ADVANCED RADIO TELECOM CORP
S-1/A, 1996-07-05
CABLE & OTHER PAY TELEVISION SERVICES
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<PAGE>
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 3, 1996
 
                                                      REGISTRATION NO. 333-03735
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                           --------------------------
                                AMENDMENT NO. 1
                                       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 (3)
Senior Discount Notes due 2006.........        (2)               N/A               N/A               (4)
Warrants to Purchase Common Stock......        (2)               N/A               N/A               (4)
</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) Includes $43,103  previously paid and  an increased filing  fee of  $17,242,
    which is being paid concurrently with this filing.
 
(4) 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 3, 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)             ,  1996
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                 , 1996. 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. 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 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)          , 1996 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)         , 1996 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
                                                , 1996 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        151,145        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 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, 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 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. 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 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
 
                                       12
<PAGE>
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
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
 
                                       13
<PAGE>
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.  Some of  these pending  applications are  in
conflict  with applications filed by third parties  and could not, in any event,
be granted unless the  conflicts were eliminated.  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."
 
                                       14
<PAGE>
    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
pursuant to management agreements (during the pendency of certain acquisitions).
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  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.
 
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
 
                                       15
<PAGE>
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 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.  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.
 
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.
 
                                       16
<PAGE>
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. Although the Company has been able to construct intermediary links
in some  instances to  solve line  of sight  limitations in  urban or  non-urban
areas, line of sight limitations can adversely impact sales to certain potential
customers. 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 the Company's  authorizations do not track
the appropriate growth  and development patterns  of potential customers  within
its  market areas or other 38 GHz  providers have greater geographic coverage or
more bandwidth, the Company may have a competitive disadvantage.
 
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."
 
                                       17
<PAGE>
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.  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."
 
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
 
                                       18
<PAGE>
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. 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."
 
                                       19
<PAGE>
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.
 
    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
 
                                       20
<PAGE>
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  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
 
                                       21
<PAGE>
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
28.4%  of the  Company's outstanding  Common Stock  (27.6% if  the underwriters'
over-allotment option is exercised  in full and 19.5%  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%  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 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
 
                                       22
<PAGE>
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. In  June 1996,  the FCC  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 Licenses Corporation," 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), DCT Agreements  (as
defined),  the Telecom One Agreements (as  defined) and the CommcoCCC Agreement,
has been reached with respect to any acquisition. Although the Company may  fund
research  and development activities and acquire or invest in related businesses
from time to time, no material agreement, agreement in principle,  understanding
or  other arrangement, other  than the letters of  intent with American Wireless
(as defined), QuestTV (as  defined) and Helioss (as  defined), has been  entered
into  with respect  to any such  funding, acquisition  or investment. 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           151,145           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 16.5  million 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  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."
 
    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.
 
                                       32
<PAGE>
    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.
 
    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.
 
                                       33
<PAGE>
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  $900,000 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  the
Company's  requirements, there can be no  assurance that such equipment would be
available to the
 
                                       34
<PAGE>
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,  it expects  to incur additional
expenses for research and development.
 
    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. 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 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
 
                                       35
<PAGE>
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, or 1.3%,  of the $97.1 billion in  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,
 
                                       37
<PAGE>
CAPs'  revenues will grow in excess 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.  EMI   Communications  Corporation   ("EMI")  (whose   licenses,
authorizations and related assets ART purchased in November 1995) was one of the
first  companies to  undertake commercial exploitation  of 38 GHz  services on a
regional basis.
 
    The 38 GHz band provides for the following additional advantages as compared
to other spectrum bands and wireline alternatives:
 
    - HIGHER 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,
 
                                       38
<PAGE>
      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.
 
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:
 
                                       39
<PAGE>
    - 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.
 
    - 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-
 
                                       40
<PAGE>
     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  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 and  will
     seek  to continue to  establish key strategic  alliances with major service
     providers,  equipment  manufacturers,  systems  integrators  and   enhanced
     service  providers.  Ameritech  Development Corp.  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."
 
                                       41
<PAGE>
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 (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
either  party if the Offerings  are not completed within 90  days of the date of
the CommcoCCC  Agreement or  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 agreed
not to  compete  with  the  Company  in  the  provision  of  wireless  broadband
telecommunication  services in  the 38  GHz band of  the radio  spectrum 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 certain of EMI's
customers on behalf of EMI for the terms provided in such EMI service agreements
for a period  of five years  from the date  of the agreement  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%. See "Certain Transactions -- ART West Joint Venture."
 
    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
 
                                       53
<PAGE>
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 closing conditions including FCC approval. ART has entered into
an exclusive  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.
 
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 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
 
                                       54
<PAGE>
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 and will  receive a per-unit fee  on radios sold  by
American  Wireless  to  third  parties. See  "Certain  Transactions  -- American
Wireless Development  Agreement."  This  arrangement is  subject  to  definitive
documentation.  The  Company has  entered  into a  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
 
                                       55
<PAGE>
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.
 
    Through June 15, 1996,  the Company has  incurred approximately $600,000  of
research and development expenses under such arrangements with several equipment
suppliers.  There can be  no assurance that the  Company can complete definitive
agreements with  any  of such  suppliers  or  that such  suppliers  can  develop
technologies with commercial value for the Company.
 
FOREIGN MARKETS
 
    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 contries. 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 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 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.
 
                                       56
<PAGE>
    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
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
 
                                       57
<PAGE>
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  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
 
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<PAGE>
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  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.
 
    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")
 
                                       59
<PAGE>
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.
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.
 
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<PAGE>
    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.
 
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-
 
                                       62
<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
 
                                       63
<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
 
                                       64
<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
 
                                       65
<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.
 
                                       66
<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 AT
                                NUMBER OF      PERCENT OF                            ASSUMED ANNUAL RATES OF STOCK
                                SECURITIES    TOTAL OPTIONS                          PRICE APPRECIATION FOR OPTION
                                UNDERLYING     GRANTED TO     EXERCISE                         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 price is based upon an estimate of the  fair
     market  value of the  Company's equity securities  at the time  of grant as
     determined by the Option Committee at the time of grant.
 
(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                                            417,693        338,998     $ 254,500    $    206,552
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 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 is
 
                                       67
<PAGE>
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 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 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  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,
 
                                       68
<PAGE>
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 exercisable immediately prior to death 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 provided.
 
    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  provided.  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 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.
 
                                       69
<PAGE>
    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 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
 
                                       70
<PAGE>
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 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
 
                                       71
<PAGE>
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,  providing 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."
 
                                       72
<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)........................      8,268,582       27.4       8,268,582               22.0
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)....................................      1,104,038        3.7       1,111,038(14)            2.9
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)................................      8,268,582       27.4       8,268,582               22.0
Thomas A. Grina (12).....................................        100,000          *         100,000                  *
James D. Miller (13).....................................         10,000          *          10,000                  *
All executive officers and directors as a group               20,476,045       66.6%     10,872,252(8)(15)        28.4%
 (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 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.
 
                                       73
<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) Includes 48,750 shares issuable  upon exercise of Indemnity Warrants.  Does
    not  include  154,000  shares  issuable upon  exercise  of  Bridge 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 c/o North American Salt
    Co., 8300 College Boulevard, Overland Park, Kansas 66210.
 
(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 will deposit all of its 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.
 
                                       74
<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 are consultants
to LHC.
 
                                       75
<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
 
                                       76
<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").
 
                                       77
<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. The Company has a call on the Telecom Series F preferred
stock and the Ameritech Warrant in the event Ameritech terminates such agreement
in the first  year or two  years, respectively,  of its term.  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 $624,305 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."
 
                                       78
<PAGE>
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
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    , 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
approved by the FCC 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  of
Telecom  on the date that the ART stockholders would have received in 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  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.
 
                                       79
<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)               , 1996 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
 
                                       80
<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.
 
                                       81
<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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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
 
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<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;
 
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<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
 
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<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
 
                                       87
<PAGE>
     (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.
 
    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 date  closest  to the  commencement  of such  12-month  period for  which  a
consolidated balance sheet of
 
                                       89
<PAGE>
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 than Common Stock
in  the surviving Person or  the Company) shall be  issued or distributed to the
 
                                       90
<PAGE>
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
 
                                       91
<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.
 
                                       92
<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.
 
                                       93
<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:
 
                                       94
<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
 
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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;
 
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(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
 
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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).
 
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<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.
 
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<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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<PAGE>
    "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
 
                                      106
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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.
 
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<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 ART  Serial  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,
 
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<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.
 
                                      115
<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
 
                                      116
<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.
 
                                      117
<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.
 
                                      118
<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.
 
                                      119
<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.
 
                                      120
<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.
 
                                      121
<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.
 
                                      122
<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.
 
                                      123
<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.
 
                                      124
<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 $10.00 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 313,644 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.......................................................   62
Principal Stockholders...........................................   73
Certain Transactions.............................................   75
Description of Units.............................................   80
Description of Notes.............................................   80
Description of Warrants..........................................  109
Description of Capital Stock.....................................  112
Description of Certain Indebtedness..............................  114
Certain Federal Income Tax Considerations........................  116
Underwriting.....................................................  119
Legal Matters....................................................  120
Experts..........................................................  120
Available Information............................................  120
Glossary.........................................................  121
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.*
      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  Form of Warrant Agreement.
      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.*
           (b) Form of Trustee Indemnification Agreement.*
           (c) Voting Agreement.*
           (d) Confidentiality Agreement.*
     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)
</TABLE>
 
                                      II-4
<PAGE>
<TABLE>
<C>        <S>                                                                              <C>
     10-4  (a) Registrant's Equity Incentive Plan, as amended.(2)
           (b) Form of Stock Option Agreement.*
     10-5  (a) Registrant's 1996 Non-Employee Directors Automatic Stock Option Plan.*
           (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.*
           (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.(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.*
           (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)
       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 will be contained in the Opinion of
            Counsel.*
</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.
 
                                      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 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 2, 1996.
 
                                          Advanced Radio Technologies
                                          Corporation
 
                                          By:     /s/ VERNON L. FOTHERINGHAM
 
                                             -----------------------------------
                                                   Vernon L. Fotheringham
                                                CHAIRMAN AND CHIEF EXECUTIVE
                                                           OFFICER
 
<TABLE>
<C>                                                     <S>                               <C>
                      SIGNATURES                                     TITLE                         DATE
- ------------------------------------------------------  --------------------------------  -----------------------
 
                 /s/ VERNON L. FOTHERINGHAM
     -------------------------------------------        Chairman, Chief Executive              July 2, 1996
                Vernon L. Fotheringham                   Officer and Director
 
                /s/ W. THEODORE PIERSON, JR.
     -------------------------------------------        Executive Vice President,              July 2, 1996
               W. Theodore Pierson, Jr.                  General Counsel and Director
 
                       /s/ MATTHEW C. GOVE
     -------------------------------------------        Director                               July 2, 1996
                   Matthew C. Gove
 
                       /s/ THOMAS A. GRINA
     -------------------------------------------        Executive Vice President               July 2, 1996
                   Thomas A. Grina                       and Chief Financial Officer
</TABLE>
 
                                      II-8
<PAGE>
                               POWER OF ATTORNEY
 
    KNOW ALL MEN  BY THESE PRESENTS,  that each person  whose signature  appears
below  hereby  severally constitutes  and  appoints Vernon  L.  Fotheringham and
Thomas A. Grina,  and each of  them, his true  and lawful attorneys-in-fact  and
agents,  with full power of substitution and  resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign any and all amendments
(including post-effective  amendments) to  this Registration  Statement and  all
documents  relating thereto, including one  or more registration statements that
may be filed to register additional securities for an offering pursuant to  Rule
462(b) under the Securities Act, and to file the same, with all exhibits hereto,
and  other documents in  connection therewith, with  the Securities and Exchange
Commission, granting  unto said  attorneys-in-fact and  agents, full  power  and
authority  to do and perform each and every act and thing necessary or advisable
to be done in and about the premises, as fully to all intents and purposes as he
might or  could do  in person,  hereby ratifying  and confirming  all that  said
attorneys-in-fact  and agents, or his substitute or substitutes, may lawfully do
or cause to be done in virtue hereof.
 
    Pursuant  to  the  requirements  of   the  Securities  Act  of  1933,   this
Registration  Statement has  been signed below  by the following  persons in the
capacities and on the dates indicated.
 
<TABLE>
<C>                                                     <S>                               <C>
                      SIGNATURES                        TITLE                                      DATE
- ------------------------------------------------------  --------------------------------  -----------------------
 
                 /s/ VERNON L. FOTHERINGHAM
     -------------------------------------------        Chairman, Chief Executive              July 2, 1996
                Vernon L. Fotheringham                   Officer and Director
 
                /s/ W. THEODORE PIERSON, JR.
     -------------------------------------------        Executive Vice President,              July 2, 1996
               W. Theodore Pierson, Jr.                  General Counsel and Director
 
                       /s/ MATTHEW C. GOVE
     -------------------------------------------        Director                               July 2, 1996
                   Matthew C. Gove
</TABLE>
 
                                      II-9
<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.*
        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    Form of Warrant Agreement.
        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.*
               (b) Form of Trustee Indemnification Agreement.*
               (c) Voting Agreement.*
               (d) Confidentiality Agreement.*
       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.*
       10-5    (a) Registrant's 1996 Non-Employee Directors Automatic Stock Option Plan.*
               (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)
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
<S>            <C>                                                                                        <C>
 EXHIBIT NO.                                          DESCRIPTION                                             PAGE
- -------------  -----------------------------------------------------------------------------------------  -------------
               (e)Asset Purchase Agreement dated June 24, 1996 with Extended Communications, Inc.*
               (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>
<PAGE>
<TABLE>
<CAPTION>
<C>            <S>                                                                                        <C>
 EXHIBIT NO.                                          DESCRIPTION                                             PAGE
- -------------  -----------------------------------------------------------------------------------------  -------------
      10-21    Services Agreement dated May 8, 1995 with Telecom.(1)
<C>            <S>                                                                                        <C>
      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.(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.*
               (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)
         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 will be contained in the Opinion of Counsel.*
</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.



<PAGE>

                                                               L&W DRAFT 6/17/96

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

                          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



                               PURCHASE AGREEMENT



                         Dated as of _____________, 1996



                MERRILL LYNCH, PIERCE FENNER & SMITH INCORPORATED

                              MONTGOMERY SECURITIES

                               SMITH BARNEY, INC.

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


<PAGE>

                          ADVANCED RADIO TELECOM CORP.
                            (a Delaware corporation)


                        _______ Units, each consisting of
         $1,000 Principal Amount of ____% Senior Discount Notes Due 2006
             and ___ Warrants to Purchase ___ Shares of Common Stock


                               PURCHASE AGREEMENT

                                                                   _______, 1996


Merrill Lynch, Pierce, Fenner & Smith Incorporated
Montgomery Securities
Smith Barney, Inc.
c/o Merrill Lynch, Pierce, Fenner & Smith Incorporated
  Merrill Lynch World Headquarters
  North Tower
  World Financial Center
  New York, New York  10281

Dear Sirs:

     Advanced Radio Telecom Corp., f/k/a Advanced Radio Technologies
Corporation, a Delaware corporation (the "COMPANY"), proposes to issue and sell
(the "OFFERING") to Merrill Lynch, Pierce, Fenner & Smith Incorporated
("MERRILL LYNCH"), Montgomery Securities ("MONTGOMERY SECURITIES") and Smith
Barney, Inc. ("SMITH BARNEY" and, together with Merrill Lynch and Montgomery
Securities, the "UNDERWRITERS") _______ units (the "UNITS"), each consisting of
(i) $1,000 aggregate principal amount at maturity of the Company's _____% Senior
Discount Notes due 2006 (the "NOTES"), to be issued under an Indenture, dated as
of ________________ __, 1996 (the "INDENTURE"), between the Company and
_____________, as trustee (the "TRUSTEE"), and (ii) _________ warrants,
(collectively, the "WARRANTS") to acquire ___ shares (collectively, the "WARRANT
SHARES") of the Company's common stock, $.001 par value per share (the "COMMON
STOCK"), to be issued under a Warrant Agreement, dated as of ______________ __,
1996 (the "WARRANT AGREEMENT"), between the Company and ________________, as
warrant agent (the "WARRANT AGENT").  The Notes and the Warrants will not be
separable until the earlier of (i) _____________, 1996 and (ii) such date as the
Underwriters may, in their discretion, deem appropriate (such date, the
"SEPARATION DATE").  The Units, the Notes and the Warrants are herein
collectively referred to as the "SECURITIES."  This Agreement, the Pricing
Agreement (as defined), the Indenture and the Warrant Agreement are herein
collectively referred to as the "OPERATIVE DOCUMENTS."  Capitalized terms used
but not otherwise defined herein shall have the meanings given to such terms in
the Indenture.


                                        1
<PAGE>

     Concurrently with the Offering, the Company is Offering, pursuant to a
separate prospectus, shares of Common Stock (the "COMMON STOCK OFFERING" and,
together with the Offering, the "OFFERINGS").  In addition, prior to
consummation of the Offerings, (i) Advanced Radio Telecom Corp. ("ART") will
merge with and into ART Merger Corporation, a subsidiary of the Company, (ii)
the Company will amend its certificate of incorporation to change its name to
"Advanced Radio Telecom Corp." and (iii) ART Merger Corporation will amend its
certificate of incorporation to change its name to ART Licenses Corporation
("ART LICENSES") (the "MERGER" and, together with the Offerings, the
"TRANSACTIONS").  Unless the context otherwise requires, the "Company" shall
refer to the Company after giving effect to the Merger.  References to
"subsidiaries" of the Company shall be deemed to include ART.

     Prior to the purchase and public offering of the Units by the Underwriters,
the Company and the Underwriters shall enter into an agreement substantially in
the form of Exhibit A hereto (the "PRICING AGREEMENT").  The Pricing Agreement
may take the form of an exchange of any standard form of written
telecommunication between the Company and the Underwriters and shall specify
such applicable information as is indicated in Exhibit A hereto.  The Offering
of the Units will be governed by this Agreement, as supplemented by the Pricing
Agreement.  From and after the date of the execution and delivery of the Pricing
Agreement, this Agreement shall be deemed to incorporate the Pricing Agreement.

     The Company has filed with the Securities and Exchange Commission (the
"COMMISSION") a registration statement on Form S-1 (No. 333-3735) with a related
preliminary prospectus for the registration of the Units under the Securities
Act of 1933, as amended (the "1933 ACT"), the Company has filed such amendments
thereto, if any, and such amended preliminary prospectuses as may have been
required to the date hereof, and will file such additional amendments thereto
and such amended prospectuses as may hereafter be required.  Such registration
statement (as amended, if applicable) and the prospectus constituting a part
thereof (including the information, if any, deemed to be part thereof pursuant
to Rule 430A(b) of the rules and regulations of the Commission under the 1933
Act (the "1933 ACT REGULATIONS")), as from time to time amended or supplemented
pursuant to the 1933 Act or otherwise, are hereinafter referred to as the
"REGISTRATION STATEMENT" and the "PROSPECTUS," except that if any revised
prospectus shall be provided to the Underwriters by the Company for use in
connection with the offering of the Units which differs from the Prospectus on
file at the Commission at the time the Registration Statement becomes effective
(whether or not such revised prospectus is required to be filed by the Company
pursuant to Rule 424(b) of the 1933 Act Regulations), the term "PROSPECTUS"
shall refer to such revised prospectus from and after the time it is first
provided to the Underwriters for such use.

     The Company understands that the Underwriters propose to make a public
offering of the Units as soon as they deem advisable after the Registration
Statement becomes effective, the Pricing Agreement has been executed and
delivered and the Indenture has been qualified under the Trust Indenture Act of
1939, as amended (the "TRUST INDENTURE ACT").

     SECTION 1.     REPRESENTATIONS AND WARRANTIES.  The Company represents and
warrants to each Underwriter as of the date hereof and as of the date of the
Pricing Agreement (such latter date being hereinafter referred to as the
"REPRESENTATION DATE") and agrees with each Underwriter that:

     (a)  At the time the Registration Statement becomes effective (including
each time a post-effective amendment thereto, if any, becomes effective), at the
Representation Date, when the Prospectus is first filed with the Commission
pursuant to Rule 424(b) of the 1933 Act Regulations, when any supplement to or
amendment of the Prospectus is filed with the Commission, and at the Closing
Date, the Registration Statement and, if filed at such time, the Prospectus and
any amendments thereof and supplements thereto will comply in all material
respects with the requirements of the 1933 Act and the


                                        2
<PAGE>

1933 Act Regulations and the requirements of the Trust Indenture Act and the
rules and regulations of the Commission under the Trust Indenture Act (the
"TRUST INDENTURE ACT REGULATIONS") and such Registration Statement did not and
will not contain an untrue statement of a material fact and will not omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading.  The Prospectus, at the Representation Date
(unless the term "Prospectus" refers to a prospectus which has been provided to
the Underwriters by the Company for use in connection with the offering of the
Units which differs from the Prospectus on file at the Commission at the time
the Registration Statement becomes effective, in which case at the time such
prospectus is first provided to the Underwriters for such use) and at the
Closing Time referred to in Section 2 hereof, did not and will not include an
untrue statement of a material fact or omit to state a material fact necessary
in order to make the statements therein, in the light of the circumstances under
which they were made, not misleading; when any related preliminary prospectus
was first filed with the Commission (whether filed as part of the Registration
Statement or an amendment thereof or pursuant to Rule 424(a) of the 1933 Act
Regulations) and when any amendment or supplement thereto was first filed with
the Commission, such preliminary prospectus and any amendment or supplement
thereto complied in all material respects with the applicable provisions of the
1933 Act, the 1933 Regulations and the Trust Indenture Act and did not contain
an untrue statement of a material fact and did not omit to state any material
fact required to be stated therein or necessary to make the statements therein,
in the light of the circumstances under which they were made not misleading;
PROVIDED, HOWEVER, that the representations and warranties in this subsection
shall not apply to statements in or omissions from the Registration Statement or
Prospectus made in reliance upon and in conformity with information furnished to
the Company in writing by the Underwriters expressly for use in the Registration
Statement or Prospectus or to information contained in the Statement of
Eligibility of the Trustee on Form T-1 under the Trust Indenture Act filed as an
exhibit to the Registration Statement; the Company and Art Corp. acknowledge for
all purposes under this Agreement (including Section 9 hereof) that the
statements set forth in the first and third paragraphs under the caption
"Underwriting" in the Prospectus constitute the only written information
furnished to the Company by the Underwriters for use in the Registration
Statement or the Prospectus or any preliminary prospectus (or any amendments or
supplements thereto).

     (b)  The Commission has not issued any order preventing or suspending the
use of any Preliminary Prospectus, and each Preliminary Prospectus has confirmed
in all material respects to the requirements of the 1933 Act and the 1933 Act
Regulations and, as of its date, has not included any untrue statement of a
material fact or omitted to state a material fact necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading; and at the time the Registration Statement becomes
effective, and at all times subsequent hereto up to and including each Closing
Date hereinafter mentioned, the Registration Statement and the Prospectus, and
any amendments or supplements thereto, will contain all material statements and
information required to be included therein by the 1933 Act and the 1933 Act
Regulations and will in all material respects conform to the requirements of the
1933 Act and the 1933 Act Regulations, and neither the Registration Statement
nor the Prospectus, nor any amendment or supplement thereto, will include any
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary to make the statements therein not misleading;
PROVIDED, HOWEVER, no representation or warranty contained in this Section 2(b)
shall be applicable to information contained in or omitted from any preliminary
prospectus, the Registration Statement, the Prospectus or any such amendment or
supplement in reliance upon and in conformity with written information furnished
to the Company by or on behalf of any Underwriter, directly or through the
Representatives, specifically for use in the preparation thereof.

     (c)  No action has been taken and no local, state or Federal law, statute,
ordinance, rules, regulation, requirement, judgment or court decree has been
enacted, adopted or issued by any


                                        3
<PAGE>

governmental agency that prevents the issuance of the Securities or prevents or
suspends the use of the Prospectus; no jurisdiction, restraining order or order
of any nature by a Federal or state court of competent jurisdiction has been
issued that prevents the issuance of the Securities or prevents or suspends the
sale of the Securities in any jurisdiction referred to in Section 3(h) hereof;
and every request of any securities authority or agency of any jurisdiction for
additional information has been complied with in all material respects.

     (d)  There are no contracts or other documents required to be described in
the Registration Statement or to be filed as exhibits to the Registration
Statement by the 1933 Act or by the 1933 Act Rules which have not been described
or filed as required.  The contracts so described in the Prospectus are accurate
and complete, and all such contracts are in full force and effect on the date
hereof.  Neither the Company nor any of its subsidiaries or, to the best of the
Company's knowledge, any other party is in breach of or default under any such
contract.

     (e)  Each of the Company and its subsidiaries has been duly formed as a
corporation and is validly existing in good standing under the laws of its
jurisdiction of incorporation and has all requisite corporate power and
authority to own, lease and operate its properties and to conduct its business
as described in the Prospectus.  Each of the Company and its subsidiaries is
duly qualified to do business and is in good standing as a foreign corporation
in each jurisdiction in which the nature of its business or its ownership or
leasing of property requires such qualification, except where the failure to be
so qualified would not have, either individually or in the aggregate, a material
adverse effect on the assets, properties, business, management, earnings, net
worth, results of operations, condition (financial or otherwise) or business
prospects of the Company and its subsidiaries, taken as a whole.  No proceeding
has been instituted in any such jurisdiction, revoking, limiting or curtailing,
or seeking to revoke, limit or curtail, such power and authority or
qualification.

     (f)  ART Licenses is the only subsidiary of the Company.  The Company owns
all of the outstanding capital stock of ART Licenses; all such capital stock has
been duly authorized and validly issued and is fully paid and nonassessable,
free and clear of any security interest, claim, lien, encumbrance or adverse
interest of any nature; and all of such capital stock was not issued in
violation of any preemptive or similar rights.  There are no outstanding
subscriptions, rights, warrants, calls, commitments of sale or options to
acquire, or instruments convertible into or exchangeable for, any such shares of
capital stock or other equity interest of ART Licenses.

     (g)  The Company and its subsidiaries do not have any ownership interest in
any joint venture, other than the Company's 50% ownership interest in ART West
Joint Venture, a Delaware partnership owned by the Company and Extended
Communications, Inc. ("ART WEST").

     (h)  Prior to consummation of the Transactions, the Company and ART have
authorized and outstanding capital stock as set forth in Exhibit B hereto.  All
such issued and outstanding shares of capital stock of the Company and ART have
been duly authorized and validly issued, are fully paid and non-assessable and
were not issued in violation of any preemptive or similar rights.  The shares of
capital stock of ART owned by the Company prior to completion of the Merger are
free and clear of any security interest, claim, lien, encumbrance or adverse
interest of any nature.  Upon consummation of the Transactions, the Company will
have authorized and outstanding capital stock as set forth in Exhibit C hereto
and an authorized and outstanding capitalization as set forth in the Prospectus
under the caption "Capitalization."  All such issued and outstanding shares of
capital stock of the Company will have been duly authorized and validly issued,
will be fully paid and non-assessable and will not have been issued in violation
of any preemptive or similar rights.  Except as disclosed in the Prospectus,
there are, and


                                        4
<PAGE>

there will be, no outstanding subscriptions, rights, warrants, calls,
commitments of sale or options to acquire, or instruments convertible into or
exchangeable for, any capital stock of the Company or ART  The description of
the Company's stock option, stock bonus and other stock plans or arrangements,
and the options or other rights granted and exercised thereunder, set forth in
the Prospectus accurately and fairly presents the information required to be
shown with respect to such plans, arrangements, options and rights.

     (i)  The Company has all requisite corporate power and authority to
execute, deliver and perform its obligations under the Operative Documents and
to consummate the transactions contemplated hereby and thereby, including,
without limitation, the corporate power and authority to issue, sell and deliver
the Securities as provided herein and therein.

     (j)  This Agreement has been, and, at the Representation Date, the Pricing
Agreement will have been, duly authorized and validly executed by the Company
and (assuming the due execution and delivery hereof by the Underwriters) are the
legally valid and binding agreements of the Company, enforceable against the
Company in accordance with their terms, except as the enforceability thereof may
be limited (i) by the effect of bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium or other similar laws now or hereafter in effect
relating to or affecting the rights and remedies of creditors, (ii) by the
effect of general principles of equity, whether enforcement is considered in a
proceeding in equity or at law, and the discretion of the court before which any
proceeding therefor may be brought and (iii) to the extent that rights to
indemnification and contribution thereunder may be limited by federal or state
securities laws or public policy relating thereto.

     (k)  The Company has duly authorized the Units and, when issued and
delivered to and paid for by the Underwriters in accordance with the terms
hereof, the Units will conform in all material respects to the description
thereof in the Prospectus.

     (l)  The Company has duly authorized the Indenture and, when the Company
has duly executed and delivered the Indenture (assuming the due authorization,
execution and delivery thereof by the Trustee), the Indenture will be the
legally valid and binding obligation of the Company, enforceable against the
Company in accordance with its terms, except as the enforceability thereof may
be limited (i) by the effect of bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium or other similar laws now or hereafter in effect
relating to or affecting the rights and remedies of creditors and (ii) by the
effect of general principles of equity, whether enforcement is considered in a
proceeding in equity or at law, and the discretion of the court before which any
proceeding therefor may be brought.  The Indenture has been duly qualified under
the Trust Indenture Act.

     (m)  The Company has duly authorized the Notes and, when issued and
authenticated in accordance with the terms of the Indenture and delivered to and
paid for by the Underwriters in accordance with the terms hereof, the Notes will
conform in all material respects to the description thereof in the Prospectus,
will be entitled to the benefits of the Indenture and will be the legally valid
and binding obligations of the Company, enforceable against the Company in
accordance with their terms, except as the enforceability thereof may be limited
(i) by the effect of bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium or other similar laws now or hereafter in effect
relating to or affecting the rights and remedies of creditors and (ii) by the
effect of general principles of equity, whether enforcement is considered in a
proceeding in equity or at law, and the discretion of the court before which any
proceeding therefor may be brought.


                                        5
<PAGE>

     (n)  The Company has duly authorized the Warrant Agreement and, when the
Company has duly executed and delivered the Warrant Agreement (assuming the due
authorization, execution and delivery thereof by the Warrant Agent), the Warrant
Agreement will be the legally valid and binding obligation of the Company,
enforceable against the Company in accordance with its terms, except as the
enforceability thereof may be limited (i) by the effect of bankruptcy,
insolvency, fraudulent transfer, reorganization, moratorium or other similar
laws now or hereafter in effect relating to or affecting the rights and remedies
of creditors, (ii) by the effect of general principles of equity, whether
enforcement is considered in a proceeding in equity or at law, and the
discretion of the court before which any proceeding therefor may be brought and
(iii) to the extent that rights to indemnification and contribution thereunder
may be limited by federal or state securities laws or public policy relating
thereto.

     (o)  The Company has duly authorized the Warrants and, when issued and
delivered in accordance with the terms of the Warrant Agreement and delivered to
and paid for by the Underwriters in accordance with the terms hereof, the
Warrants will conform in all material respects to the description thereof in the
Prospectus and will have been validly issued, and the issuance of such Warrants
will not be subject to any preemptive or similar rights.

     (p)  The Company has duly authorized and reserved for issuance the Warrant
Shares to be issued upon the exercise of the Warrants and, when issued and
delivered upon the exercise of the Warrants against payment of the Exercise
Price as provided in the Warrant Agreement, the Warrant Shares will conform in
all material respects to the description thereof in the Prospectus, will have
been duly issued and will be fully paid and non-assessable, and the issuance of
such Warrant Shares will not be subject to any preemptive or similar rights.

     (q)  No approval, authorization, order, consent, registration, filing,
qualification, license or permit of or with any court, regulatory,
administrative or other governmental body is required for the execution and
delivery of this Agreement by the Company or the consummation of the
transactions contemplated by this Agreement, except such as have been obtained
and are in full force and effect under the Act and such as may be required under
applicable Blue Sky laws in connection with the purchase and distribution of the
Common Shares by the Underwriters and the clearance of such offering with the
National Association of Securities Dealers, Inc. (the "NASD").

     (r)  None of the execution, delivery and performance of the Operative
Documents by the Company, the compliance by the Company with all of the
provisions hereof and thereof, the issuance and sale of the Securities, the
consummation by the Company and its subsidiaries of the Transactions and the
transactions contemplated hereby and thereby (i) require any consent, approval,
authorization or other order of or filing, registration, qualification, license
or permit of or with, any court, regulatory body, administrative agency or other
governmental body (including, without limitation, the Federal Communications
Commission (the "FCC")), other than those that have been obtained and are in
full force and effect, or (ii) violate, conflict with, or constitute a breach of
any of the terms or provisions of, or a default under (or an event that with
notice or the lapse of time, or both, would constitute a default), or require
consent under, or result in the imposition of a lien or encumbrance on any
properties of the Company and its subsidiaries pursuant to (A) the charter or
bylaws of the Company or any of its subsidiaries, (B) any bond, debenture, note,
mortgage, deed of trust or other agreement, indenture or other instrument to
which or by which any of them is a party or by which any of them or any of their
respective property is or may be bound, (C) any local, state or Federal law,
statute, ordinance, rule, regulation or requirement (including, without
limitation, the Communications Act of 1934, as amended by the Telecommunications
Act of 1996 (the "TELECOMMUNICATIONS ACT"), the rules and regulations of the FCC
and the environmental laws, statutes, ordinances, rules or regulations)
applicable to the Company,


                                        6
<PAGE>

any of its subsidiaries or any of their respective assets or properties or (D)
any judgment, order or decree of any court or governmental agency or authority
having jurisdiction over the Company, any of its subsidiaries or any of their
assets or properties, that, in the case of clauses (B), (C) and (D), (x) would
reasonably be expected, either individually or in the aggregate, to result in a
material adverse effect on the assets, properties, business, management,
earnings, net worth, results of operations, condition (financial or otherwise)
or business prospects of the Company and its subsidiaries, taken as a whole, (y)
would materially interfere with or adversely affect the issuance of the
Securities or the consummation of the Transactions or (z) in any manner draw
into question the validity of any of the Operative Documents (any of the events
set forth in clauses (x), (y) or (z), a "MATERIAL ADVERSE EFFECT").

     (s)  Neither the Company nor any of its subsidiaries is or, after giving
effect to the Transactions, will be (i) in violation of its charter or bylaws,
(ii) in default in the performance of any material obligation, agreement or
condition contained in any bond, debenture, note or any other evidence of
indebtedness or in any other agreement, indenture or instrument material to the
conduct of the business of the Company and its subsidiaries, taken as a whole,
to which any of them is a party, or by which any of them or any of their
respective properties is bound or (iii) in violation of any local, state or
Federal law, statute, ordinance, rule, regulation, requirement, judgment or
court decree (including, without limitation, the Telecommunications Act and the
rules and regulations of the FCC and environmental laws, statutes, ordinances,
rules, regulations, judgments or court decrees) applicable to any of them or any
of their respective assets or properties (whether owned or leased), other than,
in the case of clauses (ii) and (iii), any default or violation that could not
reasonably be expected to have a Material Adverse Effect.  There exists no
condition that, with notice, the passage of time or otherwise, would constitute
a default under any such document or instrument that could be expected to have a
Material Adverse Effect.

     (t)  There is (i) no action, suit or proceeding before or by any court,
arbitrator or governmental agency, body or official, domestic or foreign, now
pending or threatened or contemplated to which the Company or any of its
subsidiaries is or may be a party or to which the business or property of any of
them is subject, (ii) no local, state or Federal law, statute, ordinance, rule,
regulation, requirement, judgment or court decree (including, without
limitation, the Telecommunications Act and the rules and regulations of the FCC)
or order has been enacted, adopted or issued by any governmental agency or, to
the best of the Company's knowledge, that has been proposed by any governmental
body or (iii) no injunction, restraining order or order of any nature by a
Federal or state court or foreign court of competent jurisdiction to which the
Company, any of its subsidiaries or their business, assets, or property are, or
could reasonably be expected to be, subject.

     (u)  Each of the Company and its subsidiaries has (i) good and marketable
title, free and clear of all liens, claims, encumbrances and restrictions,
except for liens for taxes not yet due and payable and other liens not material
to the business, prospects, financial condition or results of operations of the
Company and its subsidiaries, taken as a whole, to all property and assets
described in the Registration Statement as currently being owned by each of the
Company and its subsidiaries and (ii) all licenses, certificates, permits,
authorizations, approvals, franchises and other rights from, and has made all
declarations and filings with, all Federal, state and local authorities
(including, without limitation, the FCC), all self-regulatory authorities and
all courts and other tribunals (each an "AUTHORIZATION") necessary to engage in
the business as presently and to be conducted by either of them in the manner
described in the Prospectus, except as described in the Prospectus.  All such
Authorizations are valid and in full force and effect and each of the Company
and its subsidiaries is in compliance with the terms and conditions of all such
Authorizations and with the rules and regulations of the regulatory authorities
having jurisdictions with respect thereto.  All leases to which the Company or
any of its subsidiaries is a party are valid and binding, and no default has
occurred or is continuing thereunder which could reasonably


                                        7
<PAGE>

be expected to result in a Material Adverse Effect.  Each of the Company and its
subsidiaries enjoys peaceful and undisturbed possession under all such Leases to
which it is a party as lessee or as assignee of lessee with such exceptions as
do not materially interfere with the use made by the Company or its
subsidiaries.

     (v)  Each of the Company and its subsidiaries has such permits, licenses,
franchises, trademarks and authorizations of governmental or regulatory
authorities ("PERMITS") as are necessary to own, lease and operate their
respective properties and to conduct their respective business in the manner
described in the Prospectus.  Each of the Company and its subsidiaries has
fulfilled and performed all of its material obligations with respect to such
Permits and no event has occurred which allows, or after notice or lapse of time
would allow, revocation or termination thereof or result in any other material
impairment of the rights of the holder of any such Permit, except for any such
impairments which would not, individually or in the aggregate, have a Material
Adverse Effect.  Except as described in the Prospectus, such Permits contain no
restrictions that are materially burdensome to the Company and its subsidiaries,
taken as a whole.

     (w)  Except as described in the Prospectus, (i) the Company and its
subsidiaries own, possess or have the right to employ or have applied for all
such Permits, licenses (including all FCC, state, local or other jurisdictional
regulatory licenses, franchises, trademarks and authorizations of governmental
or regulatory authorities ("LICENSES")), patents, patent rights, know-how
(including trade secrets and other unpatented and/or unpatentable proprietary or
confidential information, software, systems or procedures), inventions,
technical data and information (collectively with Licenses, the "INTELLECTUAL
PROPERTY") as are necessary to own, lease and operate their respective
properties and to conduct their respective business in the manner described in
the Prospectus, (ii) each of the Company and its subsidiaries has fulfilled and
performed all of its material obligations with respect to such Licenses and
other Intellectual Property and no event has occurred which allows, or after
notice or lapse of time would allow, revocation or termination thereof or result
in any other material impairment of the rights of the holder of any such
Intellectual Property, (iii) such Intellectual Property contain no restrictions
that are materially burdensome to the Company and its subsidiaries, taken as a
whole, and (iv) the use of the Intellectual Property in connection with the
business and operations of the Company and its subsidiaries does not infringe on
the rights of any person, except where such infringement would not have a
Material Adverse Effect.

     (x)  The Company and its subsidiaries have timely filed all renewal
applications with respect to all Licenses possessed by any of them.  No protests
or competing applications have been filed with respect to such renewal
applications, and nothing has come to the Company's or any of its subsidiaries'
attention that would lead them to conclude that such renewal applications will
not be granted by the appropriate regulatory agency or body in the ordinary
course.  The Company and its subsidiaries are authorized under the
Telecommunications Act, and the rules and regulations promulgated thereunder, to
continue to provide the services which are the subject of such renewal
applications during the pendency thereof.

     (y)  The development, implementation and operation of the 38 GHz wireless
broadband telecommunications services network as described, and in the markets
described, in the Prospectus will not (i) result in any violation of the
provisions of the charter or bylaws of the Company or any of its subsidiaries,
(ii) result in any violation of any applicable law, administrative regulation or
administrative or court decree (including, without limitation, the
Telecommunication Act, and the rules and regulations of the FCC and
environmental laws), or (iii) conflict with or constitute a breach or violation
of, or constitute a default under, or result in the creation or imposition of
any lien, charge or encumbrance upon any property or assets of the Company or
its subsidiaries pursuant to, any contract, indenture, mortgage,


                                        8
<PAGE>

loan agreement, note, lease or other instrument to which the Company or any of
its subsidiaries is a party or by which any of them may be bound, or to which
any of their property is subject, except, in the case of clauses (ii) and (iii)
above, any such violations, conflicts or breaches that would not, individually
or in the aggregate, have a Material Adverse Effect.

     (z)  The business and operations conducted and proposed to be conducted by
the Company and its subsidiaries as described in the Prospectus are not
regulated by any public service or public utility commissions in the States in
which the Company and its subsidiaries conduct or propose to conduct such
business and operations as described in the Prospectus; and, subject to the
provisions of Section 332(c)(3) of the Telecommunications Act, neither the
Company nor any of its subsidiaries is or will be required to obtain any License
from any public service or public utility commission in any such State.

     (aa) None of the execution, delivery and performance of the Operative
Documents by the Company, the compliance by the Company with all of the
provisions hereof and thereof, the issuance and sale of the Common Shares, the
consummation by the Company and its subsidiaries of the Transactions and the
transactions contemplated hereby and thereby (i) require any consent, approval,
authorization or other order of or filing, registration, qualification, license
or permit of or with, the FCC, other than those that have been obtained and are
in full force and effect, or (ii) violate, conflict with, or constitute a breach
of any of the terms or provisions of, or a default under (or an event that with
notice or the lapse of time, or both, would constitute a default), or require
consent under, or result in the imposition of a lien or encumbrance on any
properties of the Company or any of its subsidiaries pursuant to (A) the
Telecommunications Act or the rules and regulations of the FCC applicable to the
Company, any of its subsidiaries or any of their respective assets or properties
or (B) any judgment, order or decree of any court or governmental agency or
authority having jurisdiction over the Company, any of its subsidiaries or any
of their assets or properties, that, in the case of clauses (A) and (B), would
reasonably be expected, either individually or in the aggregate, to result in a
Material Adverse Effect.

     (ab) Neither the Company nor any of its subsidiaries is or, after giving
effect to the Transactions, will be in violation of the Telecommunications Act
and the rules and regulations of the FCC applicable to the Company, any of its
subsidiaries or any of their respective assets or properties (whether owned or
leased), other than any violation that could not reasonably be expected to have
a Material Adverse Effect.

     (ac) Other than rulemaking procedures of general applicability to the
wireless broadband telecommunications industry, there is (i) no action, suit or
proceeding before or by the FCC, now pending or threatened or contemplated to
which the Company or any of its subsidiaries is or may be a party or to which
the business or property of the Company or any of its subsidiaries is subject,
or (ii) no amendment or change to the Telecommunications Act and the rules and
regulations of the FCC has been enacted, adopted or issued by the FCC or, to the
best of such counsel's knowledge, that has been proposed by the FCC.

     (ad) Each of the Company and its subsidiaries has filed all reports
required to be filed with the FCC.

     (ae) Neither the Company nor any of its subsidiaries has violated any
foreign, Federal, state or local law or regulation relating to the protection of
human health and safety, the environment or hazardous or toxic substances or
wastes, pollutants or contaminants, except where any such violations would not,
individually or in the aggregate, have a Material Adverse Effect.


                                        9
<PAGE>

     (af) All tax returns required to be filed by the Company or any of its
subsidiaries in any jurisdiction have been so filed.  All taxes, including
withholding taxes, penalties and interest, assessments, fees and other charges
due or claimed to be due from such entities or that are due and payable have
been paid, other than those being contested in good faith and for which adequate
reserves have been provided for those currently payable without penalty or
interest.  There are no proposed additional taxes assessments against the
Company or any of its subsidiaries, and neither the Company nor any of its
subsidiaries has any knowledge of any tax deficiency which has been or might be
asserted or threatened against the Company or any of its subsidiaries which
could have a Material Adverse Effect.

     (ag) Each of the Company and its subsidiaries maintains adequate insurance
covering its properties, operations, personnel and business.  Such insurance
insures against such losses and risks as are adequate in accordance with
customary industry practice to protect the Company, its subsidiaries and their
respective businesses.  All such insurance is outstanding and duly in force on
the date hereof.

     (ah)      None of the Company, its subsidiaries or any of their respective
officers, directors, partners, employees, agents or affiliates or any other
person acting on behalf of the Company or any of its subsidiaries, as the case
may be, has, directly or indirectly, given or agreed to give any money, gift or
similar benefit (other than legal price concessions to consumers in the ordinary
course of business) to any customer, supplier, employee or agent of a customer
or supplier, official or employee of any governmental agency (domestic or
foreign), instrumentality of any government (domestic or foreign) or any
political party or candidate for office (domestic or foreign) or other person
who was, is or may be in a position to help or hinder the business of the
Company or its subsidiaries (or assist the Company or any of its subsidiaries in
connection with any actual or proposed transaction ) which (i) might subject the
Company, any of its subsidiaries or any other individual or entity to any damage
or penalty in any civil, criminal or governmental litigation or proceeding
(domestic or foreign) or (ii) could reasonably be expected to have a Material
Adverse Effect.

     (ai) Coopers & Lybrand, L.L.P., who have expressed their opinion with
respect to the financial statements and schedules filed with the Commission as
part of the Registration Statement and included in the Prospectus and in the
Registration Statement, are independent public accountants as required by the
1933 Act and the rules and regulations of the Commission thereunder.

     (aj) The financial statements, together with related schedules and notes
forming part of the Registration Statement and the Prospectus (and any amendment
or supplement thereto), present fairly the individual and consolidated financial
positions, results of operations and changes in financial position of the
Company, its subsidiaries and ART on the basis stated in the Registration
Statement and the Prospectus (and any amendment or supplement thereto) at the
respective dates or for the respective periods to which they apply.  Such
statements and related schedules and notes have been prepared in accordance with
generally accepted accounting principles consistently applied through the
periods involved, except as disclosed therein.  The other financial and
statistical information and data set forth in the Registration Statement and the
Prospectus (and any amendment or supplement thereto) is, in all material
respects, accurately presented and prepared on a basis consistent with such
financial statements and the books and records of the Company, its subsidiaries
and ART, as applicable.  The pro forma financial information and other financial
information included in the Prospectus present fairly the information shown
therein, have been prepared in accordance with the Commission's rules and
regulations with respect to pro forma financial information, have been properly
compiled on the pro forma basis described therein, and, in the opinion of the
Company, the assumptions used in the preparation thereof are reasonable and the
adjustments used therein are appropriate to give effect to the transactions or
circumstances referred to therein.  No other financial statements or schedules
are required


                                       10
<PAGE>

to be included in the Registration Statement.  The selected financial data set
forth in the Prospectus under the captions "Capitalization" and "Selected
Historical and Pro Forma Financial Data" fairly present the information set
forth therein on the basis stated in the Registration Statement.

     (ak) Each of the Company and its subsidiaries maintains a system or
internal accounting controls sufficient to provide reasonable assurance that (i)
transactions are executed in accordance with management's general or specific
authorizations, (ii) transactions are recorded as necessary to permit
preparation of financial statements in conformity with generally accepted
accounting principles and to maintain accountability for assets, (iii) access to
assets is permitted only in accordance with management's general or specific
authorizations and (iv) the recorded accountability for assets is compared with
the existing assets at reasonable intervals and appropriate action is taken with
respect thereto.

     (al) Subsequent to the respective dates as of which information is given in
the Prospectus and except as set forth in the Prospectus, (i) neither the
Company nor any of its subsidiaries has incurred any liabilities or obligations,
direct or contingent, which are material, individually or in the aggregate, to
the Company and its subsidiaries, taken as a whole, nor entered into any
transaction not in the ordinary course of business, (ii) neither the Company nor
any of its subsidiaries has sustained any material loss or interference with its
businesses or properties from fire, flood, windstorm, accident or other
calamity, whether or not covered by insurance, (iii) there has not been,
individually or in the aggregate, any change or development which could
reasonably be expected to result in a Material Adverse Effect and (iv) there has
been no dividend or distribution of any kind declared, paid or made by the
Company or any of its subsidiaries on any class of capital stock.

     (am) The Company does not intend to, nor does it believe that it will,
incur debts beyond its ability to pay such debts as they mature.  The present
fair saleable value of the assets of the Company on a consolidated basis exceeds
the amount that will be required to be paid on or in respect of the existing
debts and other liabilities (including contingent liabilities) of the Company on
a consolidated basis as they become absolute and matured.  The assets of the
Company on a consolidated basis do not constitute unreasonably small capital to
carry out the business of the Company and its subsidiaries, taken as a whole, as
conducted or as proposed to be conducted.

     (an) Neither the Company nor any of its subsidiaries is (i) an "investment
company" or a company "controlled" by an "investment company" within the meaning
of the Investment Company Act of 1940, as amended, or (ii) a "holding company"
or a "subsidiary company" or an "affiliate" of a holding company within the
meaning of the Public Utility Holding Company Act of 1935, as amended.

     (ao) No holders of any securities of the Company or affiliates or of any
options, warrants or other convertible or exchangeable securities of the Company
or ART or affiliates are entitled to include any such securities in or to have
such securities registered under the Registration Statement or any registration
statement required to be filed by the Company pursuant to the Warrant Agreement
(or, to the extent any such holders are so entitled with respect to the
Registration Statement or any registration statement required to be filed
pursuant to the Warrant Agreement, written waivers have been obtained and copies
thereof delivered to the Underwriters).

     (ap) None of the execution, delivery and performance of this Agreement, the
issuance and sale of the Securities, the application of the proceeds from the
issuance and sale of the Securities and the consummation of the transactions
contemplated thereby as set forth in the Prospectus, will violate Regulation G,
T, U or X promulgated by the Board of Governors of the Federal Service System or
analogous foreign laws and regulations.


                                       11
<PAGE>

     (aq) The Company has not distributed, and will not distribute prior to the
Closing Date, any offering material in connection with the offering and sale of
the Securities other than the Prospectus, the Registration Statement and the
other materials permitted by the Act.

     (ar) Neither the Company nor any of its subsidiaries has (i) taken,
directly or indirectly, any action designed to, or that might reasonably be
expected to, cause or result in stabilization or manipulation of the price of
any security of the Company to facilitate the sale or resale of the Securities
or (ii) since the date of the Prospectus (A) sold, bid for, purchased or paid
any person any compensation for soliciting purchases of, the Securities or (B)
paid or agreed to pay to any person any compensation for soliciting another to
purchase any other securities of the Company.

     (as) Except pursuant to this Agreement, there are no contracts, agreements
or understandings between the Company or any of its subsidiaries and any other
person that would give rise to a valid claim against the Company, any of its
subsidiaries or any of the Underwriters for a brokerage commission, finder's fee
or like payment in connection with the issuance, purchase and sale of the
Securities.

     (at) Each of the Company and its subsidiaries has complied with all
provisions of Section 517.075, Florida Statutes.

     (au) Except as disclosed in the Prospectus, there are no business
relationships or related party transactions required to be disclosed therein
pursuant to Item 404 of Regulation S-K of the Commission.

     Each certificate signed by any officer of the Company and delivered to the
Underwriters or counsel to the Underwriters pursuant to this Agreement shall be
deemed to be a representation and warranty by the Company to the Underwriters as
to the matters covered thereby.

     The Company acknowledges that each of the Underwriters and, for purposes of
the opinions to be delivered to the Underwriters pursuant to Section 5 hereof,
counsel to the Company and counsel to the Underwriters, will rely upon the
accuracy and truth of the foregoing representations and hereby consents to such
reliance.

     SECTION 2.     SALE AND DELIVERY TO THE UNDERWRITERS; CLOSING.  (a)  On the
basis of the representations and warranties herein contained and subject to the
terms and conditions herein set forth, the Company agrees to sell to each
Underwriter, and each Underwriter, severally and not jointly, agrees to purchase
from the Company, the number of Units set forth opposite the name of such
Underwriter in Schedule I hereto, at the purchase price set forth in the Pricing
Agreement.

          (i)  If the Company has elected not to rely upon Rule 430A under the
     1933 Act Regulations, the initial public offering price and the purchase
     price of the Units to be paid by the Underwriters has been determined and
     set forth in the Pricing Agreement, dated the date hereof, and an amendment
     to the Registration Statement and the Prospectus will be filed before the
     Registration Statement becomes effective.

          (ii) If the Company has elected to rely upon Rule 430A under the 1933
     Act Regulations, the purchase price of the Units to be paid by the
     Underwriters shall be agreed upon and set forth in the Pricing Agreement.
     In the event that such price has not been agreed upon and the Pricing
     Agreement has not been executed and delivered by all parties thereto by the
     close of business on the third business day following the date of this
     Agreement, this Agreement shall


                                       12
<PAGE>

     terminate forthwith without liability of any party to any other party,
     unless otherwise agreed to by the Company and the Underwriters.

     (b)  Payment of the purchase price for and delivery of the Units shall be
made at the offices of Merrill Lynch, Pierce, Fenner & Smith Incorporated at
Merrill Lynch World Headquarters, North Tower, World Financial Center, New York,
New York 10281, or at such other place as the Underwriters shall designate, at
10:00 A.M. on the third business day (unless postponed in accordance with the
provisions of Section 9) following the date the Registration Statement becomes
effective (or, if the Company has elected to rely upon Rule 430A of the 1933 Act
Regulations, the third business day after execution of the Pricing Agreement),
or such other time not later than ten business days after such date as shall be
agreed upon by the Underwriters, and the Company (such time and date of payment
and delivery being herein called the "CLOSING TIME").

     Payment shall be made to the Company, as applicable, by [certified or
official bank check or checks drawn in New York Clearing House funds payable to
the order of the Company, as applicable,] against delivery to the Underwriters
of the Units to be purchased by them hereunder, with any transfer taxes thereon
duly paid by the Company.  The Units shall be in such denominations and
registered in such names as the Underwriters may request in writing at least two
business days before the Closing Time.  The Units will be made available for
examination and packaging by the Underwriters no later than 10:00 A.M. on the
last business day prior to the Closing Time.

     SECTION 3.     COVENANTS OF THE COMPANY.  The Company covenants with each
Underwriter as follows:

     (a)  To prepare and file with the Commission, promptly upon the
Underwriters' request, any amendments or supplements to the Registration
Statement or the Prospectus as soon as practicable after the execution and
delivery of this Agreement and to use its best efforts to cause the Registration
Statements and any amendment thereof, if not effective at the time and date that
this Agreement is executed and delivered by the parties hereto, to become
effective at the earliest possible time.  If the Registration Statement has
become or becomes effective pursuant to Rule 430A of the 1933 Act Regulations,
or the filing of the Prospectus is otherwise required under Rule 424(b) of the
1933 Regulations, the Company will file the Prospectus, properly completed,
pursuant to the applicable paragraph Rule 424(b) of the 1933 Act Regulations
within the time period prescribed and will provide evidence satisfactory to you
of such timely filing.  The Company will fully and completely comply with the
provisions of Rule 430A of the 1933 Act Regulations with respect to information
omitted from the Registration Statement in reliance upon such Rule.

     (b)  To advise the Underwriters promptly and, if requested by the
Underwriters, to confirm such advice in writing, (i) when the Registration
Statement has become effective and when any post-effective amendment to it
becomes effective, (ii) of any request by the Commission for amendments to the
Registration Statement or amendments or supplements to the Prospectus or for
additional information, (iii) of the issuance by the Commission of any stop
order suspending the effectiveness of the Registration Statement or of the
suspension of qualification of the Notes for offering or sale in any
jurisdiction, or the initiation of any proceeding for such purposes, and (iv) of
the happening of any event during the period referred to in paragraph (f) below
which makes any statement of a material fact made in the Registration Statement
or the Prospectus untrue or which requires the making of any additions to or
changes in the Registration Statement or the Prospectus in order to make the
statements therein not misleading.  If at any time the Commission shall issue
any stop order suspending the effectiveness of the Registration


                                       13
<PAGE>

Statement, the Company will make every reasonable effort to obtain the
withdrawal or lifting of such order at the earliest possible time.

     (c)  To furnish to the Underwriters, without charge, three signed copies of
the Registration Statement as first filed with the Commission and of each
amendment to it, including all exhibits, and to furnish to the Underwriters such
number of conformed copies of the Registration Statement as so filed and of each
amendment to it, without exhibits, as the Underwriters may reasonably request.

     (d)  At any time prior to completion of the distribution of the Securities
by the Underwriters to purchasers who are not affiliates of the Underwriters,
the Company will, subject to Section 3(e), file promptly all documents required
to be filed with the Commission pursuant to Section 13, 14 or 15(d) of the 1934
Act.

     (e)  Not to file any amendment or supplement to the Registration Statement,
whether before or after the time when it becomes effective, or to make any
amendment or supplement to the Prospectus of which the Underwriters shall not
previously have been advised or to which the Underwriters shall reasonably
object and to prepare and file with the Commission, promptly upon the
Underwriters' reasonable request, any amendment to the Registration Statement or
supplement to the Prospectus which may be necessary or advisable in connection
with the distribution of the Securities by the Underwriters, and to use its best
efforts to cause the same to become promptly effective.

     (f)  Promptly after the Registration Statement becomes effective, and from
time to time thereafter for such period as, in the opinion of counsel to the
Underwriters, a prospectus is required by law to be delivered in connection with
sales by an Underwriter or a dealer, to furnish, without charge, to each
Underwriter and dealer as many copies of the Prospectus (and of any amendment or
supplement to the Prospectus) as such Underwriter or dealer may reasonably
request.

     (g)  If during the period specified in paragraph (f) above any event shall
occur as a result of which, in the opinion of counsel to the Underwriters, it
becomes necessary to amend or supplement the Prospectus in order to make the
statements therein, in the light of the circumstances when the Prospectus is
delivered to a purchaser, not misleading, or if it is necessary to amend or
supplement the Prospectus to comply with any law, forthwith to prepare and file
with the Commission, at its own expense, an appropriate amendment or supplement
to the Prospectus so that the statements in the Prospectus, as so amended or
supplemented, will not in the light of the circumstances when it is so
delivered, be misleading, or so that the Prospectus will comply with law, and to
furnish to each Underwriter and to such dealers as the Underwriters shall
specify, such number of copies thereof as such Underwriter or dealers may
reasonably request.

     (h)  Prior to any public offering of the Units, to cooperate with the
Underwriters and counsel to the Underwriters in connection with the registration
or qualification of the Units for offer and sale by the several Underwriters and
by dealers under the state securities or Blue Sky laws of such jurisdictions as
the Underwriters may reasonably request, to continue such qualification in
effect so long as required for distribution of the Units and to file such
consents to service of process or other documents as may be necessary in order
to effect such registration or qualification in effect so long as required for
distribution of the Units and to file such consents to service of process or
other documents as may be necessary in order to effect such registration or
qualification, PROVIDED that, in connection therewith, the Company shall not be
required to file as a foreign corporation or to file a general consent to
service of process in any jurisdiction where it is not now so subject.


                                       14
<PAGE>

     (i)  To mail and make generally available to its securityholders as soon as
reasonably practicable an earnings statement covering a period of at least
twelve months commencing no later than 90 days after the effective date of the
Registration Statement which shall satisfy the provisions of Section 11(a) of
the 1933 Act, and to advise the Underwriters in writing when such statement has
been so made available.

     (j)  During the period of five years after the date of this Agreement, (i)
to mail as soon as reasonably practicable after the end of each fiscal year to
the record holders of the Securities a financial report of the Company and its
subsidiaries on a consolidated basis (and a similar financial report of all
unconsolidated subsidiaries, if any), all such financial reports to include a
consolidated balance sheet, a consolidated statement of operations, a
consolidated statement of cash flows and a consolidated statement of
shareholders' equity as of the end of and for such fiscal year, together with
comparable information as of the end of and for the preceding year, certified by
independent certified public accountants, and (ii) to mail and make generally
available as soon as practicable after the end of each quarterly period (except
for the last quarterly period of each fiscal year) to such holders, a
consolidated balance sheet, a consolidated statement of operations and a
consolidated statement of cash flows (and similar financial reports of all
unconsolidated subsidiaries, if any) as of the end of and for such period, and
for the period from the beginning of such year to the close of such quarterly
period, together with comparable information for the corresponding periods of
the preceding year.

     (k)  During the period referred to in paragraph (j) above, to furnish to
the Underwriters as soon as available a copy of each report or other publicly
available information of the Company mailed to the holders of Securities of the
Company or filed with the Commission and such other publicly available
information concerning the Company and its subsidiaries, if any, as the
Underwriters may reasonably request.

     (l)  If, at any time that the Registration Statement becomes effective, any
information shall have been omitted therefrom in reliance upon Rule 430A of the
1933 Act Regulations, then immediately following the execution of the Pricing
Agreement, the Company will prepare, and file or transmit for filing with the
Commission in accordance with such Rule 430A and Rule 424(h) of the 1933 Act
Regulations, copies of the amended Prospectus, or, if required by such Rule
430A, a post-effective amendment to the Registration Statement (including
amended Prospectus), containing all information so omitted.

     (m)  To use the proceeds from the sale of the Units in the manner described
in the Prospectus under the caption "Use of Proceeds."

     (n)  Not to voluntarily claim, and to resist actively any attempts to
claim, the benefit of any usury laws against the holders of any Securities.

     (o)  To use its best efforts to do and perform all things required or
necessary to be done and performed under this Agreement by the Company prior to
the Closing Time and to satisfy all conditions precedent to the delivery of the
Units.

     SECTION 4.     PAYMENT OF EXPENSES.  Whether or not the transactions
contemplated hereunder are consummated or this Agreement becomes effective or is
terminated, the Company will pay all costs, expenses, fees and taxes incident to
(i) the preparation, printing, filing and distribution under the 1933 Act of the
Registration Statement (including financial statements and exhibits), each
preliminary prospectus and all amendments and supplements to any of them prior
to or during the period specified


                                       15
<PAGE>

in Section 3(f) above, (ii) the printing and delivery of the Prospectus and all
amendments or supplements to it during the period specified in Section 3(f)
above, (iii) word processing and delivery of the Operative Documents, the
Preliminary and Supplemental Blue Sky Memoranda and all other agreements,
memoranda, correspondence and other documents printed and delivered in
connection with the offering of the Securities (including in each case any
disbursements of counsel to the Underwriters relating to such printing and
delivery), (iv) the registration or qualification of the Securities for offer
and sale under the securities or Blue Sky laws of the several states (including
in each case the fees and disbursements of counsel to the Underwriters relating
to such registration or qualification and memoranda relating thereto), (v)
filings and clearance with the National Association of Securities Dealers, Inc.
(the "NASD") in connection with the offering of the Securities, (vi) furnishing
such copies of the Registration Statement, the Prospectus and all amendments and
supplements thereto as may be requested for use in connection with the offering
or sale of the Securities by the Underwriters or by dealers to whom the
Securities may be sold and (vii) all other fees, costs and expenses referred to
in Item 13 of the Registration Statement.

     If this Agreement is terminated by the Underwriters in accordance with the
provisions of Section 5, Section 8(a)(i) or Section 10, the Company shall
reimburse the Underwriters for all of their out-of-pocket expenses, including
the reasonable fees and disbursements of counsel to the Underwriters.

     SECTION 5.     CONDITIONS OF THE UNDERWRITERS' OBLIGATIONS.  The several
obligations of the Underwriters hereunder are subject to the accuracy of the
representations and warranties of the Company herein contained, to the
performance by the Company of its obligations hereunder, and to the following
further conditions:

     (a)  The Registration Statement shall have become effective not later than
5:00 P.M., New York City time, on the date of this Agreement or at such later
date and time as the Underwriters may approve in writing, and at the Closing
Time no stop order suspending the effectiveness of the Registration Statement
shall have been issued and no proceedings for that purpose shall have been
commenced or shall be pending before or contemplated by the Commission.  If the
Company has elected to rely upon Rule 430A of the 1933 Act Regulations, the
price of the Units and any price-related information previously omitted from the
effective Registration Statement pursuant to such Rule 430A shall have been
transmitted to the Commission for filing pursuant to Rule 424(b) of the 1933 Act
Regulations within the prescribed time period, and prior to the Closing Time the
Company shall have provided evidence satisfactory to the Underwriters of such
timely filing, or a post-effective amendment providing such information shall
have been promptly filed and declared effective in accordance with the
requirements of Rule 430A of the 1933 Act Regulations.

     (b)  Subsequent to the execution and delivery of this Agreement and prior
to the Closing Time, there shall not have been any downgrading, nor shall any
notice have been given of any intended or potential downgrading or of any review
for a possible change that does not indicate the direction of the possible
change, in the rating accorded any of the Company's securities by any
"nationally recognized statistical rating organization," as such term is defined
by the Commission for purposes of Rule 436(g)(2) under the 1933 Act.

     (c)  (i) Since the date of the latest balance sheet of the Company included
in the Registration Statement and the Prospectus, and except as otherwise
described in or contemplated by such Registration Statement or Prospectus, there
shall not have been any Material Adverse Effect, or any development involving a
prospective Material Adverse Effect, whether or not arising in the ordinary
course of business, (ii) since the date of the latest balance sheet included in
the Registration Statement and the Prospectus, there shall not have been any
change, or any development involving a prospective Material


                                       16
<PAGE>

Adverse Effect, in the capital stock or in the long-term debt of the Company and
its subsidiaries from that set forth in the Registration Statement and the
Prospectus, (iii) neither the Company nor any of its subsidiaries shall have any
liability or obligation, direct or contingent, which is material to the Company
and its subsidiaries, taken as a whole, other than those reflected in the
Registration Statement and the Prospectus and (iv) at the Closing Time the
Underwriters shall have received a certificate dated the Closing Time, signed by
Vernon L. Fotheringham and Thomas A. Grina in their respective capacities as the
Chief Executive Officer and the Chief Financial Officer of the Company, as to
the accuracy of the representations and warranties of the Company herein at and
as of such Closing Time, and confirming the matters set forth in paragraphs (a)
and (b) of this Section 5.

     (d)  Hahn & Hessen LLP, counsel to the Company, shall have furnished to the
Underwriters their written opinion, dated the Closing Time, in form and
substance satisfactory to the Underwriters, as to the matters set forth in
Exhibit D hereto:

     (e)  Pierson, Burnett & Hanley, special regulatory counsel to the Company
shall have furnished to the Underwriters their written opinion, dated the
Closing Time, in form and substance satisfactory to the Underwriters as to the
matters set forth in Exhibit E hereto:

     (f)  Latham & Watkins, counsel to the Underwriters, shall have furnished to
the Underwriters their written opinion, dated the Closing Time, in form and
substance satisfactory to the Underwriters, as to the matters you have
requested.

     (g)  At 10:00 a.m., New York City time, on the date of this Agreement and
at the Closing Time, Coopers & Lybrand L.L.P. shall have furnished to the
Underwriters a letter or letters, dated the respective date of delivery thereof,
in form and substance satisfactory to the Underwriters.

     (h)  The Merger shall have been completed on or prior to the date hereof.

     (i)  The Unit Offering shall have been consummated.

     SECTION 6.     INDEMNIFICATION.  (a) The Company agrees to indemnify and
hold harmless each Underwriter and each person, if any, who controls such
Underwriter within the meaning of Section 15 of the 1933 Act as follows:

          (i)  against any and all loss, liability, claim, damage and expense
     whatsoever, as incurred, arising out of an untrue statement or alleged
     untrue  statement of a material fact contained in either Registration
     Statement, any preliminarily prospectus, the Prospectus or any amendment or
     supplement thereto, including the information deemed to be part of either
     Registration Statement pursuant to Rule 430A(b) of the 1933 Act
     Regulations, if applicable, or the omission or alleged omission therefrom
     of a material fact necessary to make the statements therein, in the light
     of the circumstances under which they were made, not misleading;

          (ii) against any and all loss, liability, claim, damage and expense
     whatsoever, as incurred, to the extent of the aggregate amount paid in
     settlement of any litigation, or investigation or proceeding by any
     governmental agency or body, commenced or threatened or of any claim
     whatsoever based upon any such untrue statement or omission, or any such
     alleged untrue statement or omission, if such settlement is effected with
     the written consent of the Company; and


                                       17
<PAGE>

          (iii)     against any and all expense whatsoever, as incurred
     (including fees and disbursements of counsel chosen by the Underwriters),
     reasonably incurred in investigating preparing or defending against any
     litigation, or investigation or proceeding by any governmental agency or
     body, commenced or threatened or any claim whatsoever based upon any such
     untrue statement or omission, or any such alleged untrue statement or
     omission, to the extent that any such expense is not paid under
     subparagraph (i) or (ii) above;

PROVIDED, HOWEVER, that this indemnity does not apply to any loss, liability,
claim, damage or expense to the extent arising out of an untrue statement or
omission or alleged untrue statement or omission made in reliance upon and in
conformity with written information furnished to the Company by the Underwriters
expressly for use in the Registration Statement, any preliminary prospectus, the
Prospectus or any amendment or supplement thereto.

     (b)  Each Underwriter agrees, severally and not jointly, to indemnify and
hold harmless the Company and their respective directors, and each person, if
any, who controls the Company, within the meaning of Section 15 of the 1933 Act,
against any and all loss, liability, claim, damage and expense described in the
indemnity contained in Section 6(a), as incurred, but only with respect to
untrue statements or omissions, or alleged untrue statements or omissions, made
in the Registration Statement, any preliminary prospectus, the Prospectus or any
amendment or supplement thereto, in reliance upon and in conformity with written
information furnished to the Company by such Underwriter expressly for use
therein.

     (c)  Each indemnified party shall give prompt notice to each indemnifying
party of any action commenced against it in respect of which indemnity may be
sought hereunder, but failure to so notify an indemnifying party shall not
relieve it from any liability which it may have otherwise than on account of
this indemnity agreement.  An indemnifying party may participate at its own
expense in the defense of such action.  In no event shall the indemnifying party
or parties be liable for the fees and expenses of more than one counsel to all
indemnified parties in connection with any one action or separate but similar or
related actions in the same jurisdiction arising out of the same general
allegations or circumstances.

     (d)  If at any time an indemnified party shall have requested an
indemnifying party to reimburse such indemnified party for fees and expenses of
counsel, such indemnifying party agrees that it shall be liable for any
settlement of the nature contemplated by Section 6(a)(ii) hereof effected
without its written consent if (i) such settlement is entered into more than 45
days after receipt by such indemnifying party of the aforesaid request, (ii)
such indemnifying party shall have received notice of the terms of such
settlement at least 30 days prior to such settlement being entered into and
(iii) such indemnifying party shall not have reimbursed such indemnified party
in accordance with such request prior to the date of such settlement.

     SECTION 7.     CONTRIBUTION.  In order to provide for just and equitable
contribution in circumstances under which the indemnity provided for in Section
6 is for any reason held to be unenforceable by the indemnified parties although
applicable in accordance with its terms, the Company and the Underwriters shall
contribute to the aggregate losses, liabilities, claims, damages and expenses of
the nature contemplated by such indemnity incurred by the Company or the
Underwriters, as incurred, in such proportions that (a) each Underwriter is
responsible for that portion represented by the percentage that the underwriting
discount appearing on the cover page of the Prospectus bears to the initial
public offering price appearing thereon and (b) the Company is responsible for
the balance; PROVIDED, HOWEVER that no person guilty of fraudulent
misrepresentations (within the meaning of Section 11(f) of the 1933 Act) shall
be entitled to contribution from any person who was not guilty of such
fraudulent


                                       18
<PAGE>

misrepresentation.  For purposes of this Section, each person, if any, who
controls any Underwriter within the meaning of Section 15 of the 1933 Act shall
have the same rights to contribution as such Underwriter, and each director of
the Company and each person, if any, who controls the Company within the meaning
of Section 15 of the 1933 Act shall have the same rights to contribution as the
Company, as applicable.

     SECTION 8.     TERMINATION OF AGREEMENT.  (a) The Underwriters may
terminate this Agreement, by notice to the Company, at any time prior to Closing
Time (i) if there has been, since the date of this Agreement or since the
respective dates as of which information is given in the Registration Statement
and the Prospectus, any adverse change or development involving a prospective
adverse change in the condition, financial or otherwise, or in the earnings,
business affairs or business prospects of the Company and ART, taken as a whole,
whether or not arising in the ordinary course of business, which would, in the
judgment of the Underwriters, make it impractical to market the Securities on
the terms and in the manner contemplated in the Registration Statement and the
Prospectus, (ii) if there has occurred any outbreak or escalation of hostilities
or other national or international calamity or crisis or change in economic or
political conditions or in the financial markets of the United States or
elsewhere that, in the judgment of the Underwriters, is material and adverse and
would in the judgment of the Underwriters make it impracticable to market the
Securities or to enforce contracts for the sale of the Securities in the manner
contemplated in the Registration Statement and the Prospectus, (iii) if trading
in Common Stock has been suspended or materially limited by the Commission, or
if trading generally on the American Stock Exchange, the New York Stock Exchange
or the Nasdaq National Market has been suspended or materially limited, or
minimum or maximum prices for trading have been fixed, or maximum ranges for
prices for securities have been required, by any of said Exchanges or by order
of the Commission or any other governmental authority, or if a banking
moratorium has been declared by either Federal or New York State authorities or
(iv) if any action has been taken by any federal, state or local government or
agency in respect of its monetary or fiscal affairs which, in the opinion of the
Underwriters, has a material adverse effect on the financial markets in the
United States.

     (b)  If this Agreement is terminated pursuant to this Section, such
termination shall be without liability of any party to any other party except as
provided in Section 4.  Notwithstanding any such termination, the provisions of
Sections 6 shall remain in effect.

     SECTION 9.     DEFAULT BY ONE OR MORE OF THE UNDERWRITERS.  If any
Underwriter shall fail at Closing Time to purchase the Units which it is
obligated to purchase hereunder (the "DEFAULTED UNITS"), the remaining
Underwriter(s) (the "NON-DEFAULTING UNDERWRITER(S)") shall have the right, but
not the obligation within 24 hours thereafter, to make arrangements to purchase
all, but not less than all, of the Defaulted Units upon the terms herein set
forth; if, however, the Non-Defaulting Underwriter(s) shall not have completed
such arrangements within such 24 hour period, then this Agreement shall
terminate without liability on the part of the Non-Defaulting Underwriter(s).

     No action pursuant to this Section shall relieve the defaulting party from
liability in respect of its default.

     In the event of any such default which does not result in a termination of
this Agreement, either the Non-Defaulting Underwriter(s) or the Company shall
have the right to postpone the Closing Time for a period not exceeding seven
days in order to effect any required changes in the Registration Statement or
Prospectus or in any other documents or arrangements.


                                       19
<PAGE>

     SECTION 10.    DEFAULT BY THE COMPANY.  If the Company shall fail at
Closing Time to sell and deliver the number of Notes or Warrants, as applicable,
which it is obligated to sell hereunder, then this Agreement shall terminate
without any liability on the part of any non-defaulting party.

     No action taken pursuant to this Section shall relieve the Company from
liability, if any, in respect of such default.

     SECTION 11.    REPRESENTATIONS, WARRANTIES AND AGREEMENTS TO SURVIVE
DELIVERY.  All representations, warranties and agreements contained in this
Agreement and the Pricing Agreement, or contained in certificates of officers of
the Company submitted pursuant hereto, shall remain operative and in full force
and effect, regardless of any investigation made by or on behalf of any
Underwriter or controlling person, or by or on behalf of the Company, and shall
survive delivery of the Securities to the Underwriters.

     SECTION 12.    NOTICES.  All notices and other communications hereunder
shall be in writing and shall be deemed to have been duly given if mailed or
transmitted by any standard form of telecommunication.  Notices to the
Underwriters shall be directed to the Underwriters at Merrill Lynch World
Headquarters, North Tower, World Financial Center, New York, New York 10281,
Attention:  Bennett Rosenthal, Director; notices to the Company shall be
directed to the Company, at 500 108th Avenue, N.E., Suite 2600, Bellevue,
Washington 98004, Attention: Thomas A. Grina.

     SECTION 13.    PARTIES.  This Agreement and the Pricing Agreement shall
inure to the benefit of and be binding upon the Underwriters the Company and
their respective successors, heirs and legal representatives.  Nothing expressed
or mentioned in this Agreement or the Pricing Agreement is intended or shall be
construed to give any person, firm or corporation, other than the Underwriters,
the Company and their respective successors, heirs and legal representatives,
and the controlling persons and officers and directors referred to in Section 7
and their heirs and legal representatives, any legal or equitable right, remedy
or claim under or in respect of this Agreement or the Pricing Agreement or any
provision herein or therein contained.  This Agreement, the Pricing Agreement
and all conditions and provisions hereof and thereof are intended to be for the
sole and  exclusive benefit of the Underwriters, the Company, and their
respective successors, heirs and legal representatives and said controlling
persons and officers and directors and their heirs and legal representatives,
and for the benefit of no other person, firm or corporation.  No purchaser of
the Securities from the Underwriters shall be deemed to be a successor by reason
merely of such purchase.

     SECTION 14.    GOVERNING LAW AND TIME.  This Agreement and the Pricing
Agreement shall be governed by and construed in accordance with the laws of the
State of New York applicable to agreements made and to be performed in said
State.  Specified times of day refer to New York City time.


                                       20
<PAGE>

     If the foregoing is in accordance with your understanding of our agreement,
please sign and return to the Company five (5) counterparts hereof, whereupon
this instrument, along with all counterparts, will become a binding agreement
between the Underwriters and the Company in accordance with its terms.


                                   Very truly yours,

                                   ADVANCED RADIO TELECOM CORP.



                                   By: _________________________________
                                        Name:
                                        Title:


CONFIRMED AND ACCEPTED
as of the date first above written:

MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED



By: ____________________________
     Name:
     Title:



MONTGOMERY SECURITIES



By: ____________________________
     Name:
     Title:



SMITH BARNEY, INC.



By: ____________________________
     Name:
     Title:


                                       21
<PAGE>

                                   SCHEDULE I


                                                                 Number of Units
Underwriter                                                      to be Purchased
- -----------                                                      ---------------
Merrill Lynch, Pierce, Fenner & Smith Incorporated . . . . . . .
Montgomery Securities. . . . . . . . . . . . . . . . . . . . . .
Smith Barney, Inc. . . . . . . . . . . . . . . . . . . . . . . . ---------------

     Total . . . . . . . . . . . . . . . . . . . . . . . . . . . ---------------
                                                                 ---------------


                                       22
<PAGE>

                                    EXHIBIT A



                          ADVANCED RADIO TELECOM CORP.
                            (a Delaware corporation)

                        ______ Units, each consisting of
         $1,000 Principal Amount of ___% Senior Discount Notes Due 2006
                and ______ Warrants to Purchase ______ Shares of
                                  Common Stock


                                PRICING AGREEMENT


                                                            ___________ __, 1996

MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED
MONTGOMERY SECURITIES
SMITH BARNEY INC.
c/o Merrill Lynch World Headquarters
  North Tower
  World Financial Center
  New York, New York  10281

Dear Sirs:

     Reference is made to the Purchase Agreement, dated _______ ___, 1996 (the
"PURCHASE AGREEMENT") among Advanced Radio Telecom Corp., f/k/a Advanced Radio
Technologies Corporation (the "COMPANY"), and Merrill Lynch, Pierce, Fenner &
Smith Incorporated, Montgomery Securities and Smith Barney Inc., as underwriters
(the "UNDERWRITERS"), relating to the purchase by the Underwriters of ________
units (the "UNITS"), each consisting of (i) $1,000 aggregate principal amount at
maturity of the Company's ___% Senior Discount Notes due 2006 and (ii) ________
warrants to acquire ____________ shares of the Company's common stock, par value
$.001 per share.

     Pursuant to Section 2 of the Purchase Agreement, the Company agrees with
the Underwriters as follows:

     1.   The initial public offering price per Unit, determined as provided in
said Section 2, shall mean $______.

     2.   The purchase price per Unit to be paid by the Underwriters shall be
$________, being an amount equal to the initial public offering price set forth
above less $________ per unit.


                                       A-1
<PAGE>

     If the foregoing is in accordance with your understanding of our agreement,
please sign and return to the Company five (5) counterparts hereof, whereupon
this instrument, along with all counterparts, will become a binding agreement
between the Underwriters and the Company in accordance with its terms.


                              Very truly yours,

                              ADVANCED RADIO TELECOM CORP.



                              By: _________________________________
                                   Name:
                                   Title:


CONFIRMED AND ACCEPTED
   as of the date first
   above written:


MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED



By: ____________________________
     Name:
     Title:


MONTGOMERY SECURITIES



By: ____________________________
     Name:
     Title:


SMITH BARNEY, INC.



By: ____________________________
     Name:
     Title:


                                       A-2
<PAGE>

                                    EXHIBIT B

             PRE-TRANSACTIONS CAPITALIZATION OF THE COMPANY AND ART


                                       B-1
<PAGE>

                                    EXHIBIT C

             POST-TRANSACTIONS CAPITALIZATION OF THE COMPANY AND ART


                                       C-1
<PAGE>

                                    EXHIBIT D

                      FORM OF OPINION OF HAHN & HESSEN LLP

     (a)  Each of the Company and its subsidiaries has been duly formed as a
corporation and is validly existing in good standing under the laws of its
jurisdiction of incorporation and has all requisite corporate power and
authority to own, lease and operate its properties and to conduct its business
as described in the Prospectus.  Each of the Company and its subsidiaries is
duly qualified to do business and is in good standing as a foreign corporation
in each jurisdiction in which the nature of its business or its ownership or
leasing of property requires such qualification, except where the failure to be
so qualified would not have, either individually or in the aggregate, a material
adverse effect on the assets, properties, business, management, earnings, net
worth, results of operations, condition (financial or otherwise) or business
prospects of the Company and its subsidiaries, taken as a whole.  No proceeding
has been instituted in any such jurisdiction, revoking, limiting or curtailing,
or seeking to revoke, limit or curtail, such power and authority or
qualification.

     (b)  ART Licenses is the only subsidiary of the Company.  The Company owns
all of the outstanding capital stock of ART Licenses; all such capital stock has
been duly authorized and validly issued and is fully paid and nonassessable,
free and clear of any security interest, claim, lien, encumbrance or adverse
interest of any nature; and all of such capital stock was not issued in
violation of any preemptive or similar rights.  There are no outstanding
subscriptions, rights, warrants, calls, commitments of sale or options to
acquire, or instruments convertible into or exchangeable for, any such shares of
capital stock or other equity interest of ART Licenses.

     (c)  The Company and its subsidiaries do not have any ownership interest in
any joint venture, other than the Company's 50% ownership interest in ART West.

     (d)  Prior to consummation of the Transactions, the Company and ART have
authorized and outstanding capital stock as set forth in Exhibit A hereto.  All
such issued and outstanding shares of capital stock of the Company and ART have
been duly authorized and validly issued, are fully paid and non-assessable and
were not issued in violation of any preemptive or similar rights.  The shares of
capital stock of ART owned by the Company prior to completion of the Merger are
free and clear of any security interest, claim, lien, encumbrance or adverse
interest of any nature.  Upon consummation of the Transactions, the Company will
have authorized and outstanding capital stock as set forth in Exhibit B hereto
and an authorized and outstanding capitalization as set forth in the Prospectus
under the caption "Capitalization."  All such issued and outstanding shares of
capital stock of the Company will have been duly authorized and validly issued,
will be fully paid and non-assessable and will not have been issued in violation
of any preemptive or similar rights.  Except as disclosed in the Prospectus,
there are, and there will be, no outstanding subscriptions, rights, warrants,
calls, commitments of sale or options to acquire, or instruments convertible
into or exchangeable for, any capital stock of the Company or ART  The
description of the Company's stock option, stock bonus and other stock plans or
arrangements, and the options or other rights granted and exercised thereunder,
set forth in the Prospectus accurately and fairly presents the information
required to be shown with respect to such plans, arrangements, options and
rights.

     (e)  The Company has all requisite corporate power and authority to
execute, deliver and perform its obligations under the Operative Documents and
to consummate the transactions contemplated hereby and thereby, including,
without limitation, the corporate power and authority to issue, sell and deliver
the Securities as provided herein and therein.


                                       D-1
<PAGE>

     (f)  This Agreement has been, and, at the Representation Date, the Pricing
Agreement will have been, duly authorized and validly executed by the Company
and (assuming the due execution and delivery hereof by the Underwriters) are the
legally valid and binding agreements of the Company, enforceable against the
Company in accordance with their terms, except as the enforceability thereof may
be limited (i) by the effect of bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium or other similar laws now or hereafter in effect
relating to or affecting the rights and remedies of creditors, (ii) by the
effect of general principles of equity, whether enforcement is considered in a
proceeding in equity or at law, and the discretion of the court before which any
proceeding therefor may be brought and (iii) to the extent that rights to
indemnification and contribution thereunder may be limited by federal or state
securities laws or public policy relating thereto.

     (g)  The Company has duly authorized the Units and, when issued and
delivered to and paid for by the Underwriters in accordance with the terms
hereof, the Units will conform in all material respects to the description
thereof in the Prospectus.

     (h)  The Company has duly authorized the Indenture and, when the Company
has duly executed and delivered the Indenture (assuming the due authorization,
execution and delivery thereof by the Trustee), the Indenture will be the
legally valid and binding obligation of the Company, enforceable against the
Company in accordance with its terms, except as the enforceability thereof may
be limited (i) by the effect of bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium or other similar laws now or hereafter in effect
relating to or affecting the rights and remedies of creditors and (ii) by the
effect of general principles of equity, whether enforcement is considered in a
proceeding in equity or at law, and the discretion of the court before which any
proceeding therefor may be brought.  The Indenture has been duly qualified under
the Trust Indenture Act.

     (i)  The Company has duly authorized the Notes and, when issued and
authenticated in accordance with the terms of the Indenture and delivered to and
paid for by the Underwriters in accordance with the terms hereof, the Notes will
conform in all material respects to the description thereof in the Prospectus,
will be entitled to the benefits of the Indenture and will be the legally valid
and binding obligations of the Company, enforceable against the Company in
accordance with their terms, except as the enforceability thereof may be limited
(i) by the effect of bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium or other similar laws now or hereafter in effect
relating to or affecting the rights and remedies of creditors and (ii) by the
effect of general principles of equity, whether enforcement is considered in a
proceeding in equity or at law, and the discretion of the court before which any
proceeding therefor may be brought.

     (j)  The Company has duly authorized the Warrant Agreement and, when the
Company has duly executed and delivered the Warrant Agreement (assuming the due
authorization, execution and delivery thereof by the Warrant Agent), the Warrant
Agreement will be the legally valid and binding obligation of the Company,
enforceable against the Company in accordance with its terms, except as the
enforceability thereof may be limited (i) by the effect of bankruptcy,
insolvency, fraudulent transfer, reorganization, moratorium or other similar
laws now or hereafter in effect relating to or affecting the rights and remedies
of creditors, (ii) by the effect of general principles of equity, whether
enforcement is considered in a proceeding in equity or at law, and the
discretion of the court before which any proceeding therefor may be brought and
(iii) to the extent that rights to indemnification and contribution thereunder
may be limited by federal or state securities laws or public policy relating
thereto.

     (k)  The Company has duly authorized the Warrants and, when issued and
delivered in accordance with the terms of the Warrant Agreement and delivered to
and paid for by the Underwriters


                                       D-2
<PAGE>

in accordance with the terms hereof, the Warrants will conform in all material
respects to the description thereof in the Prospectus and will have been validly
issued, and the issuance of such Warrants will not be subject to any preemptive
or similar rights.

     (l)  The Company has duly authorized and reserved for issuance the Warrant
Shares to be issued upon the exercise of the Warrants and, when issued and
delivered upon the exercise of the Warrants against payment of the Exercise
Price as provided in the Warrant Agreement, the Warrant Shares will conform in
all material respects to the description thereof in the Prospectus, will have
been duly issued and will be fully paid and non-assessable, and the issuance of
such Warrant Shares will not be subject to any preemptive or similar rights.

     (m)  No approval, authorization, order, consent, registration, filing,
qualification, license or permit of or with any court, regulatory,
administrative or other governmental body is required for the execution and
delivery of this Agreement by the Company or the consummation of the
transactions contemplated by this Agreement, except such as have been obtained
and are in full force and effect under the Act and such as may be required under
applicable Blue Sky laws in connection with the purchase and distribution of the
Securities by the Underwriters and the clearance of such offering with the NASD.

     (n)  None of the execution, delivery and performance of the Operative
Documents by the Company, the compliance by the Company with all of the
provisions hereof and thereof, the issuance and sale of the Securities, the
consummation by the Company and its subsidiaries of the Transactions and the
transactions contemplated hereby and thereby (i) require any consent, approval,
authorization or other order of or filing, registration, qualification, license
or permit of or with, any court, regulatory body, administrative agency or other
governmental body (including, without limitation, the FCC), other than those
that have been obtained and are in full force and effect, or (ii) violate,
conflict with, or constitute a breach of any of the terms or provisions of, or a
default under (or an event that with notice or the lapse of time, or both, would
constitute a default), or require consent under, or result in the imposition of
a lien or encumbrance on any properties of the Company and its subsidiaries
pursuant to (A) the charter or bylaws of the Company or any of its subsidiaries,
(B) any bond, debenture, note, mortgage, deed of trust or other agreement,
indenture or other instrument to which or by which any of them is a party or by
which any of them or any of their respective property is or may be bound, (C)
any local, state or Federal law, statute, ordinance, rule, regulation or
requirement (including, without limitation, the Telecommunications Act, the
rules and regulations of the FCC and the environmental laws, statutes,
ordinances, rules or regulations) applicable to the Company, any of its
subsidiaries or any of their respective assets or properties or (D) any
judgment, order or decree of any court or governmental agency or authority
having jurisdiction over the Company, any of its subsidiaries or any of their
assets or properties, that, in the case of clauses (B), (C) and (D), would
reasonably be expected, either individually or in the aggregate, to result in a
Material Adverse Effect.

     (o)  Neither the Company nor any of its subsidiaries is or, after giving
effect to the Transactions, will be (i) in violation of its charter or bylaws,
(ii) in default in the performance of any material obligation, agreement or
condition contained in any bond, debenture, note or any other evidence of
indebtedness or in any other agreement, indenture or instrument material to the
conduct of the business of the Company and its subsidiaries, taken as a whole,
to which any of them is a party, or by which any of them or any of their
respective properties is bound or (iii) in violation of any local, state or
Federal law, statute, ordinance, rule, regulation, requirement, judgment or
court decree (including, without limitation, the Telecommunications Act and the
rules and regulations of the FCC and environmental laws, statutes, ordinances,
rules, regulations, judgments or court decrees) applicable to any of them or any
of their respective assets or properties (whether owned or leased), other than,
in the case of clauses (ii) and


                                       D-3
<PAGE>

(iii), any default or violation that could not reasonably be expected to have a
Material Adverse Effect.  There exists no condition that, with notice, the
passage of time or otherwise, would constitute a default under any such document
or instrument that could be expected to have a Material Adverse Effect.

     (p)  There is (i) no action, suit or proceeding before or by any court,
arbitrator or governmental agency, body or official, domestic or foreign, now
pending or threatened or contemplated to which the Company or any of its
subsidiaries is or may be a party or to which the business or property of any of
them is subject, (ii) no local, state or Federal law, statute, ordinance, rule,
regulation, requirement, judgment or court decree (including, without
limitation, the Telecommunications Act and the rules and regulations of the FCC)
or order has been enacted, adopted or issued by any governmental agency or, to
the best of such counsel's knowledge, that has been proposed by any governmental
body or (iii) no injunction, restraining order or order of any nature by a
Federal or state court or foreign court of competent jurisdiction to which the
Company, any of its subsidiaries or their business, assets, or property of the
Company or ART are, or could reasonably be expected to be subject.

     (q)  Neither the Company nor any of its subsidiaries is (i) an "investment
company" or a company "controlled" by an "investment company" within the meaning
of the Investment Company Act of 1940, as amended, or (ii) a "holding company"
or a "subsidiary company" or an "affiliate" of a holding company within the
meaning of the Public Utility Holding Company Act of 1935, as amended.

     (r)  The statements under the captions "Capitalization," "Description of
Capital Stock," "Description of Units," "Description of Notes," "Description of
Warrants," "Principal Stockholders," "Shares Eligible for Future Sale" and
"Underwriting" in the Prospectus and Items 14 and 15 of Part II of the
Registration Statement, insofar as such statements constitute a summary of legal
matters, documents or proceedings referred to therein, fairly present the
information called for with respect to such legal matters, documents and
proceedings.

     (s)  The statements under the caption "Certain Federal Income Tax
Considerations" in the Prospectus are accurate and fairly summarize the matters
referred to therein;

     (t)  The Registration Statement has become effective under the 1933 Act,
and such counsel does not know of the issuance of any stop order suspending the
effectiveness of either Registration Statement by the Commission or of any
proceedings for that purpose under the 1933 Act;

     (u)  (1) the Registration Statements and the Prospectus and any supplement
or amendment thereto (except for financial statements and notes thereto and
other financial and statistical data included therein and the statements of the
Trustee contained in the Statement of Eligibility of the Trustee on Form T-1 as
to which no opinion need be expressed) comply as to form in all material
respects with the 1933 Act; and (2) such counsel has no reason to believe that
(except for financial statements and notes thereto and other financial and
statistical data included therein and the statements of the Trustee contained in
the Statement of Eligibility of the Trustee on Form T-1 as to which no belief
need be expressed) the Registration Statements and the Prospectus included
therein at the time the Registration Statements became effective contained any
untrue statement of a material fact or omitted to state a material fact required
to be stated therein or necessary to make the statements therein not misleading,
or that the Prospectus, as amended or supplemented if applicable (except as
aforesaid), contains any untrue statement of a material fact or omits to state a
material fact necessary in order to make the statements therein, in the light of
the circumstances under which they were made, not misleading.


                                       D-4
<PAGE>

                                    EXHIBIT E

                  FORM OF OPINION OF PIERSON, BURNETT & HANLEY

     (a)  Each of the Company and its subsidiaries has such Permits as are
necessary to own, lease and operate their respective properties and to conduct
their respective business in the manner described in the Prospectus.  Each of
the Company and its subsidiaries has fulfilled and performed all of its material
obligations with respect to such Permits and no event has occurred which allows,
or after notice or lapse of time would allow, revocation or termination thereof
or result in any other material impairment of the rights of the holder of any
such Permit, except for any such impairments which would not, individually or in
the aggregate, have a Material Adverse Effect.  Except as described in the
Prospectus, such Permits contain no restrictions that are materially burdensome
to the Company and its subsidiaries, taken as a whole.

     (b)  Except as described in the Prospectus, (i) the Company and its
subsidiaries own, possess or have the right to employ or have applied for all
such Permits, Licenses and Intellectual Property as are necessary to own, lease
and operate their respective properties and to conduct their respective business
in the manner described in the Prospectus; (ii) each of the Company and its
subsidiaries has fulfilled and performed all of its material obligations with
respect to such Licenses and other Intellectual Property and no event has
occurred which allows, or after notice or lapse of time would allow, revocation
or termination thereof or result in any other material impairment of the rights
of the holder of any such Intellectual Property; (iii) such Intellectual
Property contain no restrictions that are materially burdensome to the Company
and its subsidiaries, taken as a whole; and (iv) the use of the Intellectual
Property in connection with the business and operations of the Company and its
subsidiaries does not infringe on the rights of any person, except where such
infringement would not have a Material Adverse Effect.

     (c)  The Company and its subsidiaries have timely filed all renewal
applications with respect to all Licenses possessed by any of them.  No protests
or competing applications have been filed with respect to such renewal
applications, and nothing has come to the Company's or any of its subsidiaries'
attention that would lead them to conclude that such renewal applications will
not be granted by the appropriate regulatory agency or body in the ordinary
course.  The Company and its subsidiaries are authorized under the
Telecommunications Act, and the rules and regulations promulgated thereunder, to
continue to provide the services which are the subject of such renewal
applications during the pendency thereof.

     (d)  The development, implementation and operation of the 38 GHz wireless
broadband telecommunications services network as described, and in the markets
described, in the Prospectus will not (i) result in any violation of the
provisions of the charter or bylaws of the Company or any of its subsidiaries,
(ii) result in any violation of any applicable law, administrative regulation or
administrative or court decree (including, without limitation, the
Telecommunication Act, and the rules and regulations of the FCC and
environmental laws), or (iii) conflict with or constitute a breach or violation
of, or constitute a default under, or result in the creation or imposition of
any lien, charge or encumbrance upon any property or assets of the Company or
its subsidiaries pursuant to, any contract, indenture, mortgage, loan agreement,
note, lease or other instrument to which the Company or any of its subsidiaries
is a party or by which any of them may be bound, or to which any of their
property is subject, except, in the case of clauses (ii) and (iii) above, any
such violations, conflicts or breaches that would not individually or in the
aggregate, have a Material Adverse Effect.


                                       E-1
<PAGE>

     (e)  The business and operations conducted and proposed to be conducted by
the Company and its subsidiaries as described in the Prospectus are not
regulated by any public service or public utility commissions in the States in
which the Company and its subsidiaries conduct or propose to conduct such
business and operations as described in the Prospectus; and, subject to the
provisions of Section 332(c)(3) of the Telecommunications Act, neither the
Company nor any of its subsidiaries is or will be required to obtain any License
from any public service or public utility commission in any such State.

     (f)  None of the execution, delivery and performance of the Operative
Documents by the Company, the compliance by the Company with all of the
provisions hereof and thereof, the issuance and sale of the Securities, the
consummation by the Company and its subsidiaries of the Transactions and the
transactions contemplated hereby and thereby (i) require any consent, approval,
authorization or other order of or filing, registration, qualification, license
or permit of or with, the FCC, other than those that have been obtained and are
in full force and effect, or (ii) violate, conflict with, or constitute a breach
of any of the terms or provisions of, or a default under (or an event that with
notice or the lapse of time, or both, would constitute a default), or require
consent under, or result in the imposition of a lien or encumbrance on any
properties of the Company or any of its subsidiaries pursuant to (A) the
Telecommunications Act or the rules and regulations of the FCC applicable to the
Company, any of its subsidiaries or any of their respective assets or properties
or (B) any judgment, order or decree of any court or governmental agency or
authority having jurisdiction over the Company, any of its subsidiaries or any
of their assets or properties, that, in the case of clauses (A) and (B), would
reasonably be expected, either individually or in the aggregate, to result in a
Material Adverse Effect.

     (g)  Neither the Company nor any of its subsidiaries is or, after giving
effect to the Transactions, will be in violation of the Telecommunications Act
and the rules and regulations of the FCC applicable to the Company, any of its
subsidiaries or any of their respective assets or properties (whether owned or
leased), other than any violation that could not reasonably be expected to have
a Material Adverse Effect.

     (h)  Other than rulemaking procedures of general applicability to the
wireless broadband telecommunications industry, there is (i) no action, suit or
proceeding before or by the FCC, now pending or threatened or contemplated to
which the Company or any of its subsidiaries is or may be a party or to which
the business or property of the Company or any of its subsidiaries is subject,
or (ii) no amendment or change to the Telecommunications Act and the rules and
regulations of the FCC has been enacted, adopted or issued by the FCC or, to the
best of such counsel's knowledge, that has been proposed by the FCC.

     (i)  Each of the Company and its subsidiaries has filed all reports
required to be filed with the FCC.


                                       E-2

<PAGE>

                                                               L&W DRAFT 6/17/96


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



                          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




                                WARRANT AGREEMENT




                         Dated as of _____________, 1996




                            _________________________

                                  Warrant Agent



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

     WARRANT AGREEMENT dated as of _______, 1996 between Advanced Radio Telecom
Corp., f/k/a Advanced Radio Technologies Corporation, a Delaware corporation
(the "COMPANY"), and _______________, as Warrant Agent (the "WARRANT AGENT").

     WHEREAS, the Company proposes to issue warrants (the "WARRANTS") to
purchase up to an aggregate of _______ shares of Common Stock, par value $.001
per share (the "COMMON STOCK"), of the Company (the Common Stock issuable on
exercise of the Warrants being referred to herein as the "WARRANT SHARES"), in
connection with the offering (the "UNIT OFFERING") by the Company of _____
Units, each consisting of (i) $1,000 principal amount at maturity of the
Company's ___% Senior Discount Notes due 2006 (the "NOTES") and _______
Warrants, each Warrant entitling the holder thereof to purchase _____ Warrant
Shares.

     WHEREAS, the Company desires the Warrant Agent to act on behalf of the
Company, and the Warrant Agent is willing so to act, in connection with the
issuance of Warrant Certificates (as defined below) and other matters as
provided herein;

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereto agree as follows:

     SECTION 1.     APPOINTMENT OF WARRANT AGENT.  The Company hereby appoints
the Warrant Agent to act as agent for the Company in accordance with the
instructions set forth hereinafter in this Agreement, and the Warrant Agent
hereby accepts such appointment.

     SECTION 2.     WARRANT CERTIFICATES.  The certificates evidencing the
Warrants (the "WARRANT CERTIFICATES") to be delivered pursuant to this Agreement
shall be in registered form only and shall be substantially in the form set
forth in Exhibit A attached hereto and shall, prior to the Termination Date (as
defined in Section 6 hereof), bear the legend set forth in Exhibit B attached
hereto.

     SECTION 3.     EXECUTION OF WARRANT CERTIFICATES.  (a)  Warrant
Certificates shall be signed on behalf of the Company by its Chairman of the
Board, Chief Executive Officer, its President or a Vice President and by its
Secretary or an Assistant Secretary under its corporate seal.  Each such
signature upon the Warrant Certificates may be in the form of a facsimile
signature of the present or any future Chairman of the Board, Chief Executive
Officer, President, Vice President, Secretary or Assistant Secretary and may be
imprinted or otherwise reproduced on the Warrant Certificates and for that
purpose the Company may adopt and use the facsimile signature of any person who
shall have been Chairman of the Board, Chief Executive Officer, President, Vice
President, Secretary or Assistant Secretary, notwithstanding the fact that at
the time the Warrant Certificates shall be countersigned and delivered or
disposed of he shall have ceased to hold such office.  The seal of the Company
may be in the form of a facsimile thereof and may be impressed, affixed,
imprinted or otherwise reproduced on the Warrant Certificates.

     (b)  In case any officer of the Company who shall have signed any of the
Warrant Certificates shall cease to be such officer before the Warrant
Certificates so signed shall have been countersigned by the Warrant Agent, or
disposed of by the Company, such Warrant Certificates nevertheless may be
countersigned and delivered or disposed of as though such person had not ceased
to be such officer of the Company; and any Warrant Certificate may be signed on
behalf of the Company by any person who, at the actual date of the execution of
such Warrant Certificate,
<PAGE>

shall be a proper officer of the Company to sign such Warrant Certificate,
although at the date of the execution of this Warrant Agreement any such person
was not such officer.

     (c)  Warrant Certificates shall be dated the date of countersignature by
the Warrant Agent.

     SECTION 4.     REGISTRATION AND COUNTERSIGNATURE.  (a)  The Warrant Agent,
on behalf of the Company, shall number and register the Warrant Certificates in
a register as they are issued by the Company.

     (b)  Warrant Certificates shall be manually countersigned by the Warrant
Agent and shall not be valid for any purpose unless so countersigned.  The
Warrant Agent shall, upon written instructions of the Chairman of the Board, the
Chief Executive Officer, the President, a Vice President, the Treasurer or the
Controller of the Company, initially countersign, issue and deliver Warrants
entitling the holders thereof to purchase not more than the number of Warrant
Shares referred to above in the first recital hereof and shall countersign and
deliver Warrants as otherwise provided in this Agreement.

     (c)  The Company and the Warrant Agent may deem and treat the registered
holder(s) of the Warrant Certificates as the absolute owner(s) thereof
(notwithstanding any notation of ownership or other writing thereon made by
anyone) for all purposes, and neither the Company nor the Warrant Agent shall be
affected by any notice to the contrary.

     SECTION 5.     REGISTRATION OF TRANSFERS AND EXCHANGES.  (a)  The Warrant
Agent shall from time to time, subject to the limitations of Section 6 hereof,
register the transfer of any outstanding Warrant Certificates upon the records
to be maintained by it for that purpose, upon surrender thereof accompanied (if
so required by it) by a written instrument or instruments of transfer in form
satisfactory to the Warrant Agent, duly executed by the registered holder or
holders thereof or by the duly appointed legal representative thereof or by a
duly authorized attorney.  Upon any such registration of transfer, a new Warrant
Certificate shall be issued to the transferee(s) and the surrendered Warrant
Certificate shall be cancelled by the Warrant Agent.  Cancelled Warrant
Certificates shall thereafter be disposed of in a manner satisfactory to the
Company.

     (b)  The Warrant holders agree that prior to any proposed transfer of the
Warrant Shares, if such transfer is not made pursuant to an effective
Registration Statement under the Securities Act of 1933, as amended (the
"SECURITIES ACT"), or an opinion of counsel, reasonably satisfactory in form and
substance to the Company, that the Warrant Shares may be sold publicly without
registration under the Securities Act, the Warrant holder will, if requested by
the Company, deliver to the Company:

          (i)  an investment covenant reasonably satisfactory to the Company
     signed by the proposed transferee;


                                        2
<PAGE>

          (ii)  an agreement by such transferee to the impression of the
     restrictive investment legend set forth below on the Warrant Shares;

          (iii) an agreement by such transferee that the Company may place a
     notation in the stock books of the Company or a "stop transfer order" with
     any transfer agent or registrar with respect to the Warrant Shares; and

          (iv)  an agreement by such transferee to be bound by the provisions of
     this Section 5 relating to the transfer of such Warrant Shares.

     (c)  Warrant Certificates may be exchanged at the option of the holder(s)
thereof, when surrendered to the Warrant Agent at its office for another Warrant
Certificate or other Warrant Certificates of like tenor and representing in the
aggregate a like number of Warrants.  Warrant Certificates surrendered for
exchange shall be cancelled by the Warrant Agent.  Such cancelled Warrant
Certificates shall then be disposed of by such Warrant Agent in a manner
satisfactory to the Company.

     (d)  The Warrant Agent is hereby authorized to countersign, in accordance
with the provisions of this Section 5 and of Section 4 hereof, the new Warrant
Certificates required pursuant to the provisions of this Section 5.

     SECTION 6.     SEPARATION OF WARRANTS; TERMS OF WARRANTS; EXERCISE OF
WARRANTS. (a) The Notes and Warrants will not be separately transferable prior
to the close of business on ____________, 1996 or such earlier date as may be
determined by the underwriters in the Unit Offering (the "TERMINATION DATE"), at
which time such Warrants shall become separately transferable.  Subject to the
terms of this Agreement, each Warrant holder shall have the right, which may be
exercised commencing at the opening of business on the Termination Date and
until 5:00 p.m., New York City time on _______, 2006 to receive from the Company
the number of fully paid and nonassessable Warrant Shares which the holder may
at the time be entitled to receive on exercise of such Warrants and payment of
the Exercise Price then in effect for such Warrant Shares.  In the alternative,
each holder may exercise its right, during the Exercise Period, to receive
Warrant Shares on a net basis, such that, without the exchange of any funds, the
holder receives that number of Warrant Shares otherwise issuable (or payable)
upon exercise of its Warrants less that number of Warrant Shares having an
aggregate fair market value (as defined below) at the time of exercise equal to
the aggregate Exercise Price that would otherwise have been paid by the holder
of the Warrant Shares.  For purposes of the foregoing sentence, "FAIR MARKET
VALUE" of the Warrant Shares will be determined in good faith by the Board of
Directors of the Company as of the date of any such exercise.  Each Warrant not
exercised prior to 5:00 p.m., New York City time, on _______, 2006 shall become
void and all rights thereunder and all rights in respect thereof under this
agreement shall cease as of such time.  No adjustments as to dividends will be
made upon exercise of the Warrants.

     (b)  A Warrant may be exercised upon surrender to the Company at the
principal office of the Warrant Agent of the certificate or certificates
evidencing the Warrants to be exercised with the form of election to purchase on
the reverse thereof duly filled in and signed, which signature


                                        3
<PAGE>

shall be guaranteed by a bank or trust company having an office or correspondent
in the United States or a broker or dealer which is a member of a registered
securities exchange or the National Association of Securities Dealers, Inc. (the
"NASD"), and upon payment to the Warrant Agent for the account of the Company of
the exercise price (the "EXERCISE PRICE"), which is set forth in the form of
Warrant Certificate attached hereto as Exhibit A, as adjusted as herein
provided, for the number of Warrant Shares in respect of which such Warrants are
then exercised.  Payment of the aggregate Exercise Price shall be made (i) in
cash or by certified or official bank check payable to the order of the Company,
(ii) through the surrender of debt or preferred equity securities of the Company
having a principal amount or liquidation preference, as the case may be, equal
to the aggregate Exercise Price to be paid (the Company will pay the accrued
interest or dividends on such surrendered debt or preferred equity securities in
cash at the time of surrender notwithstanding the stated terms thereof or (iii)
in the manner provided in Section 6(a) hereof.

     (c)  Subject to the provisions of Section 7 hereof, upon such surrender of
Warrants and payment of the Exercise Price, the Company shall issue and cause to
be delivered with all reasonable dispatch to or upon the written order of the
holder and in such name or names as the Warrant holder may designate, a
certificate or certificates for the number of full Warrant Shares issuable upon
the exercise of such Warrants together with cash as provided in Section 12
hereof; PROVIDED, HOWEVER, that if any consolidation, merger or lease or sale of
assets is proposed to be effected by the Company as described in Section 11(m)
hereof, or a tender offer or an exchange offer for shares of Common Stock of the
Company shall be made, upon such surrender of Warrants and payment of the
Exercise Price as aforesaid, the Company shall, as soon as possible, but in any
event not later than two business days thereafter, issue and cause to be
delivered the full number of Warrant Shares issuable upon the exercise of such
Warrants in the manner described in this sentence together with cash as provided
in Section 12 hereof. Such certificate or certificates shall be deemed to have
been issued and any person so designated to be named therein shall be deemed to
have become a holder of record of such Warrant Shares as of the date of the
surrender of such Warrants and payment of the Exercise Price.

     (d)  The Warrants shall be exercisable, at the election of the holders
thereof, either in full or from time to time in part and, in the event that a
certificate evidencing Warrants is exercised in respect of fewer than all of the
Warrant Shares issuable on such exercise at any time prior to the date of
expiration of the Warrants, a new certificate evidencing the remaining Warrant
or Warrants will be issued, and the Warrant Agent is hereby irrevocably
authorized to countersign and to deliver the required new Warrant Certificate or
Certificates pursuant to the provisions of this Section and of Section 3 hereof,
and the Company, whenever required by the Warrant Agent, will supply the Warrant
Agent with Warrant Certificates duly executed on behalf of the Company for such
purpose.

     (e)  All Warrant Certificates surrendered upon exercise of Warrants shall
be cancelled by the Warrant Agent.  Such cancelled Warrant Certificates shall
then be disposed of by the Warrant Agent in a manner satisfactory to the
Company. The Warrant Agent shall account promptly to the Company with respect to
Warrants exercised and concurrently pay to the Company all monies received by
the Warrant Agent for the purchase of the Warrant Shares through the exercise of
such Warrants.


                                        4
<PAGE>

     (f)  The Warrant Agent shall keep copies of this Agreement and any notices
given or received hereunder available for inspection by the holders during
normal business hours at its office.  The Company shall supply the Warrant Agent
from time to time with such numbers of copies of this Agreement as the Warrant
Agent may request.

     SECTION 7.     PAYMENT OF TAXES.  The Company will pay all documentary
stamp taxes attributable to the initial issuance of Warrant Shares upon the
exercise of Warrants; PROVIDED, HOWEVER, that the Company shall not be required
to pay any tax or taxes which may be payable in respect of any transfer involved
in the issue of any Warrant Certificates or any certificates for Warrant Shares
in a name other than that of the registered holder of a Warrant Certificate
surrendered upon the exercise of a Warrant, and the Company shall not be
required to issue or deliver such Warrant Certificates unless or until the
person or persons requesting the issuance thereof shall have paid to the Company
the amount of such tax or shall have established to the satisfaction of the
Company that such tax has been paid.

     SECTION 8.     MUTILATED OR MISSING WARRANT CERTIFICATES.  In case any of
the Warrant Certificates shall be mutilated, lost, stolen or destroyed, the
Company may in its discretion issue and the Warrant Agent may countersign, in
exchange and substitution for and upon cancellation of the mutilated Warrant
Certificate, or in lieu of and substitution for the Warrant Certificate lost,
stolen or destroyed, a new Warrant Certificate of like tenor and representing an
equivalent number of Warrants, but only upon receipt of evidence satisfactory to
the Company and the Warrant Agent of such loss, theft or destruction of such
Warrant Certificate and indemnity, if requested, also satisfactory to them.
Applicants for such substitute Warrant Certificates shall also comply with such
other reasonable regulations and pay such other reasonable charges as the
Company or the Warrant Agent may prescribe.

     SECTION 9.     RESERVATION OF WARRANT SHARES.  (a)  The Company will at all
times reserve and keep available, free from preemptive rights, out of the
aggregate of its authorized but unissued Common Stock or its authorized and
issued Common Stock held in its treasury, for the purpose of enabling it to
satisfy any obligation to issue Warrant Shares upon exercise of Warrants, the
maximum number of shares of Common Stock which may then be deliverable upon the
exercise of all outstanding Warrants.

     (b)  The Company or, if appointed, the transfer agent for the Common Stock
(the "TRANSFER AGENT") and every subsequent transfer agent for any shares of the
Company's capital stock issuable upon the exercise of any of the rights of
purchase aforesaid will be irrevocably authorized and directed at all times to
reserve such number of authorized shares as shall be required for such purpose.
The Company will keep a copy of this Agreement on file with the Transfer Agent
and with every subsequent transfer agent for any shares of the Company's capital
stock issuable upon the exercise of the rights of purchase represented by the
Warrants.  The Warrant Agent is hereby irrevocably authorized to requisition
from time to time from such Transfer Agent the stock certificates required to
honor outstanding Warrants upon exercise thereof in accordance with the terms of
this Agreement.  The Company will supply such Transfer Agent with duly executed
certificates for such purposes and will provide or otherwise make available any
cash which may be payable as provided in Section 12 hereof.  The Company will
furnish such Transfer


                                        5
<PAGE>

Agent a copy of all notices of adjustments, and certificates related thereto,
transmitted to each holder pursuant to Section 14 hereof.

     (c)  Before taking any action which would cause an adjustment pursuant to
Section 11 hereof to reduce the Exercise Price below the then par value (if any)
of the Warrant Shares, the Company will take any corporate action which may, in
the opinion of its counsel (which may be counsel employed by the Company), be
necessary in order that the Company may validly and legally issue fully paid and
nonassessable Warrant Shares at the Exercise Price as so adjusted.

     (d)  The Company covenants that all Warrant Shares which may be issued upon
exercise of Warrants will, upon issue, be fully paid, nonassessable, free of
preemptive rights and free from all taxes, liens, charges and security interests
with respect to the issuance thereof.

     SECTION 10.    OBTAINING STOCK EXCHANGE LISTINGS.  The Company will from
time to time take all action which may be necessary so that the Warrant Shares,
immediately upon their issuance upon the exercise of Warrants, will be listed on
the principal securities exchanges and markets within the United States of
America, if any, on which other shares of Common Stock are then listed.

     SECTION 11.    ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES
ISSUABLE.  The Exercise Price and the number of Warrant Shares issuable upon the
exercise of each Warrant are subject to adjustment from time to time upon the
occurrence of the events enumerated in this Section 11.  For purposes of this
Section 11, "COMMON STOCK" means shares now or hereafter authorized of any class
of common stock of the Company and any other stock of the Company, however
designated, that has the right (subject to any prior rights of any class or
series of preferred stock) to participate in any distribution of the assets or
earnings of the Company without limit as to per share amount.

     (a)  ADJUSTMENT FOR CHANGE IN CAPITAL STOCK.  If the Company (i) pays a
dividend or makes a distribution on its Common Stock in shares of its Common
Stock, (ii) subdivides its outstanding shares of Common Stock into a greater
number of shares, (iii) combines its outstanding shares of Common Stock into a
smaller number of shares, (iv) makes a distribution on its Common Stock in
shares of its capital stock other than Common Stock or (v) issues by
reclassification of its Common Stock any shares of its capital stock; then the
Exercise Price in effect immediately prior to such action shall be
proportionately adjusted so that the holder of any Warrant thereafter exercised
may receive the aggregate number and kind of shares of capital stock of the
Company which he would have owned immediately following such action if such
Warrant had been exercised immediately prior to such action.

     The adjustment shall become effective immediately after the record date in
the case of a dividend or distribution and immediately after the effective date
in the case of a subdivision, combination or reclassification.  If, after an
adjustment, a holder of a Warrant upon exercise of it may receive shares of two
or more classes of capital stock of the Company, the Company shall determine the
allocation of the adjusted Exercise Price between the classes of capital stock.
After such allocation, the exercise privilege and the Exercise Price of each
class of capital stock shall


                                        6
<PAGE>

thereafter be subject to adjustment on terms comparable to those applicable to
Common Stock in this Section 11.  Such adjustment shall be made successively
whenever any event listed above shall occur.

     (b)  ADJUSTMENT FOR RIGHTS ISSUE.       If the Company distributes any
rights, options or warrants to all holders of its Common Stock entitling them
for a period expiring within 60 days after the record date mentioned below to
purchase shares of Common Stock at a price per share less than the current
market price per share on that record date, the Exercise Price shall be adjusted
in accordance with the formula:

                                        O    +    N x P
                                                  -----
                    E'   =    E    x                M
                                        ---------------
                                             O + N
where:

     E'   =    the adjusted Exercise Price.

     E    =    the current Exercise Price.

     O    =    the number of shares of Common Stock outstanding on the record
               date.

     N    =    the number of additional shares of Common Stock offered.

     P    =    the offering price per share of the additional shares.

     M    =    the current market price per share of Common Stock on the record
               date.

     The adjustment shall be made successively whenever any such rights, options
or warrants are issued and shall become effective immediately after the record
date for the determination of stockholders entitled to receive the rights,
options or warrants.  If at the end of the period during which such rights,
options or warrants are exercisable, not all rights, options or warrants shall
have been exercised, the Exercise Price shall be immediately readjusted to what
it would have been if "N" in the above formula had been the number of shares
actually issued.

     (c)  ADJUSTMENT FOR OTHER DISTRIBUTIONS.  If the Company distributes to all
holders of its Common Stock any of its assets or debt securities or any rights
or warrants to purchase debt securities, assets or other securities of the
Company, the Exercise Price shall be adjusted in accordance with the formula:


                                        7
<PAGE>


                    E'   =    E    x    M    -    F
                                        -----------
                                             M
where:

     E'   =    the adjusted Exercise Price.

     E    =    the current Exercise Price.

     M    =    the current market price per share of Common Stock on the record
               date mentioned below.

     F    =    the fair market value on the record date of the assets,
               securities, rights or warrants applicable to one share of Common
               Stock.  The Board of Directors shall determine the fair market
               value.

     The adjustment shall be made successively whenever any such distribution is
made and shall become effective immediately after the record date for the
determination of stockholders entitled to receive the distribution.

     This Section 11(c) does not apply to cash dividends or cash distributions
paid out of consolidated current or retained earnings as shown on the books of
the Company prepared in accordance with generally accepted accounting
principles.  Also, this Section 11(c) does not apply to rights, options or
warrants referred to in Section 11(b) hereof.

     (d)  ADJUSTMENT FOR COMMON STOCK ISSUE.  If the Company issues shares of
Common Stock for a consideration per share less than the current market price
per share on the date the Company fixes the offering price of such additional
shares, the Exercise Price shall be adjusted in accordance with the formula:

                                                  P
                                                 --
                    E'   =    E    x    O    +    M
                                        -----------
                                             A

where:

     E'   =    the adjusted Exercise Price.

     E    =    the then current Exercise Price.

     O    =    the number of shares outstanding immediately prior to the
               issuance of such additional shares.

     P    =    the aggregate consideration received for the issuance of such
               additional shares.


                                        8
<PAGE>


     M    =    the current market price per share on the date of issuance of
               such additional shares.

     A    =    the number of shares outstanding immediately after the issuance
               of such additional shares.

     The adjustment shall be made successively whenever any such issuance is
made, and shall become effective immediately after such issuance.

     This Section 11(d) does not apply to:

          (i)    any of the transactions described in Sections 11(b) and (c);

          (ii)   the exercise of Warrants, or the conversion or exchange of
     other securities convertible or exchangeable for Common Stock;

          (iii)  Common Stock issued to the Company's employees under bona fide
     employee benefit plans adopted by the Board of Directors and approved by
     the holders of Common Stock when required by law, if such Common Stock
     would otherwise be covered by this Section 11(d) (but only to the extent
     that the aggregate number of shares excluded hereby and issued after the
     date of this Warrant Agreement shall not exceed 5% of the Common Stock
     outstanding at the time of the adoption of each such plan, exclusive of
     antidilution adjustments thereunder);

          (iv)   Common Stock upon the exercise of rights or warrants issued to
     the holders of Common Stock;

          (v)    Common Stock issued to stockholders of any person which merges
     into the Company in proportion to their stock holdings of such person
     immediately prior to such merger, upon such merger;

          (vi)   Common Stock issued in a bona fide public offering pursuant to
     a firm commitment underwriting; or

          (vii)  Common Stock issued in a bona fide private placement through a
     placement agent which is a member firm of the NASD (except to the extent
     that any discount from the current market price attributable to
     restrictions on transferability of the Common Stock, as determined  in good
     faith by the Board of Directors and described in a Board resolution which
     shall be filed with the Trustee, shall exceed 20%).

     (e)  ADJUSTMENT FOR CONVERTIBLE SECURITIES ISSUE.  If the Company issues
any securities convertible into or exchangeable for Common Stock (other than
securities issued in transactions described in Sections 11(b) and (c) hereof)
for a consideration per share of Common Stock initially deliverable upon
conversion or exchange of such securities less than the current market price per


                                        9
<PAGE>

share on the date of issuance of such securities, the Exercise Price shall be
adjusted in accordance with this formula:


                                                  P
                                                 --
                    E'   =    E    x     O   +    M
                                         ----------
                                         O   +    D

where:

     E'   =    the adjusted Exercise Price.

     E    =    the then current Exercise Price.

     O    =    the number of shares outstanding immediately prior to the
               issuance of such securities.

     P    =    the aggregate consideration received for the issuance of such
               securities.

     M    =    the current market price per share on the date of issuance of
               such securities.

     D    =    the maximum number of shares deliverable upon conversion or in
               exchange for such securities at the initial conversion or
               exchange rate.

     The adjustment shall be made successively whenever any such issuance is
made, and shall become effective immediately after such issuance.

     If all of the Common Stock deliverable upon conversion or exchange of such
securities have not been issued when such securities are no longer outstanding,
then the Exercise Price shall promptly be readjusted to the Exercise Price which
would then be in effect had the adjustment upon the issuance of such securities
been made on the basis of the actual number of shares of Common Stock issued
upon conversion or exchange of such securities.

     This Section 11(e) does not apply to:

          (i)    convertible securities issued to stockholders of any person
     which merges into the Company, or with a subsidiary of the Company, in
     proportion to their stock holdings of such person immediately prior to such
     merger, upon such merger,

          (ii)   convertible securities issued in a bona fide public offering
     pursuant to a firm commitment underwriting or

          (iii)  convertible securities issued in a bona fide private placement
     through a placement agent which is a member firm of the NASD (except to the
     extent that any


                                       10
<PAGE>

     discount from the current market price attributable to restrictions on
     transferability of Common Stock issuable upon conversion, as determined in
     good faith by the Board of Directors and described in a Board resolution
     which shall be filed with the Trustee, shall exceed 20% of the then current
     market price).

     (f)  CURRENT MARKET PRICE.  In Sections 11(b), (c), (d) and (e) hereof, the
current market price per share of Common Stock on any date is the average of the
Quoted Prices of the Common Stock for 30 consecutive trading days commencing 45
trading days prior to the date in question.  The "QUOTED PRICE" of the Common
Stock is the last reported sales price of the Common Stock as reported by the
Nasdaq National Market or, if the Common Stock is listed on a securities
exchange, the last reported sales price of the Common Stock on such exchange
which shall be for consolidated trading if applicable to such exchange, or, if
neither so reported or listed, the last reported bid price of the Common Stock.
In the absence of one or more such quotations, the Board of Directors of the
Company shall determine the current market price on the basis of such quotations
as it in good faith considers appropriate.

     (g)  CONSIDERATION RECEIVED.  For purposes of any computation respecting
consideration received pursuant to Sections 11(d) and (e), the following shall
apply:

          (i)    in the case of the issuance of shares of Common Stock for cash,
     the consideration shall be the amount of such cash, PROVIDED that in no
     case shall any deduction be made for any commissions, discounts or other
     expenses incurred by the Company for any underwriting of the issue or
     otherwise in connection therewith;

          (ii)   in the case of the issuance of shares of Common Stock for a
     consideration in whole or in part other than cash, the consideration other
     than cash shall be deemed to be the fair market value thereof as determined
     in good faith by the Board of Directors (irrespective of the accounting
     treatment thereof), whose determination shall be conclusive, and described
     in a Board resolution which shall be filed with the Warrant Agent; and

          (iii)  in the case of the issuance of securities convertible into or
     exchangeable for shares, the aggregate consideration received therefor
     shall be deemed to be the consideration received by the Company for the
     issuance of such securities plus the additional minimum consideration, if
     any, to be received by the Company upon the conversion or exchange thereof
     (the consideration in each case to be determined in the same manner as
     provided in clauses (i) and (ii) of this subsection).

     (h)  WHEN DE MINIMIS ADJUSTMENT MAY BE DEFERRED.  No adjustment in the
Exercise Price need be made unless the adjustment would require an increase or
decrease of at least 1% in the Exercise Price.  Any adjustments that are not
made shall be carried forward and taken into account in any subsequent
adjustment.  All calculations under this Section 11 shall be made to the nearest
cent or to the nearest 1/100th of a share, as the case may be.


                                       11
<PAGE>

     (i)  WHEN NO ADJUSTMENT REQUIRED.  No adjustment need be made for a
transaction referred to Section 11(a), (b), (c), (d) or (e) hereof, if Warrant
holders are to participate in the transaction on a basis and with notice that
the Board of Directors determines to be fair and appropriate in light of the
basis and notice on which holders of Common Stock participate in the
transaction.  No adjustment need be made for rights to purchase Common Stock
pursuant to a Company plan for reinvestment of dividends or interest.  No
adjustment need be made for a change in the par value or no par value of the
Common Stock.  To the extent the Warrants become convertible into cash, no
adjustment need be made thereafter as to the cash. Interest will not accrue on
the cash.

     (j)  NOTICE OF ADJUSTMENT.  Whenever the Exercise Price is adjusted, the
Company shall provide the notices required by Section 13 hereof.

     (k)  VOLUNTARY REDUCTION.  The Company from time to time may reduce the
Exercise Price by any amount for any period of time, if the period is at least
20 days and if the reduction is irrevocable during the period; PROVIDED,
HOWEVER, that in no event may the Exercise Price be less than the par value of a
share of Common Stock.  Whenever the Exercise Price is reduced, the Company
shall mail to Warrant holders a notice of the reduction.  The Company shall mail
the notice at least 15 days before the date the reduced Exercise Price takes
effect.  The notice shall state the reduced Exercise Price and the period in
which it will be in effect.  A reduction of the Exercise Price does not change
or adjust the Exercise Price otherwise in effect for purposes of Sections 11(a),
(b), (c), (d) and (e) hereof.

     (l)  NOTICE OF CERTAIN TRANSACTIONS.  If (i) the Company takes any action
that would require an adjustment in the Exercise Price pursuant to Section
11(a), (b), (c), (d) or (e) hereof and if the Company does not arrange for
Warrant holders to participate pursuant to Section 11(i) hereof, (ii) the
Company takes any action that would require a supplemental Warrant Agreement
pursuant to Section 11(m) hereof or (iii) there is a liquidation or dissolution
of the Company, then the Company shall mail to Warrant holders a notice stating
the proposed record date for a dividend or distribution or the proposed
effective date of a subdivision, combination, reclassification, consolidation,
merger, transfer, lease, liquidation or dissolution.  The Company shall mail the
notice at least 15 days before such date.  Failure to mail the notice or any
defect in it shall not affect the validity of the transaction.

     (m)  REORGANIZATION OF COMPANY.  If the Company consolidates or merges with
or into, or transfers or leases all or substantially all its assets to, any
person, upon consummation of such transaction the Warrants shall automatically
become exercisable for the kind and amount of securities, cash or other assets
which the holder of a Warrant would have owned immediately after the
consolidation, merger, transfer or lease if the holder had exercised the Warrant
immediately before the effective date of the transaction.  Concurrently with the
consummation of such transaction, the corporation formed by or surviving any
such consolidation or merger if other than the Company, or the person to which
such sale or conveyance shall have been made, shall enter into a supplemental
Warrant Agreement so providing and further providing for adjustments which shall
be as nearly equivalent as may be practical to the adjustments provided for in
this Section.  The successor Company shall mail to Warrant holders a notice
describing the supplemental Warrant


                                       12
<PAGE>

Agreement.  If the issuer of securities deliverable upon exercise of Warrants
under the supplemental Warrant Agreement is an affiliate of the formed,
surviving, transferee or lessee corporation, that issuer shall join in the
supplemental Warrant Agreement.  If this Section 11(m) applies, Sections 11(a),
(b), (c), (d) and (e) hereof do not apply.

     (n)  COMPANY DETERMINATION FINAL.  Any determination that the Company or
the Board of Directors must make pursuant to Section 11(a), (c), (d), (e), (f),
(g) or (i) hereof is conclusive.

     (o)  WARRANT AGENT'S DISCLAIMER.  The Warrant Agent has no duty to
determine when an adjustment under this Section 11 should be made, how it should
be made or what it should be.  The Warrant Agent has no duty to determine
whether any provisions of a supplemental Warrant Agreement under Section 11(m)
hereof are correct.  The Warrant Agent makes no representation as to the
validity or value of any securities or assets issued upon exercise of Warrants.
The Warrant Agent shall not be responsible for the Company's failure to comply
with this Section 11.

     (p)  WHEN ISSUANCE OR PAYMENT MAY BE DEFERRED.  In any case in which this
Section 11 shall require that an adjustment in the Exercise Price be made
effective as of a record date for a specified event, the Company may elect to
defer until the occurrence of such event (i) issuing to the holder of any
Warrant exercised after such record date the Warrant Shares and other capital
stock of the Company, if any, issuable upon such exercise over and above the
Warrant Shares and other capital stock of the Company, if any, issuable upon
such exercise on the basis of the Exercise Price and (ii) paying to such holder
any amount in cash in lieu of a fractional share pursuant to Section 12 hereof;
PROVIDED, HOWEVER, that the Company shall deliver to such holder a due bill or
other appropriate instrument evidencing such holder's right to receive such
additional Warrant Shares, other capital stock and cash upon the occurrence of
the event requiring such adjustment.

     (q)  ADJUSTMENT IN NUMBER OF SHARES.  Upon each adjustment of the Exercise
Price pursuant to this Section 11, each Warrant outstanding prior to the making
of the adjustment in the Exercise Price shall thereafter evidence the right to
receive upon payment of the adjusted Exercise Price that number of shares of
Common Stock (calculated to the nearest hundredth) obtained from the following
formula:

                    N'   =    N    x     E
                                       -----
                                         E'

where:

     N'   =    the adjusted number of Warrant Shares issuable upon exercise of a
               Warrant by payment of the adjusted Exercise Price.

     N    =    the number or Warrant Shares previously issuable upon exercise of
               a Warrant by payment of the Exercise Price prior to adjustment.

     E'   =    the adjusted Exercise Price.


                                       13
<PAGE>


     E    =    the Exercise Price prior to adjustment.

     (r)  FORM OF WARRANTS.  Irrespective of any adjustments in the Exercise
Price or the number or kind of shares purchasable upon the exercise of the
Warrants, Warrants theretofore or thereafter issued may continue to express the
same price and number and kind of shares as are stated in the Warrants initially
issuable pursuant to this Agreement.

     SECTION 12.    FRACTIONAL INTERESTS.  The Company shall not be required to
issue fractional Warrant Shares on the exercise of Warrants.  If more than one
Warrant shall be presented for exercise in full at the same time by the same
holder, the number of full Warrant Shares which shall be issuable upon the
exercise thereof shall be computed on the basis of the aggregate number of
Warrant Shares purchasable on exercise of the Warrants so presented.  If any
fraction of a Warrant Share would, except for the provisions of this Section 12,
be issuable on the exercise of any Warrants (or specified portion thereof), the
Company shall pay an amount in cash equal to the Exercise Price on the day
immediately preceding the date the Warrant is presented for exercise, multiplied
by such fraction.

     SECTION 13.    NOTICES TO WARRANT HOLDERS.  (a)  Upon any adjustment of the
Exercise Price pursuant to Section 11 hereof, the Company shall promptly
thereafter (i) cause to be filed with the Warrant Agent a certificate of a firm
of independent public accountants of recognized standing selected by the Board
of Directors of the Company (who may be the regular auditors of the Company)
setting forth the Exercise Price after such adjustment and setting forth in
reasonable detail the method of calculation and the facts upon which such
calculations are based and setting forth the number of Warrant Shares (or
portion thereof) issuable after such adjustment in the Exercise Price, upon
exercise of a Warrant and payment of the adjusted Exercise Price, which
certificate shall be conclusive evidence of the correctness of the matters set
forth therein, and (ii) cause to be given to each of the registered holders of
the Warrant Certificates at his address appearing on the Warrant register
written notice of such adjustments by first-class mail, postage prepaid.  Where
appropriate, such notice may be given in advance and included as a part of the
notice required to be mailed under the other provisions of this Section 13.

     (b)  In case:

          (i)    the Company shall authorize the issuance to all holders of
     shares of Common Stock of rights, options or warrants to subscribe for or
     purchase shares of Common Stock or of any other subscription rights or
     warrants;

          (ii)   the Company shall authorize the distribution to all holders of
     shares of Common Stock of evidences of its indebtedness or assets (other
     than cash dividends or cash distributions payable out of consolidated
     earnings or earned surplus or dividends payable in shares of Common Stock
     or distributions referred to in subsection (a) of Section 11 hereof);

          (iii)  of any consolidation or merger to which the Company is a party
     and for which approval of any stockholders of the Company is required, or
     of the conveyance or


                                       14
<PAGE>

     transfer of the properties and assets of the Company substantially as an
     entirety, or of any reclassification or change of Common Stock issuable
     upon exercise of the Warrants (other than a change in par value, or from
     par value to no par value, or from no par value to par value, or as a
     result of a subdivision or combination), or a tender offer or exchange
     offer for shares of Common Stock;

          (iv)   of the voluntary or involuntary dissolution, liquidation or
     winding up of the Company; or

          (v)    the Company proposes to take any action (other than actions of
     the character described in Section 11(a) hereof) which would require an
     adjustment of the Exercise Price pursuant to Section 11 hereof;

then the Company shall cause to be filed with the Warrant Agent and shall cause
to be given to each of the registered holders of the Warrant Certificates at his
address appearing on the Warrant register, at least 20 days (or 10 days in any
case specified in clauses (i) or (ii) above) prior to the applicable record date
hereinafter specified, or promptly in the case of events for which there is no
record date, by first-class mail, postage prepaid, a written notice stating (x)
the date as of which the holders of record of shares of Common Stock to be
entitled to receive any such rights, options, warrants or distribution are to be
determined, (y) the initial expiration date set forth in any tender offer or
exchange offer for shares of Common Stock, or (z) the date on which any such
consolidation, merger, conveyance, transfer, dissolution, liquidation or winding
up is expected to become effective or consummated, and the date as of which it
is expected that holders of record of shares of Common Stock shall be entitled
to exchange such shares for securities or other property, if any, deliverable
upon such reclassification, consolidation, merger, conveyance, transfer,
dissolution, liquidation or winding up.  The failure to give the notice required
by this Section 13 or any defect therein shall not affect the legality or
validity of any distribution, right, option, warrant, consolidation, merger,
conveyance, transfer, dissolution, liquidation or winding up, or the vote upon
any action.

     (c)  Nothing contained in this Agreement or in any of the Warrant
Certificates shall be construed as conferring upon the holders thereof the right
to vote or to consent or to receive notice as stockholders in respect of the
meetings of stockholders or the election of directors of the Company or any
other matter, or any rights whatsoever as stockholders of the Company.

     SECTION 14.    MERGER, CONSOLIDATION OR CHANGE OF NAME OF WARRANT AGENT.
(a)  Any corporation into which the Warrant Agent may be merged or with which it
may be consolidated, or any corporation resulting from any merger or
consolidation to which the Warrant Agent shall be a party, or any corporation
succeeding to the business of the Warrant Agent, shall be the successor to the
Warrant Agent hereunder without the execution or filing of any paper or any
further act on the part of any of the parties hereto, PROVIDED that such
corporation would be eligible for appointment as a successor warrant agent under
the provisions of Section 16 hereof.  In case at the time such successor to the
Warrant Agent shall succeed to the agency created by this Agreement, and in case
at that time any of the Warrant Certificates shall have been countersigned but
not delivered, any such successor to the Warrant Agent may adopt the
countersignature of the


                                       15
<PAGE>

original Warrant Agent; and in case at that time any of the Warrant Certificates
shall not have been countersigned, any successor to the Warrant Agent may
countersign such Warrant Certificates either in the name of the predecessor
Warrant Agent or in the name of the successor to the Warrant Agent; and in all
such cases such Warrant Certificates shall have the full force and effect
provided in the Warrant Certificates and in this Agreement.

     (b)  In case at any time the name of the Warrant Agent shall be changed and
at such time any of the Warrant Certificates shall have been countersigned but
not delivered, the Warrant Agent whose name has been changed may adopt the
countersignature under its prior name, and in case at that time any of the
Warrant Certificates shall not have been countersigned, the Warrant Agent may
countersign such Warrant Certificates either in its prior name or in its changed
name, and in all such cases such Warrant Certificates shall have the full force
and effect provided in the Warrant Certificates and in this Agreement.

     SECTION 15.    WARRANT AGENT.  The Warrant Agent undertakes the duties and
obligations imposed by this Agreement upon the following terms and conditions,
by all of which the Company and the holders of Warrants, by their acceptance
thereof, shall be bound:

     (a)  The statements contained herein and in the Warrant Certificates shall
be taken as statements of the Company and the Warrant Agent assumes no
responsibility for the correctness of any of the same except such as describe
the Warrant Agent or action taken or to be taken by it.  The Warrant Agent
assumes no responsibility with respect to the distribution of the Warrant
Certificates except as herein otherwise provided.

     (b)  The Warrant Agent shall not be responsible for any failure of the
Company to comply with any of the covenants contained in this Agreement or in
the Warrant Certificates to be complied with by the Company.

     (c)  The Warrant Agent may consult at any time with counsel satisfactory to
it (who may be counsel for the Company) and the Warrant Agent shall incur no
liability or responsibility to the Company or to any holder of any Warrant
Certificate in respect of any action taken, suffered or omitted by it hereunder
in good faith and in accordance with the opinion or the advice of such counsel.

     (d)  The Warrant Agent shall incur no liability or responsibility to the
Company or to any holder of any Warrant Certificate for any action taken in
reliance on any Warrant Certificate, certificate of shares, notice, resolution,
waiver, consent, order, certificate, or other paper, document or instrument
believed by it to be genuine and to have been signed, sent or presented by the
proper party or parties.

     (e)  The Company agrees to pay to the Warrant Agent reasonable compensation
for all services rendered by the Warrant Agent in the execution of this
Agreement, to reimburse the Warrant Agent for all expenses, taxes and
governmental charges and other charges of any kind and nature incurred by the
Warrant Agent in the execution of this Agreement and to indemnify the Warrant
Agent and save it harmless against any and all liabilities, including judgments,
costs and


                                       16
<PAGE>

counsel fees, for anything done or omitted by the Warrant Agent in the execution
of this Agreement except as a result of its negligence or bad faith.

     (f)  The Warrant Agent shall be under no obligation to institute any
action, suit or legal proceeding or to take any other action likely to involve
expense unless the Company or one or more registered holders of Warrant
Certificates shall furnish the Warrant Agent with reasonable security and
indemnity for any costs and expenses which may be incurred, but this provision
shall not affect the power of the Warrant Agent to take such action as it may
consider proper, whether with or without any such security or indemnity.  All
rights of action under this Agreement or under any of the Warrants may be
enforced by the Warrant Agent without the possession of any of the Warrant
Certificates or the production thereof at any trial or other proceeding relative
thereto, and any such action, suit or proceeding instituted by the Warrant Agent
shall be brought in its name as Warrant Agent and any recovery of judgment shall
be for the ratable benefit of the registered holders of the Warrants, as their
respective rights or interests may appear.

     (g)  The Warrant Agent, and any stockholder, director, officer or employee
of it, may buy, sell or deal in any of the Warrants or other securities of the
Company or become pecuniarily interested in any transaction in which the Company
may be interested, or contract with or lend money to the Company or otherwise
act as fully and freely as though it were not Warrant Agent under this
Agreement. Nothing herein shall preclude the Warrant Agent from acting in any
other capacity for the Company or for any other legal entity.

     (h)  The Warrant Agent shall act hereunder solely as agent for the Company,
and its duties shall be determined solely by the provisions hereof.  The Warrant
Agent shall not be liable for anything which it may do or refrain from doing in
connection with this Agreement except for its own negligence or bad faith.

     (i)  The Warrant Agent shall not at any time be under any duty or
responsibility to any holder of any Warrant Certificate to make or cause to be
made any adjustment of the Exercise Price or number of the Warrant Shares or
other securities or property deliverable as provided in this Agreement, or to
determine whether any facts exist which may require any of such adjustments, or
with respect to the nature or extent of any such adjustments, when made, or with
respect to the method employed in making the same.  The Warrant Agent shall not
be accountable with respect to the validity or value or the kind or amount of
any Warrant Shares or of any securities or property which may at any time be
issued or delivered upon the exercise of any Warrant or with respect to whether
any such Warrant Shares or other securities will when issued be validly issued
and fully paid and nonassessable, and makes no representation with respect
thereto.

     SECTION 16.    CHANGE OF WARRANT AGENT.  If the Warrant Agent shall become
incapable of acting as Warrant Agent, the Company shall appoint a successor to
such Warrant Agent.  If the Company shall fail to make such appointment within a
period of 30 days after it has been notified in writing of such incapacity by
the Warrant Agent or by the registered holder of a Warrant Certificate, then the
registered holder of any Warrant Certificate may apply to any court of competent
jurisdiction for the appointment of a successor to the Warrant Agent.  Pending


                                       17
<PAGE>

appointment of a successor to such Warrant Agent, either by the Company or by
such a court, the duties of the Warrant Agent shall be carried out by the
Company.  The holders of a majority of the unexercised Warrants shall be
entitled at any time to remove the Warrant Agent and appoint a successor to such
Warrant Agent.  Such successor to the Warrant Agent need not be approved by the
Company or the former Warrant Agent. After appointment the successor to the
Warrant Agent shall be vested with the same powers, rights, duties and
responsibilities as if it had been originally named as Warrant Agent without
further act or deed; PROVIDED that the former Warrant Agent shall deliver and
transfer to the successor to the Warrant Agent any property at the time held by
it hereunder and execute and deliver any further assurance, conveyance, act or
deed necessary for the purpose.  Failure to give any notice provided for in this
Section 16, however, or any defect therein, shall not affect the legality or
validity of the appointment of a successor to the Warrant Agent.

     SECTION 17.    REGISTRATION.  (a)  The Company shall prepare and cause to
be filed with the Securities and Exchange Commission (the "COMMISSION") pursuant
to Rule 415 under the Securities Act (the "SHELF REGISTRATION") a shelf
registration statement on the appropriate form (the "REGISTRATION STATEMENT")
relating to the offer and sale by the Company of the Warrant Shares to the
holders of Warrants upon exercise of the Warrants and resales of the Warrant
Shares by the holders thereof.

     (b)  The Company shall use its best efforts to cause such Registration
Statement to be declared effective by the Commission on or prior to the earlier
to occur of (i) __________, 1996 and (ii) 45 days after the date upon which (A)
a Change in Control (as such term is defined in the indenture relating to the
Notes) occurs or (B) the Warrants otherwise become exercisable.

     (c)  The Company shall use its best efforts to keep the Registration
Statement continuously effective under the Securities Act in order to permit the
prospectus included therein to be lawfully delivered by the Company to the
holders exercising the Warrants until the Expiration Date or such shorter period
that will terminate when all the Warrants have been exercised; PROVIDED that,
except as provided below with respect to any Black Out Period, the Company shall
be deemed not to have used its best efforts to keep the Registration Statement
effective during the requisite period if it voluntarily takes any action that
would result in it not being able to offer and sell the Warrant Shares upon
exercise of the Warrants during that period, unless such action is required by
applicable law.  Notwithstanding the foregoing, the Company shall not be
required to amend or supplement the Registration Statement, any related
prospectus or any document incorporated therein by reference, for a period (a
"BLACK OUT PERIOD") not to exceed, for so long as this Agreement is in effect,
an aggregate of 45 days in any calendar year, in the event that (i) an event
occurs and is continuing as a result of which the Registration Statement, any
related prospectus or any document incorporated therein by reference as then
amended or supplemented would, in the Company's good faith judgment, contain an
untrue statement of a material fact or omit to state a material fact necessary
in order to make the statements therein, in the light of the circumstances under
which they were made, not misleading, and (ii)(A) the Company determines in its
good faith judgment that the disclosure of such event at such time would have a
material adverse effect on the business, operations or prospects of the Company
or (B) the disclosure otherwise relates to a material business transaction which
has not yet been publicly disclosed;


                                       18
<PAGE>

PROVIDED that no Black Out Period may be in effect during the six months prior
to the Expiration Date.

     (d)  The Company shall cause the Registration Statement and the related
prospectus and any amendment or supplement thereto, as of the effective date of
the Registration Statement, amendment or supplement, (i) to comply in all
material respects with the applicable requirements of the Securities Act and the
rules and regulations of the Commission and (ii) not to contain any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading.

     (e)  The Company shall give prompt written notice to the holders of the
Warrants and the Warrant Agent of (i) the effectiveness of the Registration
Statement or any post-effective amendment thereto, (ii) the issuance by the
Commission of any stop order suspending the effectiveness of the Registration
Statement or the initiation or threatening of any proceedings for that purpose,
(iii) the receipt by the Company or its legal counsel of any notification with
respect to the suspension of the qualification of the Warrant Shares for sale in
any jurisdiction or the initiation or threatening of any proceeding for such
purpose, (iv) the happening of any event that requires the Company to make
changes in the Registration Statement or the prospectus in order to make the
statements therein not misleading and (v) the commencement and termination of
any Black Out Period.

     (f)  The Company shall use its best efforts to prevent the issuance or
obtain the withdrawal of any order suspending the effectiveness of the
Registration Statement at the earliest possible time.

     (g)  Upon the occurrence of any event contemplated by Section 17(e)(iv) or
(v) hereof (subject to the last sentence of Section 17(c) hereof) the Company
shall promptly prepare a post-effective amendment to the Registration Statement
or a supplement to the related prospectus or file any other required document so
that, as thereafter delivered to holders of the Warrants, the prospectus will
not contain an untrue statement of a material fact or omit to state any material
fact necessary to make the statements therein, in light of the circumstances
under which they were made, not misleading and will contain the current
information required by the Securities Act.

     (h)  Not later than the effective date of the Registration Statement, the
Company will provide a CUSIP number for the Warrant Shares and provide the
Warrant Agent with printed certificates for the Warrant Shares.

     (i)  The Company will comply with all rules and regulations of the
Commission to the extent and so long as they are applicable to the Shelf
Registration and will make generally available to its securities holders (or
otherwise provide in accordance with Section 11(a) of the Securities Act) an
earnings statement satisfying the provisions of Section 11(a) of the Securities
Act, no later than 45 days (plus any extension permitted by Rule 12b-25 under
the Exchange Act) after the end of a 12-month period (or 90 days, if such period
is a fiscal year (plus any extension permitted by Rule 12b-25 under the Exchange
Act)) beginning with the first month of the Company's first fiscal


                                       19
<PAGE>

quarter commencing after the effective date of the Registration Statement, which
statement shall cover shall 12-month period.

     (j)  The Company shall register or qualify or cooperate with the holders in
connection with the registration or qualification of the Warrant Shares for
offer and sale by the Company upon exercise of the Warrants under the securities
or blue sky laws of such states of the United States as any holder reasonably
requests and do any and all other acts or things necessary or advisable to
enable such offer and sale in such jurisdictions; PROVIDED that the Company
shall not be required to (i) qualify to do business as a broker-dealer in any
jurisdiction in which it is not then so qualified or (ii) take any action which
would subject it to general service of process or to taxation in any
jurisdiction in which it is not then so subject.

     (k)  The Company shall bear all expenses incurred by it in connection with
the performance of its obligations under this Section 17.

     (l)  The Company acknowledges and agrees that any remedy at law for breach
of any provision of this Section 17 will be inadequate and that, in addition to
any other remedies that the holder may have, the holders shall be entitled to
the remedy of specific performance to ensure the Company performs its
obligations under this Section 17.  The election of any one or more remedies by
the holders hereunder shall not constitute a waiver of the right to pursue other
available remedies.

     (m)  No person is entitled to include any securities of the Company held by
such person in, or to have such securities registered under, the Warrant
Registration Statement.

     SECTION 18.    NOTICES TO COMPANY AND WARRANT AGENT.  Any notice or demand
authorized by this Agreement to be given or made by the Warrant Agent or by the
registered holder of any Warrant Certificate to or on the Company shall be
sufficiently given or made when and if deposited in the mail, first class or
registered, postage prepaid, addressed (until another address is filed in
writing by the Company with the Warrant Agent) as follows:

                          Advanced Radio Telecom Corp.
                       500 108th Avenue, N.E., Suite 2600
                               Bellevue, WA 98004
                            Telephone: (206) 688-8700
                            Telecopy: (206) 688-0703
                           Attention: Thomas A. Grina

     In case the Company shall fail to maintain such office or agency or shall
fail to give such notice of the location or of any change in the location
thereof, presentations may be made and notices and demands may be served at the
principal office of the Warrant Agent.

     Any notice pursuant to this Agreement to be given by the Company or by the
registered holder(s) of any Warrant Certificate to the Warrant Agent shall be
sufficiently given when and if


                                       20
<PAGE>

deposited in the mail, first-class or registered, postage prepaid, addressed
(until another address is filed in writing by the Warrant Agent with the
Company) to the Warrant Agent as follows:

                            _________________________
                            _________________________
                            _________________________
                            _________________________
                            Attention: ______________

     SECTION 19.    SUPPLEMENTS AND AMENDMENTS.  The Company and the Warrant
Agent may from time to time supplement or amend this Agreement without the
approval of any holders of Warrant Certificates in order to cure any ambiguity
or to correct or supplement any provision contained herein which may be
defective or inconsistent with any other provision herein, or to make any other
provisions in regard to matters or questions arising hereunder which the Company
and the Warrant Agent may deem necessary or desirable and which shall not in any
way adversely affect the interests of the holders of Warrant Certificates.

     SECTION 20.    SUCCESSORS.  All the covenants and provisions of this
Agreement by or for the benefit of the Company or the Warrant Agent shall bind
and inure to the benefit of their respective successors and assigns hereunder.

     SECTION 21.    TERMINATION.  This Agreement shall terminate at 5:00 p.m.,
New York City time on _________, 2006.  Notwithstanding the foregoing, this
Agreement will terminate on any earlier date if all Warrants have been
exercised.  The provisions of Section 15 shall survive such termination.

     SECTION 22.    GOVERNING LAW.  This Agreement and each Warrant Certificate
issued hereunder shall be deemed to be a contract made under the laws of the
State of New York and for all purposes shall be construed in accordance with the
internal laws of said State.

     SECTION 23.    BENEFITS OF THIS AGREEMENT.  Nothing in this Agreement shall
be construed to give to any person or corporation other than the Company, the
Warrant Agent and the registered holders of the Warrant Certificates any legal
or equitable right, remedy or claim under this Agreement; but this Agreement
shall be for the sole and exclusive benefit of the Company, the Warrant Agent
and the registered holders of the Warrant Certificates.

     SECTION 24.    COUNTERPARTS.  This Agreement may be executed in any number
of counterparts and each of such counterparts shall for all purposes be deemed
to be an original, and all such counterparts shall together constitute but one
and the same instrument.

                            [Signature Page Follows]


                                       21
<PAGE>


     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed, as of the day and year first above written.


                              ADVANCED RADIO TELECOM CORP.



                              By _________________________________
                                  Name:
                                  Title:

[Seal]



Attest: ______________________
          Secretary



                              ____________________________,
                              as Warrant Agent



                              By _________________________________
                                  Name:
                                  Title:


[Seal]



Attest: _______________________
          Secretary


                                       22
<PAGE>

                                                                       EXHIBIT A
                          [Face of Warrant Certificate]

THE WARRANTS EVIDENCED BY THIS CERTIFICATE WERE ORIGINALLY ISSUED IN UNITS WITH
SENIOR DISCOUNT NOTES OF THE COMPANY.  EACH UNIT CONSISTS OF $1,000 PRINCIPAL
AMOUNT AT MATURITY OF SENIOR DISCOUNT NOTES AND ______ WARRANTS.  UNTIL
____________, 1996 OR SUCH EARLIER DATE AS MAY BE DETERMINED BY THE UNDERWRITERS
OF THE UNIT OFFERING, THE WARRANTS EVIDENCED BY THIS CERTIFICATE MAY BE
TRANSFERRED ONLY IN INTEGRAL MULTIPLES OF _____ WARRANTS AND ONLY WITH THE
SIMULTANEOUS TRANSFER TO THE TRANSFEREE OF $1,000 PRINCIPAL AMOUNT OF NOTES FOR
EACH ______ WARRANTS SO TRANSFERRED.

                   EXERCISABLE ON OR BEFORE ___________, 2006.

No. _____                                                     __________Warrants

                               Warrant Certificate

                          ADVANCED RADIO TELECOM CORP.

     This Warrant Certificate certifies that ______________, or registered
assigns, is the registered holder of Warrants expiring __________, 2006 (the
"WARRANTS") to purchase common stock, par value $.001 per share (the "COMMON
STOCK"), of Advanced Radio Telecom Corp, f/k/a Advanced Radio Technologies
Corporation, a Delaware corporation (the "COMPANY").  Each Warrant entitles the
holder upon exercise to receive from the Company on or before 5:00 p.m. New York
City Time on _____________, 2006, ____ fully paid and nonassessable shares of
Common Stock (the "WARRANT SHARES") at the initial exercise price (the "EXERCISE
PRICE") of $______ payable in lawful money of the United States of America upon
surrender of this Warrant Certificate and payment of the Exercise Price at the
office or agency of the Warrant Agent, but only subject to the conditions set
forth herein and in the Warrant Agreement referred to on the reverse hereof.
Notwithstanding the foregoing, Warrants may be exercised without the exchange of
funds pursuant to the net exercise provisions of Section 6 of the Warrant
Agreement.  The Exercise Price and number of Warrant Shares issuable upon
exercise of the Warrants are subject to adjustment upon the occurrence of
certain events set forth in the Warrant Agreement.  No Warrant may be exercised
after 5:00 p.m., New York City Time on _____________, 2006, and to the extent
not exercised by such time such Warrants shall become void.  Reference is hereby
made to the further provisions of this Warrant Certificate set forth on the
reverse hereof and such further provisions shall for all purposes have the same
effect as though fully set forth at this place.  This Warrant Certificate shall
not be valid unless countersigned by the Warrant Agent, as such term is used in
the Warrant Agreement.  This Warrant Certificate shall be governed and construed
in accordance with the internal laws of the State of New York.


                                       A-1
<PAGE>

     IN WITNESS WHEREOF, ____________________________ has caused this Warrant
Certificate to be signed by its President and by its Secretary and has caused
its corporate seal to be affixed hereunto or imprinted hereon.

Dated:  ___________ ,1996

                              ADVANCED RADIO TELECOM CORP.



                              By ________________________________
                                  Name:
                                  Title:



                              By ________________________________
                                  Name:
                                  Title:



Countersigned:

____________________
as Warrant Agent



By ________________________________
    Name:
    Title:


                                       A-2
<PAGE>

                        [Reverse of Warrant Certificate]

          The Warrants evidenced by this Warrant Certificate are part of a duly
authorized issue of Warrants expiring ____________, 2006 entitling the holder on
exercise to receive shares of Common Stock, par value $.001 per share, of the
Company (the "COMMON STOCK"), and are issued or to be issued pursuant to a
Warrant Agreement dated as of _____________, 1996 (the "WARRANT AGREEMENT"),
duly executed and delivered by the Company to _________________, a
___________________ corporation, as warrant agent (the "WARRANT AGENT"), which
Warrant Agreement is hereby incorporated by reference in and made a part of this
instrument and is hereby referred to for a description of the rights, limitation
of rights, obligations, duties and immunities thereunder of the Warrant Agent,
the Company and the holders (the words "holders" or "holder" meaning the
registered holders or registered holder) of the Warrants.  A copy of the Warrant
Agreement may be obtained by the holder hereof upon written request to the
Company.

     Warrants may be exercised at any time on or before _____________, 2006.
The holder of Warrants evidenced by this Warrant Certificate may exercise them
by surrendering this Warrant Certificate, with the form of election to purchase
set forth hereon properly completed and executed, together with payment of the
Exercise Price in cash at the office of the Warrant Agent.  In the event that
upon any exercise of Warrants evidenced hereby the number of Warrants exercised
shall be less than the total number of Warrants evidenced hereby, there shall be
issued to the holder hereof or his assignee a new Warrant Certificate evidencing
the number of Warrants not exercised.  No adjustment shall be made for any
dividends on any Common Stock issuable upon exercise of this Warrant.

     The Warrant Agreement provides that upon the occurrence of certain events
the Exercise Price set forth on the face hereof may, subject to certain
conditions, be adjusted.  If the Exercise Price is adjusted, the Warrant
Agreement provides that the number of shares of Common Stock issuable upon the
exercise of each Warrant shall be adjusted.  No fractions of a share of Common
Stock will be issued upon the exercise of any Warrant, but the Company will pay
the cash value thereof determined as provided in the Warrant Agreement.

     The Company has agreed under the terms of the Warrant Agreement to file and
use its best efforts to make effective and (subject to Black Out Periods)
maintain effective until expiration of the Warrants a shelf registration
statement (the "REGISTRATION STATEMENT") on an appropriate form under the
Securities Act covering the issuance and sale of Warrant Shares upon exercise of
the Warrants.

     Warrant Certificates, when surrendered at the office of the Warrant Agent
by the registered holder thereof in person or by legal representative or
attorney duly authorized in writing, may be exchanged, in the manner and subject
to the limitations provided in the Warrant Agreement, but without payment of any
service charge, for another Warrant Certificate or Warrant Certificates of like
tenor evidencing in the aggregate a like number of Warrants.

     Upon due presentation for registration of transfer of this Warrant
Certificate at the office of the Warrant Agent a new Warrant Certificate or
Warrant Certificates of like tenor and


                                       A-3
<PAGE>

evidencing in the aggregate a like number of Warrants shall be issued to the
transferee(s) in exchange for this Warrant Certificate, subject to the
limitations provided in the Warrant Agreement, without charge except for any tax
or other governmental charge imposed in connection therewith.

     The Company and the Warrant Agent may deem and treat the registered
holder(s) thereof as the absolute owner(s) of this Warrant Certificate
(notwithstanding any notation of ownership or other writing hereon made by
anyone), for the purpose of any exercise hereof, of any distribution to the
holder(s) hereof, and for all other purposes, and neither the Company nor the
Warrant Agent shall be affected by any notice to the contrary.  Neither the
Warrants nor this Warrant Certificate entitles any holder hereof to any rights
of a stockholder of the Company.


                                       A-4
<PAGE>

                          Form of Election to Purchase

                    (To Be Executed Upon Exercise Of Warrant)

     The undersigned hereby irrevocably elects to exercise the right,
represented by this Warrant Certificate, to receive __________ shares of Common
Stock and herewith tenders payment for such shares to the order of Advanced
Radio Telecom Corp. in the amount of $______ in accordance with the terms hereof
unless the holder is exercising Warrants pursuant to the net exercise provisions
of Section 6 of the Warrant Agreement.  The undersigned requests that a
certificate for such shares be registered in the name of ________________, whose
address is _______________________________ and that such shares be delivered to
________________ whose address is ___________ ______________________.  If said
number of shares is less than all of the shares of Common Stock purchasable
hereunder, the undersigned requests that a new Warrant Certificate representing
the remaining balance of such shares be registered in the name of
______________, whose address is  _________________________, and that such
Warrant Certificate be delivered to _________________, whose address is
__________________.


Date: ______________, ____


                              __________________________
                                   (Signature)



                              __________________________
                                 (Signature Guaranteed)


                                       A-5
<PAGE>

                                                                       EXHIBIT B


                            [FORM OF TRANSFER LEGEND]

     Each Certificate evidencing Warrants originally issued as part of a Unit of
Notes and Warrants issued by the Company (and each certificate evidencing
Warrants issued on registration of transfer thereof or in exchange or
substitution therefor prior to the close of business on ____________, 1996, or
such earlier date as may be determined by the underwriters in the Unit Offering
shall bear a legend, which may be affixed by stamp or sticker, in substantially
the following form:

     "The Warrants evidenced by this Certificate were originally issued in
     Units with Senior Discount Notes of the Company.  Each Unit consists
     of $1,000 principal amount of Senior Discount Notes and ______
     Warrants.  Until ____________, 1996 or such earlier date as may be
     determined by  the underwriters in the Unit Offering, the Warrants
     evidenced by this certificate may be transferred only in integral
     multiples of ______ Warrants and only with the simultaneous transfer
     to the transferee of $1,000 principal amount of Notes for each ______
     Warrants so transferred."


                                       B-1


<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 2, 1996


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