07.  COMPENSATION AND INDEMNITY.

     The Company shall pay to the Trustee from time to time reasonable
compensation for its acceptance of this Indenture and services hereunder.  The
Trustee's compensation shall not be limited by any law on compensation of a
trustee of an express trust.  The Company shall reimburse the Trustee promptly
upon request for all reasonable disbursements, advances and expenses incurred or
made by it in addition to the compensation for its services.  Such expenses
shall include the reasonable compensation, disbursements and expenses of the
Trustee's agents and counsel.

     The Company shall indemnify the Trustee against any and all losses,
liabilities or expenses incurred by it arising out of or in connection with the
acceptance or administration of its duties under this Indenture, except any such
loss, liability or expense as may be attributable to the negligence or bad faith
of the Trustee.  The Trustee shall notify the Company promptly of any claim for
which it may seek indemnity.  Failure by the Trustee to so notify the Company
shall not relieve the Company of its obligations hereunder.  The Company shall
defend the claim and the Trustee shall cooperate in the defense.  The Trustee
may have separate counsel and the Company shall pay the reasonable fees and
expenses of such counsel.  The Company need not pay for any settlement made
without its consent, which consent shall not be unreasonably withheld.


                                       47
<PAGE>


     The obligations of the Company under this Section 7.07 shall survive the
satisfaction and discharge of this Indenture.

     To secure the Company' payment obligations in this Section, the Trustee
shall have a Lien prior to the Notes on all money or property held or collected
by the Trustee, except that held in trust to pay principal, premium, if any, and
interest on particular Notes.  Such Lien shall survive the satisfaction and
discharge of this Indenture.

     When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 6.01(g) or (h) occurs, the expenses and the
compensation for the services (including the fees and expenses of its agents and
counsel) are intended to constitute expenses of administration under any
Bankruptcy Law.

SECTION 7.08.  REPLACEMENT OF TRUSTEE.

     A resignation or removal of the Trustee and appointment of a successor
Trustee shall become effective only upon the successor Trustee's acceptance of
appointment as provided in this Section.

     The Trustee may resign in writing at any time and be discharged from the
trust hereby created by so notifying the Company.  The Holders of Notes of a
majority in principal amount of the then outstanding Notes may remove the
Trustee by so notifying the Trustee and the Company in writing.  The Company may
remove the Trustee if: (a) the Trustee fails to comply with Section 7.10; (b)
the Trustee is adjudged a bankrupt or an insolvent or an order for relief is
entered with respect to the Trustee under any Bankruptcy Law; (c) a Custodian or
public officer takes charge of the Trustee or its property; or (d) the Trustee
becomes incapable of acting.

     If the Trustee resigns or is removed or if a vacancy exists in the office
of Trustee for any reason, the Company shall promptly appoint a successor
Trustee.  Within one year after the successor Trustee takes office, the Holders
of a majority in principal amount of the then outstanding Notes may appoint a
successor Trustee to replace the successor Trustee appointed by the Company.

     If a successor Trustee does not take office within 60 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company, or
the Holders of Notes of at least 10% in principal amount of the then outstanding
Notes may petition any court of competent jurisdiction for the appointment of a
successor Trustee.

     If the Trustee after written request by any Holder of a Note who has been a
Holder of a Note for at least six months fails to comply with Section 7.10, such
Holder of a Note may petition any court of competent jurisdiction for the
removal of the Trustee and the appointment of a successor Trustee.

     A successor Trustee shall deliver a written acceptance of its appointment
to the retiring Trustee and to the Company.  Thereupon, the resignation or
removal of the retiring Trustee shall become effective, and the successor
Trustee shall have all the rights, powers and duties of the Trustee under this
Indenture.  The successor Trustee shall mail a notice of its succession to
Holders of the Notes.  The retiring Trustee shall promptly transfer all property
held by it as Trustee to the successor Trustee, provided all sums owing to the
Trustee hereunder have been paid and subject to the Lien provided for


                                       48
<PAGE>

in Section 7.07.  Notwithstanding replacement of the Trustee pursuant to this
Section 7.08, the Company's obligations under Section 7.07 shall continue for
the benefit of the retiring Trustee.

SECTION 7.09.  SUCCESSOR TRUSTEE BY MERGER, ETC.

     If the Trustee consolidates, merges or converts into, or transfers all or
substantially all of its corporate trust business to, another corporation, the
successor corporation without any further act shall be the successor Trustee.

SECTION 7.10.  ELIGIBILITY; DISQUALIFICATION.

     There shall at all times be a Trustee hereunder which shall be a
corporation organized and doing business under the laws of the United States of
America or of any state thereof authorized under such laws to exercise corporate
trustee power, shall be subject to supervision or examination by federal or
state authority and shall have a combined capital and surplus of at least $25
million as set forth in its most recent published annual report of condition.

     This Indenture shall always have a Trustee who satisfies the requirements
of TIA Section 310(a)(1), (2) and (5).  The Trustee is subject to TIA Section
310(b).

SECTION 7.11.  PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.

     The Trustee is subject to TIA Section 311(a), excluding any creditor
relationship listed in TIA Section 311(b).  A Trustee who has resigned or been
removed shall be subject to TIA Section 311(a) to the extent indicated therein.


                                    ARTICLE 8
                    LEGAL DEFEASANCE AND COVENANT DEFEASANCE

SECTION 8.01.  OPTION TO EFFECT LEGAL DEFEASANCE OR COVENANT DEFEASANCE.

     The Company may, at the option of its Board of Directors evidenced by a
resolution set forth in an Officers' Certificate, at any time, with respect to
the Notes, elect to have either Section 8.02 or 8.03 be applied to all
outstanding Notes upon compliance with the conditions set forth below in this
Article Eight.

SECTION 8.02.  LEGAL DEFEASANCE AND DISCHARGE.

     Upon the Company's exercise under Section 8.01 of the option applicable to
this Section 8.02, the Company shall be deemed to have been discharged from its
obligations with respect to all outstanding Notes on the date the conditions set
forth below are satisfied (hereinafter, "LEGAL DEFEASANCE").  For this purpose,
such Legal Defeasance means that the Company shall be deemed to have paid and
discharged the entire Indebtedness represented by the outstanding Notes, which
shall thereafter be deemed to be "outstanding" only for the purposes of
Section 8.05 and the other Sections of this Indenture referred to in (a) and (b)
below, and to have satisfied all of its other obligations under such Notes and
this Indenture (and the Trustee, on demand of and at the expense of the Company,
shall execute proper instruments


                                       49
<PAGE>

acknowledging the same), except for the following which shall survive until
otherwise terminated or discharged hereunder: (a) the rights of holders of
outstanding Notes to receive payments in respect of the principal of, premium,
if any, and interest on, such Notes when such payments are due, or on the
redemption date, as the case may be; (b) the Company's obligations with respect
to the Notes concerning the issuance of temporary Notes, the registration of
Notes, mutilated, destroyed, lost or stolen Notes and the maintenance of an
office or agency for payment and money for security payments held in trust; (c)
the rights, powers, trust, duties and immunities of the Trustee, and the
Company's obligations in connection therewith; and (d) the legal defeasance
provisions of this Indenture.

SECTION 8.03.  COVENANT DEFEASANCE.

     Upon the Company's exercise under Section 8.01 of the option applicable to
this Section 8.03, the Company shall be released from its obligations under the
covenants contained in Sections 4.03, 4.04, 4.07, 4.08, 4.09, 4.10, 4.11, 4.12,
4.13, 4.14, 4.15, 4.16 and 4.17 and Article Five with respect to the outstanding
Notes on and after the date the conditions set forth below are satisfied
(hereinafter, "COVENANT DEFEASANCE"), and the Notes shall thereafter be deemed
not "outstanding" for the purposes of any direction, waiver, consent or
declaration or act of Holders (and the consequences of any thereof) in
connection with such covenants, but shall continue to be deemed "outstanding"
for all other purposes hereunder (it being understood that such Notes shall not
be deemed outstanding for accounting purposes).  For this purpose, such Covenant
Defeasance means that, with respect to the outstanding Notes, the Company may
omit to comply with and shall have no liability in respect of any term,
condition or limitation set forth in any such covenant, whether directly or
indirectly, by reason of any reference elsewhere herein to any such covenant or
by reason of any reference in any such covenant to any other provision herein or
in any other document and such omission to comply shall not constitute a Default
or an Event of Default under Section 6.01(c), but, except as specified above,
the remainder of this Indenture and such Notes shall be unaffected thereby.  In
addition, upon the Company' exercise under Section 8.01 of the option applicable
to this Section 8.03, Sections 6.01(d) through 6.01(f) shall not constitute
Events of Default.

SECTION 8.04.  CONDITIONS TO LEGAL OR COVENANT DEFEASANCE.

     The following shall be the conditions to the application of either
Section 8.02 or Section 8.03 to the outstanding Notes:

          (a)  The Company shall irrevocably have deposited or caused to be
     deposited with the Trustee (or another trustee satisfying the requirements
     of Section 7.10 who shall agree to comply with the provisions of this
     Article Eight applicable to it) as trust funds in trust for the purpose of
     making the following payments, specifically pledged as security for, and
     dedicated solely to, the benefit of the Holders of such Notes, (i) the
     Company shall irrevocably deposit with the Trustee, in trust, for the
     benefit of the Holders of the Notes, cash in U.S. dollars, non-callable
     U.S. government obligations, or a combination thereof, in such amounts as
     will be sufficient, in the opinion of a nationally recognized firm of
     independent public accountants selected by the Company, to pay the
     principal of, premium, if any, and interest on the outstanding Notes, on
     the stated maturity or on the applicable optional redemption date, as the
     case may be, of such principal or installment of principal of, premium, if
     any, or interest on the outstanding Notes; (ii) in the case of legal
     defeasance, the Company shall deliver to the Trustee an opinion of counsel
     in the United States reasonably acceptable to the Trustee confirming that


                                       50
<PAGE>

     (A) the Company has received from, or there has been published by, the
     Internal Revenue Service a ruling or (B) since the date hereof, there has
     been a change in the applicable federal income tax law, in either case to
     the effect that, and based thereon such opinion of counsel shall confirm
     that, the holders of the outstanding Notes will not recognize income, gain
     or loss for federal income tax purposes as a result of such legal
     defeasance and will be subject to federal income tax on the same amounts,
     in the same manner and at the same times as would have been the case if
     such legal defeasance had not occurred; (iii) in the case of covenant
     defeasance, the Company shall deliver to the Trustee an opinion of counsel
     in the United States reasonably acceptable to the Trustee confirming that
     the holders of the outstanding Notes will not recognize income, gain or
     loss for federal income tax purposes as a result of such covenant
     defeasance and will be subject to federal income tax on the same amounts,
     in the same manner and at the same times as would have been the case if
     such covenant defeasance had not occurred; (iv) no Default or Event of
     Default shall have occurred and be continuing on the date of such deposit
     or insofar as Events of Default from bankruptcy or insolvency events are
     concerned, at any time in the period ending on the 91st day after the date
     of deposit; (v) such legal defeasance or covenant defeasance shall not
     result in a breach or violation of, or constitute a default under any
     material agreement or instrument (other than this Indenture) to which the
     Company is a party or by which the Company is bound; (vi) the Company shall
     have delivered to the Trustee an Officers' Certificate stating that the
     deposit was not made by the Company with the intent of preferring the
     holders of Notes over the other creditors of the Company with the intent of
     defeating, hindering, delaying or defrauding creditors of the Company or
     others; (vii) the Company shall have delivered to the Trustee an Officers'
     Certificate and an opinion of counsel, each stating that all conditions
     precedent provided for relating to the legal defeasance or the covenant
     defeasance have been complied with; and (viii) the Company shall have paid
     or duly provided for payment of all amounts due to the Trustee pursuant to
     Section 7.07 hereof.

SECTION 8.05.  DEPOSITED MONEY AND GOVERNMENT SECURITIES TO BE HELD IN TRUST;
               OTHER MISCELLANEOUS PROVISIONS.

     Subject to Section 8.06, all money and Government Securities (including the
proceeds thereof) deposited with the Trustee (or other qualifying trustee,
collectively for purposes of this Section 8.05, the "TRUSTEE") pursuant to
Section 8.04 in respect of the outstanding Notes shall be held in trust and
applied by the Trustee, in accordance with the provisions of such Notes and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as Paying Agent) as the Company may determine, to
the Holders of such Notes of all sums due and to become due thereon in respect
of principal, premium, if any, and interest, but such money need not be
segregated from other funds except to the extent required by law.

     The Company shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the cash or Government Securities
deposited pursuant to Section 8.04 or the principal and interest received in
respect thereof other than any such tax, fee or other charge which by law is for
the account of the Holders of the outstanding Notes.

     Anything in this Article Eight to the contrary notwithstanding, the Trustee
shall deliver or pay to the Company from time to time upon the request of the
Company any money or Government Securities held by it as provided in
Section 8.04 which, in the opinion of a nationally recognized firm of
independent public accountants expressed in a written certification thereof
delivered to the Trustee (which


                                       51
<PAGE>

may be the opinion delivered under Section 8.04(a)), are in excess of the amount
thereof which would then be required to be deposited to effect an equivalent
Legal Defeasance or Covenant Defeasance.

SECTION 8.06.  REPAYMENT TO COMPANY.

     Any money deposited with the Trustee or any Paying Agent, or then held by
the Company, in trust for the payment of the principal of, premium, if any, or
interest on any Note and remaining unclaimed for two years after such principal,
and premium, if any, or interest has become due and payable shall be paid to the
Company on its request or (if then held by the Company) shall be discharged from
such trust; and the Holder of such Note shall thereafter, as a creditor, look
only to the Company for payment thereof, and all liability of the Trustee or
such Paying Agent with respect to such trust money, and all liability of the
Company as trustee thereof, shall thereupon cease; PROVIDED, HOWEVER, that the
Trustee or such Paying Agent, before being required to make any such repayment,
may at the expense of the Company cause to be published once, in the New York
Times and The Wall Street Journal (national edition), notice that such money
remains unclaimed and that, after a date specified therein, which shall not be
less than 30 days from the date of such notification or publication, any
unclaimed balance of such money then remaining will be repaid to the Company.

SECTION 8.07.  REINSTATEMENT.

     If the Trustee or Paying Agent is unable to apply any United States Dollars
or Government Securities in accordance with Section 8.02 or 8.03, as the case
may be, by reason of any order or judgment of any court or governmental
authority enjoining, restraining or otherwise prohibiting such application, then
the Company's obligations under this Indenture and the Notes shall be revived
and reinstated as though no deposit had occurred pursuant to Section 8.02 or
8.03 until such time as the Trustee or Paying Agent is permitted to apply all
such money in accordance with Section 8.02 or 8.03, as the case may be;
PROVIDED, HOWEVER, that, if the Company makes any payment of principal of,
premium, if any, or interest on any Note following the reinstatement of its
obligations, the Company shall be subrogated to the rights of the Holders of
such Notes to receive such payment from the money held by the Trustee or Paying
Agent.


                                    ARTICLE 9
                        AMENDMENT, SUPPLEMENT AND WAIVER

SECTION 9.01.  WITHOUT CONSENT OF HOLDERS OF NOTES.

     Notwithstanding Section 9.02 hereof, the Company and the Trustee may amend
or supplement this Indenture or the Notes without the consent of any Holder of a
Note: (a) to cure any ambiguity, defect or inconsistency; (b) to provide for
uncertificated Notes in addition to or in place of certificated Notes; (c) to
provide for the assumption of the Company's obligations to Holders of the Notes
in the case of a merger or consolidation; (d) to make any change that would
provide any additional rights or benefits to the Holders of the Notes or that
does not adversely affect the legal rights under this Indenture of any such
Holder; or (e) to comply with requirements of the Commission in order to effect
or maintain the qualification of this Indenture under the Trust Indenture Act.


                                       52
<PAGE>

     Upon the request of the Company accompanied by a resolution of the Board of
Directors of the Company authorizing the execution of any such amended or
supplemental indenture, and upon receipt by the Trustee of the documents
described in Section 9.06, the Trustee shall join with the Company in the
execution of any amended or supplemental indenture authorized or permitted by
the terms of this Indenture and to make any further appropriate agreements and
stipulations which may be therein contained, but the Trustee shall not be
obligated to enter into such amended or supplemental indenture which affects its
own rights, duties or immunities under this Indenture or otherwise.

SECTION 9.02.  WITH CONSENT OF HOLDERS OF NOTES.

     The Company and the Trustee may amend or supplement this Indenture or the
Notes or any amended or supplemental indenture with the written consent of the
Holders of Notes of not less than a majority in aggregate principal amount of
the Notes then outstanding (including consents obtained in connection with a
tender offer or exchange offer for the Notes), and any existing Default and its
consequences or compliance with any provision of this Indenture or the Notes may
be waived with the consent of the Holders of a majority in principal amount of
the then outstanding Notes (including consents obtained in connection with a
tender offer or exchange offer for the Notes).

     Upon the request of the Company accompanied by a resolution of the Board of
Directors of the Company authorizing the execution of any such amended or
supplemental indenture, and upon the filing with the Trustee of evidence
satisfactory to the Trustee of the consent of the Holders of Notes as aforesaid,
and upon receipt by the Trustee of the documents described in Section 9.06, the
Trustee shall join with the Company in the execution of such amended or
supplemental indenture unless such amended or supplemental indenture affects the
Trustee's own rights, duties or immunities under this Indenture or otherwise, in
which case the Trustee may in its discretion, but shall not be obligated to,
enter into such amended or supplemental indenture.

     It shall not be necessary for the consent of the Holders of Notes under
this Section 9.02 to approve the particular form of any proposed amendment or
waiver, but it shall be sufficient if such consent approves the substance
thereof.

     After an amendment, supplement or waiver under this Section becomes
effective, the Company shall mail to the Holders of Notes affected thereby a
notice briefly describing the amendment, supplement or waiver.  Any failure of
the Company to mail such notice, or any defect therein, shall not, however, in
any way impair or affect the validity of any such amended or supplemental
indenture or waiver.  Subject to Sections 6.04 and 6.07, the Holders of a
majority in aggregate principal amount of the Notes then outstanding may waive
compliance in a particular instance by the Company with any provision of this
Indenture or the Notes.  However, without the consent of each Holder affected,
an amendment or waiver may not (with respect to any Notes held by a non-
consenting Holder of Notes):

          (i)  reduce the percentage in principal amount at maturity outstanding
     of Notes whose Holders must consent to an amendment, supplement or waiver
     or consent to take any action under this Indenture or the Notes;

         (ii)  reduce the principal at maturity or extend the fixed maturity of
     any Note or alter the provisions with respect to the redemption of the
     Notes (other than Section 4.11 or Section 4.15 hereof);


                                       53
<PAGE>

        (iii)  reduce the rate of or change the time for payment of interest on
     any Notes or amend or modify the calculation of the Accreted Value or
     Default Amount so as to reduce the amount of the Accreted Value or Default
     Amount;

         (iv)  waive a Default or Event of Default in the payment of principal
     of or premium, if any, or interest on the Notes (except a rescission of
     acceleration of the Notes by the holders of at least a majority in
     aggregate principal amount of the Notes and a waiver of the payment default
     that resulted from such acceleration);

          (v)  make any Note, or any premium or accrued interest thereon,
     payable in money other than that stated in the Notes;

         (vi)  make any change in the provisions of this Indenture relating to
     waivers of past Defaults or the rights of holders of Notes to receive
     payments of principal of, premium, if any, or interest on the Notes;

        (vii)  waive a redemption payment with respect to any Note (other than a
     payment required by Sections 4.11 or 4.15 hereof);

       (viii)  make any change in the foregoing amendment and waiver provisions;

         (ix)  impair the right to institute suit for the enforcement of any
     payment on or with respect to the Notes; or

          (x)  adversely affect the ranking of the Notes in a manner adverse to
     the holders of the Notes.

     In addition, without the consent of at least 66 2/3% in principal amount at
maturity of the Notes then outstanding (including consents obtained in
connection with a tender offer or exchange offer for Notes), no amendment to
this Indenture may make any change in, and no waiver may be made with respect to
any Default in the performance of, Section 4.11 or Section 4.15 hereof.

SECTION 9.03.  COMPLIANCE WITH TRUST INDENTURE ACT.

     Every amendment or supplement to this Indenture or the Notes shall be set
forth in a amended or supplemental indenture that complies with the TIA as then
in effect.

SECTION 9.04.  REVOCATION AND EFFECT OF CONSENTS.

     Until an amendment, supplement or waiver becomes effective, a consent to it
by a Holder of a Note is a continuing consent by the Holder of a Note and every
subsequent Holder of a Note or portion of a Note that evidences the same debt as
the consenting Holder's Note, even if notation of the consent is not made on any
Note.  However, any such Holder of a Note or subsequent Holder of a Note may
revoke the consent as to its Note if the Trustee receives written notice of
revocation before the date the waiver, supplement or amendment becomes
effective.  An amendment, supplement or waiver becomes effective in accordance
with its terms and thereafter binds every Holder of a Note.


                                       54
<PAGE>

     The Company may fix a record date for determining which Holders of the
Notes must consent to such amendment, supplement or waiver.  If the Company
fixes a record date, the record date shall be fixed at (i) the later of 30 days
prior to the first solicitation of such consent or the date of the most recent
list of Holders of Notes furnished to the Trustee prior to such solicitation
pursuant to Section 2.05 or (ii) such other date as the Company shall designate.

SECTION 9.05.  NOTATION ON OR EXCHANGE OF NOTES.

     The Trustee may place an appropriate notation about an amendment,
supplement or waiver on any Note thereafter authenticated.  The Company in
exchange for all Notes may issue and the Trustee shall authenticate new Notes
that reflect the amendment, supplement or waiver.

     Failure to make the appropriate notation or issue a new Note shall not
affect the validity and effect of such amendment, supplement or waiver.

SECTION 9.06.  TRUSTEE TO SIGN AMENDMENTS, ETC.

     The Trustee shall sign any amended or supplemental indenture authorized
pursuant to this Article 9 if the amendment or supplement does not adversely
affect the rights, duties, liabilities or immunities of the Trustee.  The
Company may not sign an amendment or supplemental indenture until the Board of
Directors approves it.  If it does, the Trustee may, but need not, sign it.  In
signing such amendment or supplemental indenture, the Trustee shall be entitled
to receive, and, subject to Section 7.01 hereof, shall be fully protected in
relying upon, an Officers' Certificate and an Opinion of Counsel as conclusive
evidence that such amendment or supplemental indenture is authorized or
permitted by this Indenture, that it is not inconsistent herewith, and that it
will be valid and binding upon the Company in accordance with its terms.  The
Company may not sign an amendment or supplemental indenture until the Board of
Directors approves it.

SECTION 9.07.  PAYMENT FOR CONSENTS.

     The Company shall not, and shall not permit any of its Subsidiaries to,
directly or indirectly, pay or cause to be paid any consideration, whether by
way of interest, fee or otherwise, to any Holder of Notes for or as an
inducement to any consent, waiver or amendment of any of the terms or provisions
of this Indenture or the Notes, unless such consideration is offered to be paid
or agreed to be paid to all Holders of the Notes that consent, waive or agree to
amend in the time frame set forth in the solicitation documents relating to such
consent, waiver or agreement.


                                   ARTICLE 10
                                  MISCELLANEOUS

SECTION 10.01. TRUST INDENTURE ACT CONTROLS.

     If any provision of this Indenture limits, qualifies or conflicts with the
duties imposed by TIA Section 318(c), the imposed duties shall control.


                                       55
<PAGE>

SECTION 10.02. NOTICES.

     Any notice or communication by the Company or the Trustee to the other is
duly given if in writing and delivered in Person or mailed by first class mail
(registered or certified, return receipt requested), telex, telecopier or
overnight air courier guaranteeing next day delivery, to the other's address:

     If to the Company:

          Advanced Radio Telecom Corp.
          500 108th Avenue, N.E., Suite 2600
          Bellevue, Washington 98004
          Telecopier No.: (206) 688-0703
          Attention: Chief Financial Officer

     If to the Trustee:

          The Bank of New York
          101 Barclay Street, 21st Floor
          New York, New York 10286
          Telecopier No.: (212) 815-5915
          Attention: Corporate Trust Administration

     The Company or the Trustee, by notice to the other may designate additional
or different addresses for subsequent notices or communications.

     All notices and communications (other than those sent to Holders of Notes)
shall be deemed to have been duly given:  at the time delivered by hand, if
Personally delivered; five Business Days after being deposited in the mail,
postage prepaid, if mailed; when answered back, if telexed; when receipt
acknowledged, if telecopied; and the next Business Day after timely delivery to
the courier, if sent by overnight air courier guaranteeing next day delivery.

     Any notice or communication to a Holder of a Note shall be mailed by first
class mail, certified or registered, return receipt requested, or by overnight
air courier guaranteeing next day delivery to its address shown on the register
kept by the Registrar.  Any notice or communication shall also be so mailed to
any Person described in TIA Section 313(c), to the extent required by the TIA.
Failure to mail a notice or communication to a Holder of a Note or any defect in
it shall not affect its sufficiency with respect to other Holders of Notes.

     If a notice or communication is mailed in the manner provided above within
the time prescribed, it is duly given, whether or not the addressee receives it.

     If the Company mails a notice or communication to Holders of Notes, it
shall mail a copy to the Trustee and each Agent at the same time.


                                       56
<PAGE>

SECTION 10.03. COMMUNICATION BY HOLDERS OF NOTES WITH OTHER HOLDERS OF NOTES.

     Holders of the Notes may communicate pursuant to TIA Section 312(b) with
other Holders of Notes with respect to their rights under this Indenture or the
Notes.  The Company, the Trustee, the Registrar and anyone else shall have the
protection of TIA Section 312(c).

SECTION 10.04. CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT.

     Upon any request or application by the Company to the Trustee to take any
action under this Indenture, the Company shall furnish to the Trustee:

          (a)  an Officers' Certificate in form and substance reasonably
     satisfactory to the Trustee (which shall include the statements set forth
     in Section 10.05) stating that, in the opinion of the signers, all
     conditions precedent and covenants, if any, provided for in this Indenture
     relating to the proposed action have been satisfied; and

          (b)  an Opinion of Counsel in form and substance reasonably
     satisfactory to the Trustee (which shall include the statements set forth
     in Section 10.05) stating that, in the opinion of such counsel, all such
     conditions precedent and covenants have been satisfied.

SECTION 10.05. STATEMENTS REQUIRED IN CERTIFICATE OR OPINION.

     Each certificate or opinion with respect to compliance with a condition or
covenant provided for in this Indenture (other than a certificate provided
pursuant to TIA Section 314(a)(4)) shall include:

          (a)  a statement that the Person making such certificate or opinion
     has read such covenant or condition;

          (b)  a brief statement as to the nature and scope of the examination
     or investigation upon which the statements or opinions contained in such
     certificate or opinion are based;

          (c)  a statement that, in the opinion of such Person, he has made such
     examination or investigation as is necessary to enable him to express an
     informed opinion as to whether or not such covenant or condition has been
     satisfied; and

          (d)  a statement as to whether or not, in the opinion of such Person,
     such condition or covenant has been satisfied.

SECTION 10.06. RULES BY TRUSTEE AND AGENTS.

     The Trustee may make reasonable rules for action by or at a meeting of
Holders of Notes.  The Registrar or Paying Agent may make reasonable rules and
set reasonable requirements for its functions.


                                       57
<PAGE>

SECTION 10.07. NO PERSONAL LIABILITY OF PARTNERS, DIRECTORS, OFFICERS, EMPLOYEES
               AND STOCKHOLDERS.

     No director, officer, employee, incorporator or stockholder of the Company,
as such, shall have any liability for any obligations of the Company under the
Notes or this Indenture or for any claim based on, in respect of, or by reason
of, such obligations or their creation.  Each Holder of the Notes by accepting a
Note waives and releases all such liability.  The waiver and release are part of
the consideration for issuance of the Notes.

SECTION 10.08. GOVERNING LAW.

     The internal law of the State of New York shall govern and be used to
construe this Indenture and the Notes.

SECTION 10.09. NO ADVERSE INTERPRETATION OF OTHER AGREEMENTS.

     This Indenture may not be used to interpret another indenture, loan or debt
agreement of the Company or its Subsidiaries.  Any such indenture, loan or debt
agreement may not be used to interpret this Indenture.

SECTION 10.10. SUCCESSORS.

     All agreements of the Company in this Indenture and the Notes shall bind
its successors.  All agreements of the Trustee in this Indenture shall bind its
successor.

SECTION 10.11. SEVERABILITY.

     In case any provision in this Indenture or in the Notes shall be invalid,
illegal or unenforceable, the validity, legality and enforceability of the
remaining provisions shall not in any way be affected or impaired thereby.

SECTION 10.12. COUNTERPART ORIGINALS.

     The parties may sign any number of copies of this Indenture.  Each signed
copy shall be an original, but all of them together represent the same
agreement.

SECTION 10.13. TABLE OF CONTENTS, HEADINGS, ETC.

     The Table of Contents, Cross-Reference Table and Headings of the Articles
and Sections of this Indenture have been inserted for convenience of reference
only, are not to be considered a part of this Indenture and shall in no way
modify or restrict any of the terms or provisions hereof.


                         [Signatures on following page]


                                       58
<PAGE>

                                   SIGNATURES

Dated as of _______, 1996               ADVANCED RADIO TELECOM CORP.



(SEAL)
                                        By:
                                           --------------------------------
                                           Name:
                                           Title:

Attest:


- ------------------------------
Name:
Title:



Dated as of _______, 1996               THE BANK OF NEW YORK,
                                        as Trustee


(SEAL)
                                        By:
                                           --------------------------------
                                           Name:
                                           Title:

Attest:


- ------------------------------
Name:
Title:


                                       59
<PAGE>

                                                                       EXHIBIT A
                                 (Face of Note)

                        __% Senior Discount Note due 2006
No.                                                                  $__________

Advanced Radio Telecom Corp.

promises to pay to

_______________________________

or its registered assigns

the principal sum of  _________________________

Dollars on _______, 2006.

Interest Payment Dates: __________ and ________, commencing __________, 1996.

Record Dates: __________ and _________ (whether or not a Business Day).

                              Dated:                .

                              ADVANCED RADIO TELECOM CORP.



                              By:
                                 --------------------------------
                                 Name:
                                 Title:

(SEAL)
                              Attest:


                              By:
                                 --------------------------------
                                 Name:
                                 Title:

This is one of the Notes
referred to in the within-
mentioned Indenture:

THE BANK OF NEW YORK,
as Trustee


By:
   --------------------------------
     Authorized Signatory
<PAGE>

                                 (Back of Note)

                        __% Senior Discount Note due 2006

     Capitalized terms used herein have the meanings assigned to them in the
Indenture (as defined below) unless otherwise indicated.

     1.  INTEREST.  Advanced Radio Telecom Corp., a Delaware corporation (the
"COMPANY"), promises to pay interest on the principal amount of this Note at the
rate and in the manner specified below.  The Notes will accrete at a rate of
% compounded semiannually, to an aggregate principal amount of $   million by
       , 2001.  Cash interest will not accrue on the Notes prior to          ,
2001.  Commencing        , 2002, cash interest on the Notes will be payable, at
a rate of     % per annum, semi-annually in arrears on each              and
     (each, an "INTEREST PAYMENT DATE"), to the holders of record of Notes at
the close of business on the           and           immediately preceding such
Interest Payment Date.  Cash interest on the Notes will accrue from the most
recent Interest Payment Date to which interest has been paid or duly provided
for, or, if no interest has been paid or duly provided for,            , 2001.
Cash interest will be computed on the basis of a 360-day year of twelve 30-day
months.  If, prior to              , 2001, the Company defaults in any payment
of principal (including any accreted original issue discount), whether at
maturity, upon redemption or otherwise, if the payment of cash interest on the
Notes is then permitted by law, cash interest will accrue on the amount in
default at the rate of interest borne by the Notes on or after                ,
2001 and, if the payment of such cash interest is not permitted by law, original
issue discount will continue to accrete at the rate then in effect.  On or after
       , 2001, interest on overdue principal and, to the extent permitted by
law, on overdue installments of interest will accrue at the rate of interest
borne by the Notes.

     2.  METHOD OF PAYMENT.  The Company will pay interest on the Notes (except
defaulted interest) to the Persons who are registered Holders of Notes at the
close of business on the record date next preceding the Interest Payment Date,
even if such Notes are cancelled after such record date and on or before such
Interest Payment Date.  The Holder hereof must surrender this Note to a Paying
Agent to collect principal payments.  The Company will pay principal and
interest in money of the United States that at the time of payment is legal
tender for payment of public and private debts.  Principal of, premium, if any,
and interest on the Notes will be payable, and the Notes will be exchangeable
and transferable, at the office or agency of the Company in The City of New York
maintained for such purposes (which initially will be the office of the
Trustee); PROVIDED, HOWEVER, the payment of interest may be made by check mailed
to the address of the Person entitled thereto as shown on the security register.
The Notes will be issued only in fully registered form without coupons and only
in denominations of $1,000 and any integral multiple thereof.  No service charge
will be made for any registration of transfer, exchange or redemption of Notes,
but the Company may require payment in certain circumstances of a sum sufficient
to cover any tax or other governmental charge that may be imposed in connection
therewith.  Unless otherwise designated by the Company, the Company's office or
agency will be the office of the Trustee maintained for such purpose.

     3.  PAYING AGENT AND REGISTRAR.  Initially, the Trustee will act as Paying
Agent and Registrar.  The Company may change any Paying Agent, Registrar or
co-registrar without prior notice to any Holder of a Note.  The Company may act
in any such capacity.

     4.  INDENTURE.  The Company issued the Notes under an Indenture, dated as
of July __, 1996 (the "INDENTURE"), between the Company and the Trustee.  The
terms of the Notes include those stated in the Indenture and those made part of
the Indenture by reference to the Trust Indenture Act of 1939, as amended (15
U.S. Code Sections 77aaa-77bbbb), as in effect on the date of the Indenture.
The Notes are


                                       A-2
<PAGE>

subject to all such terms, and Holders of Notes are referred to the Indenture
and such act for a statement of such terms.  The terms of the Indenture shall
govern any inconsistencies between the Indenture and the Notes.  The Notes are
obligations of the Company limited to the sum of $_____________ in aggregate
face amount (at maturity) of Notes to be issued on the Issue Date.

     5.  OPTIONAL REDEMPTION.  The Notes will be redeemable at the option of the
Company, in whole or in part, at any time on or after          , 2001, upon not
less than 30 nor more than 60 days' notice, at the redemption prices (expressed
as percentages of principal amount at maturity) set forth below, plus accrued
and unpaid interest, if any, to the date of redemption, if redeemed during the
12-month period beginning on           of the years indicated below:
                                                                      Redemption
          Year                                                           Price
          ----                                                        ----------

          2001 . . . . . . . . . . . . . . . . . . . . . . . . . . .           %
          2002 . . . . . . . . . . . . . . . . . . . . . . . . . . .           %
          2003 . . . . . . . . . . . . . . . . . . . . . . . . . . .           %
          2004 and thereafter. . . . . . . . . . . . . . . . . . . .    100.000%

     Notwithstanding the foregoing, in the event a sale by the Company of its
Common Stock in one or more Equity Offerings or Investments by one or more
Strategic Equity Investors for an aggregate purchase price equal to or exceeding
$70.0 million, on or prior to           , 1999, the Company may, at its option,
use all or a portion of the net proceeds thereof to redeem up to a maximum of 33
1/3% of the initially outstanding aggregate principal amount at maturity of the
Notes at a redemption price equal to      % of the Accreted Value of the Notes
(determined as of the redemption date); PROVIDED that not less than 66 2/3% of
the initially outstanding aggregate principal amount at maturity of the Notes
remain outstanding following such redemption.  Any such redemption must be
effected upon not less than 30 nor more than 60 days' notice given within 30
days after any such Equity Offering or sale to a Strategic Equity Investor
resulting in such gross proceeds, as the case may be.

     6.  MANDATORY REDEMPTION.  The Company is not required to make mandatory
sinking fund payments with respect to the Notes.  However, (i) upon the
occurrence of a Change in Control, the Company is obligated to make an offer to
purchase all outstanding Notes at a price of (A) 101% of the Accreted Value
thereof (determined at the date of purchase), if such purchase is prior to
, 2001, or (B) 101% of the principal amount at maturity thereof, plus accrued
interest thereon, if any, to the date of purchase, if such purchase is on or
after            , 2001 and (ii) the Company may be obligated to make an offer
to purchase Notes with the Net Cash Proceeds of certain Asset Sales at a price
of (A) 101% of the Accreted Value thereof (determined at the date of purchase),
if such purchase is prior to            , 2001, or (B) 101% of the principal
amount at maturity thereof, plus accrued and unpaid interest, if any, to the
date of purchase, if such purchase is on or after         , 2001.  Holders of
Notes that are the subject of an Offer to Purchase will receive an Offer to
Purchase from the Company prior to any related purchase date and may elect to
have such Notes purchased by completing the form entitled "Option of Holder to
Elect Purchase" appearing below.

     7.  NOTICE OF REDEMPTION.  Notice of redemption shall be mailed at least 30
days but not more than 60 days before the redemption date to each Holder whose
Notes are to be redeemed at its registered address.  Notes may be redeemed in
part but only in whole multiples of $1,000, unless all of the Notes held by a
Holder of Notes are to be redeemed.  On and after the redemption date, interest
ceases to accrue on Notes or portions of them called for redemption.


                                       A-3
<PAGE>

     8.  DENOMINATIONS, TRANSFER, EXCHANGE.  The Notes are in registered form
without coupons in denominations of $1,000 and integral multiples of $1,000.
The transfer of Notes may be registered and Notes may be exchanged as provided
in the Indenture.  The Registrar and the Trustee may require a Holder of a Note,
among other things, to furnish appropriate endorsements and transfer documents
and to pay any taxes and fees required by law or permitted by the Indenture.
Neither the Company nor the Registrar need exchange or register the transfer of
any Note or portion of a Note selected for redemption.  Also, neither the
Company nor the Registrar need exchange or register the transfer of any Notes
for a period of 15 days before a selection of Notes to be redeemed.

     9.  PERSONS DEEMED OWNERS.  Prior to due presentment to the Trustee for
registration of the transfer of this Note, the Trustee, any Agent and the
Company may deem and treat the Person in whose name this Note is registered as
its absolute owner for the purpose of receiving payment of principal of,
premium, if any, and interest on this Note and for all other purposes
whatsoever, whether or not this Note is overdue, and neither the Trustee, any
Agent nor the Company shall be affected by notice to the contrary.  The
registered Holder of a Note shall be treated as its owner for all purposes.

     10.  AMENDMENTS, SUPPLEMENT AND WAIVERS.  Subject to certain exceptions,
the Indenture or the Notes may be amended or supplemented with the consent of
the Holders of at least a majority in principal amount of the then outstanding
Notes, and any existing default or compliance with any provision of the
Indenture or the Notes may be waived with the consent of the Holders of a
majority in principal amount of the then outstanding Notes.  Without the consent
of any Holder of a Note, the Indenture or the Notes may be amended or
supplemented to cure any ambiguity, defect or inconsistency, to provide for
uncertificated Notes in addition to or in place of certificated Notes, to
provide for the assumption of the Company's obligations to Holders of the Notes
in case of a merger or consolidation, to make any change that would provide any
additional rights or benefits to the Holders of the Notes or that does not
adversely affect the legal rights under the Indenture of any such Holder, or to
comply with the requirements of the Commission in order to effect or maintain
the qualification of the Indenture under the Trust Indenture Act.  However,
without the consent of each Holder affected, an amendment or waiver may not
(with respect to any Notes held by a non-consenting Holder of Notes): reduce the
percentage in principal amount at maturity outstanding of Notes whose Holders
must consent to an amendment, supplement or waiver or consent to take any action
under the Indenture or the Notes; reduce the principal at maturity or extend the
fixed maturity of any Note or alter the provisions with respect to the
redemption of the Notes (other than Section 4.11 or 4.15 of the Indenture);
reduce the rate of or change the time for payment of interest on any Notes or
amend or modify the calculation of the Accreted Value or Default Amount so as to
reduce the amount of the Accreted Value or Default Amount; waive a Default or
Event of Default in the payment of principal of or premium, if any, or interest
on the Notes (except a rescission of acceleration of the Notes by the holders of
at least a majority in aggregate principal amount of the Notes and a waiver of
the payment default that resulted from such acceleration); make any Note, or any
premium or accrued interest thereon, payable in money other than that stated in
the Notes; make any change in the provisions of this Indenture relating to
waivers of past Defaults or the rights of holders of Notes to receive payments
of principal of, premium, if any, or interest on the Notes; waive a redemption
payment with respect to any Note (other than a payment required by Sections 4.11
or 4.15 of the Indenture); make any change in the foregoing amendment and waiver
provisions; impair the right to institute suit for the enforcement of any
payment on or with respect to the Notes; or adversely affect the ranking of the
Notes in a manner adverse to the holders of the Notes.

     11.  DEFAULTS AND REMEDIES.  The following events are "Events of Default"
under the Indenture: (i) default in the payment of interest on the Notes when it
becomes due and payable, and continuance of such default for a period of 30 days
or more; (ii) default in the payment of principal of, or premium, if any, on the
Notes when due; (iii) default in the performance, or breach, of any covenant
described


                                       A-4
<PAGE>

under Sections 4.07, 4.09, 4.11 and 4.15 and Article 5 of the Indenture; (iv)
default in the performance, or breach, of any covenant in the Indenture (other
than defaults specified in clause (i), (ii) or (iii) above), and the continuance
of such default or breach for a period of 30 days or more after written notice
to the Company by the Trustee or to the Company and the Trustee by the holders
of at least 25% in aggregate principal amount at maturity of the outstanding
Notes (in each case, when such notice is deemed received in accordance with the
Indenture); (v) default under any mortgage, indenture or instrument under which
there may be issued or by which there may be secured or evidenced any
Indebtedness for money borrowed by the Company or any of its Restricted
Subsidiaries (or the payment of which is Guaranteed by the Company or any of its
Restricted Subsidiaries) whether such Indebtedness or Guarantee now exists, or
is created after the Issue Date, which default (A) is caused by a failure to pay
principal of or premium, if any, or interest on such Indebtedness prior to the
expiration of the grace period provided in such Indebtedness on the date of such
default (a "PAYMENT DEFAULT") or (B) results in the acceleration of such
Indebtedness prior to its express maturity and, in each case, the principal
amount of any such Indebtedness, together with the principal amount of any other
such Indebtedness under which there has been a Payment Default, or the maturity
of which has been so accelerated, aggregates $5.0 million or more; (vi) any
final judgment or order (not covered by insurance) for the payment of money in
excess of $5.0 million in the aggregate for all such final judgments or orders
against all such Persons (treating any deductibles, self-insurance or retention
as not so covered) shall be rendered against the Company or any Significant
Subsidiary and shall not be paid or discharged, and there shall be any period of
60 consecutive days following entry of the final judgment or order that causes
the aggregate amount for all such final judgments or orders outstanding and not
paid or discharged against all such Persons to exceed $5.0 million during which
a stay of enforcement of such final judgment or order, by reason of a pending
appeal or otherwise, shall not be in effect; or (vii) certain events of
bankruptcy or insolvency with respect to the Company or any Significant
Subsidiary.  If any Event of Default (other than an Event of Default specified
in clause (vii) or (viii) above with respect to the Company) occurs and is
continuing, then the Trustee or the holders of at least 25% in principal amount
at maturity of outstanding Notes may, by written notice, and the Trustee upon
the request of the holders of not less than 25% in principal amount at maturity
of the outstanding Notes shall, declare the Default Amount of, and any accrued
and unpaid interest on, all outstanding Notes to be immediately due and payable
and upon any such declaration such amounts shall become immediately due and
payable.  If an Event of Default specified in clause (vii) or (viii) above with
respect to the Company occurs and is continuing, then the Default Amount of, and
any accrued and unpaid interest on, all outstanding Notes shall IPSO FACTO
become and be immediately due and payable without any declaration or other act
on the part of the Trustee or any holder.  Holders of the Notes may not enforce
the Indenture or the Notes except as provided in the Indenture.  Subject to
certain limitations, Holders of a majority in principal amount of the then
outstanding Notes may direct the Trustee in its exercise of any trust or power.
The Trustee may withhold from Holders of the Notes notice of any continuing
Default or Event of Default (except a Default or Event of Default relating to
the payment of principal or interest) if it determines that withholding notice
is in their interest.  The Holders of a majority in aggregate principal amount
of the Notes then outstanding, by notice to the Trustee, may on behalf of the
Holders of all of the Notes waive any existing Default or Event of Default and
its consequences under the Indenture except a continuing Default or Event of
Default in the payment of interest or premium on, or the principal of, the
Notes.  The Company is required to deliver to the Trustee annually a statement
regarding compliance with the Indenture, and the Company is required upon
becoming aware of any Default or Event of Default, to deliver to the Trustee a
statement specifying such Default or Event of Default.

     12.  TRUSTEE DEALINGS WITH COMPANY.  The Trustee under the Indenture, in
its individual or any other capacity, may make loans to, accept deposits from,
and perform services for the Company or its Affiliates, and may otherwise deal
with the Company or its Affiliates, as if it were not Trustee; however, if the
Trustee acquires any conflicting interest, it must eliminate such conflict
within 90 days or resign.


                                       A-5
<PAGE>

     13.  NO PERSONAL LIABILITIES OF DIRECTORS, OFFICERS, EMPLOYEES AND
STOCKHOLDERS.  No director, officer, employee, incorporator or stockholder of
the Company, as such, shall have any liability for any obligations of the
Company under the Notes or the Indenture or for any claim based on, in respect
of, or by reason of, such obligations or their creation.  Each Holder of the
Notes by accepting a Note waives and releases all such liability.  The waiver
and release are part of the consideration for issuance of the Notes.

     14.  AUTHENTICATION.  This Note shall not be valid until authenticated by
the manual signature of the Trustee or an authenticating agent.

     15.  ABBREVIATIONS.  Customary abbreviations may be used in the name of a
Holder of a Note or an assignee, such as:  TEN COM (= tenants in common), TEN
ENT (= tenants by the entireties), JT TEN (= joint tenants with right of
survivorship and not as tenants in common), CUST (= Custodian), and U/G/M/A (=
Uniform Gifts to Minors Act).

     16.  CUSIP NUMBERS.  Pursuant to a recommendation promulgated by the
Committee on Uniform Security Identification Procedures, the Company has caused
CUSIP numbers to be printed on the Notes and has directed the Trustee to use
CUSIP numbers in notices of redemption as a convenience to Holders of Notes.  No
representation is made as to the accuracy of such numbers either as printed on
the Notes or as contained in any notice of redemption and reliance may be placed
only on the other identification numbers placed thereon.

     The Company will furnish to any Holder of a Note upon written request and
without charge a copy of the Indenture.  Request may be made to:

                          Advanced Radio Telecom Corp.
                       500 108th Avenue, N.E., Suite 2600
                           Bellevue, Washington 98004
                       Attention: Chief Financial Officer


                                       A-6
<PAGE>

                                 ASSIGNMENT FORM


     To assign this Note, fill in the form below: (I) or (we) assign and
transfer this Note to

________________________________________________________________________________

                  (Insert assignee's soc. sec. or tax I.D. no.)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

              (Print or type assignee's name, address and zip code)

and irrevocably appoint _______________________________________________________
agent to transfer this Note on the books of the Company.  The agent may
substitute another to act for him.

________________________________________________________________________________

Date: ______________

                              Your Signature:
                              (Sign exactly as your name appears on the face of
                              this Note)

Signature Guarantee.


                                       A-7
<PAGE>

                       OPTION OF HOLDER TO ELECT PURCHASE


     If you want to elect to have all or any part of this Note purchased by the
Company pursuant to Section 4.11 or Section 4.15 of the Indenture check the
appropriate box:

                      / /  Section 4.11   / /  Section 4.15

     If you want to have only part of the Note purchased by the Company pursuant
to Section 4.11 or Section 4.15 of the Indenture, state the amount you elect to
have purchased:

$ _______________


Date:____________


                              Your Signature:
                              (Sign exactly as your name appears on the face of
                              this Note)

Signature Guarantee.


                                       A-8

<PAGE>
                                                                      EXHIBIT 11
 
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
               COMPUTATION OF NET LOSS PER SHARE OF COMMON STOCK
                                  (UNAUDITED)
<TABLE>
<CAPTION>
                                                                                                                    YEAR ENDED
                                                                                                                   DECEMBER 31,
                                                                                                                       1995
                                                                                                                  ---------------
 
<S>                                                                                                               <C>
Net loss applicable to Common Stock.............................................................................  $   1,267,655
                                                                                                                  ---------------
                                                                                                                  ---------------
  Shares:
    Weighted average number of shares of Common Stock outstanding for primary computation.......................     10,013,055(1)
                                                                                                                  ---------------
                                                                                                                  ---------------
Net loss per share of Common Stock..............................................................................  $        0.13
                                                                                                                  ---------------
                                                                                                                  ---------------
 
Pro Forma:
  Shares:
    Weighted average number of shares of Common Stock outstanding for primary computation.......................     10,013,055
    Issuances of shares of Telecom serial preferred stock as converted into shares of ART Common Stock..........     10,916,807
    Issuance of Telecom common stock as converted into shares of ART Common Stock...............................      8,100,807(2)
    Options and warrants issued and outstanding ................................................................      2,620,936
                                                                                                                  ---------------
  Pro forma weighted average number of shares of Common Stock...................................................     31,651,605(3)
                                                                                                                  ---------------
                                                                                                                  ---------------
Pro forma net loss per share of Common Stock....................................................................  $        0.04
                                                                                                                  ---------------
                                                                                                                  ---------------
 
Pro Forma As Adjusted
  Shares:
    Pro forma weighted average number of shares of Common Stock.................................................     31,651,605
    Common Stock issued in connection with the Common Stock Offering and the acquisition of the CommcoCCC
     Assets.....................................................................................................     24,000,000
                                                                                                                  ---------------
  Pro forma as adjusted weighted average number of shares of Common Stock.......................................     55,651,605(3)
                                                                                                                  ---------------
                                                                                                                  ---------------
Pro forma as adjusted net loss per share of Common Stock........................................................  $        0.02
                                                                                                                  ---------------
                                                                                                                  ---------------
 
<CAPTION>
                                                                                                                   FOR THE THREE
 
                                                                                                                   MONTHS ENDED
 
                                                                                                                  MARCH 31, 1996
 
                                                                                                                  ---------------
 
<S>                                                                                                               <C>
Net loss applicable to Common Stock.............................................................................  $   3,654,775
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
  Shares:
    Weighted average number of shares of Common Stock outstanding for primary computation.......................     10,013,055(1)
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
Net loss per share of Common Stock..............................................................................  $        0.37
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
Pro Forma:
  Shares:
    Weighted average number of shares of Common Stock outstanding for primary computation.......................     10,013,055
 
    Issuances of shares of Telecom serial preferred stock as converted into shares of ART Common Stock..........     10,916,807
 
    Issuance of Telecom common stock as converted into shares of ART Common Stock...............................      8,100,807(2)
 
    Options and warrants issued and outstanding ................................................................      2,620,936
 
                                                                                                                  ---------------
 
  Pro forma weighted average number of shares of Common Stock...................................................     31,651,605(3)
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
Pro forma net loss per share of Common Stock....................................................................  $        0.12
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
Pro Forma As Adjusted
  Shares:
    Pro forma weighted average number of shares of Common Stock.................................................     31,651,605
 
    Common Stock issued in connection with the Common Stock Offering and the acquisition of the CommcoCCC
     Assets.....................................................................................................     24,000,000
 
                                                                                                                  ---------------
 
  Pro forma as adjusted weighted average number of shares of Common Stock.......................................     55,651,605(3)
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
Pro forma as adjusted net loss per share of Common Stock........................................................  $        0.07
 
                                                                                                                  ---------------
 
                                                                                                                  ---------------
 
</TABLE>
 
(1)  The  weighted  average  number  of  shares  of  Common  Stock  for  primary
    computation exclude all common stock equivalents, which are anti-dilutive.
 
(2) Excludes shares of Telecom common stock owned by ART.
 
(3) The Securities  and Exchange Commission  requires that potentially  dilutive
    instruments  issued  within  one year  prior  to a  proposed  initial public
    offering at exercise prices below the expected initial public offering price
    be treated  as outstanding  for the  entire period  presented. The  weighted
    average  number of shares of Common Stock on  a pro forma and on a pro forma
    as adjusted basis  reflect those potentially  dilutive instruments  assuming
    the  sale of  shares of  Common Stock offered  in the  Common Stock Offering
    based on an assumed  initial public offering price  of $10.00 per share.  In
    measuring the dilutive effect, the treasury stock method was used.

<PAGE>
                                                                   EXHIBIT 23(A)
 
                       CONSENT OF INDEPENDENT ACCOUNTANTS
 
    We  consent to the inclusion  in this registration statement  on Form S-1 of
our report dated  April 26, 1996,  except for Note  2C, Note 5B  and the  second
paragraph  of Note 9, as to which the date is June 26, 1996, on our audit of the
financial statements of Advanced Radio  Technologies Corporation as of  December
31,  1995 and 1994, for the years then ended, and for the period from August 23,
1993 (date of inception) to December 31, 1993 and of our report dated April  26,
1996,  except for Note 2B as to which the date is June 26, 1996, on our audit of
the financial statements of Advanced Radio Telecom Corp. as of December 31, 1995
and for the period from March 28, 1995 (date of inception) to December 31, 1995.
We also consent to the reference to our firm under the caption "Experts."
 
                                          COOPERS & LYBRAND L.L.P.
 
New York, New York
July 18, 1996

 <PAGE>


================================================================================


                                    FORM T-1

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C.  20549

                            STATEMENT OF ELIGIBILITY
                   UNDER THE TRUST INDENTURE ACT OF 1939 OF A
                    CORPORATION DESIGNATED TO ACT AS TRUSTEE

                      CHECK IF AN APPLICATION TO DETERMINE
                      ELIGIBILITY OF A TRUSTEE PURSUANT TO
                        SECTION 305(b)(2)           |__|

                           --------------------------

                              THE BANK OF NEW YORK
               (Exact name of trustee as specified in its charter)


     New York                                             13-5160382
     (State of incorporation                              (I.R.S. employer
     if not a U.S. national bank)                         identification no.)

     48 Wall Street, New York, N.Y.                       10286
     (Address of principal executive offices)             (Zip code)


                            -------------------------


                          ADVANCED RADIO TELECOM CORP.
               (Exact name of obligor as specified in its charter)


     Delaware                                             52-1348016
     (State or other jurisdiction of                      (I.R.S. employer
     incorporation or organization)                       identification no.)


     Advanced Radio Telecom Corp.                            
     500 108th Avenue, N.E., Suite 2600
     Bellevue, Washington                                 98004
     (Address of principal executive offices)             (Zip code)

                             ______________________

                         Senior Discount Notes due 2006
                       (Title of the indenture securities)


================================================================================

<PAGE>


1.   GENERAL INFORMATION.  FURNISH THE FOLLOWING INFORMATION AS TO THE TRUSTEE:

     (a)  NAME AND ADDRESS OF EACH EXAMINING OR SUPERVISING AUTHORITY TO WHICH
          IT IS SUBJECT.
          
- --------------------------------------------------------------------------------
                  Name                                        Address
- --------------------------------------------------------------------------------

     Superintendent of Banks of the State of      2 Rector Street, New York,
     New York                                     N.Y.  10006, and Albany, N.Y.
                                                  12203

     Federal Reserve Bank of New York             33 Liberty Plaza, New York,
                                                  N.Y.  10045

     Federal Deposit Insurance Corporation        Washington, D.C.  20429

     New York Clearing House Association          New York, New York

     (b)  WHETHER IT IS AUTHORIZED TO EXERCISE CORPORATE TRUST POWERS.

     Yes.

2.   AFFILIATIONS WITH OBLIGOR.

     IF THE OBLIGOR IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH SUCH
     AFFILIATION. 

     None.  (See Note on page 3.)

16.  LIST OF EXHIBITS. 

     EXHIBITS IDENTIFIED IN PARENTHESES BELOW, ON FILE WITH THE COMMISSION, ARE
     INCORPORATED HEREIN BY REFERENCE AS AN EXHIBIT HERETO, PURSUANT TO RULE
     7a-29 UNDER THE TRUST INDENTURE ACT OF 1939 (THE "ACT") AND RULE 24 OF THE
     COMMISSION'S RULES OF PRACTICE.

     1.   A copy of the Organization Certificate of The Bank of New York
          (formerly Irving Trust Company) as now in effect, which contains the
          authority to commence business and a grant of powers to exercise
          corporate trust powers.  (Exhibit 1 to Amendment No. 1 to Form T-1
          filed with Registration Statement No. 33-6215, Exhibits 1a and 1b to
          Form T-1 filed with Registration Statement No. 33-21672 and Exhibit 1
          to Form T-1 filed with Registration Statement No. 33-29637.)

     4.   A copy of the existing By-laws of the Trustee.  (Exhibit 4 to Form T-1
          filed with Registration Statement No. 33-31019.)


                                       -2-

<PAGE>

     6.   The consent of the Trustee required by Section 321(b) of the Act. 
          (Exhibit 6 to Form T-1 filed with Registration Statement No.
          33-44051.)

     7.   A copy of the latest report of condition of the Trustee published
          pursuant to law or to the requirements of its supervising or examining
          authority.



                                      NOTE


     Inasmuch as this Form T-1 is filed prior to the ascertainment by the
Trustee of all facts on which to base a responsive answer to Item 2, the answer
to said Item is based on incomplete information.


     Item 2 may, however, be considered as correct unless amended by an
amendment to this Form T-1.


                                       -3-

<PAGE>


                                    SIGNATURE



     Pursuant to the requirements of the Act, the Trustee, The Bank of New York,
a corporation organized and existing under the laws of the State of New York,
has duly caused this statement of eligibility to be signed on its behalf by the
undersigned, thereunto duly authorized, all in The City of New York, and State
of New York, on the 18th day of July, 1996.


                                           THE BANK OF NEW YORK



                                           By:   /S/ VIVIAN GEORGES 
                                              -------------------------------
                                           Name:  VIVIAN GEORGES
                                           Title: ASSISTANT VICE PRESIDENT


                                       -4- 
<PAGE>


                       Consolidated Report of Condition of

                              THE BANK OF NEW YORK

                     of 48 Wall Street, New York, N.Y. 10286
                     And Foreign and Domestic Subsidiaries,
a member of the Federal Reserve System, at the close of business March 31, 1996,
published in accordance with a call made by the Federal Reserve Bank of this
District pursuant to the provisions of the Federal Reserve Act.

                                                          Dollar Amounts
ASSETS                                                      in Thousands
                                                          --------------
Cash and balances due from depos-
  itory institutions:
  Noninterest-bearing balances and
  currency and coin ..................                       $ 2,461,550
  Interest-bearing balances ..........                           835,563
Securities:
  Held-to-maturity securities ........                           802,064
  Available-for-sale securities ......                         2,051,263
Federal funds sold in domestic offices 
of the bank:
  Federal funds sold .................                         3,885,475
Loans and lease financing
  receivables:
  Loans and leases, net of unearned
    income .................27,820,159
  LESS: Allowance for loan and
    lease losses ..............509,817
  LESS: Allocated transfer risk
    reserve......................1,000
  Loans and leases, net of unearned
    income and allowance, and reserve                         27,309,342
Assets held in trading accounts ......                           837,118
Premises and fixed assets (including
  capitalized leases) ................                           614,567
Other real estate owned ..............                            51,631
Investments in unconsolidated
  subsidiaries and associated
  companies ..........................                           225,158
Customers' liability to this bank on
  acceptances outstanding ............                           800,375
Intangible assets ....................                           436,668
Other assets .........................                         1,247,908
                                                             -----------
Total assets .........................                       $41,558,682
                                                             -----------
                                                             -----------

LIABILITIES
Deposits:
  In domestic offices ................                       $18,851,327
  Noninterest-bearing .......7,102,645
  Interest-bearing .........11,748,682
  In foreign offices, Edge and
  Agreement subsidiaries, and IBFs ...                        10,965,064
  Noninterest-bearing ..........37,855
  Interest-bearing .........10,927,749
Federal funds purchased and secu-
  rities sold under agreements to re-
  purchase in domestic offices of
  the bank and of its Edge and
  Agreement subsidiaries, and in
  IBFs:
  Federal funds purchased ............                         1,224,886
  Securities sold under agreements
    to repurchase ....................                            29,728
Demand notes issued to the U.S.
  Treasury ...........................                           118,870
Trading liabilities ..................                           673,994
Other borrowed money:
  With original maturity of one year
    or less ..........................                         2,713,248
  With original maturity of more than
    one year .........................                            20,780
Bank's liability on acceptances exe-
  cuted and outstanding ..............                           803,292
Subordinated notes and debentures ....                         1,022,860
Other liabilities ....................                         1,590,564
                                                             -----------
Total liabilities ....................                        38,015,103
                                                             -----------

EQUITY CAPITAL
Common stock ........................                            942,284
Surplus .............................                            525,666
Undivided profits and capital
  reserves ..........................                          2,078,197
Net unrealized holding gains
  (losses) on available-for-sale
  securities ........................                              3,197
Cumulative foreign currency transla-
  tion adjustments ..................                        (    5,765)
                                                             -----------
Total equity capital ................                          3,543,579
                                                             -----------
Total liabilities and equity  capital                        $41,558,682
                                                             -----------
                                                             -----------


           I, Robert E. Keilman, Senior Vice President and Comptroller of the
above-named bank do hereby declare that this Report of Condition has been
prepared in conformance with the instructions issued by the Board of Governors
of the Federal Reserve System and is true to the best of my knowledge and
belief.

                                                         Robert E. Keilman

           We, the undersigned directors, attest to the correctness of this
Report of Condition and declare that it has been examined by us and to the best
of our knowledge and belief has been prepared in conformance with the
instructions issued by the Board of Governors of the Federal Reserve System and
is true and correct.


           J. Carter Bacot   }   
           Thomas A. Renyi   }   Directors
           Alan R. Griffith  }   --------------

 


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