ADVANCED RADIO TELECOM CORP
S-1/A, 1996-07-19
CABLE & OTHER PAY TELEVISION SERVICES
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<PAGE>
   
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 19, 1996
    
                                                      REGISTRATION NO. 333-04388
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
   
                                AMENDMENT NO. 2
    
                                       TO
                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
                          ADVANCED RADIO TELECOM CORP.
              (Currently Advanced Radio Technologies Corporation)
             (Exact name of registrant as specified in its charter)
 
<TABLE>
<S>                              <C>                            <C>
           DELAWARE                          4812                  52-1348016
 (State or Other Jurisdiction    (Primary Standard Industrial   (I.R.S. Employer
              of                 Classification Code Number)     Identification
Incorporation or Organization)                                        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      500 108TH AVENUE, N.E.,
             2600                         SUITE 2600
  BELLEVUE, WASHINGTON 98004      BELLEVUE, WASHINGTON 98004
        (206) 688-8700                  (206) 688-8700
(Address, Including Zip Code,     (Name, Address, Including
    and Telephone Number,          Zip Code, and Telephone
   Including Area Code, of       Number, Including Area Code,
    Registrant's Principal          of Agent for Service)
      Executive Offices)
</TABLE>
 
<TABLE>
<S>                              <C>                            <C>
                                   COPIES TO:
      JAMES KARDON, ESQ.          JOHN D. WATSON, JR., ESQ.       W. THEODORE
      HAHN & HESSEN LLP                LATHAM & WATKINS          PIERSON, JR.,
       350 FIFTH AVENUE          1001 PENNSYLVANIA AVE., N.W.         ESQ.
   NEW YORK, NEW YORK 10118         WASHINGTON, D.C. 20004         PIERSON &
        (212) 736-1000                  (202) 637-2200            BURNETT, LLP
                                                                1667 K. STREET,
                                                                N.W., SUITE 801
                                                                WASHINGTON, D.C.
                                                                     20006
                                                                 (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         PROPOSED
 TITLE OF EACH CLASS OF                              MAXIMUM          MAXIMUM         AMOUNT OF
    SECURITIES TO BE            AMOUNT TO        OFFERING PRICE      AGGREGATE      REGISTRATION
       REGISTERED             BE REGISTERED         PER SHARE     OFFERING PRICE         FEE
<S>                        <C>                   <C>              <C>              <C>
Common Stock, $.001 par
 value...................  8,625,000 Shares (1)    $      (2)       $77,625,000        $26,767
</TABLE>
    
 
(1)  Includes 1,125,000 shares that the Underwriters have the option to purchase
    to cover over-allotments, if any.
 
   
(2) Proposed  maximum offering  price per  share to  be supplied  by  amendment.
    Estimated  solely for purposes of  calculating the registration fee pursuant
    to Rule 457 under the Securities Act.
    
 
    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.............................................  Dilution; Shares Eligible for Future Sale
       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 Capital Stock; Shares
                                                                   Eligible for Future Sale
      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 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>
                                7,500,000 SHARES
 
                                     [LOGO]
                                  COMMON STOCK
 
    ALL OF THE SHARES OF COMMON STOCK OFFERED HEREBY ARE BEING SOLD BY  ADVANCED
RADIO  TELECOM CORP. ("ART" OR THE "COMPANY"). PRIOR TO THIS OFFERING, THERE HAS
BEEN NO PUBLIC  MARKET FOR  THE COMMON  STOCK OF  THE COMPANY.  IT IS  CURRENTLY
ESTIMATED  THAT  THE INITIAL  PUBLIC OFFERING  PRICE WILL  BE BETWEEN  $8.00 AND
$10.00 PER  SHARE. SEE  "UNDERWRITING" FOR  A DISCUSSION  OF THE  FACTORS TO  BE
CONSIDERED  IN DETERMINING THE  INITIAL PUBLIC OFFERING  PRICE. THE COMMON STOCK
HAS BEEN APPROVED FOR QUOTATION ON  THE NASDAQ NATIONAL MARKET UNDER THE  SYMBOL
"ARTT."
 
    CONCURRENTLY  WITH THE OFFERING  OF THE SHARES OF  COMMON STOCK (THE "COMMON
STOCK OFFERING"), THE COMPANY  IS OFFERING, PURSUANT  TO A SEPARATE  PROSPECTUS,
     UNITS (THE "UNITS"), EACH CONSISTING OF $1,000 PRINCIPAL AMOUNT AT MATURITY
OF  SENIOR  DISCOUNT NOTES  DUE 2006  (THE "NOTES")  AND                WARRANTS
(COLLECTIVELY, THE  "WARRANTS")  TO PURCHASE          SHARES  OF  COMMON  STOCK,
SUFFICIENT  TO GENERATE GROSS PROCEEDS OF $175,000,000 (THE "UNIT OFFERING" AND,
TOGETHER WITH  THE COMMON  STOCK OFFERING,  THE "OFFERINGS").  THE COMMON  STOCK
OFFERING IS CONDITIONED UPON THE CONSUMMATION OF THE UNIT OFFERING.
 
    AN  INVESTMENT IN THE COMMON STOCK OFFERED  HEREBY INVOLVES A HIGH DEGREE OF
RISK. SEE "RISK FACTORS" BEGINNING ON PAGE 9 FOR A DISCUSSION OF CERTAIN FACTORS
WHICH SHOULD BE CONSIDERED BY PROSPECTIVE INVESTORS IN EVALUATING AN  INVESTMENT
IN THE COMMON STOCK.
                               -----------------
 
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>
                                              PRICE          UNDERWRITING        PROCEEDS TO
                                            TO PUBLIC        DISCOUNT (1)        COMPANY (2)
<S>                                     <C>                <C>                <C>
PER SHARE.............................          $                  $                  $
TOTAL (3).............................          $                  $                  $
</TABLE>
 
(1)  SEE  "UNDERWRITING"  FOR  INFORMATION  CONCERNING  INDEMNIFICATION  OF  THE
    UNDERWRITERS AND OTHER MATTERS.
 
(2) BEFORE DEDUCTING EXPENSES PAYABLE BY THE COMPANY ESTIMATED AT $       .
 
(3)  THE COMPANY HAS GRANTED TO THE  UNDERWRITERS A 30-DAY OPTION TO PURCHASE UP
    TO  1,125,000   ADDITIONAL  SHARES   OF  COMMON   STOCK  SOLELY   TO   COVER
    OVER-ALLOTMENTS,  IF ANY. IF THE UNDERWRITERS  EXERCISE THIS OPTION IN FULL,
    THE PRICE TO PUBLIC WILL  TOTAL $          , THE UNDERWRITING DISCOUNT  WILL
    TOTAL  $          AND  THE PROCEEDS TO  COMPANY WILL TOTAL  $          . SEE
    "UNDERWRITING."
 
    THE SHARES OF  COMMON STOCK ARE  OFFERED BY THE  SEVERAL UNDERWRITERS  NAMED
HEREIN  SUBJECT TO RECEIPT AND ACCEPTANCE BY  THEM AND SUBJECT TO THEIR RIGHT TO
REJECT ANY  ORDER IN  WHOLE OR  IN PART.  IT IS  EXPECTED THAT  DELIVERY OF  THE
CERTIFICATES  REPRESENTING SUCH SHARES WILL BE  MADE AGAINST PAYMENT THEREFOR AT
THE OFFICE OF MONTGOMERY SECURITIES ON OR ABOUT           , 1996.
                              -------------------
MONTGOMERY SECURITIES
            MERRILL LYNCH & CO.
                                                        DEUTSCHE MORGAN GRENFELL
 
                                          , 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  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
 
                                       4
<PAGE>
     authorizations  which it currently manages but does not own. These spectrum
     assets provide the Company with the  foundation on which to create a  large
     scale commercial system of 38 GHz wireless broadband operations. As of June
     28,  1996, the Company was operating revenue-generating, wireless broadband
     links in  15  cities.  The Company  plans  to  continue to  build  out  its
     infrastructure and to intensify its marketing effort in its market areas in
     order to exploit the value inherent in its spectrum assets. The Company may
     seek  to acquire additional spectrum rights  in new and existing markets in
     order to  expand its  geographic  footprint or  enhance its  services.  See
     "Business -- Agreements Relating to Licenses and Authorizations."
 
   
    -  MARKET INITIALLY  AS A  CARRIER'S CARRIER.  The Company's  initial target
     customers include CAPs, IXCs, cellular  and mobile radio service  providers
     and  ISPs. The Company's wireless broadband  services enable CAPs to extend
     their broadband services to locations where it is either not cost-efficient
     or too  difficult to  extend  their fiber  optic  network due  to  physical
     limitations,  franchise fees or other  restrictions. The Company's services
     may also be attractive  to certain LECs, which  generally do not  currently
     have   broadband  networks  capable  of  reaching  the  majority  of  their
     customers. All telecommunications service  providers can use the  Company's
     services  as alternate or redundant routes to increase network reliability.
     The Company  has  entered  into a  strategic  distribution  agreement  (the
     "Ameritech   Strategic  Distribution   Agreement")  with   Ameritech  Corp.
     ("Ameritech") for  delivery of  the Company's  wireless broadband  services
     throughout  Ameritech's  midwest  operating region  and  for  certain large
     customers located  outside  its  region.  The  Company  currently  provides
     services   to  Ameritech,  Bell  Atlantic  NYNEX  Mobile,  UUNet,  Electric
     Lightwave,  NEXTLINK,  American  Personal  Communications,  American   Show
     Management,  Capital Area Internet Service, Brooks Fiber Communications and
     Western  Wireless,   among  others.   See   "Business  --   Customers   and
     Applications."  As regulatory and competitive  conditions permit and as the
     Company's customer base  and market presence  develop, the Company  expects
     that  its market focus will expand  from a wholesale "carrier's carrier" to
     include provision of services directly to commercial end users.
    
 
    - PURSUE  OPPORTUNITIES TO  PROVIDE VALUE-ADDED  SERVICES. The  Company  has
     identified  and  plans to  pursue additional  market niches  with immediate
     needs for reliable, high bandwidth last mile access services. For  example,
     the  market for  Internet services  urgently requires  broadband "pipes" to
     facilitate high  speed  access for  corporate  users, and  the  Company  is
     pursuing  agreements to package  its 38 GHz solutions  with the services of
     leading  ISPs.   Other   potential   value-added   uses   include   desktop
     videoconferencing,   high  resolution   imaging  for   healthcare  and  law
     enforcement applications and video on  demand. The Company may also  decide
     to  offer switched-based services  to end users who  desire a single source
     telecommunications solution.
 
    - MAINTAIN  TECHNOLOGY LEADERSHIP  IN SPECTRUM  MANAGEMENT. The  Company  is
     currently developing proprietary site selection and network design software
     which it believes will provide for faster site development at a lower cost.
     In addition, through the Company's internal technology development efforts,
     as  well as on-going participation in equipment manufacturers' research and
     development activities, the  Company is  seeking to  achieve a  competitive
     advantage through proprietary methods designed to increase the capacity and
     quality of its networks.
 
   
    -  ESTABLISH AND EXPAND KEY STRATEGIC ALLIANCES. The Company has established
     and will seek to continue to  establish key strategic alliances with  major
     service   providers,  equipment  manufacturers,   systems  integrators  and
     enhanced  service  providers.  Ameritech  owns  a  5.5%  beneficial  equity
     interest  in the Company as  of June 28, 1996  (4.3% after giving effect to
     the Common  Stock  Offering)  and  entered  into  the  Ameritech  Strategic
     Distribution  Agreement in April 1996. The Company also has agreements with
     Harris Corporation, Farinon Division ("Harris") for marketing ART's 38  GHz
     services   to  PCS   providers  and   with  GTE   Corporation  ("GTE")  for
     installation, field  servicing and  network  monitoring. In  addition,  the
     Company  is seeking  to develop  relationships with  a number  of equipment
     manufacturers focusing on 38 GHz technology development, wireless broadband
     standards and  joint sales  efforts.  The Company  plans to  utilize  these
     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 COMMON STOCK OFFERING
 
<TABLE>
<S>                                            <C>
Common Stock offered by the Company..........  7,500,000 shares
Common Stock outstanding after the
 offering....................................  37,586,498 shares (1)
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 the  acquisition of  additional  spectrum
                                               rights and, potentially, related businesses.
Nasdaq National Market symbol................  ARTT
</TABLE>
 
- ------------------------------
 
(1)  Assumes completion of  the Merger and the  Conversion. Excludes (i) 877,136
    shares of Common Stock subject to  the Ameritech Warrant (as defined),  (ii)
    1,100,000  shares  of  Common  Stock  subject  to  the  Bridge  Warrants (as
    defined), (iii)  325,000 shares  of Common  Stock subject  to the  Indemnity
    Warrants  (as defined),  (iv) 1,664,732  shares of  Common Stock  subject to
    outstanding options under the Equity Incentive Plan (as defined), (v) 28,000
    shares of  Common Stock  anticipated to  be subject  to outstanding  options
    under  the Directors Plan  (as defined) upon  consummation of the Offerings,
    (vi) 50,000 shares subject to the CommcoCCC Warrants (as defined) and  (vii)
    16,500,000   shares  issuable   upon  the  consummation   of  the  CommcoCCC
    Acquisition (as defined). As of June 28, 1996, an additional 835,268  shares
    of Common Stock were available for issuance under the Equity Incentive Plan.
    As  of the date of  this Prospectus, an additional  172,000 shares of Common
    Stock were available  for issuance  under the Directors  Plan. See  "Certain
    Transactions"  and "Management -- Stock Option Plans." In addition, does not
    give effect to the exercise of (i) the over-allotment option granted to  the
    Underwriters  by  the Company  in  the Common  Stock  Offering and  (ii) the
    Warrants. See "Underwriting."
 
                              CONCURRENT OFFERING
 
    Concurrently with  the  Common  Stock Offering,  the  Company  is  offering,
pursuant to a separate prospectus,    Units, each consisting of $1,000 principal
amount at maturity of Notes and
Warrants  to purchase       shares of Common Stock of the Company, sufficient to
generate gross proceeds of $175,000,000 (the "Unit Offering" and, together  with
the Common Stock Offering, the "Offerings"). The Warrants, when exercised, would
entitle  the holders thereof to purchase shares  of Common Stock representing  %
of the Common Stock of the Company on a fully diluted basis after giving  effect
to the Offerings. The Common Stock Offering is conditioned upon the consummation
of the Unit Offering. See "Description of Certain Indebtedness."
 
                                  RISK FACTORS
 
    An  investment in the Common Stock offered  hereby involves a high degree of
risk. See "Risk Factors" beginning on page 9 for a discussion of certain factors
which should be considered by prospective investors in evaluating an  investment
in the Common Stock.
 
                                       6
<PAGE>
              SUMMARY HISTORICAL AND PRO FORMA FINANCIAL DATA (1)
 
   
<TABLE>
<CAPTION>
                                  YEAR ENDED DECEMBER 31, 1995                     THREE MONTHS ENDED MARCH 31, 1996
                       --------------------------------------------------  --------------------------------------------------
                        HISTORICAL                          PRO FORMA       HISTORICAL                          PRO FORMA
                       COMBINED (2)    PRO FORMA (3)     AS ADJUSTED (4)   COMBINED (2)    PRO FORMA (3)     AS ADJUSTED (4)
                       -------------  ----------------  -----------------  -------------  ----------------  -----------------
<S>                    <C>            <C>               <C>                <C>            <C>               <C>
STATEMENT OF
 OPERATIONS DATA:
Operating revenue....   $     5,793     $      5,793      $      5,793      $     9,620     $      9,620      $       9,620
Non-cash compensation
 expense.............     1,089,605        1,089,605         1,089,605        7,221,000        7,221,000          7,221,000
Depreciation and
 amortization........        15,684           15,684         5,418,452           89,279           89,279          1,439,971
Interest, net........       121,986        1,974,275        23,931,008          131,145          528,739          5,989,300
Net loss.............     3,234,843        5,087,132        30,609,692       10,694,588       11,092,182         17,444,199
Pro forma net loss
 per share of Common
 Stock (5)...........            --     $       0.16      $       0.55               --     $       0.35      $        0.31
Pro forma weighted
 average number of
 shares of Common
 Stock outstanding
 (5).................            --       31,651,605        55,651,605               --       31,651,605         55,651,605
 
OTHER FINANCIAL DATA:
EBITDA (6)...........   $(1,936,141)    $ (1,936,141)     $ (1,936,141)     $(2,156,893)    $ (2,156,893)     $  (2,156,893)
Capital
 expenditures........     3,585,144        3,585,144         3,585,144        2,861,241        2,861,241          2,861,241
</TABLE>
    
 
<TABLE>
<CAPTION>
                                                 AS OF
                                           DECEMBER 31, 1995                  AS OF MARCH 31, 1996
                                           ------------------  --------------------------------------------------
                                               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 (as
    defined) and Indemnity Warrants 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 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
 
                                       7
<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 (as defined). 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 above noted 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.
 
                                       8
<PAGE>
                                  RISK FACTORS
 
   
    IN  ADDITION  TO THE  OTHER INFORMATION  CONTAINED  IN THIS  PROSPECTUS, THE
FOLLOWING  RISK  FACTORS  SHOULD  BE  CONSIDERED  CAREFULLY  IN  EVALUATING   AN
INVESTMENT IN THE COMMON STOCK 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
 
                                       9
<PAGE>
wireline and wireless operators in the same market area, changes in the  federal
and  state  regulatory schemes  affecting  the operation  of  wireless broadband
systems (including the enactment of new statutes and the promulgation of changes
in the interpretation or enforcement of  existing or new rules and  regulations)
and  changes in  technology that  have the  potential of  rendering obsolete the
Company's wireless broadband equipment. In addition, the extent of the potential
demand for wireless broadband services in  the Company's market areas cannot  be
estimated  with certainty. There can  be no assurance that  one or more of these
factors will not have an adverse effect on the Company's financial condition and
results of operations.
 
RISK OF NON-CONSUMMATION OF COMMCOCCC ACQUISITION
 
   
    On July  3, 1996,  the Company  entered into  an agreement  (the  "CommcoCCC
Agreement")  to  acquire the  CommcoCCC  Assets from  CommcoCCC  (the "CommcoCCC
Acquisition") in exchange for 16,500,000  shares of Common Stock. See  "Business
- -- Agreements Relating to Licenses and Authorizations -- CommcoCCC Acquisition."
The  CommcoCCC Acquisition is subject to various conditions including receipt of
FCC and  other approvals  (including Hart-Scott-Rodino  approval, if  required),
receipt by CommcoCCC of an opinion as to the tax-free nature of the transaction,
consummation  of the  Offerings on  terms reasonably  satisfactory to CommcoCCC,
minimum population  coverage  requirements for  the  authorizations of  ART  and
CommcoCCC,  accuracy of representations and  warranties except for breaches that
do not have in the aggregate a material adverse effect, no pending or threatened
material litigation  and other  customary closing  conditions. There  can be  no
assurance  that  all  such  conditions  will  be  satisfied.  See  "Business  --
Agreements Relating to Licenses and Authorizations -- CommcoCCC Acquisition." In
particular, to obtain FCC  approval, the Company will  need to demonstrate  that
the  shareholders  of  CommcoCCC  acquired the  authorizations  that  are  to be
assigned to the Company with the intent  of providing service to the public  and
not  for the speculative  purpose of reselling such  authorizations and may need
certain waivers or consents from the FCC. The FCC may be unwilling to grant  its
approval  or may grant its approval subject to conditions that may be adverse to
the Company. There can be no assurance  that the FCC will grant such waivers  or
that  there would not be substantial delays in its doing so. If the Company were
unable to  complete the  CommcoCCC  Acquisition for  any reason,  the  Company's
footprint  would be considerably  smaller than planned  and the Company's growth
could be limited.
    
 
COMPETITION
 
    The telecommunications services industry is highly competitive. The  Company
has  only recently begun to market  its wireless broadband services to potential
customers and is currently providing services on a limited basis. In each market
area in  which  the Company  is  authorized  to provide  services,  the  Company
competes  or will compete with several other service providers and technologies.
The Company expects  to compete  primarily on  the basis  of wireless  broadband
service  features,  quality,  price,  reliability,  customer  service  and rapid
response to customer needs. The Company faces significant competition from other
38 GHz  providers  and incumbent  LECs,  such  as the  Regional  Bell  Operating
Companies  ("RBOCs"). The Company  may also compete  with CAPs, cable television
operators, electric  utilities,  LECs  operating  outside  their  current  local
service  areas and IXCs. There can be no assurance that the Company will be able
to  compete  effectively  in  any  of   its  market  areas.  See  "Business   --
Competition."
 
    COMPETITION  FROM 38 GHZ  SERVICE PROVIDERS.   The Company faces competition
from other  38  GHz service  providers,  such as  WinStar  Communications,  Inc.
("WinStar") and BizTel Communications, Inc. ("BizTel"), within its market areas.
In  many cases, one or both of  these service providers hold licenses to operate
in other portions  of the 38  GHz band  in geographic areas  which encompass  or
overlap  the Company's market  areas. In certain of  the Company's market areas,
other 38 GHz service providers may have a longer history of operations, a larger
geographic footprint  or  substantially  greater financial  resources  than  the
Company. WinStar commenced its 38 GHz operations approximately one year prior to
the  Company, has raised significant capital  and has the competitive advantages
inherent in being the
 
                                       10
<PAGE>
first to market 38 GHz services. In addition to WinStar and BizTel, at least one
other substantial  entity,  Milliwave  L.P.  ("Milliwave"),  and  several  dozen
smaller  ones have been  granted 38 GHz authorizations  in geographic regions in
which the  Company  plans  to  operate. WinStar  has  recently  entered  into  a
definitive  agreement  with Milliwave  to acquire  Milliwave's 38  GHz licenses,
subject to FCC  approval, and  has agreed to  manage such  licenses pending  the
consummation  of  such  acquisition.  Due  to the  relative  ease  and  speed of
deployment  of  38  GHz  technology,  the  Company  could  face  intense   price
competition  and competition  for customers  (including other telecommunications
service providers) from other 38 GHz service providers.
 
    The Company also faces potential competition from new entrants to the 38 GHz
market, including LECs and other leading telecommunications companies. The  NPRM
(as  defined) contemplates an auction of  certain spectrum assets, including the
lower fourteen proposed 100 MHz channels (which are similar to those used by the
Company) and four proposed 50  MHz channels in the  38 GHz spectrum band,  which
have  not  been  previously available  for  commercial use.  See  "-- Government
Regulation." The grant  of additional authorizations  by the FCC  in the 38  GHz
band,  or other  portions of  the spectrum  with similar  characteristics, could
result in  increased  competition.  The Company  believes  that,  assuming  that
additional  channels  are made  available as  proposed  by the  NPRM, additional
entities having greater resources than the Company could acquire  authorizations
to  provide 38 GHz  services. See "Business --  Government Regulation -- Federal
Regulation -- FCC Rulemaking."
 
   
    COMPETITION FROM  INCUMBENT  LECS.    The  Company  also  faces  significant
competition  from incumbent  LECs, irrespective of  whether they  provide 38 GHz
services. Incumbent LECs have long-standing relationships with their  customers,
generally  own  significant  PCS  or  cellular  assets,  have  the  potential to
subsidize competitive services with  revenues from a  variety of businesses  and
benefit  from favorable federal  and state policies  and regulations. Regulatory
decisions and recent  legislation, such  as the Telecommunications  Act of  1996
(the "Telecommunications Act"), have partially deregulated the
telecommunications  industry and reduced barriers to  entry into new segments of
the industry. In particular, the Telecommunications Act, among other things, (i)
enhances local exchange competition  by preempting laws prohibiting  competition
in  the  local exchange  market  by requiring  LECs  to provide  fair  and equal
standards for  interconnection  and  by  requiring  incumbent  LECs  to  provide
unbundling of services and (ii) permits an RBOC to compete in the interLATA long
distance  service market once certain competitive characteristics emerge in such
RBOC's service  area.  The Company  believes  that this  trend  towards  greater
competition will continue to provide opportunities for broader entrance into the
local  exchange markets. However, as LECs face increased competition, regulatory
decisions are likely to provide  them with increased pricing flexibility,  which
in  turn may result  in increased price  competition. There can  be no assurance
that such increased price competition will not have a material adverse effect on
the Company's results of operations.
    
 
    OTHER COMPETITORS.  The Company may  compete with CAPs for the provision  of
last  mile access and additional services in  most of its market areas. However,
the Company believes  that many CAPs  may utilize 38  GHz transmission links  to
augment  their own service offerings to IXCs and end users, and that the Company
is well positioned to provide such 38  GHz services to CAPs. However, there  can
be  no assurance that  CAPs will utilize  the Company's 38  GHz services or that
CAPs will not  seek to  acquire their  own 38  GHz licenses  or use  the 38  GHz
licenses  of other licensees. Furthermore, the ability of CAPs to compete in the
local exchange market is limited by regulations relating to number  portability,
dialing  parity  and  reasonable  interconnection.  The  Telecommunications  Act
requires the FCC and the  states to implement regulations  that place CAPs on  a
more  equal  competitive footing  with  LECs. To  the  extent these  changes are
implemented, CAPs may be  able to compete more  effectively with LECs.  However,
there  can be no  assurance that CAPs or  38 GHz service  providers, such as the
Company, will be  able to  compete effectively for  the provision  of last  mile
access and other services.
 
    The  Company  may  also  face competition  from  cable  television operators
deploying cable modems, which provide high speed data capability over  installed
coaxial  cable  television  networks.  Although  cable  modems  are  not  widely
available currently, the Company  believes that the  cable industry may  support
 
                                       11
<PAGE>
the  deployment of cable  modems to residential  cable customers through methods
such as price subsidies. Notwithstanding the cable industry's interest in  rapid
deployment  of  cable modems,  the  Company believes  that  in order  to provide
broadband capacity  to a  significant number  of business  and government  users
cable  operators will be required to spend significant time and capital in order
to upgrade  their existing  networks  to the  next  generation of  hybrid  fiber
coaxial  network architecture.  However, there  can be  no assurance  that cable
television operators will not emerge as a source of competition to the Company.
 
    The  Company  may  also  face  competition  from  electric  utilities,  LECs
operating  outside their current local service  areas, IXCs and other providers.
These entities provide transmission services using technologies which may  enjoy
a  greater degree of market acceptance than 38 GHz wireless broadband technology
in the provision of last mile  broadband services. In addition, the Company  may
face  competition  from  new market  entrants  using wireless,  fiber  optic and
enhanced copper based networks to provide local service and from wireless  cable
providers  and other  service providers operating  in frequencies  other than 38
GHz.
 
   
    Many of  the Company's  competitors  have long-standing  relationships  with
customers  and  suppliers,  greater  name  recognition  and  greater  financial,
technical  and  marketing  resources  than  the  Company.  As  a  result,  these
competitors  may be  able to  more quickly develop  and exploit  new or emerging
technologies, adapt  to  changes  in customer  requirements  or  devote  greater
resources to the marketing of their services than the Company. The consolidation
of  telecommunications companies  and the  formation of  strategic alliances and
cooperative relationships  in the  telecommunications and  related industry,  as
well  as the development of new technologies, could give rise to significant new
competitors to the Company. In  such case, there can be  no assurance as to  the
degree to which the Company will be able to compete effectively.
    
 
GOVERNMENT REGULATION
 
    The  telecommunications  services  offered  by the  Company  are  subject to
regulation by  federal, state  and  local government  agencies. At  the  federal
level,  the FCC  has jurisdiction over  the use of  the electromagnetic spectrum
(I.E., wireless services)  and has  exclusive jurisdiction  over all  interstate
telecommunications  services, that  is, those  that originate  in one  state and
terminate in another state. State regulatory commissions have jurisdiction  over
intrastate  communications, that is,  those that originate  and terminate in the
same state.  Municipalities  may  regulate  limited  aspects  of  the  Company's
business   by,  for   example,  imposing   zoning  requirements   and  requiring
installation permits. See "Business -- Government Regulation."
 
    The Company  is  licensed  by  the  FCC as  a  common  carrier  provider  of
facilities-based  local telecommunications services. For  many of its intrastate
services, the Company will need to  seek authorizations from the states and,  in
most  cases, file tariffs. The  Company is in the  process of filing tariffs for
some of its  services with  the FCC  and with  certain state  authorities on  an
ongoing  basis. Certain of its proposed services  have not yet been permitted in
most states. Although the Telecommunications Act requires the states to open  up
all  of the Company's  services to competition,  there can be  no assurance that
this  will  occur  on  a  timely  basis.  Challenges  to  its  applications  for
authorizations  or its tariffs by third parties could cause the Company to incur
substantial legal and administrative expenses and time delay in implementing its
business  plan.   Although  many   of  the   Company's  applications   for   FCC
authorizations  were subject to  challenge, the Company  nonetheless was granted
authorizations for  a  majority of  its  applications. The  Company's  remaining
applications  were  either  dismissed,  voluntarily  or  involuntarily,  or  are
currently pending before the FCC.
 
   
    Twenty of the Company's applications were dismissed by the FCC because  they
overlapped  either with  authorizations granted to  third parties  or with third
party applications that held  superior rights by virtue  of the timing of  their
filing.  Five of  the Company's applications  were dismissed  voluntarily by the
Company because they could not be  granted under FCC policies. In one  instance,
the geographic area sought was larger than that permitted by the FCC's September
1994 Policy Statement. In the other four
    
 
                                       12
<PAGE>
   
instances  the dismissed applications overlapped with  each other and thus could
not be granted  under then-existing FCC  policies. None of  the dismissals  will
impact  the financial condition  or operations of the  Company because they have
not  been  included  in  the  Company's  business  plan.  Some  of  the  pending
applications propose the same channel in part of the same geographic area as one
or  more applications filed by third parties  and therefore could not be granted
under the  FCC  rules  generally prohibiting  the  grant  of  mutually-exclusive
applications.  Elimination of the conflicts generally would require dismissal of
a majority of  the applications  as part  of a  settlement. All  of the  pending
applications are subject to the freeze on the grant of additional authorizations
pending   completion  of  the  NPRM,  which   proposes  dismissal  of  all  such
applications. The  Company's business  plans do  not assume  that any  of  these
pending  applications  will be  granted.  The Company  does  not believe  that a
failure to grant  these applications  will impair  its ability  to operate.  See
"Business -- Government Regulation."
    
 
    In its provision of local wireless broadband services, the Company currently
is  not subject to rate  regulation by the FCC, but  is subject to regulation by
most states. Additionally, the Company is required to comply with all applicable
local zoning and  other laws  governing the  installation and  operation of  its
wireless broadband services.
 
    Changes  in existing laws  and regulations, including  those relating to the
provision of wireless local telecommunications services via 38 GHz licenses,  or
any  failure or significant  delay in obtaining  necessary regulatory approvals,
could have a material adverse effect on  the Company. On November 13, 1995,  the
FCC  released an  order barring  the acceptance of  new applications  for 38 GHz
authorizations. On December 15, 1995, the FCC announced the issuance of a notice
of proposed rulemaking (the "NPRM"), pursuant to which it proposed to amend  its
current rules to provide for, among other things, (i) the adoption of an auction
procedure  for the issuance  of authorizations in  the 38 GHz  band, including a
possible auction of the  lower fourteen 100 MHz  channels (which are similar  to
those used by the Company) and the lower four 50 MHz channels in the 38 GHz band
that   have  not  been  previously  available   for  commercial  use,  (ii)  the
continuation of  the  100 MHz-based  channeling  plan and  licensing  rules  for
point-to-point  microwave operations in  the lower 14  channels, (iii) licensing
frequencies using predefined geographic  service areas ("Basic Trading  Areas"),
(iv)  the  imposition of  substantially  stricter construction  requirements for
authorizations that are not received pursuant to auctions as a condition to  the
retention of such authorizations and (v) the implementation of certain technical
rules  designed  to  avoid  radio  frequency  interference  among  licensees. In
addition, the FCC ordered that those applications subject to mutual  exclusivity
with  other applicants or placed on public notice by the FCC after September 13,
1995 would be held in abeyance pending the outcome of the NPRM and might then be
dismissed. Final rules issued  in connection with the  NPRM may require that  38
GHz service providers share other yet-to-be licensed portions of the 38 GHz band
with  other telecommunications service  providers. The implementation  of such a
measure could materially affect the Company's ability to provide services to its
customers by  imposing power  and other  limitations upon  existing  operations.
There  can be no  assurance that the  final rules (if  any) issued in connection
with the NPRM will resemble the rules proposed in the NPRM. There also can be no
assurance that any  proposed or  final rules will  not have  a material  adverse
effect  on the Company. Statutes and  regulations which may become applicable to
the Company  as  it  expands could  require  the  Company to  alter  methods  of
operations  at costs which could be substantial  or otherwise limit the types of
services offered by the Company.
 
   
    The Company manages the systems of ART West, DCT, Telecom One and  CommcoCCC
(during the pendency of certain acquisitions) pursuant to management agreements.
See  "Business  --  Agreements  Relating to  Licenses  and  Authorizations." The
Company believes that the provisions of these management agreements comply  with
the  FCC's  policies  concerning licensee  control  of  FCC-licensed facilities.
Because the 38 GHz service is a new service, however, there is no FCC  precedent
addressing  the  limits of  such management  arrangements  for this  service. No
assurance can be given that the management arrangements or proposed acquisitions
will,  if  challenged,  be  found  to   satisfy  the  FCC's  policies  or   what
modifications, if any, may need to be made to satisfy those policies. If the FCC
were  to  void  or require  modifications  of the  management  arrangements, the
operations of the Company could be adversely affected.
    
 
                                       13
<PAGE>
RISK OF FORFEITURE, NON-RENEWAL AND FLUCTUATION IN VALUE OF FCC LICENSES
 
   
    Upon completion of the CommcoCCC Acquisition, the Company will own or manage
a total of  237 authorizations that  will allow  it to provide  38 GHz  wireless
broadband  services in 169  U.S. markets. The Company  currently owns or manages
108 authorizations (exclusive of the CommcoCCC Assets) that allow it to  provide
38  GHz wireless broadband services in 89 markets,  73 of which are owned by the
Company and the remaining  35 of which  are managed by  the Company through  the
Company's  interests in or arrangements with  other companies. Under the current
FCC rules, the recipient of an authorization for 38 GHz microwave facilities  is
required  to complete  construction of such  facilities within 18  months of the
date of grant of the authorization  (authorizations for facilities that are  not
constructed  are referred  to in this  Prospectus as  "construction permits" and
authorizations for  facilities that  are  constructed are  referred to  in  this
Prospectus  as  "licenses"). Upon  completion of  construction, the  licensee is
required to certify that the station is operational and ready to provide service
to the public. Although under current FCC regulations the term "operational"  is
not  defined, the industry custom is to  establish at least one link between two
transceivers in each market area for which a construction permit is held. In the
event that the  recipient fails to  comply with the  construction deadline,  the
construction  permit  is  subject  to forfeiture,  absent  an  extension  of the
deadline. Of the 108 authorizations that the Company owns or manages  (exclusive
of  the CommcoCCC 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.
 
                                       14
<PAGE>
MANAGEMENT OF GROWTH
 
    The Company  is currently  experiencing  a period  of  rapid growth  and  is
pursuing  a  business plan  that, if  successfully  implemented, will  result in
expansion of its operations and the provision of 38 GHz services on a widespread
basis over the next two to five years. The Company's success will depend on  its
ability  to manage growth effectively, to  enhance its operational and financial
control and information systems and to attract, assimilate and retain additional
qualified personnel. Failure by the Company to meet the demands of customers and
to manage the  expansion of its  business and operations  could have a  material
adverse effect on the Company's development and results of operations.
 
LINE OF SIGHT; ROOF RIGHTS; OTHER LIMITATIONS
 
    Wireless broadband services over 38 GHz frequencies require a direct line of
sight between two transceivers comprising a link and are subject to distance and
rain  attenuation. The maximum length  of a single link  is generally limited to
three to five miles, and, as  a result, intermediate links (or "repeaters")  are
required  to permit wireless broadband transmission to extend beyond this limit.
In the  absence  of  a direct  line  of  sight, repeaters  may  be  required  to
circumvent  obstacles, such as buildings in urban areas or hills in rural areas.
In addition, in areas of heavy rainfall, the intensity of rainfall and the  size
of   raindrops  can  affect  the  transmission   quality  of  38  GHz  services.
Transmission links  in these  areas  are engineered  for shorter  distances  and
greater power to maintain transmission quality. The use of intermediate links to
overcome  obstructions or rain  fade increases the cost  of service. While these
increased costs  may not  be significant  in all  cases, such  costs may  render
wireless broadband services uneconomical in certain circumstances.
 
   
    Due  to  line  of  sight limitations,  the  Company  currently  installs its
transceivers and  antennas  on the  rooftops  of  buildings and  on  other  tall
structures.  In order to obtain the necessary access, the Company generally must
secure roof rights from the owners of each building or other structure on  which
its  equipment is installed. Line of sight and distance limitations generally do
not present problems in urban areas due to the ability of the licensee to select
unobstructed  structures  from  which  to  transmit  and  the  concentration  of
customers  within  a  limited area  although  the  Company may  have  to install
intermediate links. Line of  sight and distance  limitations in non-urban  areas
can  arise  due to  lack of  structures  with sufficient  height to  clear local
obstructions. The  Company has  generally been  able to  construct  intermediary
repeater  links  and  other  solutions  to reduce  line  of  sight  and distance
limitations in urban or non-urban areas; however, in a minority of instances the
Company has encountered line of sight and distance limitations that could not be
solved economically. In  such instances,  sales to  certain potential  customers
have  been or in the  future may be adversely affected,  and, in some cases, the
Company may determine to provide certain services on terms that are uneconomical
in the near  term as  a result  of these limitations.  While the  effect on  the
financial condition and results of operations of the Company resulting from such
cases has been minimal, there can be no assurance that such limitations will not
have  a material adverse effect on  the Company's future development and results
of operations.  Failure to  obtain roof  rights in  a timely  fashion may  cause
potential  customers  to use  alternative  providers of  38  GHz services  or to
refrain from using 38  GHz services altogether. There  can be no assurance  that
the  Company will  succeed in obtaining  the roof rights  necessary to establish
wireless broadband services to  all potential customers in  its market areas  on
favorable  terms, if at  all, or that  delays in obtaining  such rights will not
have a  material adverse  effect on  the Company's  development and  results  of
operations.
    
 
   
    The relative significance of the size of a market area served depends on the
concentration  within  that area  of potential  customers. The  Company's market
areas were defined by the Company in  preparing its FCC applications for 38  GHz
licenses. The definitions of these areas were based on the Company's analysis of
the  then existing  local demographic  characteristics in  each market,  such as
concentrations of  employees and  income  levels. In  certain of  the  Company's
market  areas, other 38 GHz service  providers have larger geographic footprints
or greater bandwidth.  To the extent  that the Company's  authorizations do  not
track  the appropriate  growth and  development patterns  of potential customers
within its market areas or that  other 38 GHz providers have greater  geographic
coverage or more bandwidth, the Company may have a competitive disadvantage.
    
 
                                       15
<PAGE>
RELIANCE ON EQUIPMENT SUPPLIERS; LACK OF INDUSTRY STANDARDS
 
   
    The  Company  currently  purchases the  majority  of  its telecommunications
equipment pursuant  to an  agreement  with P-Com,  Inc. ("P-Com")  and  recently
entered  into  an equipment  purchase agreement  with  Harris. Any  reduction or
interruption in supply from  either supplier could have  a disruptive effect  on
the  Company.  Although six  manufacturers currently  produce or  are developing
equipment that will meet the Company's current and anticipated requirements,  no
industry  standard or  uniform protocol currently  exists for  38 GHz equipment.
Consequently, a single manufacturer's equipment  must be used in establishing  a
link  and generally will be used across an  entire market area. As a result, the
failure of the  Company to  procure sufficient  equipment produced  by a  single
manufacturer  for service in a particular market area could adversely affect the
Company's results of operations. See "Business -- Strategic Alliances."
    
 
DEPENDENCE ON THIRD PARTIES FOR MARKETING AND SERVICE
 
    The Company  is  partly  dependent  upon third  parties  for  marketing  its
services  and maintaining its operational  systems. The Company recently entered
into the Ameritech Strategic Distribution  Agreement, which allows Ameritech  to
resell  the Company's 38 GHz services to customers within Ameritech's midwestern
region and  to  major  Ameritech  customers nationwide.  The  Company  also  has
agreements  with  subsidiaries  of  GTE to  provide  field  service  and network
monitoring and a joint  marketing agreement with Harris.  The failure of any  of
these third parties to perform or the loss of any of these agreements could have
a  material adverse effect on the Company's results of operations or its ability
to service its customers.  The Company plans to  enter into sales and  marketing
agreements with other companies, and the failure to successfully implement these
agreements could have an adverse effect on the Company's development and results
of operations. See "Business -- Strategic Alliances."
 
ACQUISITION OF ADDITIONAL BANDWIDTH IN SELECTED AREAS
 
   
    Although  the Company believes the 38 GHz authorizations it owns, manages or
has agreed to acquire  are sufficient in  each of its  markets to implement  its
current  business strategy, the Company may  seek to acquire or lease additional
authorizations to expand its geographic footprint  or to enhance its ability  to
provide  service to its current target market  or customers it may target in the
future.  The  FCC  has  suspended  granting  additional  licenses,  subject   to
resolution  of the NPRM. The Company does  not believe that the FCC's suspension
on acceptance of new applications will  have a material effect on the  Company's
financial  condition,  results of  operation and  plans  of expansion  since the
Company's business plan does not depend  on the grant thereof. See "Business  --
Government  Regulation." However, the Company  believes that additional channels
may become available by virtue  of (i) the obligations  of other 38 GHz  service
providers  as  common carriers  to make  their services  available and  (ii) FCC
auctions of and  adoption of other  licensing procedures for  additional 38  GHz
authorizations.   Nevertheless,  there  can  be  no  assurance  that  access  to
additional 38 GHz authorizations will be acquired on favorable terms, if at all.
See "Business -- Business Strategy," "-- 38 GHz Wireless Broadband Licenses  and
Authorizations" and "-- Government Regulation."
    
 
NEW SERVICES; TECHNOLOGICAL CHANGE
 
    The   telecommunications   industry   has   been   characterized   by  rapid
technological advances, changes in end  user requirements, frequent new  service
introductions,  evolving  industry  standards  and  decreases  in  the  cost  of
equipment. The Company expects these changes to continue, and believes that  its
long-term  success will increasingly  depend on its  ability to exploit advanced
technologies and anticipate or adapt  to evolving industry standards. There  can
be  no assurance that (i) the Company's  wireless broadband services will not be
outmoded by technology or services now existing or developed and implemented  in
the  future,  (ii) the  Company  will have  sufficient  resources to  develop or
acquire new technologies or to introduce new services capable of competing  with
future  technologies  or service  offerings,  (iii) the  Company's  inventory of
equipment will not be  rendered obsolete or  (iv) the cost  of 38 GHz  equipment
will decline as rapidly as that of competitive alternatives. See "Business."
 
                                       16
<PAGE>
DEPENDENCE ON KEY EMPLOYEES
 
    The  success of the Company is dependent, in part, on its ability to attract
and retain  qualified  technical,  marketing, sales  and  management  personnel,
especially  the Company's executive officers.  Competition for such personnel is
intense, and  the  Company's inability  to  attract and  retain  additional  key
employees  or the loss of one or more  of its current key employees could have a
material adverse affect on the Company's business and results of operations. The
Company has employment agreements with each of its officers. See "Management."
 
                                FINANCIAL RISKS
 
SIGNIFICANT CAPITAL REQUIREMENTS; UNCERTAINTY OF ADDITIONAL FINANCING
 
    Management anticipates  that,  based on  its  current plan  of  development,
assuming  that no material new acquisitions are consummated, the net proceeds of
the Offerings, after  the use of  approximately $8.0 million  to repay  existing
indebtedness  and  $9.6  million  to complete  pending  acquisitions  of certain
spectrum  rights,  will  be  sufficient  to  fund  the  operations  and  capital
requirements  of  the Company  for  at least  the next  two  years. See  "Use of
Proceeds." Management also believes that the Company's future capital needs will
continue to be significant and that it will be necessary for the Company to seek
additional  sources  of  financing.  The   Company  expects  to  incur   capital
expenditures of approximately $100.0 million through 1997 as the development and
expansion  of its wireless broadband business  continues. The Company expects to
generate significant operating losses for at  least the next several years.  The
Company   will  require   substantial  investment  capital   for  the  continued
development and expansion  of its wireless  broadband operations, the  continued
funding  of related operating losses, and the possible acquisition of additional
licenses, other assets or other businesses. On a historical combined basis, from
its inception through March 31, 1996, the  Company reported a net loss of  $14.1
million.  In addition, if  (i) the Company's plan  of development or projections
change or prove to be inaccurate,  (ii) the proceeds of the Offerings,  together
with  other existing financial  resources, prove to be  insufficient to fund the
Company for at  least the  next two  years or  (iii) the  Company completes  any
material  acquisitions not  now under contract,  the Company may  be required to
seek additional financing sooner  than currently anticipated. See  "Management's
Discussion and Analysis of Financial Condition and Results of Operations." There
can  be no  assurance that  the Company  will be  able to  obtain any additional
financing, or, if such financing is available, that the Company will be able  to
obtain  it on acceptable  terms. In the  event that the  Company fails to obtain
additional financing, such failure  could result in  the modification, delay  or
abandonment of some or all of the Company's development and expansion plans. Any
such  modification, delay  or abandonment is  likely to have  a material adverse
effect on the Company's business, which could adversely affect the value of  the
Common  Stock, the Notes and the Warrants and may limit the Company's ability to
make principal and interest payments on its indebtedness.
 
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.
 
                                       17
<PAGE>
    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 Certain Indebtedness -- The
Notes" and "--  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 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 Certain  Indebtedness -- The
Notes."
 
                            LEGAL AND TRADING RISKS
 
ABSENCE OF PUBLIC MARKET; POSSIBLE VOLATILITY OF STOCK PRICE
 
    Prior to the Common Stock Offering, there has been no public market for  the
Company's  Common Stock. While the Common  Stock has been approved for quotation
on the Nasdaq National Market, there can  be no assurance that an active  public
trading  market will  develop or  be sustained after  the Offerings  or that the
initial public offering price will correspond  to the price at which the  Common
Stock  will trade in  the public market thereafter.  The initial public offering
price will be  determined solely  by negotiations  between the  Company and  the
Representatives.  See  "Underwriting"  for a  discussion  of the  factors  to be
considered in  determining  the  initial  public  offering  price.  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
 
                                       18
<PAGE>
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  Common Stock  to fluctuate,
perhaps substantially.
 
CONTROL BY MANAGEMENT AND PRINCIPAL STOCKHOLDERS
 
   
    Upon consummation  of  the  Offerings,  the  Company's  executive  officers,
directors  and their affiliates, as a group, will beneficially own approximately
28.3% of  the Company's  outstanding Common  Stock (27.4%  if the  Underwriters'
over-allotment  option is exercised  in full and 19.3%  upon consummation of the
CommcoCCC  Acquisition).  In   addition,  upon  completion   of  the   CommcoCCC
Acquisition,  Columbia Capital  Corporation, as  general partner  of two  of the
stockholders of  CommcoCCC, and  Commco, L.L.C.,  the remaining  stockholder  of
CommoCCC,  will beneficially own approximately 16.3% and 14.2%, respectively, of
the Company's outstanding Common  Stock (15.9% and  13.9%, respectively, if  the
Underwriters'  over-allotment option 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 Certain Indebtedness --
The Notes."
 
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 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."
 
                                       19
<PAGE>
DILUTION
 
    Purchasers  of  shares of  Common Stock  in the  Common Stock  Offering will
experience immediate dilution  of $7.19 in  net tangible book  value per  share,
assuming  an initial  public offering  price of $9.00  per share.  To the extent
outstanding options  and warrants  (including the  Warrants issued  in the  Unit
Offering)  are exercised, there will be  further dilution. Assuming the issuance
of  16,500,000  shares  of  Common  Stock  in  connection  with  the   CommcoCCC
Acquisition  as of  the date  of this  Prospectus, the  purchasers of  shares of
Common Stock in the Common Stock Offering will experience immediate dilution  of
$8.73 in net tangible book value per share. See "Dilution."
 
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. See "Shares Eligible For Future Sale."
    
 
                                       20
<PAGE>
                                  THE COMPANY
 
    Advanced  Radio Telecom Corp. provides wireless broadband telecommunications
services using  point-to-point  microwave  transmissions in  the  37.0  to  40.0
gigahertz  portion of the radio  spectrum ("38 GHz"). The  Company is seeking to
address  the   growing   demand   for  high   speed,   high   capacity   digital
telecommunications services on the part of business and government end users who
require  cost effective, high  bandwidth local access to  voice, video, data and
Internet services.  The Company's  last mile  services are  a complement  and  a
viable alternative to fiber optic networks and offer rapidly deployable coverage
throughout  the 89 markets in  which the Company is  currently authorized by the
FCC to provide services.
 
    The business of  the Company is  comprised of (i)  the business of  Advanced
Radio  Technologies Corporation ("ART" or the "Company"), a company organized by
Vernon L. Fotheringham and W. Theodore Pierson,  Jr. in 1993 for the purpose  of
acquiring 38 GHz licenses, and (ii) the business of Advanced Radio Telecom Corp.
("Telecom"),  a corporation organized  in Delaware in March  1995 under the name
Advanced Radio Technology, Ltd. for the purposes of acquiring additional 38  GHz
licenses and developing and operating the business of ART and Telecom on a joint
basis.  In April 1995, ART entered into the ART West Joint Venture Agreement (as
defined) to apply for, acquire and develop 38 GHz operations in 13 states in the
western  United  States.  In  November  1995,  the  Company  completed  the  EMI
Acquisition  (as  defined),  pursuant to  which  it acquired  thirty-two  38 GHz
licenses and certain  related assets  in the  northeast United  States. In  July
1996,  the Company entered into the CommcoCCC Agreement to acquire the CommcoCCC
Assets and other agreements to acquire authorizations it currently manages. Upon
completion of these pending acquisitions, the Company will own or manage a total
of 237 authorizations to provide 38 GHz wireless broadband services in 169  U.S.
markets.   See  "Risk   Factors  --   Risk  of   Non-Consummation  of  CommcoCCC
Acquisition," "Business -- Agreements Relating to Licenses and Authorizations --
ART West Joint Venture," "-- EMI Acquisition" and " -- CommcoCCC Acquisition."
 
   
    To date,  the  business  of  the  Company  has  been  operated  and  managed
(including  all FCC licenses  and construction permits held  by ART and Telecom)
pursuant to a services agreement. On June 26, 1996, ART and Telecom entered into
the Merger Agreement (as  defined), pursuant to which  a subsidiary of ART  will
merge  with and  into Telecom. The  FCC has  indicated that it  will approve the
Merger. Upon  completion of  the  Merger, Telecom  will  become a  wholly  owned
subsidiary  of ART and  change its name  to "ART Licensing  Corp.," and ART will
change its name  to "Advanced  Radio Telecom  Corp." See  "Business --  Proposed
Merger" and "Certain Transactions -- Merger." Prior to completion of the Merger,
Telecom  will manage the  combined businesses of the  Company in accordance with
the terms  of  the existing  services  agreement. See  "Business  --  Agreements
Relating to Licenses and Authorizations -- ART Services Agreement."
    
 
    DIGIWAVE,  ART, OZ BOX and  ADVANCED RADIO TELECOM are  service marks of the
Company. The  Company's principal  executive offices  are located  at 500  108th
Avenue, N.E., Suite 2600, Bellevue, Washington 98004 and its telephone number is
(206) 688-8700.
 
                                       21
<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 $175.0  million of gross
proceeds, and, in each case, after deducting the estimated underwriting discount
and offering expenses.
 
    Of the net proceeds, approximately $100.0 million is expected to be used for
capital expenditures through December  31, 1997 and  an additional $9.6  million
will  be used for the  acquisition of certain spectrum  rights from ART West and
DCT. See "Business -- Agreements Relating to Licenses and Authorizations --  ART
West Joint Venture" and " -- DCT System Purchase Agreements." Approximately $8.0
million will be used for the repayment of indebtedness, consisting of the Bridge
Notes,  which were issued  on March 8, 1996  and which bear  interest at 10% per
annum, and the CommcoCCC Notes,  which were issued on June  27 and July 3,  1996
and  which  bear  interest  at  the  prime  rate.  See  "Certain  Transactions,"
"Description  of  Certain  Indebtedness  --  Bridge  Notes"  and  "--  CommcoCCC
Financing."  The  expected  amount of  capital  expenditures  includes estimated
construction costs under service  agreements with CommcoCCC,  ART West, DCT  and
Telecom   One.   See  "Business   --   Agreements  Relating   to   Licenses  and
Authorizations." Such amount also includes the cost to complete construction  of
initial transmission facilities estimated at less than $5.0 million.
 
   
    The  remainder  of  the net  proceeds  will  be used  for  general corporate
purposes, including the  funding of operating  cash flow shortfalls,  technology
development  and acquisitions  of additional  spectrum rights  and, potentially,
related businesses. Although the  Company considers potential acquisitions  from
time  to  time, no  agreement, agreement  in  principle, understanding  or other
arrangement, other than the Extended Agreement (as defined), the DCT  Agreements
(as  defined),  the  Telecom  One  Agreements  (as  defined)  and  the CommcoCCC
Agreement, has  been  reached  with  respect to  any  acquisition.  The  Company
anticipates  that it  will fund approximately  an aggregate of  $3.5 million for
research and development activities and  other investment upon the  consummation
of currently anticipated agreements with American Wireless (as defined), QuestTV
(as  defined) and Helioss (as defined). Although the Company does not have other
material commitments to fund research and development or to make investments  in
other   companies,  the  Company  expects   to  incur  additional  research  and
development expenses  or to  make  other such  investments  from time  to  time.
Management  anticipates  that,  based on  its  current plan  of  development and
assuming that no material new  acquisitions or investments are consummated,  the
remaining  net  proceeds  of  the  Offerings  will  be  sufficient  to  fund the
operations of  the  Company  for  the  next two  years.  See  "Risk  Factors  --
Significant Capital Requirements; Uncertainty of Additional Financing."
    
 
                                DIVIDEND POLICY
 
    The  Company has not paid and does  not anticipate paying any cash dividends
on the Common Stock in the foreseeable future. The Company intends to retain its
earnings, if any,  for use in  the Company's growth  and ongoing operations.  In
addition, the terms of the Indenture will restrict the ability of the Company to
pay  dividends on the Common Stock.  See "Description of Certain Indebtedness --
The Notes."
 
                                       22
<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 concurrently (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 both as  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.
 
                                       23
<PAGE>
                                    DILUTION
 
    The  pro forma net tangible  book value of the Company  as of March 31, 1996
was $5,673,585, or $0.19 per share of  Common Stock, after giving effect to  the
Equipment  Financing,  the  Conversion,  the  CommcoCCC  Financing,  the  Merger
(including  the  issuance  of  Common   Stock  to  Telecom's  stockholders   and
cancellation  of all Telecom common stock) and  the issuance of the Units in the
Unit Offering and the  use of the  net proceeds therefrom  for the repayment  of
certain  indebtedness and completion of certain pending acquisitions of spectrum
rights. "Pro forma net tangible book  value per share" represents the amount  of
the  Company's total  tangible assets  comprised of  cash and  cash equivalents,
other current  assets,  net property  and  equipment, and  equipment  and  other
deposits,  less total liabilities (net of deferred finance costs) divided by the
pro forma number  of shares  of Common  Stock outstanding.  Without taking  into
account  any other changes in the net  tangible book value after March 31, 1996,
other than to  give effect  to the  receipt by the  Company of  net proceeds  of
approximately  $62.4 million from  the sale of 7,500,000  shares of Common Stock
offered by the Common Stock Offering based on an assumed initial public offering
price of $9.00 per  share, after deducting  the estimated underwriting  discount
and  offering expenses, the pro forma net  tangible book value of the Company as
of March 31,  1996 would  have been approximately  $68.0 million,  or $1.81  per
share  of Common Stock. This  represents an immediate increase  in pro forma net
tangible book value of $1.62 per share to existing stockholders and an immediate
dilution of $7.19 per  share to new investors.  The following table  illustrates
this per share dilution:
 
<TABLE>
<S>                                                                 <C>        <C>
Assumed initial public offering price per share...................             $    9.00
  Pro forma net tangible book value per share as of March 31, 1996
   before giving effect to the Common Stock Offering..............  $    0.19
  Increase in pro forma net tangible book value per share
   attributable to new investors..................................       1.62
                                                                    ---------
Pro forma net tangible book value per share as of March 31, 1996,
 as adjusted for the Common Stock Offering........................                  1.81
                                                                               ---------
Dilution in pro forma net tangible book value per share to new
 investors........................................................             $    7.19
                                                                               ---------
                                                                               ---------
</TABLE>
 
    The following table summarizes, as of March 31, 1996, after giving effect to
the  Offerings, the number of shares of Common Stock purchased from the Company,
the total consideration paid to the Company and the average price per share paid
by the existing stockholders and by new investors purchasing Common Stock in the
Common Stock Offering. In the Common Stock Offering, based on an assumed initial
public offering  price  of  $9.00  per  share  before  deducting  the  estimated
underwriting  discount and  offering expenses,  the number  of shares  of Common
Stock purchased from the Company is  7,500,000, the total consideration paid  to
the  Company is $67,500,000,  the average price  per share paid  by the existing
stockholders is $0.32 and the price per share paid by new investors is $9.00.
 
<TABLE>
<CAPTION>
                                         SHARES PURCHASED          TOTAL CONSIDERATION
                                     ------------------------  ---------------------------  AVERAGE PRICE
                                        NUMBER       PERCENT       AMOUNT        PERCENT      PER SHARE
                                     -------------  ---------  --------------  -----------  -------------
<S>                                  <C>            <C>        <C>             <C>          <C>
Existing stockholders..............     30,086,498       80.0% $    9,622,156        12.5%    $    0.32
New investors......................      7,500,000       20.0      67,500,000        87.5          9.00
                                     -------------  ---------  --------------  -----------
    Total..........................     37,586,498      100.0% $   77,122,156       100.0%
                                     -------------  ---------  --------------  -----------
                                     -------------  ---------  --------------  -----------
</TABLE>
 
    The foregoing computations do not give effect to the exercise of any of  the
following  as of March 31,  1996: (i) 877,136 shares  of Common Stock subject to
the Ameritech Warrant;  (ii) 1,100,000  shares of  Common Stock  subject to  the
Bridge  Warrants; (iii) 325,000 shares of  Common Stock subject to the Indemnity
Warrants; (iv) 50,000 shares of Common Stock subject to the CommcoCCC  Warrants;
(v)  1,664,732 shares of  Common Stock subject to  outstanding options under the
Equity Incentive Plan; and (vi) 28,000 shares of Common Stock anticipated to  be
subject  to outstanding options  under the Directors  Plan upon the  date of the
Offerings. As of  June 28, 1996,  an additional 835,268  shares of Common  Stock
were  available for issuance  under the Equity Incentive  Plan and an additional
172,000 shares of Common Stock were  available for issuance under the  Directors
Plan.  See "Certain  Transactions" and "Management  -- Stock  Option Plans." The
computations also do  not give effect  to the issuance  of 16,500,000 shares  of
Common  Stock in connection with the  CommcoCCC Acquisition which, at an assumed
value of  $9.00 per  share, would  result in  a decrease  in the  pro forma  net
tangible  book value of $53.5 million or $1.54 per share. In addition, the above
does not give effect to the exercise of (i) the over-allotment option granted to
the Underwriters  by the  Company in  the  Common Stock  Offering and  (ii)  the
Warrants.  See "Underwriting."  To the  extent that  any outstanding  options or
warrants are exercised,  there will be  further dilution to  new investors.  See
"Risk Factors -- Dilution."
 
                                       24
<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                    PRO FORMA AS
                                  COMBINED (1)   PRO FORMA (2)   ADJUSTED (3)    COMBINED (1)   PRO FORMA (2)   ADJUSTED (3)
                                  -------------  -------------  ---------------  -------------  -------------  ---------------
<S>                               <C>            <C>            <C>              <C>            <C>            <C>
STATEMENT OF OPERATIONS DATA:
Operating revenue...............   $     5,793    $     5,793    $       5,793    $     9,620    $     9,620    $       9,620
Non-cash compensation expense...     1,089,605      1,089,605        1,089,605      7,221,000      7,221,000        7,221,000
Depreciation and amortization...        15,684         15,684        5,418,452         89,279         89,279        1,439,971
Interest, net...................       121,986      1,974,275       23,931,008        131,145        528,739        5,989,300
Net loss........................     3,234,843      5,087,132       30,609,692     10,694,588     11,092,182       17,444,199
Pro forma net loss per share of
 Common Stock (4)...............            --   $       0.16   $         0.55             --   $       0.35   $         0.31
Pro forma weighted average
 number of shares of Common
 Stock outstanding (4)..........            --     31,651,605       55,651,605             --     31,651,605       55,651,605
 
OTHER FINANCIAL DATA:
EBITDA (5)......................  $ (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
                                               DECEMBER 31,
                                                   1995                      AS OF MARCH 31, 1996
                                               -------------  --------------------------------------------------
                                                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>
 
                                       25
<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:
Capital expenditures......       $      --           $    5,175         $         --        $      --      $          --
</TABLE>
 
<TABLE>
<CAPTION>
                                                                AS OF DECEMBER 31,                       AS OF 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>
 
                                       26
<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:
Capital expenditures.........................................................     $  3,585,144       $    2,861,241
 
<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."
 
(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.
 
                                       27
<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,
 
                                       28
<PAGE>
net  losses and negative operating cash flow will continue for at least the next
several years. Accordingly, the Company  will be dependent on various  financing
sources  to fund  its growth  as well as  continued losses  from operations. See
"Liquidity and Capital Resources."
 
ACQUISITIONS, BUSINESS DEVELOPMENT AND CAPITAL EXPENDITURES
 
   
    From inception through March 31, 1996, the Company has invested an aggregate
of $4.2  million  to  obtain  interests  in  FCC  authorizations  and  licenses,
including  those acquired from EMI, and invested  $285,000 in the ART West Joint
Venture. From inception, expenditures for  property and equipment have  totalled
$6.5  million. In addition, the Company has incurred significant other costs and
expenses in the development of its  business and has recorded cumulative  losses
from  inception through March 31, 1996 of approximately $14.1 million, including
$9.4 million of non-cash compensation and  marketing expenses, and used cash  in
operating  activities of approximately  $3.1 million. The  Company has agreed to
acquire,  subject  to  FCC  approval   and  other  conditions,  additional   FCC
authorizations  and licenses for an aggregate  purchase price of $9.6 million in
cash and 16,500,000 shares of the Company's Common Stock. The Company may,  when
and  if the opportunity arises, acquire  other spectrum rights and, potentially,
related businesses, incur expenses  in the development  of new technologies  and
expand its wireless broadband services into new market areas.
    
 
   
    The   recoverability  of  property  and   equipment  and  intangible  assets
representing FCC authorizations is dependent upon the successful development  of
systems  in each  of the  respective markets,  or through  sale of  such assets.
Management estimates that it will recover  the carrying amounts of those  assets
from  cash flow generated by the systems once they have been developed. However,
it is possible that such estimate will change as a result of any failure by  the
Company  to develop its FCC authorizations  on a timely basis, or technological,
regulatory  or  other  changes.  The  Company  anticipates  that  it  will  fund
approximately  an  aggregate  of  $3.5  million  for  research  and  development
activities and other investment upon  the consummation of currently  anticipated
agreements  with American  Wireless, QuestTV  and Helioss.  Although the Company
does not have other material commitments to fund research and development or  to
make  investments in  other companies, the  Company expects  to incur additional
research and development expenses or to make other such investments from time to
time.
    
 
    The Company  is  exploring  the  possibilities  of  providing  its  wireless
broadband  services  in  other countries  including  Canada and  in  Europe. The
Company has  entered  into agreements  with  certain consultants  and  potential
partners  to identify foreign opportunities and  expects to file application 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."
 
                                       29
<PAGE>
    THREE MONTHS ENDED MARCH 31, 1996 COMPARED TO MARCH 31, 1995
 
    Revenue for the three months ended March 31, 1996 was $9,620 compared to  no
revenue  in 1995. The increase in revenues  was due to operating revenues earned
from wireless broadband telecommunications services provided by the Company.
 
    Operating expenses  other than  interest were  $10.6 million  for the  three
months  ended  March 31,  1996 compared  to  $40,878 in  1995. The  increase was
primarily due to $7.2 million  of non-cash compensation expense, including  $6.8
million  arising  from  the  termination of  the  Escrow  Share  Arrangement (as
defined) and subsequent  release of  shares to certain  employees in  connection
with  the February 1996  Reorganization (as defined), as  well as higher general
and administrative, increased market  development, and research and  development
expenses.  See  "Certain  Transactions."  Excluding  the  non-cash  compensation
expense, general and administrative expenses  increased primarily due to  higher
payroll  and  consulting costs  relating  to the  ramp-up  in operations  of the
Company. Market  development  expenses increased  primarily  due to  a  non-cash
marketing   expense  of  $1.1   million  related  to   the  Ameritech  Strategic
Distribution Agreement.  Research and  development costs  were incurred  as  the
Company  initiated its research  and development of  microwave radio technology.
The Company expects cash expenses for general and administrative, marketing  and
research  and development  to increase  substantially in  future periods  as the
development and deployment of the Company's business continues.
 
    Interest expense was  $174,416 for  the three  months ended  March 31,  1996
compared  to $875 in 1995. The increase in interest expense was primarily due to
interest on the EMI Note  and the Bridge Notes.  Interest expense in the  second
quarter  of  1996 will  increase primarily  due  to a  full quarter  of interest
expense on the Bridge Notes and also due to the Equipment Note executed in April
1996, and the  issuance of  the Notes will  cause interest  expense to  increase
substantially  in future periods. The write-off of unamortized offering discount
and deferred  finance costs  associated with  the Bridge  Notes is  expected  to
result  in  a non-cash  extraordinary loss  of  approximately $1.0  million upon
repayment at the closing of the Offerings.
 
    FISCAL 1995 COMPARED TO FISCAL 1994
 
    ART was formed in 1993, and, accordingly, the Company's historical financial
statements for 1994 reflect ART's activities in applying for 38 GHz licenses and
building operating systems.
 
    The Company had $137,489 in  consulting services income for engineering  and
management  services related  to filing of  applications for 38  GHz licenses on
behalf of others, including Extended, in 1994 and $5,793 in operating revenue in
1995 derived from customers for wireless broadband services attributable to  the
markets  for  which  licenses  were  acquired from  EMI  in  November  1995. See
"Business  --  Agreements  Relating  to  Licenses  and  Authorizations  --   EMI
Acquisition."
 
    Total  expenses other than interest increased  from $261,734 in 1994 to $3.1
million in 1995  due to the  expansion of  the business and  the recognition  of
non-cash  compensation  expenses  associated  with  employee  stock  options  of
$287,603 and certain Escrow Shares (as defined) of $802,002 associated with  the
release  to certain  employees of  the Company  as a  result of  meeting certain
performance objectives for an aggregate of $1.1 million of non-cash compensation
expenses. See "Certain Transactions --  LHC Purchase Agreement -- February  1996
Reorganization."  General and administrative  expenses, including these non-cash
compensation expenses, increased to $2.9 million for fiscal 1995, from  $253,453
for  1994. Market development expenses increased to  $191,693 in 1995 from $0 in
1994. Net interest expenses increased to  $121,986 in 1995 from $4,375 in  1994.
As  a result, the net loss for 1995 was  $3.2 million, as compared to a net loss
of $128,620 in 1994.
 
    FISCAL 1994 COMPARED TO FISCAL 1993
 
    The Company had $137,489 in consulting  services income in 1994 compared  to
no  revenue  in 1993.  The  increase in  1994  was primarily  due  to consulting
services related to 38 GHz license applications.
 
                                       30
<PAGE>
    Total expenses other  than interest  expense increased to  $261,734 in  1994
from  $6,594 in 1993. The  increases were due primarily  to consulting and legal
fees related to the initial operations of the Company.
 
LIQUIDITY AND CAPITAL RESOURCES
 
    The Company's operations  have required substantial  capital investment  for
the  acquisition  of  FCC authorizations  and  related assets,  the  purchase of
telecommunications equipment, staffing, and the development and expansion of the
Company's infrastructure to support  anticipated growth. From inception  through
March  31,  1996,  the  Company  used $3.1  million  of  cash  in  its operating
activities and $7.3  million of  cash in  its investing  activities. These  cash
outflows  were financed  primarily through  private equity  and debt placements,
including the issuance of convertible  notes payable to the Advent  Partnerships
which  were converted  into equity  in February 1996.  At December  31, 1995 the
Company had a working capital deficit of  $3.0 million and cash of $633,654,  as
compared  to a working capital deficit of $76,556 and cash of $5,133 at December
31, 1994. The Company had a working capital deficit of $1.1 million and cash  of
$3.0 million at March 31, 1996. Subsequent to March 31, 1996, the Company raised
$2.2  million in cash  (net of expenses)  from the Equipment  Financing and $3.0
million in cash from the CommcoCCC Financing. See "Certain Transactions."
 
    The Company's total assets increased from $42,611 as of December 31, 1994 to
$9.9 million at December 31, 1995 and $15.0 million at March 31, 1996.  Property
and  equipment, net of accumulated depreciation, comprised $3.6 million of total
assets at December 31, 1995 and $6.4 million at March 31, 1996. FCC licenses and
the investment  in the  ART West  Joint  Venture increased  to $4.5  million  at
December 31, 1995 and March 31, 1996, as compared to $0.0 at December 31, 1994.
 
    Cash  used in operating activities increased by $1.4 million to $1.5 million
in 1995 over 1994.  The increase in cash  used in operating activities  resulted
primarily  from the increase  in net loss  to $3.2 million,  partially offset by
non-cash compensation expenses of $1.1 million and increased payables in 1995.
 
   
    Cash used in investing activities increased by $4.2 million in 1995 compared
to minimal amounts in 1994. The increase was primarily due to $3.0 million  paid
for  the  EMI  acquisition, and  approximately  $600,000 used  for  property and
equipment additions in 1995.
    
 
    Cash provided by financing activities increased by $6.2 million in 1995 over
1994. The  increase  was  primarily  due to  the  issuances  of  the  Advent/ART
Securities  of  $5.0  million and  of  Telecom  serial preferred  stock,  net of
redemptions of $2.0 million issued in 1995, partially offset by the use of  cash
for stock and debt issuance costs.
 
    Capital  expenditures, including deposits  on equipment for  fiscal 1995 and
1994,  were  $3.9  million  and  $5,175,  respectively.  The  Company  currently
purchases  the majority  of its  wireless transmission  equipment from  a single
vendor, P-Com, Inc., under an equipment purchase agreement which expires at  the
end  of 1998. The Company  is committed to purchase a  total of $13.3 million of
equipment under this agreement. The Company  has also entered into an  equipment
purchase agreement, expiring in 1997, with Harris, providing for the purchase of
wireless transmission equipment.
 
    Cash  used in operating  activities increased to $1.5  million for the three
months ended March 31, 1996 compared to $49,212 for the three months ended March
31, 1995. The increase was primarily due to higher operating costs. Cash used in
investing activities was approximately $3.1  million for the three months  ended
March  31, 1996 compared to $0.0 for the  three months ended March 31, 1995. The
increase was  due to  additions  to property  and  equipment. Cash  provided  by
financing  activities increased to $6.9 million  in the three months ended March
31, 1996 compared  to $44,334 for  the three  months ended March  31, 1995.  The
increase  was primarily due  to the private equity  placement with Ameritech and
the Bridge Notes.
 
    The Company does  not currently  manufacture, nor does  it have  or plan  to
develop  the  capability  to  manufacture,  any  of  the  wireless  transmission
equipment necessary to provide its services. Although there are a limited number
of manufacturers  who  have,  or  are  developing,  equipment  that  would  meet
 
                                       31
<PAGE>
the  Company's requirements, there can be no assurance that such equipment would
be available to the Company on comparable terms or on terms more favorable  than
those  included in its current arrangements  in the event that such arrangements
are terminated.  Moreover,  a change  in  vendors could  cause  a delay  in  the
Company's  ability to provide its services,  which would affect future operating
results adversely.
 
   
    The Company has  entered into an  agreement with American  Wireless to  fund
$700,000  to $1.0 million of research  and development costs related to wireless
transmission equipment. Vernon L. Fotheringham, the Chairman of the Company,  is
a director and a 6% shareholder of American Wireless. The Company will receive a
first  right of refusal on production capacity and a license fee in exchange for
its funding. The Company has also entered  into a letter of intent with  Helioss
Communications  Corporation ("Helioss") for  the development of  advanced 38 GHz
radios.  Under  the   letter  of   intent,  which  is   subject  to   definitive
documentation, the Company will fund up to $1.0 million of Helioss' research and
development  expenses.  The  Company  will  have a  right  of  first  refusal on
production capacity of the radios  and will receive a royalty  on the sale of  a
certain  number of radios to  customers other than the  Company. The Company has
also entered into  a letter  of intent  to invest  $1.5 million  in QuestTV  (as
defined),  a provider of  video and data transmission  and storage services. See
"Certain Transactions  --  American  Wireless  Development  Agreement"  and  "--
QuestTV  Investment."  Although the  Company does  not  have any  other material
commitments to fund  research and development  or to make  investments in  other
companies,  it expects to incur additional expenses for research and development
or to make other such investments from time to time.
    
 
   
    The Company currently expects that  its capital expenditures (excluding  the
acquisition  of  certain spectrum  rights)  will aggregate  approximately $100.0
million through  December  31,  1997.  The  Company  currently  expects  capital
expenditures through December 31, 1997 to consist of approximately $65.0 million
for  wireless transmission  equipment, approximately  $20.0 million  for network
design and development and related equipment and approximately $15.0 million for
computer equipment and other related capital. Included in these amounts are  the
costs of initial construction of all owned and managed authorizations, estimated
to  be  less  than  $5.0  million,  including  wireless  transmission equipment.
Although the Company does not anticipate substantial difficulties in  completing
such  initial construction on a timely basis, the  failure to do so could have a
material adverse effect on  the number of licenses  available to the Company  to
carry  out  its  business. The  Company  expects that  capital  expenditures for
wireless transmission equipment  will be  largely variable  with market  demand,
increasing  over the remainder of 1996 and  the next several years as demand for
the Company's 38 GHz services increases  in the targeted geographic markets  and
industry segments. In addition, the Company has agreed to acquire authorizations
and  licenses for $9.6  million from DCT  and ART West.  The Company has entered
into an  agreement  to acquire  129  38  GHz authorizations  from  CommcoCCC  in
exchange  for 16,500,000  shares of Common  Stock. CommcoCCC has  entered into a
management agreement with the  Company under which  the Company will  construct,
manage and operate the authorizations 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 Authorizations -- 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
 
                                       32
<PAGE>
and  (iv)  developing and  deploying its  operational  and support  systems. The
Company believes it has an opportunity to expand its wireless broadband services
business significantly and that access to capital will enable it to expand  more
quickly and effectively.
 
    The  Company has incurred significant operating  and net losses and negative
operating cash flow attributable  to the development  of its wireless  broadband
services  and anticipates that such losses and negative operating cash flow will
increase as the Company implements its growth strategy. Accordingly, the Company
will be dependent on additional capital to  fund its growth, as well as to  fund
continued losses from operations.
 
    Management anticipates that, based on current plans of development, assuming
that  no new material  acquisitions (other than  those currently under contract)
are consummated, the net proceeds of the Offerings after the use of $8.0 million
to  repay  existing   indebtedness  and   $9.6  million   to  complete   pending
acquisitions,  and  the  proceeds  of  the  Credit  Facility  (as  defined),  if
consummated, will be  sufficient to fund  the operations of  the Company for  at
least  the next two years. See "Description of Certain Indebtedness." Management
believes that the Company's future capital needs will continue to be significant
and that thereafter  it will  be necessary for  the Company  to seek  additional
sources  of financing. In addition, if (i)  the Company's plan of development or
projections change  or  prove  to  be  inaccurate,  (ii)  the  proceeds  of  the
Offerings,  together  with  other  existing  financial  resources,  prove  to be
insufficient to fund  the Company for  at least  the next two  years, (iii)  the
Company  fails to consummate  the Credit Facility or  (iv) the Company completes
any material acquisitions, other than those now under contract or buys  spectrum
at auction, the Company may be required to seek additional financing sooner than
currently  anticipated. There can be no assurance  that the Company will be able
to obtain any additional financing, or, if such financing is available, that the
Company will be able  to obtain it  on acceptable terms. In  the event that  the
Company  fails to obtain additional financing,  such failure could result in the
modification, delay or abandonment of some  or all of the Company's  development
and  expansion plans. Any  such modification, delay or  abandonment is likely to
have a material adverse effect on the Company's business, which could  adversely
affect  the value of the Common Stock, the  Notes and the Warrants and may limit
the  Company's  ability  to  make   principal  and  interest  payments  on   its
indebtedness.
 
NEW ACCOUNTING PRONOUNCEMENT
 
    In  October 1995, the Financial  Accounting Standards Board issued Statement
of  Financial  Accounting  Standards   No.  123,  "Accounting  for   Stock-Based
Compensation."  This Statement encourages, but  does not require, accounting for
stock compensation awards granted to employees based on their fair value at  the
date  the awards are granted.  Companies may elect to  continue to apply current
accounting requirements for employee stock compensation awards, which  generally
will  result in no compensation cost for  most fixed stock option plans, such as
the Company's Equity Incentive Plan.  The expense measurement provisions of  the
Statement apply to all equity instruments issued for goods and services provided
by  persons other than employees. All companies  are required to comply with the
disclosure requirements  of  the  Statement. The  Company  expects  to  continue
accounting  for  employee  stock compensation  awards  using  current accounting
requirements.
 
INFLATION
 
    Management does not believe that its business is impacted by inflation to  a
significantly different extent than is the general economy.
 
                                       33
<PAGE>
                                    BUSINESS
 
    Advanced  Radio  Telecom Corp.  ("ART" or  the "Company")  provides wireless
broadband   telecommunications   services    using   point-to-point    microwave
transmissions  in the 37.0 to 40.0 gigahertz  portion of the radio spectrum ("38
GHz"). The Company is seeking to address the growing demand for high speed, high
capacity digital  telecommunications  services  on  the  part  of  business  and
government  end users who require cost effective, high bandwidth local access to
voice, video,  data  and  Internet  services. Upon  completion  of  its  pending
acquisition  of  129 38  GHz wireless  broadband authorizations  (the "CommcoCCC
Assets") from CommcoCCC, Inc.  ("CommcoCCC"), the Company will  own or manage  a
total  of 237  authorizations granted  by the  Federal Communications Commission
("FCC") covering an  aggregate population  of approximately 143  million in  169
U.S. markets.
 
TELECOMMUNICATIONS INDUSTRY OVERVIEW
 
    The   current  telecommunications   landscape  is  being   reshaped  by  the
convergence of three  major trends: (i)  the accelerating growth  in demand  for
high   speed,  high  capacity  digital  telecommunications  services,  (ii)  the
deregulation of  telecommunications  markets and  (iii)  the rapid  advances  in
wireless   technologies.   The  growth   in  demand   for  high   speed  digital
telecommunications services is being driven by the revolution in  microprocessor
power  and  advances in  new  multimedia and  on-line  applications such  as the
Internet. The ability to  access and distribute  information quickly has  become
critical  to business and  government users of  telecommunications services. The
proliferation  of  local  area  networks  ("LANs"),  rapid  growth  of  Internet
services,  rising demand for video teleconferencing and other demand factors are
significantly increasing the volume of broadband telecommunications traffic. The
inability of the existing infrastructure to meet this demand is creating a "last
mile" bottleneck in  the copper wire  networks of the  incumbent local  exchange
carriers  ("LECs").  This  increasing  demand,  together  with  changes  in  the
regulatory environment, are  creating an  opportunity to  offer cost  effective,
high capacity last mile access using both wireline and wireless solutions.
 
    The  present structure  of the  U.S. telecommunications  industry was shaped
principally by  the 1984  court-directed  divestiture of  the Bell  System  (the
"Divestiture").  As  part  of  the Divestiture,  seven  Regional  Bell Operating
Companies ("RBOCs") were created  and separated from  the long distance  service
provider,  AT&T, resulting in two  distinct telecommunications industries: local
exchange and inter-exchange  (commonly known as  long distance). Local  exchange
services typically involve the carriage of telecommunications within FCC-defined
local  access and  transport areas  ("LATAs"), and  the provision  of access, or
connections,  between  LECs  and   inter-exchange  carriers  ("IXCs")  for   the
completion of long distance calls.
 
    Since  the Divestiture, the local exchange segment of the telecommunications
market has remained the domain of LECs. Recently, however, regulatory policy has
shifted away from  monopoly protection of  the LECs. U.S.  court decisions,  FCC
actions  and most recently the  Telecommunications Act have dramatically changed
the regulatory environment. These  changes have permitted increased  competition
in  the local exchange market and  created opportunities for new companies, such
as competitive access providers ("CAPs").
 
   
    Beginning in the late 1980s, CAPs emerged to compete with LECs by  providing
dedicated  private line transmission and access services. CAP networks typically
consist of fiber  optic facilities  connecting IXC points  of presence  ("POPs")
with  customer locations  and LEC switches  within a  limited metropolitan area.
Initially, demand for alternative local access  was driven by access charges  of
approximately  40% to 45% of the cost of  a long distance call levied by LECs on
the IXCs.  In  addition to  providing  lower  access charges,  CAP  fiber  optic
services,  where available, have  generally been considered  to provide superior
quality and  higher capacity  services than  those available  from LECs'  legacy
copper  wire networks.  A leading research  company estimates that  in 1994 CAPs
captured approximately  $1.3 billion  of  the revenues  generated by  the  local
exchange  market.  Such research  company  also projects  that,  as a  result of
increased competition and the growth  of enhanced services, CAPs' revenues  will
grow in excess
    
 
                                       34
<PAGE>
of  150% per year over the next two years.  In addition to CAPs, a wide range of
alternative access  providers, including  cable television  operators,  wireless
local loop service providers and others, are expected to emerge.
 
    Continued  growth  in the  quality and  number of  competitors in  the local
telecommunications market will be driven principally by (i) the growing interest
among business customers  for an  alternative to the  LEC networks  in order  to
obtain   higher  capacity  and  better  pricing,  (ii)  the  increases  in  data
applications  and  capacity  requirements  for  local  and  wide  area   network
connections,  high speed Internet access  and videoconferencing, (iii) the LECs'
inability to  upgrade their  copper  networks quickly,  (iv) the  preference  of
competing  telecommunications providers to  control the points  of connection to
their  customers  and  prevent   LECs  from  obtaining  confidential   marketing
information  and (v) new state and federal legislation mandating interconnection
and competition in the local exchange market.
 
    Wireless broadband  telecommunications services  are developing  rapidly  to
handle these growing needs for alternative access. In particular, the successful
deployment  of 38  GHz links by  European cellular service  providers and recent
advances  in  38  GHz  technology,  coupled  with  metropolitan-wide   footprint
licensing,  has enabled the  provision of greater capacity  and reliability at a
lower cost per customer than  traditional copper wire networks. Furthermore,  38
GHz  facilities  can be  installed, deinstalled  and reinstalled  elsewhere with
minimal time and cost compared to both fiber optic and copper wire facilities.
 
38 GHZ TECHNOLOGY
 
    The FCC has allocated  fourteen 100 MHz channels  between 38.6 GHz and  40.0
GHz  for wireless broadband transmissions and has  allocated the 37.0 - 38.5 GHz
band to wireless broadband transmissions (the 37.0 - 38.5 GHz band and the  38.6
- -40.0  GHz band  are collectively  referred to  as "38  GHz"), which  enable the
licensee to  provide  point-to-point  services  within  a  specified  geographic
footprint usually of up to a 50-mile radius.
 
   
    38  GHz technology was first widely deployed in Europe by cellular telephone
service providers for the  interconnection of cell sites  with switches. In  the
early  1990s, technological advances resulted in  a substantial reduction in the
cost and size of millimetric  microwave components with a simultaneous  increase
in  reliability and  quality, allowing for  the provision  of wireless broadband
telecommunication links  at competitive  prices.  By 1993,  advances in  38  GHz
technology,  combined with its growing use in Europe and Central America, led to
increasing awareness of  and interest in  the potential  uses of 38  GHz in  the
United States.
    
 
    The 38 GHz band provides for the following additional advantages as compared
to other spectrum bands and wireline alternatives:
 
   
    - HIGH  DATA TRANSFER RATES.  The total  amount of bandwidth for each 38 GHz
      channel is  100 MHz,  which exceeds  the bandwidth  of any  other  present
      terrestrial   wireless  channel  allotment  and  supports  full  broadband
      capability. For example, one  38 GHz DS-3 link  at 45 megabits per  second
      ("Mbps")  today can transfer data at a  rate which is over 1,500 times the
      rate of the fastest  dial-up modem currently in  use (28.8 Kbps) and  over
      350  times the  rate of  the fastest  integrated services  digital network
      ("ISDN") line currently in  use (128 Kbps).  In addition to  accommodating
      standard  voice  and data  requirements, 45  Mbps data  transmission rates
      allow end users to receive real  time, full motion video and 3-D  graphics
      at  their workstations and  to utilize highly  interactive applications on
      the Internet and other networks.
    
 
    - SIGNIFICANT CHANNEL  CAPACITY.   Because  38 GHz  radio emissions  have  a
      narrow  beam width,  a relatively  short range  and in  most instances the
      capability to  intersect without  creating  interference, 38  GHz  service
      providers  can efficiently reuse  their bandwidth within  a licensed area,
      thereby increasing the number of customers  to which such services can  be
      provided.  Management believes that by using technology currently employed
      by the Company it can serve  virtually all of the immediately  addressable
      market in its market areas.
 
                                       35
<PAGE>
    - RAPID  DEPLOYMENT.   38 GHz technology  can be  deployed considerably more
      rapidly than wireline and other wireless technologies, generally within 72
      hours after  obtaining access  to customer  premises. In  contrast to  the
      relative ease of installing a 38 GHz transmission link, extending fiber or
      copper-based networks to reach new customers requires significant time and
      expense. In addition, unlike providers of point-to-point microwave service
      in  other spectrum bands, a 38 GHz  license holder can install and operate
      as many transmission links as it can engineer in the licensed area without
      obtaining additional  approvals  from  the  FCC.  This  is  a  substantial
      advantage over other portions of the microwave radio spectrum that must be
      licensed  on a link-by-link basis  following frequency coordination, which
      in total can take from three to five months.
 
    - EASE OF INSTALLATION.  The equipment used for point-to-point  applications
      in  38 GHz (I.E.,  antennae, transceivers and  digital interface units) is
      smaller, less obtrusive and  less expensive than  that used for  microwave
      equipment applications at lower frequencies, making it less susceptible to
      zoning   restrictions.  In  addition,  38  GHz  equipment  can  be  easily
      redeployed to meet changing customer requirements.
 
    - ADDITIONAL  ADVANTAGES  OVER  OTHER  PORTIONS  OF  RADIO  SPECTRUM.     At
      frequencies   above  38  GHz,   point-to-point  applications  become  less
      practical because attenuation increases  and the maximum distance  between
      transceivers  accordingly decreases.  Additionally, the  FCC has specified
      the use  of many  portions of  the spectrum  for applications  other  than
      point-to-point,  such  as  satellite  and  wireless  cable  services, and,
      accordingly, these portions of the radio spectrum often are not  available
      for point-to-point applications. Finally, 38 GHz has characteristics which
      provide  better signal quality  and performance in  inclement weather than
      those offered in other portions of the radio spectrum.
 
THE ART SOLUTION
 
    The Company is positioned to solve the need for broadband last mile  access,
linking   end  users  to  fiber  optic   based  facilities  of  CAPs  and  other
telecommunications service providers without  the need to  deploy fiber all  the
way to end users' premises. The Company provides point-to-point wireless digital
circuits  ranging in  capacity from  DS-1 (capable  of carrying  24 simultaneous
voice conversations at 1.544 Mbps) to DS-3 (capable of carrying 672 simultaneous
voice conversations at 45 Mbps).  The Company's wireless broadband services  are
engineered  to provide 99.999% availability, with  better than a 10-13 (unfaded)
bit error rate.  This level of  availability exceeds the  performance of  copper
based  networks  and  is a  viable  alternative  to fiber  based  networks. When
measured as the  total amount  of time  "out of  service" over  a year,  99.999%
availability under conditions of no path fading equates to less than six minutes
of  down-time  compared to  a  range of  four hours  to  44 hours  of historical
performance of  similar  copper-based LEC  circuits.  In addition,  the  Company
believes  that  ART's  last  mile solution  is  competitively  priced  with most
broadband wireline solutions.
 
    The Company's  initial target  customers include  CAPs, IXCs,  cellular  and
mobile  radio service  providers and  ISPs. The  Company's services  may also be
attractive to certain LECs which do  not currently have broadband networks  that
reach  the majority of their customers. The Company has entered into a strategic
distribution agreement with  Ameritech for  delivery of  the Company's  wireless
broadband  services  throughout  Ameritech's midwest  operating  region  and for
certain large customers located outside its region. See "-- Strategic  Alliances
- -- Ameritech Strategic Distribution Agreement."
 
    The  Company believes  that the  following factors  provide it  with certain
significant competitive  advantages  in  offering broadband  last  mile  access,
including:
 
    - The  characteristics  of  38  GHz technology  (high  data  transfer rates,
      significant channel  capacity,  rapid deployment,  easy  installation  and
      efficient network design) are ideal for the provision of last mile access.
 
                                       36
<PAGE>
    - The  Company  minimizes its  initial capital  expenditures because  of the
      installation-to-meet-demand  and  redeployable  nature  of  the  Company's
      wireless  broadband  equipment, as  compared to  the significant  cost and
      expense of installation of fiber based networks.
 
    - As  one  of  the   first  38  GHz  service   providers,  the  Company   is
      well-positioned to capture a large percentage of early adopters, which are
      generally among the heaviest users.
 
    - The  Company's industry relationships should  enable it to forge strategic
      alliances  with   other  carriers,   equipment  vendors   and   technology
      development  companies,  thus  gaining  access  to  important  channels of
      distribution and early deployment of advanced technologies.
 
    - The scope  of the  Company's  market area  enables  it to  offer  wireless
      broadband  services  targeting  much of  the  United  States's addressable
      business market.
 
    As regulatory and competitive conditions permit, the Company's market  focus
will  evolve  from a  wholesale "carrier's  carrier"  orientation to  the retail
provision of services directly to  government and commercial end-user  customers
of  telecommunications services. The Company will focus on its initial wholesale
"carrier's carrier" strategy at  least through the first  half of 1997. At  that
time,  the  Company anticipates  it will  have developed  its customer  base and
market presence to a  level that will  enable the Company  to expand its  direct
sales  efforts. At the same  time, the Company anticipates  it will commence the
development of switched services to expand the Company's service offerings  both
geographically  and  demographically,  to  business  and  residential customers,
offering a  wider  array  of  voice, data,  Internet  and  multimedia  services,
depending on further advances in wireless technology.
 
BUSINESS STRATEGY
 
    ART began providing 38 GHz wireless broadband services in the fourth quarter
of  1995 and has generated only nominal revenues from such services to date. The
Company is seeking to capitalize on its broad footprint of 38 GHz authorizations
to become a leading provider of wireless broadband solutions to a diverse  group
of  traditional and emerging telecommunications  service providers and end users
of telecommunications services.  The Company  plans to  implement the  following
strategic initiatives to achieve this objective:
 
    -  EXPLOIT SPECTRUM POSITION IN KEY  MARKETS. Upon completion of its pending
     acquisition of the CommcoCCC Assets, the Company will own or manage a total
     of 237  authorizations  that will  allow  it  to provide  38  GHz  wireless
     broadband  services  in 169  U.S. markets.  The  Company currently  owns or
     manages 108 authorizations (exclusive of  the CommcoCCC Assets) that  allow
     it to provide 38 GHz wireless broadband services in 89 markets, 73 of which
     are  owned by the Company and the remaining  35 of which are managed by the
     Company through  the  Company's interests  in  or arrangements  with  other
     companies.  The Company  has agreed  to acquire  all of  the authorizations
     which it currently manages but does not own. These spectrum assets  provide
     the Company with the foundation on which to create a large scale commercial
     system  of 38 GHz wireless  broadband operations. As of  June 28, 1996, the
     Company was operating  revenue-generating, wireless broadband  links in  15
     cities.  The Company plans to continue  to build out its infrastructure and
     to intensify its marketing effort in  its market areas in order to  exploit
     the  value inherent in its spectrum assets. See " -- Agreements Relating to
     Licenses and Authorizations."  The Company may  seek to acquire  additional
     spectrum  rights  in  new  and  existing markets  in  order  to  expand its
     geographic footprint or enhance its services.
 
    - MARKET  INITIALLY AS  A CARRIER'S  CARRIER. The  Company's initial  target
     customers  include CAPs, IXCs, cellular  and mobile radio service providers
     and ISPs. The Company's wireless  broadband services enable CAPs to  extend
     their broadband services to locations where it is either not cost-efficient
     or  too  difficult to  extend  their fiber  optic  network due  to physical
     limitations, franchise fees or  other restrictions. The Company's  services
     may  also be attractive  to certain LECs, which  generally do not currently
     have  broadband  networks  capable  of  reaching  the  majority  of   their
     customers.  All telecommunications service providers  can use the Company's
     services as alternate
 
                                       37
<PAGE>
     or redundant  routes  to  increase network  reliability.  The  Company  has
     entered  into a strategic distribution  agreement (the "Ameritech Strategic
     Distribution Agreement") with Ameritech Corp. ("Ameritech") for delivery of
     the Company's wireless  broadband services  throughout Ameritech's  midwest
     operating  region  and  for  certain large  customers  located  outside its
     region. The Company currently provides services to Ameritech, Bell Atlantic
     NYNEX  Mobile,  UUNet,  Electric  Lightwave,  NEXTLINK,  American  Personal
     Communications,  American Show  Management, Capital  Area Internet Service,
     Brooks Fiber Communications and  Western Wireless, among  others. See "  --
     Customers  and  Applications."  As  regulatory  and  competitive conditions
     permit and as the Company's customer base and market presence develop,  the
     Company  expects  that  its  market  focus  will  expand  from  a wholesale
     "carrier's carrier" to include provision of services directly to commercial
     end users.
 
    - PURSUE  OPPORTUNITIES TO  PROVIDE VALUE-ADDED  SERVICES. The  Company  has
     identified  and  plans to  pursue additional  market niches  with immediate
     needs for reliable, high bandwidth last mile access services. For  example,
     the  market for  Internet services  urgently requires  broadband "pipes" to
     facilitate high speed  access for corporate  users. The amount  of time  it
     takes  to  download  graphics  and images  from  the  Internet  to personal
     computers over dial-up copper circuits hinders demand for the Internet. For
     example, a 38 GHz DS-1 circuit (1.544 Mbps), linking a corporate user to an
     ISP's POP, is approximately 53 times faster than a 28.8 kbps dial-up  modem
     and   12  times  faster  than  the  fastest  ISDN  connection  (128  Kbps).
     Alternatively, one 38 GHz DS-3 link at 45 Mbps can currently transfer  data
     at  a rate that is  over 1,500 times the rate  of the fastest dial-up modem
     currently in use (28.8  Kbps) and over  350 times the  rate of the  fastest
     ISDN line currently in use (128 Kbps). Each of the Company's DS-3 links can
     support 28 DS-1 circuits per channel. The Company is pursuing agreements to
     package  its  38 GHz  solutions with  the services  of leading  ISPs. Other
     potential  value-added   uses  include   desktop  videoconferencing,   high
     resolution  imaging  for healthcare  and  law enforcement  applications and
     video on  demand.  The Company  may  also decide  to  offer  switched-based
     services  to  end  users  who  desire  a  single  source telecommunications
     solution.
 
    - MAINTAIN  TECHNOLOGY LEADERSHIP  IN SPECTRUM  MANAGEMENT. The  Company  is
     currently developing proprietary site selection and network design software
     which it believes will provide for faster site development at a lower cost.
     In addition, through the Company's internal technology development efforts,
     as  well as on-going participation in equipment manufacturers' research and
     development activities, the  Company is  seeking to  achieve a  competitive
     advantage through proprietary methods designed to increase the capacity and
     quality of its networks.
 
   
    -  ESTABLISH AND EXPAND KEY STRATEGIC ALLIANCES. The Company has established
     and will seek to continue to  establish key strategic alliances with  major
     service   providers,  equipment  manufacturers,   systems  integrators  and
     enhanced  service  providers.  Ameritech  owns  a  5.5%  beneficial  equity
     interest  in the Company as  of June 28, 1996  (4.3% after giving effect to
     the Common  Stock  Offering)  and  entered  into  the  Ameritech  Strategic
     Distribution  Agreement in April 1996. The Company also has agreements with
     Harris Corporation, Farinon Division ("Harris") for marketing ART's 38  GHz
     services  to PCS providers and with GTE Corporation for installation, field
     servicing and network monitoring.  In addition, the  Company is seeking  to
     develop  relationships with a number of equipment manufacturers focusing on
     38 GHz technology development, wireless broadband standards and joint sales
     efforts. The Company  plans to  utilize strategic alliances  to bundle  its
     services with those of its partners to provide for alternative distribution
     channels  and  to  gain  access  to  technological  advancements.  See  "--
     Strategic Alliances."
    
 
WIRELESS BROADBAND SERVICES
 
    The Company's wireless broadband links  deliver high quality voice and  data
transmissions  at a level of performance which exceeds the performance of copper
based networks and is  a viable alternative to  fiber optic based networks.  The
Company  provides point-to-point  wireless digital circuits  ranging in capacity
from DS-1  (capable of  carrying 24  simultaneous voice  conversations at  1.544
Mbps) to DS-3
 
                                       38
<PAGE>
(capable  of  carrying 672  simultaneous voice  conversations  at 45  Mbps). The
Company believes that it generally owns  or manages sufficient 38 GHz  bandwidth
to  satisfy the anticipated service requirements of its target customers in each
of the Company's existing markets and  the additional 78 markets to be  acquired
under the CommcoCCC Agreement.
 
    Significant  features of  the Company's wireless  broadband services include
(i) sufficient bandwidth and  flexibility in each channel  for most present  day
applications,  (ii) minimal  channel interference from  other sources, resulting
from dedicated spectrum, (iii)  range of up to  five miles between  transmission
links  (depending  upon  moisture conditions),  (iv)  performance  engineered to
provide a minimum of 99.999% availability, (v) transmission accuracy  engineered
to provide bit error rates of better than 10-13 (unfaded), (vi) optional forward
error  correction for  even higher data  reliability, insuring  the integrity of
transmitted data over  wireless broadband paths,  (vii) rapid deployment  (where
roof  rights have  been previously obtained),  (viii) 24-hour, seven-days-a-week
network monitoring  by the  Company's network  management control  center,  (ix)
available  nationwide  four-hour  emergency  restoral  time  from  GTE  in  most
circumstances and (x) optional  "hot" standby links that  remain powered up  and
switch "on line" if the primary link fails.
 
   
    Each  of ART's wireless  broadband links consists  of paired millimeter wave
radio transceivers installed at a distance of up to five miles from one  another
within  a direct line of  sight. The transceivers currently  used by the Company
are supplied principally by P-Com, Inc. ("P-Com") and are installed primarily on
rooftops and on other tall structures. In order to deploy its links quickly, the
Company plans to  obtain roof  rights on buildings  with fiber  optic points  of
termination  for transceiver sites. To accomplish this objective, the Company is
developing proprietary site  selection and  network design  software which  will
significantly  reduce the  amount of  time necessary  to select  optimal network
sites. In coordination with its marketing plans, the Company will dispatch  site
acquisition  specialists  to such  locations  to obtain  renewable  options. The
Company intends  to use  a  combination of  its  own employees  and  independent
contractors for site acquisition.
    
 
CUSTOMERS AND APPLICATIONS
 
    The  Company introduced its wireless broadband services in November 1995 and
began marketing its  services in January  1996. The Company  has generated  only
nominal  revenues  from  its  operations  to  date.  Currently,  the  Company is
providing or has received orders to provide carrier's carrier wireless broadband
services to CAPs, a  LEC, ISPs, cellular and  mobile carriers and several  IXCs,
and  is in the process of becoming a qualified vendor to all the major IXCs. The
Company currently provides  services to Ameritech,  Bell Atlantic NYNEX  Mobile,
UUNet,  Electric Lightwave, NEXTLINK, American Personal Communications, American
Show Management, Capital Area Internet Service, Brooks Fiber Communications  and
Western  Wireless, among others. As of June  28, 1996, the Company was operating
revenue-generating wireless broadband links in 15 cities.
 
    The Company currently provides, or anticipates providing, wireless broadband
services to the following types of customers, among others:
 
                                       39
<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]
 
                                       40
<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]
 
                                       41
<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]
 
                                       42
<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]
 
                                       43
<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]
 
                                       44
<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
 
                                       45
<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 TO
                 MARKET                       OWNED       MANAGED (1)       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>
 
                                       46
<PAGE>
<TABLE>
<CAPTION>
                                                  BANDWIDTH COVERED BY AUTHORIZATIONS (MHZ)
                                           --------------------------------------------------------
                                                                             UNDER
                                                                          DEFINITIVE
                                                                         AGREEMENT TO
                 MARKET                       OWNED       MANAGED (1)       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
Tucson, 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>
 
                                       47
<PAGE>
<TABLE>
<CAPTION>
                                                  BANDWIDTH COVERED BY AUTHORIZATIONS (MHZ)
                                           --------------------------------------------------------
                                                                             UNDER
                                                                          DEFINITIVE
                                                                         AGREEMENT TO
                 MARKET                       OWNED       MANAGED (1)       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.
 
                                       48
<PAGE>
AGREEMENTS RELATING TO LICENSES AND AUTHORIZATIONS
 
   
    COMMCOCCC  ACQUISITION.    On July  3,  1996,  the Company  entered  into an
agreement (the "CommcoCCC Agreement") to  acquire 129 38 GHz wireless  broadband
authorizations  (the "CommcoCCC  Assets") from  CommcoCCC, Inc.  (the "CommcoCCC
Acquisition") in exchange for 16,500,000  shares of Common Stock. CommcoCCC  was
formed in a transaction arranged by Columbia Capital Corporation to acquire, own
and  operate the 38 GHz authorizations owned by Columbia Capital Corporation and
its affiliates and those  owned by Commco, L.L.C.  The CommcoCCC Acquisition  is
subject  to various  conditions including  receipt of  FCC and  other approvals,
receipt by CommcoCCC of an opinion as to the tax-free nature of the transaction,
consummation of the  Offerings on  terms reasonably  satisfactory to  CommcoCCC,
minimum  population coverage requirements for  the authorizations of the Company
and CommcoCCC, accuracy  of representations and  warranties except for  breaches
that  do not  have in  the aggregate  a material  adverse effect,  no pending or
threatened material litigation and other customary closing conditions. There can
be no assurance that  all such conditions will  be satisfied. In particular,  to
obtain  FCC approval, the  Company will need  to make certain "anti-trafficking"
showings and may need certain waivers or  consents from the FCC. The FCC may  be
unwilling  to grant its approval or may grant its approval subject to conditions
that may be adverse to the Company. The CommcoCCC Agreement may be terminated by
CommcoCCC if the Offerings are not completed  within 90 days of the date of  the
CommcoCCC  Agreement  or by  either party  if the  CommcoCCC Acquisition  is not
consummated within one year  of the date of  the CommcoCCC Agreement. See  "Risk
Factors -- Risk of Non-Consummation of CommcoCCC Acquisition."
    
 
    In  the CommcoCCC Agreement, the Company  and Telecom have each agreed that,
prior to the consummation of the transaction, except in certain circumstances or
with the consent of CommcoCCC, they  will not issue equity, incur debt,  acquire
spectrum,  make investments, consolidate, merge or sell all or substantially all
of its  assets. CommcoCCC  has  entered into  a  management agreement  with  the
Company  pursuant  to  which the  Company  bears the  responsibility  during the
pendency of  the CommcoCCC  Acquisition  to construct,  manage and  operate  the
CommcoCCC  Assets, consistent  with FCC  rules. Under  the management agreement,
CommcoCCC is  obligated  to  reimburse  ART for  up  to  $100,000  of  operating
expenses,  which obligation  will be cancelled  if the  CommcoCCC Acquisition is
consummated. In the event the management agreement is terminated other than as a
result of the consummation of the CommcoCCC Acquisition, CommcoCCC is  obligated
to  purchase and  ART is obligated  to sell  at the Company's  original cost the
equipment purchased by ART necessary  to meet the FCC construction  requirements
for the CommcoCCC authorizations.
 
    The  stockholders  of  CommcoCCC  loaned the  Company  $3.0  million payable
September 30, 1996  pursuant to  a subordinated bridge  financing facility  (the
"CommcoCCC   Financing")  and,  in  connection  therewith,  received  three-year
warrants to purchase  50,000 shares of  Common Stock  at a price  of $15.00  per
share  (the  "CommcoCCC  Warrants"). The  CommcoCCC  Financing is  secured  by a
security interest in all of the assets of the Company, including a pledge of the
Company's stock in Telecom. If the CommcoCCC Financing is not paid in full  when
due, the unpaid principal and interest could be converted into Common Stock on a
formula  basis at  the option  of the holders.  The CommcoCCC  Financing will be
repaid with the proceeds of the Offerings.
 
    The Company has given Commco, L.L.C., a stockholder of CommcoCCC, an  option
(the  "Commco Option")  to purchase  one authorization  in each  of 12 specified
market areas in which the Company  will have more than one authorization,  which
authorizations  cover  in the  aggregate  approximately 19  million  people. The
Commco Option  will be  exercisable only  if (i)  the CommcoCCC  Acquisition  is
consummated  and (ii) Commco, L.L.C.  obtains authorizations pursuant to certain
pending applications frozen under the NPRM in market areas covering an aggregate
population of at least 40  million people, and will  terminate on the date  nine
months  after the consummation of the  Common Stock Offering. The purchase price
for any  authorizations acquired  under the  Commco Option  is determined  by  a
formula  based  upon the  fair market  value at  the time  the Commco  Option is
exercised of up to approximately 2,600,000 shares of Common Stock depending upon
the number of authorizations
 
                                       49
<PAGE>
purchased. The purchase price  is payable in  cash or, if  the Commco Option  is
exercised  within  the later  of 120  days  after the  closing of  the CommcoCCC
Acquisition or the date of grant by  the FCC of the authorizations necessary  to
exercise  the Commco Option,  with a two-year  note secured by  shares of Common
Stock having a value on  the date of exercise equal  to two times the  principal
amount of the note.
 
   
    In arranging the CommcoCCC Acquisition, Columbia Capital Corporation and its
affiliates  agreed not to compete with the  Company in the provision of wireless
broadband telecommunication services in  the 38 GHz band  of the radio  spectrum
for  a five year period commencing upon the closing of the CommcoCCC Acquisition
and has  granted the  Company a  right  of first  offer to  acquire any  38  GHz
authorizations  that Columbia Capital Corporation  or its affiliates may acquire
in the future with respect to their pending applications.
    
 
    Promptly upon closing of the  CommcoCCC Acquisition, the Company has  agreed
to nominate one individual designated by CommcoCCC's stockholders and acceptable
to the Company as a director of the Company.
 
    In  late  1994 and  1995, Columbia  Capital Corporation  and certain  of its
affiliates ("Columbia")  entered into  several  letter agreements  (the  "Letter
Agreements")  with Video/Phone  Systems, Inc.  ("Video/Phone"). In consideration
for services to  be rendered under  the Letter Agreements,  Columbia granted  or
agreed  to grant to Video/Phone options to purchase minority equity interests in
entities formed or to be  formed to apply for  38 GHz licenses. Columbia  agreed
not  to assign these licenses to any  person controlling, controlled by or under
common control with Columbia  unless such transferee  granted to Video/Phone  an
equivalent option. The CommcoCCC Assets include 67 authorizations transferred by
Columbia  to CommcoCCC, subject to FCC approval. Columbia and Video/Phone are in
a dispute with respect to the  performance and obligations of the parties  under
the  Letter Agreements. Columbia  has agreed to indemnify  and hold harmless the
Company with respect to any loss or damage resulting from the Letter Agreements.
 
   
    EMI ACQUISITION.  On April 4, 1995,  ART entered into an agreement with  EMI
Communications  Corporation ("EMI") to acquire EMI's  thirty two 38 GHz wireless
broadband licenses and  related assets  in the northeastern  United States  (the
"EMI Assets") in exchange for $3.0 million in cash and a $1.5 million three-year
non-negotiable  and  non-transferable  promissory  note  (the  "EMI  Note").  In
November 1995, ART assigned all of its rights and obligations under the purchase
agreement to Telecom.  The FCC  subsequently approved  the transfer  of the  EMI
Assets to Telecom, and the EMI Assets were acquired by Telecom in November 1995.
ART  has also agreed to provide wireless  broadband services to EMI for a period
of five years from the date of  the agreement and to certain of EMI's  customers
on  behalf of EMI for the terms provided in such EMI service agreements, and EMI
agreed to provide certain services to Telecom for an initial period of one  year
from  the date of the agreement. See "Description of Certain Indebtedness -- EMI
Note."
    
 
    ART WEST JOINT VENTURE.  On April 4, 1995, ART and Extended  Communications,
Inc.  ("Extended")  entered  into  a  joint  venture  agreement  (the  "ART West
Agreement") resulting in the formation of ART West Joint Venture ("ART West"), a
Delaware partnership equally owned by ART  and Extended. Under the terms of  the
ART West Agreement, ART and Extended agreed to transfer to ART West all of their
respective  interests  in  all of  their  38 GHz  authorizations  (currently, 12
authorizations)  in  Alaska,  Arizona,  California,  Colorado,  Hawaii,   Idaho,
Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming (the "ART West
Markets"),  subject  to  FCC  approval. Under  a  separate  management agreement
between ART  and ART  West, ART  is obligated  to bear  all costs  and  expenses
relating  to construction, operation and management  of the ART West Markets and
has agreed to utilize  the ART West  authorizations before other  authorizations
owned  or managed by ART in the  ART West Markets. As compensation, ART receives
90%  of  the  recurring   revenues  of  ART  West,   with  ART  West   receiving
 
                                       50
<PAGE>
   
the  remaining 10%.  To date, Extended  has had  no significant responsibilities
with respect to ART  West, and is  not expected to invest  in or contribute  any
services  to ART  West pending the  proposed acquisition  of Extended's interest
described below. See "Certain Transactions -- ART West Joint Venture."
    
 
    In  June  1996,  the  Company  entered  into  an  agreement  (the  "Extended
Agreement")  to acquire Extended's interest in ART West for an aggregate of $6.0
million in  cash,  subject  to  adjustment and  subject  to  closing  conditions
including  final FCC approval. Of the  $6.0 million purchase price, $3.0 million
is payable upon consummation of the  Offerings as a non-refundable deposit  (the
"ART  West  Deposit")  and  the  balance is  payable  upon  consummation  of the
transaction. Under this agreement, upon payment by ART of the ART West  Deposit,
Extended  has agreed to surrender its rights under the ART West Agreement (i) to
participate in  the  acquisition of  additional  licenses or  authorizations  in
certain  of  the ART  West Markets  through ART  West and  (ii) to  prohibit the
acquisition by ART of additional licenses or authorizations in certain other ART
West Markets.
 
   
    DCT SYSTEM PURCHASE AGREEMENTS.  On July 1, 1996 the Company entered into  a
definitive agreement (the "DCT Agreement") with DCT to acquire DCT's interest in
certain  38 GHz  licenses (the  "DCT Systems") in  exchange for  $3.6 million in
cash, subject to FCC approval, consummation of the DCT Agreement by September 1,
1997  and   other   customary   closing   conditions   including   accuracy   of
representations  and warranties; absence of litigation and receipt of opinion of
counsel. ART has entered  into a services agreement  with DCT pursuant to  which
ART  bears the responsibility for the  construction, operation and management of
the DCT  Systems.  The  agreement  expires  on December  31,  1998  and  may  be
terminated  earlier by DCT if  the DCT Agreement terminates.  Under the terms of
the services agreement, ART is obligated to bear all costs and expenses relating
to construction, operation and management  of the DCT Systems. As  compensation,
ART  is entitled  to receive all  of the  revenues generated by  the DCT Systems
until December 31, 1996. From January 1, 1997 until the later of January 1, 1998
and the termination  of the DCT  Agreement, a license  fee equal to  15% of  the
gross revenue generated by the DCT Systems will be paid to DCT, and thereafter a
license  fee based on the number and types  of circuits operated by ART over the
DCT Systems will be paid to DCT. After  December 31, 1997, DCT has the right  to
market  to  third  parties utilizing  the  DCT Systems.  The  services agreement
terminates with respect to each DCT 38  GHz license upon the acquisition by  ART
of  such license. The  Company is currently  completing the initial construction
requirements of the DCT Systems and expects such construction to be completed in
the third quarter of 1996.
    
 
    TELECOM ONE SERVICES AGREEMENT.  On April 24, 1996, the Company and  Telecom
One,  Inc. ("Telecom One")  entered into a services  agreement (the "Telecom One
Services Agreement") pursuant to which the Company agreed to construct,  operate
and manage all 38 GHz wireless broadband licenses and related telecommunications
systems owned by Telecom One that are granted by the FCC. At present Telecom One
has  been granted two authorizations. Under  the Telecom One Services Agreement,
the Company is obligated to pay all costs and expenses related to  construction,
operation  and management of the systems.  As compensation, the Company receives
90% of the net revenues  generated by the systems  and Telecom One receives  the
remaining 10% for ten years.
 
   
    TELECOM  ONE PURCHASE AGREEMENT.  On June  27, 1996, the Company and Telecom
One entered  into an  agreement  pursuant to  which  the Company  will  acquire,
subject   to  FCC  approval,   from  Telecom  One   the  two  currently  granted
authorizations that are the  subject of the Telecom  One Services Agreement  for
approximately  $111,000 in cash. In  addition, the Company will  have a right of
first refusal on all future  grants of 38 GHz  authorizations to Telecom One  or
its current stockholders.
    
 
STRATEGIC ALLIANCES
 
    AMERITECH  STRATEGIC DISTRIBUTION AGREEMENT.  On April 29, 1996, the Company
and Ameritech entered  into a three-year  strategic distribution agreement  (the
"Ameritech  Strategic  Distribution Agreement")  pursuant  to which  the Company
provides 38 GHz  services to Ameritech,  who will in  turn market the  Company's
services  under  the Ameritech  name.  Ameritech has  agreed  to be  the primary
provider of the
 
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<PAGE>
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  equipment staging  and outfitting,  site
preparation,  equipment installation and maintenance  for the Company's wireless
broadband services. Under the agreement, it is anticipated that GTE will perform
at least 75% of the Company's installations. The Company will pay a fee equal to
$1,550 for the installation of each link and a maintenance fee equal to $85  per
hour.  The aggregate  amount of  the fee  will depend  on the  Company's rate of
growth. The Company believes that GTE's nationwide presence and experience  will
provide the Company with efficient, quality installation and maintenance for its
nationwide  services.  See  "Risk Factors  --  Dependence on  Third  Parties for
Marketing and Service."
 
    GTE SOFTWARE LICENSE AGREEMENT.  On March 29, 1996, the Company entered into
a software license agreement with  GTE's Network Management Organization.  Under
this  agreement, the Company  will purchase software  and centralize its network
management functions to reduce costs and increase reliability. GTE's "Integrated
Network Management  Products" enable  the Company  to quickly  identify  service
interruptions  and to simultaneously alert the field service teams, who are able
to restore services in a  timely manner. The Company will  pay a license fee  of
approximately   $2.4  million   and  an   annual  maintenance   support  fee  of
approximately $300,000. The  license fee  will be paid  in monthly  installments
commencing  January 1, 1997 of $67,000  per month, including interest. After the
first year,  fees  are subject  to  renegotiation  based on  market  prices  and
conditions.  See "Risk Factors -- Dependence  on Third Parties for Marketing and
Service."
 
    HARRIS AGREEMENTS.  On April 26,  1996, the Company and Harris  Corporation,
Farinon Division ("Harris") entered into a one-year PCS marketing agreement (the
"Harris  Marketing Agreement") pursuant  to which the  Company granted to Harris
the right to use  its 38 GHz  authorizations, including associated  coordination
services,  installation and network  monitoring and field  services. Pursuant to
the Harris Marketing Agreement, Harris  agreed to market the Company's  services
in  the emerging  PCS market.  The Harris  Marketing Agreement  is automatically
renewable for successive one-year terms  unless either party delivers notice  of
non-renewal  at  least 60  days prior  to the  end  of the  initial term  or any
successive term. The  agreement is also  subject to termination  at any time  by
either party on 90 days' notice.
 
    Concurrently with the Harris Marketing Agreement, the parties entered into a
one-year  purchase agreement (the "Harris Purchase Agreement") pursuant to which
the  Company  agreed  to  purchase  certain  microwave  transmission  equipment,
software  and services relating  thereto (the "Harris  Products"). The agreement
sets minimum purchase goals for the purchase by the Company of Harris  Products.
If  either the Harris Purchase Agreement or the Harris Marketing Agreement shall
terminate, the other shall also terminate.
 
   
    TECHNOLOGY DEVELOPMENT AGREEMENTS.   The  Company has  had discussions  with
several  microwave equipment or technology development companies for development
of technologies owned by  such companies, for advanced  38 GHz radios  highspeed
converters,  innovative telecommunications platforms and other technologies. The
Company will continue to monitor new developments in technology and may elect to
fund research and development activity in  such new technology. The Company  has
also  entered  into  a  letter  of  intent  with  American  Wireless Corporation
("American Wireless") providing for  the funding by the  Company of $700,000  to
$1.0 million for research and development. In consideration of such funding, the
Company  will  have  a first  right  to purchase  American  Wireless' production
capacity of the new radios for a period of 18 months from the date of the  first
order and will receive a
    
 
                                       52
<PAGE>
   
per-unit  fee on  radios sold  by American  Wireless to  third parties,  and the
Company will have  no other  rights to  any technology  developed. See  "Certain
Transactions  -- American  Wireless Development Agreement."  This arrangement is
subject to definitive documentation. The Company has entered into a  non-binding
arrangement  with QuestTV  providing for  an investment  of $1.5  million in the
development of  a nationwide  network of  franchises offering  retail access  to
sophisticated  video  data  transmission and  storage  technology.  See "Certain
Transactions -- QuestTV Investment."
    
 
   
    The  Company  has  also  entered  into  a  letter  of  intent  with  Helioss
Communications  Corporation ("Helioss") for  the development of  advanced 38 GHz
radios. Under the letter of intent which is subject to definitive documentation,
the Company will fund  up to $1.0 million  of Helioss' research and  development
expenses.  The Company will have a right of first refusal on production capacity
of the radios for three  years from delivery of  the first radios produced,  and
will  receive a royalty on  the sale of a certain  number of radios to customers
other than  the Company,  and  the Company  will have  no  other rights  to  any
technology developed.
    
 
   
    Through  June 15, 1996,  the Company has  incurred approximately $600,000 of
research and  development expenses  under  such arrangements.  There can  be  no
assurance  that the Company can complete  definitive agreements with any of such
companies or that such companies can develop technologies with commercial  value
for  the  Company.  Although  the  Company  does  not  have  any  other material
commitments to fund  research and development  or to make  investments in  other
companies,  the  Company expects  to incur  additional research  and development
expenses or to make other such investments from time to time.
    
 
FOREIGN MARKETS
 
   
    The Company  is  exploring  the  possibilities  of  providing  its  wireless
broadband  services in other countries including  Canada and in Europe. Pursuant
to a  consulting agreement,  the  Company has  retained  the services  of  Trond
Johannessen  for a period of two years  to assist the Company in the exploration
of foreign  opportunities,  including  the  acquisition  of  wireless  broadband
licenses and identification of local operating partners. In addition to payments
of  $6,500 per  month to  Mr. Johannessen, Mr.  Johannessen will  be entitled to
purchase, on the  same terms  as the Company,  up to  20% of the  equity of  any
entity  formed to exploit any such opportunities. The Company has entered into a
letter of  intent with  Advantage Telecom,  Inc. ("ATI").  ATI has  received  an
experimental  license to provide 38 GHz  services in Vancouver, British Columbia
and intends to seek authority to provide 38 GHz services in other major  markets
in Canada whenever Canadian regulators adopt appropriate policies. The letter of
intent  anticipates that the Company would provide initial funds and services to
ATI in amounts to be determined. There can be no assurance that the Company  can
acquire such licenses or develop and operate such systems.
    
 
COMPETITION
 
    The  telecommunications services industry is highly competitive. The Company
has only recently begun to market  its wireless broadband services to  potential
customers and is currently providing services on a limited basis. In each market
area  in  which  the Company  is  authorized  to provide  services,  the Company
competes or will compete with several other service providers and  technologies.
The  Company expects  to compete  primarily on  the basis  of wireless broadband
service features, quality, price, reliability, customer service and response  to
customer  needs. The  Company faces  significant competition  from other  38 GHz
providers and incumbent LECs,  such as the RBOCs.  The Company may also  compete
with  CAPs,  cable  television  operators,  electric  utilities,  LECs operating
outside their current local  service areas and IXCs.  There can be no  assurance
that the Company will be able to compete effectively in any of its market areas.
 
    COMPETITION  FROM 38 GHZ  SERVICE PROVIDERS.   The Company faces competition
from other 38  GHz service  providers, such as  WinStar and  BizTel, within  its
market  areas.  In many  cases,  one or  both  of these  service  providers hold
licenses to  operate  in  other  portions  of the  38  GHz  band  in  geographic
 
                                       53
<PAGE>
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 the lower fourteen
proposed 100 MHz channels (which are similar  to those used by the Company)  and
four  proposed 50 MHz channels in the 38  GHz spectrum band, which have not been
previously available  for  commercial  use.  See  "Risk  Factors  --  Government
Regulation."  The grant of  additional authorizations by  the FCC in  the 38 GHz
band, or  other portions  of the  spectrum with  similar characteristics,  could
result  in  increased  competition.  The Company  believes  that,  assuming that
additional channels  are made  available  as proposed  by the  NPRM,  additional
entities  having greater resources than the Company could acquire authorizations
to provide 38 GHz services.
    
 
   
    COMPETITION FROM  INCUMBENT  LECS.    The  Company  also  faces  significant
competition  from incumbent  LECs, irrespective of  whether they  provide 38 GHz
services. Incumbent LECs have long-standing relationships with their  customers,
generally  own  significant  PCS  or  cellular  assets,  have  the  potential to
subsidize competitive services with  revenues from a  variety of businesses  and
benefit  from favorable federal  and state policies  and regulations. Regulatory
decisions and  recent  legislation, such  as  the Telecommunications  Act,  have
partially  deregulated the  telecommunications industry and  reduced barriers to
entry into new segments of  the industry. In particular, the  Telecommunications
Act,  among other things, (i) enhances  local exchange competition by preempting
laws prohibiting competition in the local  exchange market by requiring LECs  to
provide  fair and equal standards for interconnection and by requiring incumbent
LECs to provide unbundling of  services and (ii) permits  an RBOC to compete  in
the   interLATA   long  distance   service   market  once   certain  competitive
characteristics emerge in such  RBOC's service area.  The Company believes  that
this  trend towards greater  competition will continue  to provide opportunities
for broader entrance  into the  local exchange  markets. However,  as LECs  face
increased  competition,  regulatory decisions  are likely  to provide  them with
increased pricing  flexibility, which  in  turn may  result in  increased  price
competition.  There can  be no assurance  that such  increased price competition
will not have a material adverse effect on the Company's results of operations.
    
 
    OTHER COMPETITORS.  The Company may  compete with CAPs for the provision  of
last  mile access and additional services in  most of its market areas. However,
the Company believes  that many CAPs  may utilize 38  GHz transmission links  to
augment  their own service offerings to IXCs and end users, and that the Company
is well positioned to provide such 38  GHz services to CAPs. However, there  can
be  no assurance that  CAPs will utilize  the Company's 38  GHz services or that
CAPs will not  seek to  acquire their  own 38  GHz licenses  or use  the 38  GHz
licenses  of other licensees. Furthermore, the ability of CAPs to compete in the
local exchange market is limited by regulations relating to number  portability,
dialing  parity  and  reasonable  interconnection.  The  Telecommunications  Act
requires the FCC and the  states to implement regulations  that place CAPs on  a
more  equal  competitive footing  with  LECs. To  the  extent these  changes are
implemented, CAPs may be  able to compete more  effectively with LECs.  However,
there  can be no  assurance that CAPs or  38 GHz service  providers, such as the
Company, will be  able to  compete effectively for  the provision  of last  mile
access and other services.
 
                                       54
<PAGE>
    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 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
 
                                       55
<PAGE>
"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 mid-September 1996, 39 construction
permits by December 1996 and the remaining 82 between mid-April and August 1997.
The Company  believes that,  in light  of current  FCC practice,  extensions  of
construction  periods  are  highly  unlikely.  See  "Risk  Factors  --  Risk  of
Forfeiture, Non-Renewal and Fluctuation in Value of FCC Licenses."
 
    COMMON CARRIER REGULATION.  Under the terms of its licenses, the Company  is
classified  as a common carrier,  and as such is required  to offer service on a
non-discriminatory basis  at  just and  reasonable  rates to  anyone  reasonably
requesting  such service. Although the  Communications Act prohibits the Company
from discriminating among  its customers, the  Communications Act, as  currently
interpreted  by  the  FCC, does  permit  the Company  substantial  discretion in
classifying its  customers and  discriminating among  such classifications.  The
Company  generally is obligated to furnish  service to its competitors and might
be obligated to allow other 38 GHz providers to install links within one of  the
Company's market areas for a non-discriminatory fee. Under the FCC's streamlined
regulation  of non-dominant  carriers, the  Company, as  a non-dominant carrier,
must file tariffs  with the FCC  for certain interstate  services on an  ongoing
basis.  The Company  is in the  process of filing  tariffs with the  FCC, to the
extent required, with respect  to its provision of  interstate service. The  FCC
has  recently initiated a  rulemaking proceeding to  eliminate the tariff filing
requirement  pursuant   to   new   forbearance  authority   contained   in   the
Telecommunications Act. The Company, as a non-dominant carrier, is not currently
subject  to rate regulation, and it may install and operate non-radio facilities
for the transmission  of interstate  communications without prior  FCC or  state
authorization.
 
   
    The  Company manages the systems of ART West, DCT, Telecom One and CommcoCCC
(during the pendency of certain acquisitions) pursuant to management agreements.
See "Business  --  Agreements  Relating to  Licenses  and  Authorizations."  The
Company  believes that the provisions of these management agreements comply with
the FCC's  policies  concerning  licensee control  of  FCC-licensed  facilities.
Because  the 38 GHz service is a new service, however, there is no FCC precedent
addressing the limits  of such  management arrangements for  these services.  No
assurance can be given that the management arrangements or proposed acquisitions
will, if challenged, be found to satisfy the FCC's
    
 
                                       56
<PAGE>
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")
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
 
                                       57
<PAGE>
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.
 
    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.
 
                                       58
<PAGE>
EMPLOYEES
 
    As of June 15, 1996, the Company  had a total of 70 employees, including  20
in   engineering  and  field  services,  25   in  sales  and  marketing,  13  in
administration and finance, 8 in operations  and 4 in corporate development  and
advanced  services.  None  of  the  Company's  employees  is  represented  by  a
collective bargaining  agreement.  The  Company has  never  experienced  a  work
stoppage and believes that its employee relations are good.
 
PROPERTIES
 
    The  Company leases  approximately 22,000  square feet  of office, technical
operations and engineering field services  depot space in Bellevue,  Washington.
The  Company's  corporate headquarters,  network  operations center  and western
regional sales office occupy approximately  15,000 square feet under a  sublease
expiring   in  January   2000.  The  Company's   engineering  department  leases
approximately 5,000 square feet and  2,000 square feet for technical  operations
and  an  engineering  field  services depot,  respectively,  pursuant  to leases
expiring in May 1997. In addition the Company leases 1,100 square feet of office
space in Portland, Oregon for sales and marketing personnel pursuant to a  lease
expiring  in  March 1998.  The  Company also  leases  temporary office  space in
Washington, D.C. under a sub-lease from  Pierson & Burnett, L.L.P. See  "Certain
Transactions -- Pierson & Burnett Transactions."
 
LITIGATION
 
    The Company is not a party to any litigation.
 
                                       59
<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  Omni TRACS  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
 
                                       60
<PAGE>
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-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:
 
                                       61
<PAGE>
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  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.
 
                                       62
<PAGE>
    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 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  Commco  CCC  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.
 
                                       63
<PAGE>
    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 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.
 
                                       64
<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 ASSUMED ANNUAL
                                   NUMBER OF      PERCENT OF                              RATES OF STOCK PRICE
                                   SECURITIES    TOTAL OPTIONS                          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  prices  were determined  by  the Option
     Committee, who considered the fair market value of the Company's securities
     at the time of  grant based upon analysis  of recent private placements  of
     securities.  Subsequently, the  Company engaged  an independent  expert who
     conducted a more thorough analysis of the value of the Company's securities
     considering such placements as well  as comparable market transactions  and
     other  relevant  factors specific  to  the placements  (such  as underlying
     security interest  and liquidity).  In all  cases, the  exercise price  was
     equal to, or in excess of, the estimated fair value of the Company's Common
     Stock at the date of grant as determined by the independent expert.
    
 
(2)  See "-- Stock Option Plans -- Equity Incentive Plan -- Grants."
 
     AGGREGATE  STOCK OPTION EXERCISES  IN LAST FISCAL  YEAR AND FISCAL YEAR-END
OPTION VALUES.   The  following table  sets forth  the number  and value  as  of
December  31, 1995 of shares underlying unexercised  options held by each of the
Named Executive Officers.  As of December  31, 1995, no  stock options had  been
exercised by any Named Executive Officers.
 
                         FISCAL YEAR-END OPTION VALUES
 
   
<TABLE>
<CAPTION>
                                                              NUMBER OF SHARES
                                                           UNDERLYING UNEXERCISED        VALUE OF UNEXERCISED
                                                                 OPTIONS AT             IN-THE-MONEY OPTIONS AT
                                                               FISCAL YEAR END            FISCAL YEAR END (1)
                                                         ---------------------------  ---------------------------
NAME                                                     EXERCISABLE  UNEXERCISABLE   EXERCISABLE  UNEXERCISABLE
- -------------------------------------------------------  -----------  --------------  -----------  --------------
<S>                                                      <C>          <C>             <C>          <C>
Steven D. Comrie                                            302,676        454,015     $ 184,420    $    276,631
James D. Miller                                              10,000         40,000            --              --
</TABLE>
    
 
- ------------------------------
(1)  Based  on the estimated fair market value  of the Company's Common Stock as
     of December 31, 1995  of $1.20 per share,  less the exercise price  payable
     upon  exercise  of such  options. Such  estimated fair  market value  as of
     December 31, 1995 is  substantially lower than the  price to the public  in
     the Common Stock Offering.
 
STOCK OPTION PLANS
 
    EQUITY INCENTIVE PLAN.
 
    The  Equity Incentive Plan  was adopted by  the Company on  May 30, 1996 and
approved by the stockholders on June 25, 1996.
 
    The Equity Incentive Plan is designed to advance the Company's interests  by
enhancing  its ability to attract and retain  employees and others in a position
to make  significant  contributions  to  the  success  of  the  Company  through
ownership  of shares of Common Stock. The Equity Incentive Plan provides for the
grant  of  incentive  stock   options  ("ISOs"),  non-statutory  stock   options
("NQSOs"),  stock appreciation  rights ("SARs"),  restricted stock, unrestricted
stock, deferred stock grants, and  performance awards, loans to participants  in
connection  with awards,  supplemental grants and  combinations of  the above. A
total of 2,500,000 shares  of common stock are  reserved for issuance under  the
Equity Incentive
 
                                       65
<PAGE>
   
Plan. The maximum number of shares as to which options or SARs may be granted to
any  participant in any one calendar year is 800,000. The shares of Common Stock
issuable under the  Equity Incentive Plan  are subject to  adjustment for  stock
dividends  and similar events.  Awards under the Equity  Incentive Plan may also
include provision for payment of dividend equivalents with respect to the shares
subject to the award.
    
 
    The Equity Incentive  Plan is administered  by the Option  Committee of  the
Board of Directors (the
"Option  Committee").  The  Option  Committee  shall  consist  of  at  least two
directors. If the Common Stock is  registered under the Securities Exchange  Act
of  1934, all members  of the Option  Committee shall be  "outside directors" as
defiined. All employees  of the Company  and any of  its subsidiaries and  other
persons  or entities  (including non-employee directors  of the  Company and its
subsidiaries) who, in the opinion of the Option Committee, are in a position  to
make   a  significant  contribution  to  the  success  of  the  Company  or  its
subsidiaries are eligible to participate in the Equity Incentive Plan.
 
   
    STOCK OPTIONS.   The  exercise price  of  an ISO  granted under  the  Equity
Incentive  Plan may not be less than 100% (110% in the case of 10% shareholders)
of the fair market value of the Common Stock at the time of grant. The  exercise
price  of  a nonstatutory  option  granted under  the  Equity Incentive  Plan is
determined by the Option Committee.  The term of each option  may be set by  the
Option  Committee but cannot exceed ten years  from grant (five years from grant
in the case of an incentive stock option granted to a 10% shareholder), and each
option will  be  exercisable at  such  time or  times  as the  Option  Committee
specifies.  The option  price may  be paid  in cash  or check  acceptable to the
Company or,  if  permitted  by  the Option  Committee  and  subject  to  certain
additional  limitations,  by  tendering  shares  of  Common  Stock,  by  using a
promissory note, by delivering to  the Company an unconditional and  irrevocable
undertaking by a broker promptly to deliver sufficient funds to pay the exercise
price, or a combination of the foregoing.
    
 
   
    STOCK  APPRECIATION RIGHTS.  SARs  may be granted either  alone or in tandem
with stock option  grants. Each  SAR entitles  the participant,  in general,  to
receive  upon exercise  the excess  of a  share's fair  market value  in cash or
common stock at the date of exercise  over the share's fair market value on  the
date the SAR was granted. The Option Committee may also grant SARs which provide
that  following a change in  control of the Company  as determined by the Option
Committee, the  holder of  such right  will  be entitled  to receive  an  amount
measured  by  specified values  or averages  of  values prior  to the  change in
control. If  an SAR  is  granted in  tandem  with an  option,  the SAR  will  be
exercisable  only to  the extent  the option is  exercisable. To  the extent the
option is exercised, the accompanying SAR will cease to be exercisable, and vice
versa. An SAR  granted in  tandem with  an ISO may  be exercised  only when  the
market price of common stock subject to the option exceeds the exercise price of
such  option. SARs not granted in tandem  shall be exercisable at such time, and
on such conditions, as the Option Committee may specify.
    
 
    STOCK  AWARDS.    The   Equity  Incentive  Plan   provides  for  awards   of
nontransferable  shares of restricted Common Stock subject to forfeiture as well
as of unrestricted shares of Common Stock. Awards may provide for acquisition of
restricted and unrestricted Common Stock for  a purchase price specified by  the
Option  Committee, but in no event less  than par value. Restricted Common Stock
is subject to repurchase  by the Company  at the original  purchase price or  to
forfeiture  if no cash was paid by  the participant if the participant ceases to
be an employee  before the  restrictions lapse.  Other awards  under the  Equity
Incentive  Plan may  also be  settled with  restricted Common  Stock. Restricted
securities  shall  become  freely  transferable  upon  the  completion  of   the
Restricted  Period including  the passage of  any applicable period  of time and
satisfaction of any  conditions to vesting.  The Option Committee,  in its  sole
discretion,  may waive  all or  part of the  restrictions and  conditions at any
time.
 
    The Equity Incentive Plan  also provides for  deferred grants entitling  the
recipient  to receive shares of Common Stock in  the future at such times and on
such conditions as the Option Committee may
 
                                       66
<PAGE>
specify, and  performance awards  entitling  the recipient  to receive  cash  or
Common  Stock following  the attainment of  performance goals  determined by the
Option Committee. Performance conditions and  provisions for deferred stock  may
also be attached to other awards under the Equity Incentive Plan.
 
    A loan may be made under the Equity Incentive Plan either in connection with
the  purchase of Common Stock under an award or with the payment of any federal,
state and local tax with respect to  income recognized as a result of an  award.
The  Option  Committee  will determine  the  terms  of any  loan,  including the
interest rate (which may be zero). No  loan may have a term exceeding ten  years
in duration. In connection with any award, the Option Committee may also provide
for and grant a cash award to offset federal, state and local income taxes or to
make a participant whole for certain taxes.
 
   
    Except as otherwise provided by the Option Committee, if a participant dies,
options  and SARs held  by such participant  immediately prior to  death, to the
extent then  exercisable,  may  be  exercised  by  the  participant's  executor,
administrator or transferee during a period of one year following such death (or
for  the  remainder  of  their  original term,  if  less).  Except  as otherwise
determined by  the Option  Committee,  options and  SARs  not exercisable  at  a
participant's  death terminate.  Outstanding awards  of restricted  Common Stock
must be transferred to  the Company upon a  participant's death and,  similarly,
deferred  Common  Stock grants,  performance awards  and supplemental  awards to
which a  participant  was  not  irrevocably entitled  prior  to  death  will  be
forfeited, except as otherwise determined by the Option Committee.
    
 
   
    In  the case of termination of  a participant's association with the Company
for reasons other than death, options and SARs remain exercisable, to the extent
they were exercisable immediately prior to termination, for three months (or for
the remainder of  their original  term, if  less), shares  of restricted  Common
Stock  must be resold to the Company,  and other awards to which the participant
was not  irrevocably entitled  prior to  termination will  be forfeited,  unless
otherwise  determined  by  the  Option Committee.  If  any  such  association is
terminated due to the participant's discharge for cause which, in the opinion of
the Option Committee,  casts such  discredit on  the participant  as to  justify
immediate  termination  of  any  award under  the  Equity  Incentive  Plan, such
participant's options and SARs may be terminated immediately.
    
 
    In the event of a  consolidation or merger in which  the Company is not  the
surviving  corporation or which results in  the acquisition of substantially all
of the Company's outstanding Common Stock by  a single person or entity or by  a
group  of persons and/or entities acting in concert  or in the event of the sale
or transfer of substantially all of  the Company's assets, the Option  Committee
may  determine that (i) each outstanding  option and SAR will become immediately
exercisable  unless  otherwise  provided  at  the  time  of  grant,  (ii)   each
outstanding share of restricted Common Stock will immediately become free of all
restrictions   and  conditions,   (iii)  all  conditions   on  deferred  grants,
performance awards and supplemental grants which  relate only to the passage  of
time  and continued  employment will  be removed  and (iv)  all loans  under the
Equity Incentive Plan will be forgiven.  The Committee may also arrange to  have
the  surviving or acquiring corporation or affiliate  assume any award held by a
participant or grant a replacement award. If the optionee is terminated after  a
change  in  control by  the Company  without cause,  or in  the case  of certain
officers designated from  time to  time by  the Option  Committee resigns  under
certain  circumstances, within  two years following  the change  in control, all
unvested options will vest and all  options will be exercisable for the  shorter
of  four years or their original duration and all other awards will vest. If the
option committee makes no such  determination, outstanding awards to the  extent
not fully vested will be forfeited.
 
    CERTAIN FEDERAL INCOME TAX CONSEQUENCES.  The following discussion, which is
based on the law as in effect on June 1, 1996, summarizes certain federal income
tax consequences of participation in the Equity Incentive Plan. The summary does
not  purport to cover  federal employment tax or  other federal tax consequences
that may  be associated  with  the plans,  nor does  it  cover state,  local  or
non-U.S. taxes.
 
    In  general,  an  optionee realizes  no  taxable  income upon  the  grant or
exercise of an ISO. However, the exercise of an ISO may result in an alternative
minimum tax liability to the optionee. With certain
 
                                       67
<PAGE>
exceptions, a disposition of shares purchased under an ISO within two years from
the date of grant or within one year after exercise produces ordinary income  to
the  optionee (and a corresponding deduction  is available to the company) equal
to the value of the shares at the time of exercise less the exercise price.  Any
additional  gain recognized in the disposition is  treated as a capital gain for
which the Company  is not  entitled to  a deduction.  If the  optionee does  not
dispose  of the  shares until  after the expiration  of these  one- and two-year
holding periods, any gain or loss  recognized upon a subsequent sale is  treated
as  a long-term capital gain or loss for  which the Company is not entitled to a
deduction.
 
    In general, in the case of a nonstatutory option the optionee has no taxable
income at the time of grant but  realizes income in connection with exercise  of
the  option in an  amount equal to the  excess (at the time  of exercise) of the
fair market value of the shares acquired upon exercise over the exercise  price,
a  corresponding deduction  is available to  the Company, and  upon a subsequent
sale or exchange of the shares,  appreciation or depreciation after the date  of
exercise  is  treated as  capital  gain or  loss for  which  the Company  is not
entitled to a deduction. In  general, an ISO that  is exercised more than  three
months  after termination  of employment  (other than  termination by  reason of
death) is treated  as a nonstatutory  option. ISOs granted  after 1986 are  also
treated  as nonstatutory options to the  extent they first become exercisable by
an individual  in  any calendar  year  for shares  having  a fair  market  value
(determined as of the date of grant) in excess of $100,000.
 
    Under  the so-called "golden  parachute" provisions of  the Internal Revenue
Code, the vesting or accelerated exercisability  of awards in connection with  a
change  in control of  the Company may be  required to be  valued and taken into
account in determining whether participants have received compensatory payments,
contingent on  the change  in control,  in excess  of certain  limits. If  these
limits   are  exceeded,  a  substantial  portion   of  amounts  payable  to  the
participant, including  income recognized  by reason  of the  grant, vesting  or
exercise  of  awards under  the  Equity Incentive  Plan,  may be  subject  to an
additional 20% federal tax and may be nondeductible to the Company.
 
    GRANTS.  Mr. Comrie has been granted NQSOs expiring on various dates through
June 17, 2005 to purchase 756,691 shares  of Common Stock at a price of  $0.5907
per  share. Of  the NQSOs, 417,693  are currently exercisable,  and 111,990 will
become exercisable on July 17, 1997 and up to an additional 227,008 shares  (the
"Additional  Shares") will become  exercisable on June 17,  2000. The vesting of
NQSOs to purchase  56,752 Additional  Shares will  be accelerated  in each  year
based  upon the  attainment of  certain performance  goals as  determined by the
Board of Directors. Each of Mr. Comrie's options are exercisable for a period of
five years from the date of vesting.
 
    Mr. Grina has been granted NQSOs expiring on various dates through April 26,
2003 to purchase 300,000 shares of Common  Stock at a price of $6.25 per  share.
The  NQSOs are subject to vesting over a three-year period, of which 100,000 are
fully vested and currently  exercisable. NQSOs to  purchase 200,000 shares  will
become  exercisable on April 26,  1999; however, the vesting  of 100,000 of such
shares will be accelerated on  each of the first  and second anniversary of  the
date  of grant based upon attainment  of certain performance goals as determined
by the Board of  Directors. Each of  Mr. Grina's options  are exercisable for  a
period of five years from the date of vesting. Mr. Grina's options will be fully
vested,  notwithstanding the attainment of performance goals, on April 26, 1999.
In addition, all of his  options become immediately exercisable, without  regard
to  the  vesting period,  upon a  Change of  Control (as  defined in  the Equity
Incentive Plan)  and upon  other corporate  changes described  in the  agreement
evidencing his options.
 
    Mr.  Miller has  been granted NQSOs  expiring December 29,  2000 to purchase
50,000 shares of Common Stock at a price of $1.652 per share. The NQSOs vest  at
a rate of 20% on each anniversary of the date of grant.
 
    THE DIRECTORS PLAN.
 
    On  May  30,  1996,  the Company  adopted  the  1996  Non-Employee Directors
Automatic Stock  Option Plan  (the  "Directors Plan"),  which provides  for  the
automatic  grant of stock options to non-employee directors to purchase up to an
aggregate   of   200,000   shares.    Under   the   Directors   Plan,    options
 
                                       68
<PAGE>
to  acquire  6,000 shares  of  Common Stock  are  automatically granted  to each
non-employee director who is a director on January 1 of each year. In  addition,
each  non-employee director serving  on the Board of  Directors effective on the
date of the Common  Stock Offering will  receive, and in  the future each  newly
elected  non-employee director on  the date of  his or her  first appointment or
election to the Board of Directors  will receive, an automatic grant of  options
to acquire 7,000 shares of Common Stock.
 
    Although  grants of the options under  the Directors Plan are automatic, and
the Directors Plan is intended  to be largely self-administering, the  Directors
Plan  will  be administered  by either  the  Board of  Directors or  a committee
designated by  the Board  of Directors,  which will,  to the  extent  necessary,
administer  and interpret the  Directors Plan (the  "Plan Administrator"). Stock
options awarded under the Directors Plan are priced automatically at an exercise
price equal to the market price of the Common Stock on the date of grant. If  at
any time no public market for the Common Stock exists, the Plan Administrator is
empowered  to determine the fair market value. Under the Directors Plan, initial
option grants vest over a three-year period and are exercisable for a period  of
10  years from  the date of  grant. On the  date of this  Prospectus, options to
purchase an aggregate of 28,000 shares at an exercise price equal to the initial
offering price of  the Common Stock  will be granted  to non-employee  directors
under the Directors Plan.
 
EMPLOYMENT AND CONSULTING AGREEMENTS
 
    The  Company has  entered into  a three-year  employment agreement  with Mr.
Fotheringham providing for full-time employment at an annualized base salary  of
$250,000  for 1996, $275,000  for 1997 and  $300,000 for 1998.  In addition, Mr.
Fotheringham is entitled to receive an annual bonus of up to $100,000  depending
on  the achievement  of specified annual  link installation goals.  The goal for
each year will  be established  based on the  operating budget  approved by  the
Board of Directors. The agreement precludes Mr. Fotheringham from competing with
the  Company for one year  after the cessation of  his employment, regardless of
the reason for such cessation.
 
    The Company  has entered  into a  three-year employment  agreement with  Mr.
Comrie  providing  for full  time  employment at  an  annualized base  salary of
$160,000 through December 31,  1995, $200,000 from January  1, 1996 to July  16,
1997 and $240,000 from July 17, 1997 to July 16, 1998. Mr. Comrie is entitled to
receive  an  annual bonus  of up  to  $100,000 depending  on the  achievement of
specified annual  link  installation goals.  The  goal  for each  year  will  be
established based on the operating budget approved by the Board of Directors. As
part   of  the  employment  agreement,  the   Company  provided  Mr.  Comrie  an
interest-free loan in the amount of $30,000 and forgave payment of such loan  on
January  1,  1996.  The forgiveness  of  such  loan has  been  accounted  for as
compensation expense on  the 1995 statement  of operations of  the Company.  The
agreement also precludes Mr. Comrie from competing with the Company for one year
after  the cessation of employment, regardless of the reason for such cessation.
The agreement may be terminated at any  time by either party and provides  that,
if the Company terminates Mr. Comrie without cause or Mr. Comrie's employment is
terminated  due  to his  disability or  death,  Mr. Comrie  will be  entitled to
continue to receive the full amount of his base salary and any other benefits to
which he would have otherwise  been entitled for a period  of one year from  the
date  of such termination.  See "-- Stock Option  Plans" regarding stock options
granted to Mr. Comrie pursuant to his employment agreement.
 
    The Company  has  entered  into  an employment  agreement  with  Mr.  Grina,
providing  for full time  employment on an  at will basis  at an annualized base
salary of $190,000 through April 30, 1997. In addition, Mr. Grina is entitled to
receive an annual  bonus of  up to $100,000  depending upon  the achievement  of
specified  annual  link  installation goals.  The  goal  for each  year  will be
established based on the  operating budget approved by  the Board of  Directors.
The  agreement precludes Mr. Grina from competing  with the Company for one year
after the  cessation  of his  employment,  regardless  of the  reason  for  such
cessation.  The agreement  may be  terminated at  any time  by either  party and
provides that, if the Company terminates Mr. Grina without cause or Mr.  Grina's
employment  is terminated  due to  his disability  or death,  Mr. Grina  will be
entitled   to   continue   to   receive   the   full   amount   of   his    base
 
                                       69
<PAGE>
salary and any other benefits to which he would have otherwise been entitled for
a  period of six months from the date  of such termination. See "-- Stock Option
Plans" regarding stock options granted to  Mr. Grina pursuant to his  employment
agreement.
 
    The  Company has also entered into  an employment agreement with Mr. Miller,
providing for full time employment at  an annual base salary equal to  $150,000.
His  employment agreement provides for  the payment by the  Company of an annual
bonus in designated amounts based upon the achievement of specified  performance
goals.  The agreement has a term of three years and precludes him from competing
with the Company for one year  after the cessation of employment, regardless  of
the  reason  for such  cessation. See  "-- Stock  Option Plans"  regarding stock
options granted  to  Mr.  Miller  pursuant  to  his  employment  agreement.  The
employment  agreement may be terminated at any time by the Company or Mr. Miller
and provides that,  if the  Company terminates Mr.  Miller's employment  without
cause or his employment is terminated due to his disability or death, Mr. Miller
may  continue  to receive  the  full amount  of his  base  salary and  any other
benefits to which  he would have  otherwise been  entitled for a  period of  six
months from the date of such termination.
 
   
    The  Company has  entered into  a three-year  consulting agreement  with Mr.
Pierson on May  8, 1995, under  which Mr. Pierson  agreed to provide  strategic,
business and other advisory services to the Company for base fees of $80,000 for
1995, $140,000 for 1996 and $80,000 for 1997, subject to extension at the option
of the Company. The agreement also precludes Mr. Pierson from competing with the
Company  for  one year  after termination  of the  agreement, regardless  of the
reason for such  termination. The  agreement may be  terminated at  any time  by
either  party and provides  that, if the Company  terminates Mr. Pierson without
cause or Mr. Pierson terminates his  consulting agreement for "good reason"  (as
specified in the agreement), Mr. Pierson will be entitled to continue to receive
the  full amount of his base fees and  any other benefits to which he would have
otherwise been  entitled  for  a period  of  one  year from  the  date  of  such
termination. See "Certain Transactions -- Pierson & Burnett Transactions."
    
 
                                       70
<PAGE>
                             PRINCIPAL STOCKHOLDERS
 
    The  following table  sets forth certain  information, as of  June 19, 1996,
regarding the beneficial  ownership of  the Company's  Common Stock  by (i)  the
directors  and executive officers of the Company,  (ii) each person known by the
Company to own beneficially more than five percent of the outstanding shares  of
the  Company's Common Stock and (iii) all  executive officers and directors as a
group assuming,  in  each case,  that  the Merger  has  been completed  and  the
Landover Partnerships have been dissolved.
 
   
<TABLE>
<CAPTION>
                                                             BENEFICIAL OWNERSHIP         BENEFICIAL OWNERSHIP AFTER
                                                              PRIOR TO OFFERINGS                  OFFERINGS
                                                           -------------------------  ----------------------------------
NAME                                                          NUMBER       PERCENT           NUMBER           PERCENT
- ---------------------------------------------------------  -------------  ----------  --------------------  ------------
<S>                                                        <C>            <C>         <C>                   <C>
Vernon L. Fotheringham (1)...............................      3,545,063       11.8%       3,545,063               9.4%
W. Theodore Pierson, Jr. (2).............................      2,455,407        8.2        2,455,407               6.5
High Sky Inc. (3)........................................      1,748,604        5.8        1,748,604               4.7
Landover Holdings Corporation (4)........................      8,068,582       26.8        8,068,582              21.4
Advent International Corporation (5).....................      3,186,238       10.5        3,186,238               8.4
Ameritech Development Corp. (6)..........................      1,677,745        5.5        1,677,745               4.3
Steven D. Comrie (7).....................................        302,676        1.0          302,676                 *
James C. Cook (8)........................................        133,830          *          140,830(14)             *
J.C. Demetree, Jr. (9)...................................      1,055,288        3.5        1,055,288               2.8
Mark C. Demetree (10)....................................      1,055,288        3.5        1,062,288(14)           2.8
Andrew I. Fillat (5).....................................      3,186,238       10.5        3,193,238(14)           8.4
Matthew C. Gove (11).....................................        441,753        1.5          441,753               1.2
T. Allan McArtor.........................................              0          *            7,000(14)             *
Laurence S. Zimmerman (4)................................      8,068,582       26.8        8,068,582              21.4
Thomas A. Grina (12).....................................        100,000          *          100,000                 *
James D. Miller (13).....................................         10,000          *           10,000                 *
All executive officers and directors as a group
 (1)(2)(4)(5)(7)(8)(9)(10)(11)(12)(13)(14)...............     20,276,045       65.6%      10,816,502(8)(15)       28.2%
</TABLE>
    
 
- ------------------------
Unless  otherwise indicated, the business address of each director and executive
officer named above is c/o Advanced Radio Telecom Corp., 500 108th Avenue  N.E.,
Suite 2600, Bellevue, Washington 98004.
 
 *  Less than 1.0%.
 
 (1) Includes 104,273 shares of Common Stock subject to an option owned by SERP.
    See "Certain Transactions -- SERP Agreement."
 
 (2)  Includes 2,455,407 shares of Common  Stock issuable upon completion of the
    Merger. Also includes 44,694 shares subject to an option owned by SERP.  See
    "Certain  Transactions  -- SERP  Agreement."  Mr. Pierson's  address  is c/o
    Pierson & Burnett L.L.P., 1667 K. Street, N.W., Washington, D.C. 20006.
 
 (3) High Sky Inc. is the general partner of High Sky and High Sky II and may be
    deemed the  beneficial  owner  of  all shares  held  by  such  partnerships.
    Includes  1,398,883  and  349,721  shares  of  Common  Stock  issuable  upon
    completion of the  Merger to High  Sky and High  Sky II, respectively.  Also
    includes  119,171  and 29,796  shares  held by  High  Sky and  High  Sky II,
    respectively, subject to an option owned by SERP. See "Certain  Transactions
    --  SERP  Agreement."  High Sky  Inc.'s  address  is c/o  Frank  S. Phillips
    Company, 6106 MacArthur Blvd., Bethesda, Maryland 20816.
 
   
 (4) Includes 37,500 shares issuable  upon exercise of Indemnity Warrants.  Does
    not include 100,000 shares and 100,000 shares respectively owned by the wife
    and  a family trust  of Laurence S. Zimmerman,  respectively of which shares
    LHC and  Mr.  Zimmerman  disclaim beneficial  ownership.  Does  not  include
    294,489  shares,  1,375,699  shares,  5,276,440  shares  and  95,719  shares
    issuable upon the Merger held by E1, E2, E2-2 and E2-3, respectively, each a
    limited partnership whose  general partner  is controlled by  LHC. Upon  the
    effectiveness of the Merger, these partnerships will dissolve. Including the
    shares  owned by such partnerships,  LHC beneficially owns 15,310,929 shares
    of Common Stock constituting 50.9%  of the Company's outstanding  securities
    prior  to the Offerings.  LHC is controlled by  Laurence S. Zimmerman. LHC's
    address is 667  Madison Avenue,  New York, New  York 10021.  See "--  Voting
    Trust Agreement."
    
 
 (5)  Includes 2,882,659 shares,  3,029 shares and  141,050 shares issuable upon
    the Merger and  151,908 shares, 160  shares and 7,432  shares issuable  upon
    exercise of Bridge Warrants, respectively owned by Global Private Equity II,
    L.P., Advent International II, L.P. and Advent Partners, L.P. (collectively,
    the "Advent Partnerships"), each a limited partnership whose general partner
    is  controlled by  Advent International  Corp. ("Advent").  Mr. Fillat  is a
    director, officer and stockholder of Advent. The address of Advent and  each
    of  the  Advent Partnerships  is 101  Federal Street,  Boston, Massachusetts
    02110.
 
                                       71
<PAGE>
 (6) Includes 635,609  shares issuable upon  the Merger and  877,136 shares  and
    165,000  shares issuable upon  exercise of the  Ameritech Warrant and Bridge
    Warrants, respectively. The address of  Ameritech is 30 South Wacker  Drive,
    Chicago,  Illinois 60601. See "Certain  Transactions -- Ameritech Financing;
    Ameritech Strategic Distribution Agreement."
 
 (7) Includes 302,676 shares currently  issuable upon exercise of options.  Does
    not  include 454,015  issuable upon  exercise of  the non-vested  portion of
    options. See "Management -- Stock Option Plans."
 
 (8) Includes  140,830 shares  beneficially  owned by  James C.  Cook  including
    22,000  shares issuable upon  exercise of Bridge  Warrants and 73,542 shares
    and 38,288 shares issuable upon the Merger  as a limited partner in E-2  and
    E2-3,  respectively. Mr. Cook will become a director of the Company upon the
    date of this Prospectus.
 
(9) Does not include 154,000 shares  issuable upon exercise of Bridge  Warrants,
    162,500  shares issuable  upon exercise  of Indemnity  Warrants or 4,221,152
    shares issuable  upon  the  Merger held  in  each  case by  members  of  Mr.
    Demetree's  family (or  a trust  for their  benefit), of  which he disclaims
    beneficial ownership. J.C. Demetree, Jr.'s address is c/o Demetree Brothers,
    3740 Beach Boulevard, Suite 300, Jacksonville, Florida 32207.
 
   
(10) Does not include 154,000 shares issuable upon exercise of Bridge  Warrants,
    48,750  shares issuable upon exercise  of Indemnity Warrants, 113,750 shares
    issuable upon exercise  of Indemnity Warrants  or 4,221,152 shares  issuable
    upon  the Merger held in each case by members of Mr. Demetree's family (or a
    trust for their benefit), of  which he disclaims beneficial ownership.  Mark
    C. Demetree's address is 505 Lancaster Street, #8AB, Jacksonville, FL 32204.
    
 
(11)  Includes  441,753  shares  issuable  upon  the  Merger  owned  by Hedgerow
    Corporation of Maine ("Hedgerow"), which is controlled by Mr. Gove. Does not
    include shares  owned  beneficially by  LHC,  of which  Mr.  Gove  disclaims
    beneficial  ownership. Hedgerow  from time to  time acts as  a consultant to
    LHC. Mr. Gove's address is 215 West 84th Street, New York, New York 10024.
 
(12) Includes 100,000 shares currently issuable upon exercise of an option.
 
(13) Includes 10,000 shares currently issuable upon exercise of an option.
 
(14) Includes 7,000 shares issuable upon  exercise of options anticipated to  be
    granted under the Directors Plan upon the consummation of the Offerings.
 
(15) Reflects the resignations of Messrs. J.C. Demetree, Jr., Gove and Zimmerman
    and  the elections as directors of Messrs. Cook and McArtor upon the date of
    this Prospectus. Does not include 8,268,582 shares beneficially owned by LHC
    and held in trust  by trustees, all  of whom are  directors of the  Company,
    pursuant  to  a  Voting Trust  Agreement,  of which  such  trustees disclaim
    beneficial ownership. See "-- Voting Trust Agreement." Includes 7,000 shares
    beneficially owned by  each of Messrs.  Mark C. Demetree,  Fillat, Cook  and
    McArtor  issuable upon exercise of options to be granted under the Directors
    Plan upon the consummation of the Offerings.
 
    Upon completion of the CommcoCCC Acquisition, Columbia Capital  Corporation,
as  general partner of two of the stockholders of CommcoCCC, and Commco, L.L.C.,
the remaining  stockholder of  CommcoCCC, will  beneficially own  8,842,154  and
7,707,846  shares, respectively,  of Common  Stock, including  26,715 and 23,285
shares,  respectively,  issuable  upon  exercise  of  the  CommcoCCC   Warrants,
constituting  16.3% and 14.2%, respectively, of the Company's Common Stock after
the  Offerings  (assuming  the   Underwriters'  over-allotment  option  is   not
exercised).  Assuming  the  consummation  of  the  Offerings  and  the CommcoCCC
Acquisition as of the date of this Prospectus, the Company would have 54,086,498
shares of Common Stock outstanding.
 
VOTING TRUST AGREEMENT
 
   
    Pursuant to  a  proposed  Voting  Trust  and  Irrevocable  Proxy  Agreement,
effective  on the date of this Prospectus, LHC  and the wife and a trust for the
benefit of the family of Laurence S. Zimmerman will deposit all of their  shares
of ART Common Stock in trust with Messrs. Mark C. Demetree, Andrew I. Fillat and
Vernon  L. Fotheringham with irrevocable instructions to vote such shares on all
matters submitted to a vote of the stockholders of the Company in proportion  to
the  vote of other stockholders of the  Company. The voting trust will expire on
the tenth anniversary of the  date of this Prospectus,  but is subject to  early
termination  in the event of (i) the death  of Laurence S. Zimmerman or (ii) the
sale by LHC of such  shares to unaffiliated parties.  The trustees of the  trust
will be indemnified by the Company.
    
 
                                       72
<PAGE>
                              CERTAIN TRANSACTIONS
 
FORMATION OF ART
 
    The  Company was organized in  August 1993 by Vernon  L. Fotheringham and W.
Theodore Pierson, Jr.,  for the purpose  of obtaining 38  GHz licenses from  the
FCC.  The  initial  stockholders, including  Messrs.  Fotheringham  and Pierson,
purchased for $.01 per share ART Common Stock in a private placement which,  net
of  certain subsequent transfers, currently constitute an aggregate of 6,000,470
shares of Common Stock.
 
HIGH SKY PRIVATE PLACEMENTS
 
    In November 1993 and March 1994, ART raised $60,000 and $30,000 through  the
sale  of its common  stock (which, net  of sales and  acquisitions of additional
shares, now constitute an  aggregate of 1,398,883 shares  and 349,721 shares  of
Common  Stock, respectively)  to High  Sky Limited  Partnership and  High Sky II
Limited  Partnership  ("High   Sky  II"   and,  collectively,   the  "High   Sky
Partnerships").  In March 1994, ART borrowed $70,000  from High Sky II. The loan
was evidenced by a promissory  note executed by ART and  payable to High Sky  II
(the "High Sky Note"). Pursuant to an Agreement dated March 1, 1995, High Sky II
sold the High Sky Note to Vernon L. Fotheringham and W. Theodore Pierson, Jr. in
exchange  for  two new  promissory notes,  bearing interest  at 7.5%  per annum,
executed by Messrs. Fotheringham and Pierson in the principal amounts of $52,675
and $22,575,  respectively  (the  "Fotheringham/Pierson  Notes"),  with  payment
secured  by pledges of  shares of Common Stock  owned by them.  The terms of the
notes were as  favorable as could  be negotiated with  unrelated third  parties.
After  the assignment and exchange, Messrs. Fotheringham and Pierson transferred
the  High   Sky  Note   to  the   Company  as   a  capital   contribution.   The
Fotheringham/Pierson  Notes,  which are  due in  August 1997  and which  are now
unsecured, are currently held by LHC (as defined below).
 
ART WEST JOINT VENTURE
 
    The Company is party to the ART West Management Agreement, pursuant to which
it manages the business and assets of ART West, a joint venture between ART  and
Extended.  Mark  T. Marinkovich,  Vice  President and  General  Manager, Western
Region of the Company is also the  President and a stockholder of Extended.  See
"Business  -- Agreements  Relating to  Licenses and  Authorizations --  ART West
Joint Venture" and  "Principal Stockholders."  In connection with  the ART  West
Joint  Venture, ART issued to Extended 368,127  shares of Common Stock. Of these
368,127 shares,  15,678 shares  are  subject to  an  option owned  by  Southeast
Research  Partners. See "-- SERP Agreement." In June 1996, the Company agreed to
acquire Extended's interest in ART West  for $6,000,000 in cash, subject to  FCC
approval.
 
ORGANIZATION OF TELECOM
 
   
    ART  and  Landover  Holdings Corporation  ("LHC")  organized  Advanced Radio
Telecom Corp. ("Telecom") on March 28,  1995, and purchased for $.001 per  share
340,000  shares of  Class A common  stock and  640,000 shares of  Class B common
stock of  Telecom, respectively,  which, after  giving effect  to  anti-dilution
adjustments  resulting from issuances of preferred stock as described in "-- LHC
Purchase Agreement," certain  transfers and  the transactions  described in  "--
February  1996  Reorganization" and  "--  Merger," currently  are  equivalent to
10,013,055 shares and 7,512,076, shares respectively, after giving effect to the
November 1995  redemption  of shares  of  Common Stock.  In  addition,  Hedgerow
Corporation  of Maine ("Hedgerow")  and Toro Financial  Corp. ("Toro") purchased
for $.001 per  share 15,000 shares  and 5,000 shares,  respectively, of  Telecom
Class A common stock which, after such anti-dilution adjustments and the Merger,
currently  are equivalent to 441,753 shares  and 147,251 shares of Common Stock,
respectively. LHC is controlled by Laurence S. Zimmerman. Hedgerow is controlled
by Matthew  C.  Gove, a  director  of the  Company.  Hedgerow and  Toro  provide
management and strategic consulting services to LHC, including services relating
to analysis and negotiation of acquisitions.
    
 
                                       73
<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 to  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."
 
                                       74
<PAGE>
    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 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
 
                                       75
<PAGE>
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").
 
AMERITECH FINANCING; AMERITECH STRATEGIC DISTRIBUTION AGREEMENT
 
   
    On February 2, 1996, Ameritech Development Corp. ("Ameritech") purchased for
an aggregate of $2.5 million 48,893 shares of Telecom Series F preferred  stock,
par value $0.001 per share, (the "Ameritech Financing") convertible into 635,609
shares of Common Stock prior to the Offerings. In addition, Telecom entered into
a  letter of intent with Ameritech Corp., the parent of Ameritech, to enter into
the Ameritech  Strategic  Distribution  Agreement and  in  connection  therewith
granted  to Ameritech  a ten-year warrant  to purchase 877,136  shares of Common
Stock of the Company exercisable  at a price of  $.01 per share (the  "Ameritech
Warrant").  On  April 29,  1996, Telecom  entered  into the  Ameritech Strategic
Distribution Agreement.  See  "Business  --  Strategic  Alliances  --  Ameritech
Strategic Distribution Agreement."
    
 
BRIDGE FINANCING
 
    On  March 8, 1996, Telecom entered into a financing (the "Bridge Financing")
pursuant to which it issued $5.0 million of 10% unsecured notes due in 1998 (the
"Bridge Notes")  and  five-year warrants  to  purchase  up to  an  aggregate  of
1,100,000  shares of  Telecom common stock  at a  price of $6.25  per share (the
"Bridge Warrants")  to  private  investors  including  (i)  affiliates  of  J.C.
Demetree,  Jr. and Mark C.  Demetree, directors of the  Company, (ii) the Advent
Partnerships and (iii) Ameritech, who invested $700,000, $725,000 and  $750,000,
respectively,   in  the  Bridge  Notes   and  Bridge  Warrants.  See  "Principal
Stockholders."
 
EQUIPMENT FINANCING
 
   
    On April 1, 1996 CRA, Inc.  ("CRA") provided the Company with $2,445,000  in
equipment  financing (the "Equipment Financing") for  the purchase from P-Com of
38 GHz radio  equipment secured  by the  equipment, the  Company's $1.0  million
letter  of credit and a $500,000 letter of credit provided by J.C. Demetree, Jr.
and Mark C. Demetree, directors of the Company, and LHC, a principal stockholder
of the  Company  (the "Indemnitors").  To  evidence its  obligations  under  the
Equipment  Financing  the  Company  executed  in  favor  of  CRA  its $2,445,000
Promissory Note  (the "Equipment  Note") which  note is  payable in  24  monthly
installments  of $92,694 with a final payment of $642,305 due April 1, 1998. The
Indemnitors also agreed to provide the Company with funds and support for up  to
$2.0 million of its obligations in the event of default on the Equipment Note or
draw against the Company's letter of credit. Pursuant to an arrangement approved
by  the Company's disinterested directors on February 16, 1996, the Company paid
to the Indemnitors,  or their  designees an aggregate  of $225,000  in cash  and
five-year  warrants to purchase  an aggregate of 325,000  shares of Common Stock
(the "Indemnity Warrants") on terms substantially similar to the Bridge Warrants
as compensation  for such  indemnity.  LHC has  assigned Indemnity  Warrants  to
purchase 125,000 shares of Common Stock to a consultant to LHC.
    
 
PIERSON & BURNETT TRANSACTIONS
 
    W.  Theodore  Pierson, Jr.,  Executive Vice  President, General  Counsel and
Secretary of the Company is  a principal in the law  firm of Pierson &  Burnett,
L.L.P.,  which regularly provides legal services to the Company. During the year
ended December 31, 1995, the Company paid Pierson & Burnett, L.L.P. $210,000 for
such services. The  Company believes  that the  terms of  its relationship  with
Pierson  & Burnett, L.L.P. are at least as  favorable to the Company as could be
obtained from an unaffiliated party. See "Management -- Executive  Compensation"
and "Principal Stockholders" for a description of
 
                                       76
<PAGE>
Mr.  Pierson's  consulting  agreement  with  the  Company  and  for  information
regarding his  share  ownership. The  Company  subleases office  space  for  its
regional  office in Washington, D.C. from  Pierson & Burnett, L.L.P. The Company
believes that the terms of its sublease are at least as favorable to the Company
as could be obtained from an unaffiliated party. See "Business -- Properties."
 
AMERICAN WIRELESS DEVELOPMENT AGREEMENT
 
    The Company is party to a  letter of intent with American Wireless  pursuant
to which the Company will fund, subject to definitive documentation, $700,000 to
$1.0  million for  research and  development in  exchange for  a first  right to
purchase American  Wireless' production  capacity  of the  new radios  and  will
receive  a per-unit fee  on radios sold  by American Wireless  to third parties.
Vernon L. Fotheringham, the Chairman  of the Company, is  a director and a  6.0%
stockholder  of American Wireless.  Mr. Fotheringham has  recused himself in all
negotiations regarding agreements between the Company and American Wireless.
 
QUESTTV INVESTMENT
 
    The Company has  a non-binding  arrangement with  Quest Computer  Television
Company,  L.L.C.  ("QuestTV")  pursuant  to which  the  Company  would purchase,
subject to, among other things, definitive documentation and consummation of the
Offerings, equity interests of QuestTV for  $1.5 million. QuestTV is seeking  to
develop   a  nationwide  network   of  franchises  offering   retail  access  to
sophisticated video  and  data transmission  and  storage technology.  T.  Allan
McArtor,  who  will become  a  director of  the Company  upon  the date  of this
Prospectus, is the president and chief executive officer of QuestTV.
 
COMMCOCCC ACQUISITION
 
   
    On July  3, 1996,  the Company  entered into  the CommcoCCC  Agreement  with
CommcoCCC which provides for the acquisition, subject to FCC approval, of 129 38
GHz  wireless  broadband authorizations  in  exchange for  16,500,000  shares of
Common Stock, or  30.5% of the  Company on  a fully diluted  basis after  giving
effect  to the  Offerings. The  stockholders of  CommcoCCC simultaneously loaned
$3.0 million to the Company, bearing interest  at the prime rate and payable  on
September  30,  1996, and  received  three-year warrants  to  purchase up  to an
aggregate of 50,000 shares of Common Stock  at a price of $15.00 per share.  The
CommcoCCC  Financing is secured by  a security interest in  all of the assets of
the Company, including a pledge of the Company's stock in Telecom. After closing
of the CommcoCCC Acquisition, the Company has agreed to nominate one  individual
designated  by  CommcoCCC's  stockholders and  acceptable  to the  Company  as a
director of the Company.
    
 
MERGER
 
   
    On June 26, 1996, Telecom, ART and a wholly-owned subsidiary of ART ("Merger
Sub") entered  into  a revised  merger  agreement, superseding  the  Old  Merger
Agreement  (the "Merger Agreement"), which provides for the Merger of Merger Sub
into Telecom. Upon completion  of the Merger, the  stockholders of Telecom  will
receive   20,073,443  shares  of  Common  Stock,   and  Telecom  will  become  a
wholly-owned subsidiary of ART and change its name to "ART Licensing Corp."  The
consummation  of the Merger  is contingent on receipt  of FCC approval therefor,
approval of the holders  of Telecom capital stock  and all ART stockholders  and
receipt of a tax opinion. The FCC has indicated that it will approve the Merger,
and  the  Company expects  to  complete it  shortly prior  to  the date  of this
Prospectus. The Merger  Agreement further  provides that  if the  Merger is  not
effective  for any reason  by May 13,  1997, the shares  of Telecom common stock
owned by ART will be surrendered  to Telecom for nominal consideration, and  the
ART Services Agreement will be amended to provide that (i) the term thereof will
be  extended to 40 years,  (ii) ART will receive, in  the event of any dividends
paid by Telecom  to its stockholders,  an amount equal  to the percentage  share
that  the ART  stockholders would have  owned of the  combined corporation after
giving effect to the Merger of such aggregate dividends, (iii) ART would have  a
right  of co-sale, subject  to FCC approval, in  accordance with such percentage
share of  the  aggregate  consideration  payable to  Telecom  and  ART  in  such
transaction  in the event of any merger or sale of substantial assets by Telecom
and (iv)  in the  event ART  agrees  to merge  into another  entity or  to  sell
substantially  all its assets to another entity, Telecom shall, upon the request
of the Company, use  its best efforts,  subject to FCC  approval, to merge  into
such  entity or sell substantially  all its assets to  such entity for aggregate
consideration equal to the percentage share of the aggregate consideration to be
paid for ART and Telecom in such transaction.
    
 
                                       77
<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 Certain Indebtedness -- The Notes."
 
CHANGE IN CONTROL PROVISIONS
 
    Certain  provisions of the Company's Certificate of Incorporation and Bylaws
may have the effect  of preventing, discouraging or  delaying any change in  the
control of the Company any may maintain the incumbency of the Board of Directors
and  management. The authorization of Preferred  Stock makes it possible for the
Board of  Directors to  issue Preferred  Stock with  voting or  other rights  or
preferences  that could impede the success of  any attempt to effect a change in
control of the  Company. In  addition, on  the effectiveness  of the  Offerings,
certain provisions of the Certificate of Incorporation will create three classes
of directors serving for staggered three-year terms and prevent any amendment to
such  provisions without the  consent of holders  of at least  two-thirds of the
then outstanding shares of Common Stock. These provisions could also impede  the
success of any attempt to effect a change in control of the Company.
 
    The  Company is subject  to Section 203 of  the Delaware General Corporation
Law ("Section 203"). Section 203 prohibits a publicly-held Delaware  corporation
from engaging in a "business combination" with an "interested stockholder" for a
period  of three  years after the  date of  the transaction in  which the person
became an interested stockholder,  unless (i) prior to  such date, the board  of
directors  of the  corporation approves either  the business  combination or the
transaction  which   resulted  in   the  stockholder   becoming  an   interested
stockholder,  (ii)  upon  consummation  of  the  transaction  which  resulted in
 
                                       78
<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."
 
                                       79
<PAGE>
                        SHARES ELIGIBLE FOR FUTURE SALE
 
GENERAL
 
    Upon  consummation  of  the Common  Stock  Offering, the  Company  will have
outstanding 37,586,498  shares of  Common  Stock (assuming  no exercise  of  the
Underwriters'  over-allotment  option and  options  or warrants  after  June 28,
1996). Of these  shares, the  7,500,000 shares being  sold in  the Common  Stock
Offering  will be freely tradable without  restriction under the Securities Act,
unless purchased by "affiliates" of the Company.
 
    The  remaining  30,086,498   shares  of  Common   Stock  held  by   existing
stockholders  are "restricted" shares under  the Securities Act (the "Restricted
Shares"), all of which  are also subject to  certain lock-up agreements  between
certain  stockholders and  the Representatives  (as defined).  Beginning 90 days
after the date of this Prospectus,  10,013,055 shares will become available  for
immediate  sale to the public market subject  to certain volume and other resale
restrictions pursuant  to Rule  144  promulgated under  the Securities  Act,  as
described  below, unless such shares  are registered. See "Registration Rights."
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. In addition,  under a proposal  currently pending before
the Securities and Exchange Commission, the date on which shares of Common Stock
become available for sale under Rule 144 may be significantly accelerated.
 
    As of June 28, 1996, an aggregate  of 4,044,868 shares of Common Stock  will
be  subject to  outstanding options and  warrants and an  aggregate of 1,007,268
shares are  reserved  for  future  issuance pursuant  to  the  Company's  Equity
Incentive  Plan and Directors  Plan (collectively, the "Plans").  As of June 28,
1996, 639,302 of such shares  were vested, and, 180  days following the date  of
this Prospectus, an additional 59,109 of such shares will be vested. The Company
intends  to file a Registration Statement on  Form S-8 to register the shares of
Common Stock to be issued and issuable pursuant to the Plans. Thereafter, shares
of Common Stock issued under the Plans will be available for sale in the  public
market  upon vesting of such shares, subject,  with respect to affiliates of the
Company, to certain volume limitations under Rule 144.
 
    In general, under Rule 144 as  currently in effect, beginning 90 days  after
the  Effective Date, a person  (or persons whose shares  are aggregated) who has
beneficially owned Restricted Shares for at least two years, will be entitled to
sell in any  three-month period  a number  of shares  that does  not exceed  the
greater  of (i)  1% of  the number  of shares  of Common  Stock then outstanding
(approximately 375,865  shares  immediately  after  the  Common  Stock  Offering
assuming  no exercise of  the Underwriters' over-allotment  option) and (ii) the
average weekly  trading volume  of  the Company's  Common  Stock in  the  Nasdaq
National Market during the four calendar weeks immediately preceding the date on
which  notice of the sale is filed  with the Securities and Exchange Commission.
Sales pursuant  to Rule  144 are  subject to  certain requirements  relating  to
manner  of sale, notice and availability of current public information about the
Company. A person (or persons whose shares are aggregated) who is not deemed  to
have been an affiliate of the Company at any time during the 90 days immediately
preceding the sale and who has beneficially owned Restricted Shares for at least
three  years is  entitled to  sell such shares  pursuant to  Rule 144(k) without
regard to the limitations and requirements described above.
 
    All holders  of  the Company's  Common  Stock, as  well  as all  holders  of
warrants  or options to purchase Common Stock, have agreed not to sell, offer to
sell, contract to sell or otherwise sell, dispose of, loan, pledge or grant  any
rights  with respect to any  shares of Common Stock,  any options or warrants to
purchase Common Stock, or any securities convertible or exchangeable for  Common
Stock,  owned directly by such holders or  with respect to which they have power
of disposition  for a  period of  180 days  after the  date of  this  Prospectus
without   the  prior  written  consent   of  Montgomery  Securities.  Montgomery
Securities may, in its sole discretion  and at any time without notice,  release
all  or any portion  of the securities  subject to these  lock-up agreements. In
addition, the Company has agreed not to sell, offer to sell, contract to sell or
otherwise sell or dispose of any shares of Common Stock or any rights to acquire
 
                                       80
<PAGE>
Common Stock, other than  pursuant to the Restated  Equity Incentive Plan,  upon
exercise  of  outstanding  warrants and  options  or pursuant  to  the CommcoCCC
Agreement for a period of 180 days after the date of this Prospectus without the
prior consent of Montgomery Securities. See "Underwriting."
 
    Prior to the Common Stock Offering, there has been no public market for  the
Common  Stock and there can be no assurance that a significant public market for
the Common Stock will develop or  be sustained after the Common Stock  Offering.
Sales  of  substantial  amounts  of  Common Stock  in  the  public  market could
adversely affect  the market  price of  the Common  Stock and  could impair  the
Company's  future  ability  to raise  capital  through  the sale  of  its equity
securities.
 
REGISTRATION RIGHTS
 
   
    Under the terms of  an amended and  restated registration rights  agreement,
dated  as  of  July  3,  1996,  among  the  Company,  Telecom,  their respective
stockholders and  the holders  of the  Bridge Warrants,  Indemnity Warrants  and
CommcoCCC  Warrants (as amended, the "Registration Rights Agreement"), following
the consummation of  the Offerings,  such stockholders  and the  holders of  the
Bridge  Warrants, Indemnity Warrants and CommcoCCC Warrants, who are the holders
of an aggregate 31,561,498 shares of Common Stock on a fully-diluted basis  (the
"Registrable  Securities"),  will  be  entitled to  certain  demand  rights with
respect to  the  registration  of  such shares  under  the  Securities  Act.  In
addition,  under the Registration  Rights Agreement, if  the Company proposes to
register any of  its securities  under the Securities  Act, either  for its  own
account  or the  account of other  security holders, the  holders of Registrable
Securities are  entitled to  notice of  such registration  and are  entitled  to
include  their Registrable Securities in  any such registration; PROVIDED, that,
among other things,  that the underwriters  have the right,  subject to  certain
limitations, to limit the number of such shares included therein.
    
 
    Upon the consummation of the CommcoCCC Acquisition, the 16,500,000 shares to
be  issued  in connection  therewith will  also be  subject to  the Registration
Rights Agreement.
 
                                       81
<PAGE>
                      DESCRIPTION OF CERTAIN INDEBTEDNESS
 
THE NOTES
 
    Concurrently with  the  Common  Stock Offering,  the  Company  is  offering,
pursuant  to  a separate  prospectus,         Units,  each consisting  of $1,000
principal amount at maturity of the Notes and   Warrants to purchase      shares
of  Common  Stock  of the  Company,  sufficient  to generate  gross  proceeds of
$175,000,000 in the Unit Offering.  The Warrants, when exercised, would  entitle
the  holders thereof to purchase  shares of Common Stock  representing 5% of the
Common Stock of the Company on a fully diluted basis after giving effect to  the
Offerings.  The  Common  Stock  Offering  is  conditioned  upon  the  successful
consummation of the Unit  Offering. The yield-to-maturity of  the Notes will  be
   % (computed on a semiannual bond basis) calculated from               , 1996.
Cash  interest will not  accrue on the Notes  prior to                   , 2001,
however the  principal  amount of  the  Notes  will accrete  from  the  original
principal  amount at issuance at a rate of    % per annum until                ,
2001. Thereafter, cash interest will accrue at a rate of    % per annum, payable
semiannually in  arrears. The  Notes will  be redeemable  at the  option of  the
Company on or after               , 2001, and the holders of the Notes will have
the  right to  require the Company  to repurchase  all or part  of such holders'
Notes in the event of certain events involving a change of control with  respect
to, or certain sales of assets by, the Company and its subsidiaries.
 
    Subject  to certain exceptions and qualifications, the Indenture will, among
other things, restrict the  ability of the Company  and its subsidiaries to  (i)
incur  indebtedness, (ii) pay dividends and 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 businesses other than  those permitted by the Indenture  or
(vi)  sell certain assets. In addition, the  Indenture will limit the ability of
the Company  to consolidate,  merge or  sell  all or  substantially all  of  its
assets.
 
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
 
                                       82
<PAGE>
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  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, or  merging and  will  limit investments  and  assets 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 dependent 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.
 
                                       83
<PAGE>
                                  UNDERWRITING
 
    The underwriters named below (the "Underwriters"), represented by Montgomery
Securities, Merrill Lynch, Pierce, Fenner & Smith Incorporated ("Merrill Lynch")
and   Deutsche   Morgan   Grenfell/C.   J.   Lawrence   Inc.   (together,    the
"Representatives"),  have severally agreed, subject  to the terms and conditions
set forth in the Underwriting Agreement, to purchase from the Company the number
of shares of Common Stock indicated below opposite their respective names at the
initial public offering price  less the underwriting discount  set forth on  the
cover  page of  this Prospectus.  The Underwriting  Agreement provides  that the
obligations of  the Underwriters  are subject  to certain  terms and  conditions
precedent  and  that the  Underwriters  are committed  to  purchase all  of such
shares, if any are purchased.
 
<TABLE>
<CAPTION>
                                                                   NUMBER OF
                  UNDERWRITERS                                      SHARES
                                                                   ---------
 
<S>                                                                <C>
Montgomery Securities............................................
Merrill Lynch, Pierce, Fenner & Smith
           Incorporated..........................................
Deutsche Morgan Grenfell/C. J. Lawrence Inc......................
                                                                   ---------
              Total..............................................  7,500,000
                                                                   ---------
                                                                   ---------
</TABLE>
 
    The Representatives have advised the Company that the Underwriters initially
propose to offer the Common  Stock to the public on  the terms set forth on  the
cover  page of this Prospectus. The Underwriters may allow to selected dealers a
concession of not more than $        per share, and the Underwriters may  allow,
and  any such dealers may reallow,  a concession of not more  than $         per
share to certain other dealers. After the initial public offering, the price and
concessions and reallowances to dealers  may be changed by the  Representatives.
The   Common  Stock  is  offered  subject  to  receipt  and  acceptance  by  the
Underwriters and  to certain  other conditions,  including the  right to  reject
orders in whole or in part.
 
    The  Company has granted  an option to  the Underwriters, exercisable during
the 30-day period after the date of this Prospectus, to purchase up to a maximum
of 1,125,000 additional shares of Common Stock to cover over-allotments, if any,
at the same price per share as  the initial 7,500,000 shares to be purchased  by
the  Underwriters. To the extent the  Underwriters exercise this option, each of
the Underwriters will be committed,  subject to certain conditions, to  purchase
such  additional shares in approximately the same proportion as set forth in the
above table.
 
    The Underwriting Agreement contains certain covenants of indemnity among the
Underwriters and  the  Company  against  certain  civil  liabilities,  including
liability under the Securities Act of 1933, as amended (the "Securities Act").
 
    Concurrently  with  the  Common  Stock Offering,  the  Company  is offering,
pursuant to a separate prospectus,       Units in the Unit Offering.  Montgomery
Securities and Merrill Lynch are acting as underwriters in the Unit 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.
 
    All holders of the Company's Common Stock prior to this offering, as well as
all  holders of options, warrants or other rights to purchase Common Stock, have
agreed not to sell, offer to sell,  contract to sell or otherwise sell,  dispose
of, loan, pledge or grant any rights with respect to any shares of Common Stock,
any  options or warrants to purchase Common Stock, or any securities convertible
or exchangeable for Common Stock, owned directly by such holders or with respect
to which they have power of disposition for a period of 180 days after the  date
of  this Prospectus without the prior  written consent of Montgomery Securities.
Montgomery Securities  may, in  its  sole discretion  and  at any  time  without
notice,  release all or any  portion of the securities  subject to these lock-up
agreements. In addition, the
 
                                       84
<PAGE>
Company has agreed not  to sell, offer  to sell, contract  to sell or  otherwise
sell  or dispose of any  shares of Common Stock or  any rights to acquire Common
Stock, other  than pursuant  to  the Equity  Incentive  Plan, upon  exercise  of
outstanding  options and warrants or pursuant  to the CommcoCCC Agreement, for a
period of  180  days after  the  Effective Date  without  the prior  consent  of
Montgomery Securities.
 
    The  Representatives have advised  the Company that  the Underwriters do not
intend to confirm sales to any  accounts over which they exercise  discretionary
authority  in  excess of  5% of  the number  of shares  of Common  Stock offered
hereby.
 
    Prior to the Common Stock Offering, there has been no public market for  the
Common  Stock of  the Company. Consequently,  the initial  public offering price
will  be   determined   through  negotiations   among   the  Company   and   the
Representatives. Among the factors to be considered in such negotiations will be
the  history of,  and prospects for,  the Company  and the industry  in which it
competes, an assessment of  the Company's management, the  present state of  the
Company's  development, the  prospects for future  earnings of  the Company, the
prevailing market conditions at  the time of the  Common Stock Offering,  market
valuations of publicly traded companies that the Company and the Representatives
believe  to be comparable to the Company, and other factors deemed relevant. See
"Risk Factors -- Absence of Public Market; Possible Volatility of Stock Price."
 
                                 LEGAL MATTERS
 
    The validity of the issuance of  shares of Common Stock offered hereby  will
be passed upon for the Company by Hahn & Hessen LLP, New York, New York. Certain
legal  matters in connection with the Common  Stock 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
 
                                       85
<PAGE>
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.
 
                                       86
<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 Telecommunication 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.
 
                                       87
<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 intra-LATA calls can also 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.
 
                                       88
<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 30 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 communication 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.
 
                                       89
<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.
 
                                       90
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                            ---------
<S>                                                                                                         <C>
Advanced Radio Technologies Corporation
  Unaudited Pro Forma:
    Unaudited Pro Forma Condensed Balance Sheets as of December 31, 1995 and March 31, 1996...............     F-3
    Unaudited Pro Forma Condensed Balance Sheets -- Supplementary Combining Balance Sheet Data as of
     December 31, 1995 and March 31, 1996.................................................................     F-4
    Unaudited Pro Forma Condensed Statement of Operations for the three months ended March 31, 1996 and
     for the year ended December 31, 1995.................................................................     F-5
    Notes to Unaudited Pro Forma Condensed Financial Statements...........................................     F-6
  Historical:
    Report of Independent Accountants.....................................................................     F-8
    Balance Sheets as of December 31, 1995 and 1994.......................................................     F-9
    Statements of Operations for the years ended December 31, 1995 and 1994, for the period from August
     23, 1993 (date of inception) to December 31, 1993 and cumulative for the period from August 23, 1993
     (date of inception) to December 31, 1995.............................................................    F-10
    Statements of Stockholders' Equity (Deficit) for the years ended December 31, 1995 and 1994, for the
     period from August 23, 1993 (date of inception) to December 31, 1993 and cumulative for the period
     from August 23, 1993 (date of inception) to December 31, 1995........................................    F-11
    Statements of Cash Flows for the years ended December 31, 1995 and 1994, for the period from August
     23, 1993 (date of inception) to December 31, 1993 and cumulative for the period from August 23, 1993
     (date of inception) to December 31, 1995.............................................................    F-12
    Notes to Financial Statements.........................................................................    F-13
    Unaudited Interim Condensed Balance Sheets as of March 31, 1996 and 1995..............................    F-24
    Unaudited Interim Condensed Statements of Operations for the three months ended March 31, 1996 and
     1995.................................................................................................    F-25
    Unaudited Interim Condensed Statements of Cash Flows for the three months ended March 31, 1996 and
     1995.................................................................................................    F-26
    Notes to Unaudited Interim Condensed Financial Statements.............................................    F-27
 
Advanced Radio Telecom Corp.
 
  Historical:
    Report of Independent Accountants.....................................................................    F-30
    Balance Sheet as of December 31, 1995.................................................................    F-31
    Statement of Operations for the period from March 28, 1995 (date of inception) to December 31, 1995...    F-32
    Statement of Stockholders' Deficit for the period from March 28, 1995 (date of inception) to December
     31, 1995.............................................................................................    F-33
    Statement of Cash Flows for the period from March 28, 1995 (date of inception) to December 31, 1995...    F-34
    Notes to Financial Statements.........................................................................    F-35
    Unaudited Interim Condensed Balance Sheet as of March 31, 1996........................................    F-47
    Unaudited Interim Condensed Statement of Operations for the three months ended March 31, 1996.........    F-48
    Unaudited Interim Condensed Statement of Stockholders' Equity (Deficit) for the three months ended
     March 31, 1996.......................................................................................    F-49
    Unaudited Interim Condensed Statement of Cash Flows for the three months ended March 31, 1996.........    F-50
    Notes to Unaudited Interim Condensed Financial Statements.............................................    F-51
</TABLE>
 
                                      F-1
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
               UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS
 
    The  following  unaudited  pro  forma  condensed  financial  statements  are
presented as if all of the following transactions had occurred: (i) the March 8,
1996 issuance of the Bridge Notes in connection with the Bridge Financing;  (ii)
the  receipt of $2,220,000 in  cash proceeds from the  issuance of the Equipment
Note and Indemnity Warrants  in connection with  the Equipment Financing,  after
deducting  related expenses of $225,000; (iii) the receipt of $3,000,000 in cash
proceeds from the issuance of the CommcoCCC Notes and the CommcoCCC Warrants  in
connection  with  the  CommcoCCC Financing;  (iv)  the Conversion;  and  (v) the
Merger, including the issuance of ART  Common Stock to Telecom stockholders  and
the cancellation of all outstanding Telecom common stock.
 
    The following unaudited pro forma as adjusted condensed financial statements
reflect  further adjustments assuming  (i) the sale by  the Company of 7,500,000
shares of Common Stock offered in the Common Stock Offering based on an  assumed
initial  public offering price of  $9.00 per share and  the Units offered in the
Unit Offering  assuming $175,000,000  in  gross proceeds,  in each  case,  after
deducting  the estimated underwriting  discount and offering  expenses; (ii) the
receipt and application of the net proceeds therefrom to repay the Bridge  Notes
and  the CommcoCCC Notes and  to acquire the 50%  ownership interest of ART West
held by Extended for $6.0 million in cash and the DCT Assets for $3.6 million in
cash; and  (iii) the  consummation of  the  acquisition by  the Company  of  the
CommcoCCC Assets in exchange for 16,500,000 shares of Common Stock at an assumed
value of $9.00 per share.
 
    All  such  transactions are  reflected as  if  they had  occurred as  of the
beginning of  the  respective periods  for  the unaudited  pro  forma  condensed
statements  of  operations and  at  the respective  balance  sheet date  for the
unaudited pro forma condensed balance sheet.
 
    These unaudited pro forma condensed  financial statements were derived  from
and  should  be  read in  conjunction  with  the audited  and  unaudited interim
condensed financial statements of ART and Telecom and the related notes thereto,
included elsewhere herein. In management's opinion, all adjustments necessary to
reflect the foregoing and related transactions have been made.
 
    The unaudited pro forma condensed  financial statements are not  necessarily
indicative  of what the actual financial position or results of operations would
have been assuming that the  transactions described in the preceding  paragraphs
had occurred on the dates indicated, nor does it purport to represent the future
financial position or results of operations of the Company.
 
                                      F-2
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                  UNAUDITED PRO FORMA CONDENSED BALANCE SHEETS
 
                                     ASSETS
<TABLE>
<CAPTION>
                         AS OF
                      DECEMBER 31,  AS OF MARCH
                          1995        31, 1996
                      ------------  ------------
                       HISTORICAL    HISTORICAL
                      COMBINED (A)  COMBINED (A)
                      ------------  ------------
<S>                   <C>           <C>
Current assets:
  Cash and cash
   equivalents......  $ 633,654     $ 3,024,161
  Other current
   assets...........     52,325          61,226
                      ------------  ------------
    Total current
     assets.........    685,979       3,085,387
Property and
 equipment, net.....  3,581,561       6,380,895
Equity
 investments........    285,000         285,000
FCC licenses........  4,235,734       4,235,734
Deferred financing
 costs..............    778,897         681,692
Equipment and other
 deposits...........    284,012         344,417
Other assets........     25,376          23,212
                      ------------  ------------
                      $9,876,559    $15,036,337
                      ------------  ------------
                      ------------  ------------
 
      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable
   and accrued
   liabilities......  $3,694,489    $ 4,213,517
  CommcoCCC Notes...                    --
                      ------------  ------------
    Total current
     liabilities....  3,694,489       4,213,517
Convertible notes
 payable............  4,950,000
Note payable to
 EMI................  1,500,000       1,500,000
Bridge notes
 payable............     --           3,983,082
Equipment financing
 note payable.......     --             --
Senior discount
 notes..............     --             --
Deferred tax
 liability..........     --             --
                      ------------  ------------
    Total
     liabilities....  10,144,489      9,696,599
                      ------------  ------------
Redeemable Preferred
 Stock..............     44,930         --
                      ------------  ------------
Stockholders'
 equity:
  Preferred stock,
   par..............        488             921
  Common stock,
   par..............     25,304          28,127
  Additional paid-in
   capital..........  3,031,405      19,375,335
  Accumulated
   deficit..........  (3,370,057  ) (14,064,645)
                      ------------  ------------
    Total
     stockholders'
     equity.........   (312,860   )   5,339,738
                      ------------  ------------
                      $9,876,559    $15,036,337
                      ------------  ------------
                      ------------  ------------
 
<CAPTION>
 
                         PRO FORMA                      OFFERING       PRO FORMA
                      ADJUSTMENTS (B)    PRO FORMA    ADJUSTMENTS (C) AS ADJUSTED
                      ---------------   ------------  -------------   -----------
<S>                   <C>               <C>           <C>             <C>
Current assets:
  Cash and cash
   equivalents......    $3,000,000(2)
                        $2,220,000(3)   $  8,244,161  62,35$7,474(1)
                                                      168,667,526(2)
                                                      (8,000,000)(3)
                                                      (6,000,000)(5)
                                                      (3,600,000)(6)
                                                      (3,000,000)(4)  218$,669,161
  Other current
   assets...........                          61,226                       61,226
                      ---------------   ------------  -------------   -----------
    Total current
     assets.........     5,220,000         8,305,387  210,425,000     218,730,387
Property and
 equipment, net.....                       6,380,895                    6,380,895
Equity
 investments........                         285,000    (285,000)(5)      --
FCC licenses........                       4,235,734  201,990,000(4)
                                                       6,285,000(5)
                                                       3,600,000(6)   216,110,734
Deferred financing
 costs..............       175,899(3)        857,591    (189,749)(1)
                                                       6,332,474(2)     7,000,316
Equipment and other
 deposits...........                         344,417                      344,417
Other assets........                          23,212                       23,212
                      ---------------   ------------  -------------   -----------
                        $5,395,899      $ 20,432,236  428,1$57,725    448$,589,961
                      ---------------   ------------  -------------   -----------
                      ---------------   ------------  -------------   -----------
      LIABILITIES AN
Current liabilities:
  Accounts payable
   and accrued
   liabilities......    $               $  4,213,517       $            4$,213,517
  CommcoCCC Notes...     2,975,000(2)      2,975,000  (2,975,000)(3)      --
                      ---------------   ------------  -------------   -----------
    Total current
     liabilities....     2,975,000         7,188,517  (2,975,000)       4,213,517
Convertible notes
 payable............       --                --                           --
Note payable to
 EMI................                       1,500,000                    1,500,000
Bridge notes
 payable............                       3,983,082  (3,983,082)(3)
Equipment financing
 note payable.......     1,911,439(3)      1,911,439                    1,911,439
Senior discount
 notes..............                         --       159,800,000(2)  159,800,000
Deferred tax
 liability..........                                  50,490,000(4)    50,490,000
                      ---------------   ------------  -------------   -----------
    Total
     liabilities....     4,886,439        14,583,038  203,331,918     217,914,956
                      ---------------   ------------  -------------   -----------
Redeemable Preferred
 Stock..............                         --           --              --
                      ---------------   ------------  -------------   -----------
Stockholders'
 equity:
  Preferred stock,
   par..............          (921)(1)       --
  Common stock,
   par..............         1,959(1)         30,086       7,500(1)       --
                                                          16,500(4)        54,086
  Additional paid-in
   capital..........        (1,038)(1)
                            25,000(2)
                           484,460(3)     19,883,757  62,160,225(1)
                                                      15,200,000(2)
                                                      148,483,500(4)  245,727,482
  Accumulated
   deficit..........                     (14,064,645) (1,041,918)(3)  (15,106,563)
                      ---------------   ------------  -------------   -----------
    Total
     stockholders'
     equity.........       509,460         5,849,198  224,825,807     230,675,005
                      ---------------   ------------  -------------   -----------
                        $5,395,899      $ 20,432,236  428,1$57,725    448$,589,961
                      ---------------   ------------  -------------   -----------
                      ---------------   ------------  -------------   -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                      F-3
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                  UNAUDITED PRO FORMA CONDENSED BALANCE SHEETS
                  SUPPLEMENTARY COMBINING BALANCE SHEET DATA:
<TABLE>
<CAPTION>
                                           AS OF DECEMBER 31, 1995
                      -----------------------------------------------------------------
                                                 HISTORICAL
                      -----------------------------------------------------------------
                      ADVANCED RADIO   ADVANCED RADIO
                       TECHNOLOGIES       TELECOM                           HISTORICAL
                      CORPORATION (D)    CORP. (E)      ELIMINATIONS (F)     COMBINED
                      --------------   --------------   ----------------   ------------
<S>                   <C>              <C>              <C>                <C>
Current assets:
  Cash and cash
   equivalents......   $     6,069      $    627,585                       $    633,654
  Due from ART......       --                738,680      $  (738,680)          --
  Other current
   assets...........       --                 52,325                             52,325
                      --------------   --------------   ----------------   ------------
    Total current
     assets.........         6,069         1,418,590         (738,680)          685,979
Note receivable from
 Telecom............     5,000,000          --             (5,000,000)          --
Property and
 equipment, net.....         1,723         3,579,838                          3,581,561
Equity investments..       285,000          --                                  285,000
FCC licenses........         8,913         4,226,821                          4,235,734
Deferred financing
 costs, net.........       457,543           321,354                            778,897
Equipment and other
 deposits...........       --                284,012                            284,012
Investment in ART...       --               --                                  --
Other assets........        25,376          --                                   25,376
                      --------------   --------------   ----------------   ------------
                       $ 5,784,624      $  9,830,615      $(5,738,680)     $  9,876,559
                      --------------   --------------   ----------------   ------------
                      --------------   --------------   ----------------   ------------
                    LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable
   and accrued
   liabilities......   $   243,952      $  3,450,537                       $  3,694,489
  Due to Telecom....       738,680          --            $  (738,680)          --
  Commco Notes......       --               --                                  --
                      --------------   --------------   ----------------   ------------
    Total current
     liabilities....       982,632         3,450,537         (738,680)        3,694,489
Convertible notes
 payable............     4,950,000          --                                4,950,000
Losses in excess of
 equity investment..       211,543          --               (211,543)          --
Note payable to
 ART................       --              5,000,000       (5,000,000)          --
Note payable to
 EMI................       --              1,500,000                          1,500,000
Bridge notes
 payable............       --               --                                  --
Equipment financing
 note payable.......       --               --                                  --
Senior discount
 notes..............       --               --                                  --
                      --------------   --------------   ----------------   ------------
    Total
     liabilities....     6,144,175         9,950,537       (5,950,223)       10,144,489
                      --------------   --------------   ----------------   ------------
Redeemable Preferred
 Stock..............        44,930          --                                   44,930
                      --------------   --------------   ----------------   ------------
Stockholders'
 equity:
  Preferred stock,
   par..............       --                    488                                488
  Common stock,
   par..............        10,013            15,291                             25,304
  Additional paid-in
   capital..........       988,375         2,845,372         (802,002)
                                                                 (340)        3,031,405
  Accumulated
   deficit..........    (1,402,869)       (2,981,073)       1,013,885        (3,370,057)
                      --------------   --------------   ----------------   ------------
    Total
     stockholders'
     equity
     (deficit)......      (404,481)         (119,922)         211,543          (312,860)
                      --------------   --------------   ----------------   ------------
                       $ 5,784,624      $  9,830,615      $(5,738,680)     $  9,876,559
                      --------------   --------------   ----------------   ------------
                      --------------   --------------   ----------------   ------------
 
<CAPTION>
                                          AS OF MARCH 31, 1996
                      -------------------------------------------------------------
 
                                               HISTORICAL
                      -------------------------------------------------------------
                                          ADVANCED
                      ADVANCED RADIO       RADIO
                       TECHNOLOGIES       TELECOM                       HISTORICAL
                      CORPORATION (D)    CORP. (E)    ELIMINATIONS (F)   COMBINED
                      ---------------   ------------  ---------------   -----------
<S>                   <C>               <C>           <C>               <C>
Current assets:
  Cash and cash
   equivalents......    $    5,970      $3,018,191                        3$,024,161
  Due from ART......       --              498,100      (49$8,100)          --
  Other current
   assets...........       --               61,226                           61,226
                      ---------------   ------------  ---------------   -----------
    Total current
     assets.........         5,970       3,577,517      (498,100)         3,085,387
Note receivable from
 Telecom............       --               --                              --
Property and
 equipment, net.....         1,292       6,379,603                        6,380,895
Equity investments..     3,242,401          --        (2,957,401)           285,000
FCC licenses........         8,913       4,226,821                        4,235,734
Deferred financing
 costs, net.........       --              681,692                          681,692
Equipment and other
 deposits...........       --              344,417                          344,417
Investment in ART...       --               44,930       (44,930)           --
Other assets........        23,212          --                               23,212
                      ---------------   ------------  ---------------   -----------
                        $3,281,788      $15,254,980   (3,50$0,431)       15$,036,337
                      ---------------   ------------  ---------------   -----------
                      ---------------   ------------  ---------------   -----------
 
Current liabilities:
  Accounts payable
   and accrued
   liabilities......         2,500      $4,211,017                        4$,213,517
  Due to Telecom....       498,100          --          (49$8,100)          --
  Commco Notes......       --               --                              --
                      ---------------   ------------  ---------------   -----------
    Total current
     liabilities....       500,600       4,211,017      (498,100)         4,213,517
Convertible notes
 payable............       --               --                              --
Losses in excess of
 equity investment..                        --                              --
Note payable to
 ART................                        --                              --
Note payable to
 EMI................       --            1,500,000                        1,500,000
Bridge notes
 payable............       --            3,983,082                        3,983,082
Equipment financing
 note payable.......       --               --                              --
Senior discount
 notes..............       --               --                              --
                      ---------------   ------------  ---------------   -----------
    Total
     liabilities....       500,600       9,694,099      (498,100)         9,696,599
                      ---------------   ------------  ---------------   -----------
Redeemable Preferred
 Stock..............        44,930          --           (44,930)           --
                      ---------------   ------------  ---------------   -----------
Stockholders'
 equity:
  Preferred stock,
   par..............       --                  921                              921
  Common stock,
   par..............        10,013          18,114                           28,127
  Additional paid-in
   capital..........     7,783,889      19,189,302    (7,597,856)        19,375,335
 
  Accumulated
   deficit..........    (5,057,644)     (13,647,456 )  4,640,455        (14,064,645)
                      ---------------   ------------  ---------------   -----------
    Total
     stockholders'
     equity
     (deficit)......     2,736,258       5,560,881    (2,957,401)         5,339,738
                      ---------------   ------------  ---------------   -----------
                        $3,281,788      $15,254,980   (3,50$0,431)       15$,036,337
                      ---------------   ------------  ---------------   -----------
                      ---------------   ------------  ---------------   -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                      F-4
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
             UNAUDITED PRO FORMA CONDENSED STATEMENT OF OPERATIONS
<TABLE>
<CAPTION>
                                                      THREE MONTHS ENDED MARCH 31, 1996
                         --------------------------------------------------------------------------------------------
                                                   HISTORICAL
                         --------------------------------------------------------------
                          ADVANCED RADIO   ADVANCED RADIO
                           TECHNOLOGIES       TELECOM                                       PRO FORMA
                         CORPORATION (D)     CORP. (E)     ELIMINATIONS (F)  COMBINED    ADJUSTMENTS (B)   PRO FORMA
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
<S>                      <C>               <C>             <C>              <C>          <C>              <C>
Operating revenue......    $                $      9,620                    $     9,620                   $     9,620
                         ----------------  --------------                   -----------                   -----------
Expenses:
  General and
   administrative
   (H).................          24,939        8,889,364                      8,914,303                     8,914,303
  Market development
   (I).................         --             1,150,063                      1,150,063                     1,150,063
  Research &
   development.........         --               419,418                        419,418                       419,418
Depreciation and
 amortization..........           2,595           86,684                         89,279                        89,279
  Interest, net........             671          130,474                        131,145     $ 198,425(4)
                                                                                              157,316(5)
                                                                                               86,360(6)
                                                                                              (44,507)(7)     528,739
                         ----------------  --------------                   -----------  ---------------  -----------
    Total expenses.....          28,205       10,676,003                     10,704,208       397,594      11,101,802
Equity loss in
 Telecom...............       3,626,570          --          $(3,626,570)       --                            --
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
Pretax loss............       3,654,775       10,666,383      (3,626,570)    10,694,588       397,594      11,092,182
Deferred tax benefit...         --               --                             --                            --
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
      Net loss.........    $  3,654,775     $ 10,666,383     ($3,626,570)   $10,694,588     $ 397,594     $11,092,182
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
                         ----------------  --------------  ---------------  -----------  ---------------  -----------
Pro forma net loss per
 share of common stock
 (G)...................    $       0.12                                                                   $      0.35
                         ----------------                                                                 -----------
                         ----------------                                                                 -----------
Pro forma weighted
 average number of
 shares of Common Stock
 outstanding (G).......      31,651,605                                                                    31,651,605
                         ----------------                                                                 -----------
                         ----------------                                                                 -----------
 
<CAPTION>
 
                             OFFERING       PRO FORMA
                         ADJUSTMENTS (C)   AS ADJUSTED
                         ----------------  ------------
<S>                      <C>               <C>
Operating revenue......                     $    9,620
                                           ------------
Expenses:
  General and
   administrative
   (H).................                      8,914,303
  Market development
   (I).................                      1,150,063
  Research &
   development.........                        419,418
Depreciation and
 amortization..........    $  1,350,692(8)   1,439,971
  Interest, net........
 
                               (264,658)(3)
                                (86,360)(3)
                              5,811,579(7)   5,989,300
                         ----------------  ------------
    Total expenses.....       6,811,253     17,913,055
Equity loss in
 Telecom...............                         --
                         ----------------  ------------
Pretax loss............       6,811,253     17,903,435
Deferred tax benefit...        (459,236)(8)    (459,236)
                         ----------------  ------------
      Net loss.........    $  6,352,017     $17,444,199
                         ----------------  ------------
                         ----------------  ------------
Pro forma net loss per
 share of common stock
 (G)...................                     $     0.31
                                           ------------
                                           ------------
Pro forma weighted
 average number of
 shares of Common Stock
 outstanding (G).......                     55,651,605
                                           ------------
                                           ------------
</TABLE>
<TABLE>
<CAPTION>
                                       YEAR ENDED DECEMBER 31, 1995
                      --------------------------------------------------------------
                                                HISTORICAL
                      --------------------------------------------------------------
                      ADVANCED RADIO     ADVANCED
                       TECHNOLOGIES    RADIO TELECOM
                      CORPORATION (D)    CORP. (E)     ELIMINATIONS (F)    COMBINED
                      --------------   -------------   ----------------   ----------
<S>                   <C>              <C>             <C>                <C>
Operating revenue...    $  --           $     5,793                       $   5,793
                      --------------   -------------                      ----------
Expenses:
  General and
   administrative
   (G)..............       204,937        2,706,336                       2,911,273
  Market
   development......       --               191,693                         191,693
  Depreciation and
   amortization.....        10,378            5,306                          15,684
  Interest, net.....        38,455           83,531                         121,986
                      --------------   -------------                      ----------
    Total
     expenses.......       253,770        2,986,866                       3,240,636
Equity loss in
 Telecom............     1,013,885                       $(1,013,885)        --
                      --------------   -------------   ----------------   ----------
Pretax Loss.........     1,267,655        2,981,073       (1,013,885)     3,234,843
Deferred tax
 benefit............       --               --                               --
                      --------------   -------------   ----------------   ----------
      Net loss......    $1,267,655      $ 2,981,073      $(1,013,885)     $3,234,843
                      --------------   -------------   ----------------   ----------
                      --------------   -------------   ----------------   ----------
Pro forma net loss
 per share of Common
 Stock (G)..........    $     0.04
                      --------------
                      --------------
Pro forma weighted
 average number of
 shares of Common
 Stock outstanding
 (G)................    31,651,605
                      --------------
                      --------------
 
<CAPTION>
 
                         PRO FORMA                     OFFERING        PRO FORMA
                      ADJUSTMENTS (B)   PRO FORMA   ADJUSTMENTS (C)   AS ADJUSTED
                      ---------------   ----------  ---------------   -----------
<S>                   <C>               <C>         <C>               <C>
Operating revenue...                    $   5,793       $               $5,793
                                        ----------  ---------------   -----------
Expenses:
  General and
   administrative
   (G)..............                    2,911,273                     2,911,273
  Market
   development......                      191,693                      191,693
  Depreciation and
   amortization.....                       15,684    5,402,768(8)     5,418,452
  Interest, net.....  $1,019,145(4)
                         673,534(5)
                         270,438(6)
                        (110,828)(7)    1,974,275   (1,019,145)(3)
                                                      (270,438)(3)
                                                    23,246,316(7)     23,931,008
                      ---------------   ----------  ---------------   -----------
    Total
     expenses.......   1,852,289        5,092,925   27,359,501        32,452,426
Equity loss in
 Telecom............                       --                            --
                      ---------------   ----------  ---------------   -----------
Pretax Loss.........   1,852,289        5,087,132   27,359,501        32,446,633
Deferred tax
 benefit............      --                        (1,836,941)(8)    (1,836,941)
                      ---------------   ----------  ---------------   -----------
      Net loss......  $1,852,289        $5,087,132  25,5$22,560       30$,609,692
                      ---------------   ----------  ---------------   -----------
                      ---------------   ----------  ---------------   -----------
Pro forma net loss
 per share of Common
 Stock (G)..........                    $    0.16                       $ 0.55
                                        ----------                    -----------
                                        ----------                    -----------
Pro forma weighted
 average number of
 shares of Common
 Stock outstanding
 (G)................                    31,651,605                    55,651,605
                                        ----------                    -----------
                                        ----------                    -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                      F-5
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
          NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS
 
(A)  Represents the historical  combined balance sheets of  ART and Telecom. See
    supplementary combining balance sheet data on page F-4.
 
(B) Pro forma adjustments:
 
    (1) Conversion of Telecom serial preferred stock into Telecom common  stock,
       issuance of ART Common Stock to Telecom stockholders, and cancellation of
       the  outstanding Telecom  common stock  and the  ART Redeemable Preferred
       Stock in connection with the Merger.
 
    (2) Proceeds of $3,000,000 in cash from the CommcoCCC Financing in  exchange
       for the CommcoCCC Notes and CommcoCCC Warrants. The value ascribed to the
       CommcoCCC Warrants totaled $25,000.
 
    (3) Proceeds of $2,220,000 in cash from the Equipment Financing and issuance
       of  the  Indemnity  Warrants,  net  of  the  related  financing  costs of
       $225,000. The value ascribed to the Indemnity Warrants totaled $484,460.
 
    (4) Interest expense from the  Bridge Financing provided by stockholders  of
       Telecom  at the effective interest rate  after giving effect to the value
       ascribed to the Bridge Warrants, as if the Bridge Notes were issued as of
       the beginning of the respective periods.
 
    (5) Interest expense from the Equipment Financing at the effective  interest
       rate after giving effect to the value ascribed to the Indemnity Warrants,
       as  if  the  Equipment Notes  were  issued  as of  the  beginning  of the
       respective periods.
 
    (6) Interest expense from the CommcoCCC Financing, at the effective interest
       rate after giving effect to the value ascribed to the CommcoCCC Warrants,
       as if  the  CommcoCCC  Notes were  issued  as  of the  beginning  of  the
       respective periods.
 
    (7)  Elimination  of  interest  expense  from  the  Advent  Notes  that were
       converted into shares of Telecom stock on February 2, 1996.
 
(C) Offering adjustments:
 
    (1) Issuance of 7,500,000 shares of Common Stock offered in the Common Stock
       Offering based on an assumed initial  public offering price of $9.00  per
       share,  after  deducting  the  estimated  offering  discount  and related
       expenses of $5,332,275.
 
    (2) Assumed gross proceeds  of $175,000,000 from the  issuance of the  Notes
       and  Warrants  in  the  Unit  Offering,  and  related  estimated offering
       discount and related expenses  of $6,824,417. The  value ascribed to  the
       Unit Warrants totaled $15,200,000.
 
    (3) Repayment of the Bridge Financing and CommcoCCC Financing out of the net
       proceeds  from the  Offerings and  the reversal  of the  related interest
       expense. The  unamortized offering  discount and  deferred finance  costs
       associated  with the Bridge Financing and CommcoCCC Financing will result
       in an  extraordinary  loss of  approximately  $1,000,000 which  has  been
       excluded from the pro forma as adjusted presentation.
 
    (4)  The  acquisition of  the CommcoCCC  Assets  in exchange  for 16,500,000
       shares of Common Stock of the Company based on an assumed value of  $9.00
       per share, the related deferred tax liabilities and the estimated related
       expenses of $3,000,000.
 
    (5)  The  acquisition of  the 50%  ownership  interest of  ART West  held by
       Extended for $6 million in cash, to be paid out of the net proceeds  from
       the Offerings..
 
    (6)  The acquisition of the DCT assets for  $3.6 million in cash, to be paid
       out of the net proceeds from the Offerings.
 
    (7) Interest  expense on  the Notes,  at  an assumed  coupon rate  of  13.5%
       (resulting in an effective interest rate of 15.2% on the Notes, including
       the  amortization of debt issuance costs and original issue discount), as
       if the Notes were issued as  of the beginning of the respective  periods.
       If the interest rate on the Notes changed by 0.5%, interest expense would
       change by approximately $765,000 and $191,250 for the year ended December
       31, 1995 and three months ended March 31, 1996, respectively.
 
                                      F-6
<PAGE>
    (8)  Depreciation and amortization expense related to the acquisition of the
       CommcoCCC Assets, the 50% ownership interest in ART West, the DCT  Assets
       and the related deferred taxes.
 
(D)  Represents the  historical amounts of  ART as  of and for  the three months
    ended March 31, 1996 and as of and for the year ended December 31, 1995.
 
(E) Represents the historical amounts of Telecom as of and for the three  months
    ended  March 31, 1996, as of December 31, 1995 and for the period from March
    28, 1995 (date of inception) to December 31, 1995.
 
(F)  Represents  the  elimination  of  inter-entity  transactions  and  balances
    consisting  of  (i)  receivables  and  payables,  (ii)  ART's  investment in
    Telecom,  Telecom's  corresponding  stockholder   equity  amounts  and   the
    recognition  by ART of its  equity in losses of  Telecom and (iii) Telecom's
    investment in ART Redeemable Preferred Stock.
 
(G) Pro forma net loss  per share and the weighted  average number of shares  of
    Common  Stock reflect  (i) the  conversion of  all shares  of Telecom serial
    preferred stock to Telecom common stock;  (ii) issuance of ART Common  Stock
    to  Telecom stockholders, (iii) the  cancellation of the outstanding Telecom
    common stock and the ART Series  A Redeemable Preferred Stock; and (iv)  the
    issuance of potentially dilutive instruments issued within one year prior to
    a  proposed initial  public offering  at exercise  prices below  the assumed
    initial public offering price of $9.00 per share as if they were outstanding
    as of the beginning of the respective periods.
 
<TABLE>
<S>                                                                   <C>
Pro Forma:
  Weighted average number of shares of Common Stock outstanding for
   primary computation..............................................      10,013,055(1)
  Issuances of shares of Telecom serial preferred stock as converted
   into shares of ART Common Stock..................................      10,916,807
  Issuances of shares of Telecom common stock as converted into
   shares of ART Common Stock.......................................       8,100,807(2)
  Options and warrants issued and outstanding.......................       2,620,936
                                                                      --------------
  Pro forma weighted average number of shares of Common Stock.......      31,651,605(3)
                                                                      --------------
                                                                      --------------
Pro Forma As Adjusted:
  Pro forma weighted average number of shares of Common Stock.......      31,651,605
  Common Stock issued in connection with the Common Stock Offering
   and the acquisition of the CommcoCCC Assets......................      24,000,000
                                                                      --------------
  Pro forma as adjusted weighted average number of shares of Common
   Stock............................................................      55,651,605(3)
                                                                      --------------
                                                                      --------------
</TABLE>
 
    (1) The  weighted average  number  of shares  of  Common Stock  for  primary
       computation   exclude   all   common   stock   equivalents,   which   are
       anti-dilutive.
 
    (2) Excludes shares of Telecom common stock owned by ART.
 
   
    (3)  The  Securities  and  Exchange  Commission  requires  that  potentially
       dilutive  instruments issued within one year  prior to a proposed initial
       public offering  at exercise  prices below  the expected  initial  public
       offering price be treated as outstanding for the entire period presented.
       The  weighted average number of shares of Common Stock on a pro forma and
       a pro  forma  as  adjusted  basis  reflects  those  potentially  dilutive
       instruments  assuming the sale  of shares of Common  Stock offered in the
       Common Stock Offering based on  an assumed initial public offering  price
       of  $9.00 per share. In measuring the dilutive effect, the treasury stock
       method was used.
    
 
(H) General  and  administrative  expense  includes  a  non-recurring,  non-cash
    compensation  expense of $802,002 and $6,795,514 for the year ended December
    31, 1995  and for  the  three months  ended  March 31,  1996,  respectively,
    associated  with the release of Escrow Shares in 1995 and the termination of
    the Escrow Shares arrangement in 1996.
 
(I) Market  development  expense for  the  three  months ended  March  31,  1996
    includes  $1,053,000,  representing  the  value  ascribed  to  the Strategic
    Distribution Agreement in  connection with the  February 1996 investment  in
    Telecom by Ameritech.
 
                                      F-7
<PAGE>
                       REPORT OF INDEPENDENT ACCOUNTANTS
 
To the Stockholders of
Advanced Radio Technologies Corporation:
 
    We   have  audited  the  accompanying   balance  sheets  of  Advanced  Radio
Technologies Corporation (a development stage  company) as of December 31,  1995
and  1994, and the  related statements of  operations, stockholders' deficit and
cash flows for the years ended December  31, 1995 and 1994, for the period  from
August  23, 1993 (date of inception) to December 31, 1993 and for the cumulative
period from August  23, 1993  (date of inception)  to December  31, 1995.  These
financial  statements are  the responsibility  of the  Company's management. Our
responsibility is to express an opinion  on these financial statements based  on
our audits.
 
    We  conducted  our audits  in  accordance with  generally  accepted auditing
standards. Those standards require that we plan and perform the audits to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence  supporting
the  amounts and disclosures in the financial statements. An audit also includes
assessing the  accounting  principles used  and  significant estimates  made  by
management,  as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
    In our opinion, the financial  statements referred to above present  fairly,
in  all material respects, the financial position of Advanced Radio Technologies
Corporation as of December 31, 1995 and 1994, and the results of its  operations
and  its cash flows for the years ended  December 31, 1995 and 1994, and for the
period from  August  23, 1993  (date  of inception)  to  December 31,  1993,  in
conformity with generally accepted accounting principles.
 
    The  accompanying  financial  statements  have been  prepared  on  the going
concern basis  of  accounting,  which contemplates  realization  of  assets  and
liquidation  of liabilities in the ordinary  course of business. As described in
Note 1, the Company  has a substantial working  capital deficit at December  31,
1995,  has  incurred operating  losses since  inception and  does not  expect to
generate significant operating revenues until fiscal 1996. The Company estimates
that revenues  in  1996 will  not  be sufficient  to  fund its  initial  capital
requirements,  operating expenses and other  working capital needs. In addition,
as set forth in  Notes 5, 7,  8, and 11, the  Company has significant  financial
commitments.   The   Company's  continued   funding   of  its   initial  capital
requirements,  operating  expenses,  working   capital  needs  and   contractual
commitments  is  dependent  upon  its  ability  to  raise  additional financing.
Management's plans in  this regard  are discussed  in Note  1. These  conditions
raise  substantial  doubt about  the Company's  ability to  continue as  a going
concern. The  financial statements  do not  include any  adjustments that  might
result from the outcome of these uncertainties.
 
                                          COOPERS & LYBRAND L.L.P.
 
New York, New York
April 26, 1996, except for Note 2C, Note 5B and
  the second paragraph of Note 9
  as to which the date is June 26, 1996
 
                                      F-8
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                                 BALANCE SHEETS
                           DECEMBER 31, 1995 AND 1994
 
<TABLE>
<CAPTION>
                                                                                           1995           1994
                                                                                      --------------  ------------
<S>                                                                                   <C>             <C>
                                                      ASSETS
Current assets:
  Cash..............................................................................  $        6,069  $      5,133
                                                                                      --------------  ------------
      Total current assets..........................................................           6,069         5,133
Note receivable from Telecom (Note 4)...............................................       5,000,000
Equity investments (Note 5).........................................................         285,000
Deferred financing costs, net.......................................................         457,543
FCC licenses........................................................................           8,913
Property and equipment, net.........................................................           1,723         3,448
Other assets........................................................................          25,376        34,030
                                                                                      --------------  ------------
      Total assets..................................................................  $    5,784,624  $     42,611
                                                                                      --------------  ------------
                                                                                      --------------  ------------
 
                                      LIABILITIES AND STOCKHOLDERS' DEFICIT
Current liabilities:
  Accounts payable and accrued liabilities..........................................  $      243,952  $     11,689
  Due to Telecom (Note 11)..........................................................         738,680
  Note payable to related party (Note 11)...........................................                        70,000
                                                                                      --------------  ------------
      Total current liabilities.....................................................         982,632        81,689
Equity loss in excess of investment (Note 5)........................................         211,543
Convertible note payable (Note 4)...................................................       4,950,000
                                                                                      --------------  ------------
      Total liabilities.............................................................       6,144,175        81,689
                                                                                      --------------  ------------
Redeemable Preferred Stock, $.01 par value; 1,000 shares authorized; 1 share issued
 and outstanding at December 31,
 1995 (Note 4)......................................................................          44,930
                                                                                      --------------  ------------
Commitments and contingencies (Notes 1, 5, 7, 8, 11 and 12).........................
 
Stockholders' deficit (Note 9):
  Common Stock, $.001 par value; 58,900,320 shares authorized; 10,013,055 and
   5,890,032 shares issued and outstanding..........................................          10,013         5,890
  Additional paid-in capital........................................................         988,375        90,246
  Deficit accumulated during the development stage..................................      (1,402,869)     (135,214)
                                                                                      --------------  ------------
      Total stockholders' deficit...................................................        (404,481)      (39,078)
                                                                                      --------------  ------------
        Total liabilities and stockholders' deficit.................................  $    5,784,624  $     42,611
                                                                                      --------------  ------------
                                                                                      --------------  ------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-9
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENTS OF OPERATIONS
                FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1994,
            FOR THE PERIOD FROM AUGUST 23, 1993 (DATE OF INCEPTION)
               TO DECEMBER 31, 1993 AND CUMULATIVE FOR THE PERIOD
         FROM AUGUST 23, 1993 (DATE OF INCEPTION) TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                                                                        CUMULATIVE
                                                                                         PERIOD FROM    FROM AUGUST
                                                                                         AUGUST 23,      23, 1993
                                                                   YEARS ENDED          1993 (DATE OF    (DATE OF
                                                                   DECEMBER 31,         INCEPTION) TO  INCEPTION) TO
                                                            --------------------------  DECEMBER 31,   DECEMBER 31,
                                                                1995          1994          1993           1995
                                                            -------------  -----------  -------------  -------------
<S>                                                         <C>            <C>          <C>            <C>
Consulting income.........................................  $    --        $   137,489    $  --         $   137,489
                                                            -------------  -----------  -------------  -------------
Expenses:
  General and administrative expenses.....................        204,937      253,453        5,906         464,296
  Depreciation and amortization...........................         10,378        8,281          688          19,347
  Interest expense, net (Note 11).........................         38,455        4,375                       42,830
                                                            -------------  -----------  -------------  -------------
      Total expenses......................................        253,770      266,109        6,594         526,473
Equity loss on investment in Telecom (Note 5).............      1,013,885                                 1,013,885
                                                            -------------  -----------  -------------  -------------
      Net loss............................................  $   1,267,655  $   128,620    $   6,594     $ 1,402,869
                                                            -------------  -----------  -------------  -------------
                                                            -------------  -----------  -------------  -------------
Pro forma net loss per share (unaudited)..................  $        0.04
                                                            -------------
                                                            -------------
Pro forma weighted average number of shares of Common
 Stock outstanding (unaudited)............................     31,651,605
                                                            -------------
                                                            -------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-10
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                  STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)
                FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1994,
            FOR THE PERIOD FROM AUGUST 23, 1993 (DATE OF INCEPTION)
               TO DECEMBER 31, 1993 AND CUMULATIVE FOR THE PERIOD
         FROM AUGUST 23, 1993 (DATE OF INCEPTION) TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                                                         DEFICIT
                                                                                       ACCUMULATED
                                                                         ADDITIONAL       DURING
                                                               COMMON      PAID-IN     DEVELOPMENT
                                                                STOCK      CAPITAL        STAGE           TOTAL
                                                              ---------  -----------  --------------  --------------
<S>                                                           <C>        <C>          <C>             <C>
Net issuance of 2,945,016 shares of Common Stock for cash...  $   2,945  $    58,191                  $       61,136
Net loss....................................................                          $       (6,594)         (6,594)
                                                              ---------  -----------  --------------  --------------
Balance, December 31, 1993..................................      2,945       58,191          (6,594)         54,542
Issuance of 2,945,016 shares of Common Stock for cash.......      2,945       32,055                          35,000
Net loss....................................................                                (128,620)       (128,620)
                                                              ---------  -----------  --------------  --------------
Balance, December 31, 1994..................................      5,890       90,246        (135,214)        (39,078)
Issuance of 73,625 shares of Common Stock to ART West.......         74       24,926                          25,000
Issuance of 4,049,398 shares of Common Stock to existing
 shareholders...............................................      4,049       (4,049)
Conversion of note payable and interest to paid-in
 capital....................................................                  75,250                          75,250
Investment in Telecom as a result of the release of escrow
 shares.....................................................                 802,002                         802,002
Net loss....................................................                              (1,267,655)     (1,267,655)
                                                              ---------  -----------  --------------  --------------
Balance, December 31, 1995..................................  $  10,013  $   988,375  $   (1,402,869) $     (404,481)
                                                              ---------  -----------  --------------  --------------
                                                              ---------  -----------  --------------  --------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-11
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENTS OF CASH FLOWS
                FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1994,
            FOR THE PERIOD FROM AUGUST 23, 1993 (DATE OF INCEPTION)
               TO DECEMBER 31, 1993 AND CUMULATIVE FOR THE PERIOD
         FROM AUGUST 23, 1993 (DATE OF INCEPTION) TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                                                            PERIOD FROM     CUMULATIVE
                                                                                            AUGUST 23,     FROM AUGUST
                                                                     YEARS ENDED           1993 (DATE OF  23, 1993 (DATE
                                                                    DECEMBER 31,           INCEPTION) TO  OF INCEPTION)
                                                            -----------------------------  DECEMBER 31,    TO DECEMBER
                                                                 1995           1994           1993          31, 1995
                                                            --------------  -------------  -------------  --------------
<S>                                                         <C>             <C>            <C>            <C>
Cash flows from operating activities:
  Net loss................................................  $   (1,267,655) $    (128,620)  $    (6,594)  $   (1,402,869)
  Adjustments to reconcile net loss to net cash used in
   operating activities:
    Non-cash interest expense.............................         110,828                                       110,828
    Depreciation and amortization.........................          10,378          8,281           688           19,347
    Equity loss on investment in Telecom..................       1,013,885                                     1,013,885
  Changes in operating assets and liabilities:
    Accounts payable and accrued liabilities..............          (3,939)        (8,282)       19,971            7,750
                                                            --------------  -------------  -------------  --------------
      Net cash (used in) provided by operating
       activities.........................................        (136,503)      (128,621)       14,065         (251,059)
                                                            --------------  -------------  -------------  --------------
Cash flows from investing activities:
  Additions to property and equipment.....................                         (5,175)                        (5,175)
  Investment in ART West and Telecom......................        (255,340)                                     (255,340)
  Note receivable from Telecom............................      (5,000,000)                                   (5,000,000)
  Acquisition of FCC Licenses.............................         (13,912)                                      (13,912)
  Increase in other assets................................                                      (41,272)         (41,272)
                                                            --------------  -------------  -------------  --------------
      Net cash used in investing activities...............      (5,269,252)        (5,175)      (41,272)      (5,315,699)
                                                            --------------  -------------  -------------  --------------
Cash flows from financing activities:
  Proceeds from issuance of Common Stock..................                         35,000        61,136           96,136
  Proceeds from loan and note payable.....................           8,500         70,000                         78,500
  Proceeds from issuance of Preferred Stock...............          50,000                                        50,000
  Preferred Stock issuance costs..........................          (5,070)                                       (5,070)
  Repayment of loan.......................................          (8,500)                                       (8,500)
  Proceeds from convertible note payable..................       4,950,000                                     4,950,000
  Deferred financing costs................................        (326,919)                                     (326,919)
  Due to Telecom..........................................         738,680                                       738,680
                                                            --------------  -------------  -------------  --------------
      Net cash provided by financing activities...........       5,406,691        105,000        61,136        5,572,827
                                                            --------------  -------------  -------------  --------------
      Net increase (decrease) in cash.....................             936        (28,796)       33,929            6,069
Cash, beginning of period.................................           5,133         33,929
                                                            --------------  -------------  -------------  --------------
Cash, end of period.......................................  $        6,069  $       5,133   $    33,929   $        6,069
                                                            --------------  -------------  -------------  --------------
                                                            --------------  -------------  -------------  --------------
Supplemental cash flow information:
Non-cash investing and financing activities:
  Release of escrow shares and increase in the investment
   in Telecom.............................................  $      802,002                                $      802,002
  Issuance of stock and contribution of licenses to ART
   West...................................................  $       30,000                                $       30,000
  Conversion of note payable and interest to Common
   Stock..................................................  $       75,250                                $       75,250
  Accrued deferred financing costs........................  $      175,000                                $      175,000
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-12
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                         NOTES TO FINANCIAL STATEMENTS
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION:
 
THE COMPANY
 
    Advanced  Radio  Technologies  Corporation  ("ART"  or  the  "Company")  was
organized as a  Delaware corporation on  August 23, 1993,  to provide  broadband
wireless  digital telecommunications services to the domestic telecommunications
market. The  Company's  operations  to  date include  the  application  for  and
acquisition  of certain  38 GHz licenses  granted by  the Federal Communications
Commission ("FCC") and costs incurred for the deployment of such services.
 
    During 1995,  The Company  established a  strategic alliance  with  Extended
Communications,  Inc. ("Extended") to form the  ART West joint venture. ART West
was formed on April 4, 1995 to develop and expand the Company's wireless digital
telecommunications services  in various  markets throughout  the western  United
States (see Note 5).
 
    During  1995, Advanced Radio Telecom Corp.  ("Telecom") was organized by the
Company and Landover Holdings Corporation  ("Landover") with one of its  initial
objectives  to acquire certain 38 GHz licenses in the northeastern United States
from EMI Communications, Corp. ("EMI"). Under the terms of a purchase  agreement
between  the Company, Landover, and Telecom dated April 21, 1995, (the "Purchase
Agreement") Landover  was  obligated to  purchase  $7,000,000 of  securities  of
Telecom.  Pursuant  to  the  Purchase Agreement  and  a  stockholders' agreement
between the Company, Telecom and their respective shareholders dated May 8, 1995
(the "Stockholders'  Agreement"), the  Company and  Telecom were  to merge  once
approval from the FCC had been granted. (See Note 2).
 
INITIAL CAPITALIZATION
 
    The  Company was  formed on August  23, 1993  by two of  its executives (the
"Founding Stockholders") by issuing 2,945,016 shares of Common Stock in exchange
for $1,136. During November 1993, ART redeemed 1,178,006 shares of Common  Stock
from  the Founding Stockholders and through a private placement issued 1,178,006
shares of Common Stock to High Sky Limited Partnership ("High Sky") in  exchange
for $60,000. During March 1994, High Sky II Limited Partnership ("High Sky II"),
an   affiliate  of  High  Sky  (collectively   referred  to  as  the  "High  Sky
Partnerships") contributed  $100,000  to the  Company  in exchange  for  589,003
shares  of Common Stock  and a $70,000  Promissory Note. In  connection with the
High Sky II financing, ART issued an additional aggregate of 2,356,013 shares to
the Founding Stockholders and High Sky whereby the Founding Stockholders and the
High Sky Partnerships would each own a 50% interest in ART. Additionally, during
1994, one  of the  Founding Stockholders  contributed an  additional $5,000  for
which contribution there were no shares issued.
 
    Pursuant  to an agreement dated March 1,  1995, High Sky II agreed to assign
the $70,000 Promissory Note, plus accrued interest, to the Founding Stockholders
in exchange for two new promissory notes executed by the Founding  Stockholders.
Concurrent  with the exchange of the promissory notes, the Founding Stockholders
contributed the $70,000 Promissory Note plus  accrued interest of $5,250 to  the
Company, for which contribution there were no additional shares issued.
 
BASIS OF PRESENTATION
 
    The  financial statements have  been prepared on the  going concern basis of
accounting,  which  contemplates  realization  of  assets  and  liquidation   of
liabilities  in the ordinary  course of business. The  Company has a substantial
working capital deficit, has incurred operating losses since inception and  does
not expect to recognize significant operating revenues until the commencement of
its  commercial  services, which  is anticipated  to occur  in fiscal  1996. The
Company estimates  that revenues  in 1996  will not  be sufficient  to fund  its
initial   operating  expenses   and  other  working   capital  needs,  including
 
                                      F-13
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION, CONTINUED:
consulting, service and purchase commitments set forth in Notes 5, 7, 8 and  11.
The  Company's  continued funding  of  its initial  operating  expenses, working
capital needs and contractual commitments is dependent upon its ability to raise
additional financing. The  Company and Telecom  have engaged various  investment
bankers  to assist them  in raising financing  through a public  equity and debt
offering. There  can  be no  assurance  that the  Company  and Telecom  will  be
successful in their effort to raise additional financing through these offerings
or,  if available,  that the Company  and Telecom will  be able to  obtain it on
acceptable terms. These conditions raise  substantial doubt about the  Company's
ability  to continue as a going concern. The financial statements do not include
any adjustments that might result from the outcome of these uncertainties.
 
2.  PURCHASE AGREEMENT:
 
A -- INITIAL CAPITALIZATION OF TELECOM
 
    Pursuant to  the  Purchase  Agreement, as  its  initial  capitalization,  an
aggregate of 8,580,000 shares of Class B and Class A common stock were issued by
Telecom  to Landover and consultants to Landover, respectively, for an aggregate
cash consideration of $1,020. Such  shares of Class B  and Class A common  stock
represented  64% and  2%, respectively,  of the  total number  shares of capital
stock of Telecom then outstanding. Concurrently, the Company received  4,420,000
shares  of Class A common stock, representing  34% of the total number of shares
of capital stock of Telecom  then outstanding in exchange  for $340. All of  the
above  references to  shares of  common stock of  Telecom have  been adjusted to
reflect a 13 for 1 stock split which occurred in February 1996, but are prior to
the issuance of anti-dilutive shares described below.
 
    Under the  Purchase Agreement,  Landover agreed  to invest  or cause  to  be
invested  $7,000,000 in ART, Telecom and their affiliates (the "Landover Funding
Commitment"). In consideration for this $7,000,000 investment, Telecom agreed to
issue preferred stock,  the number  of shares of  which would  be designated  by
Landover.  Under the  anti-dilution provisions of  the Class A  common stock, in
respect of each such preferred stock  issuance, Telecom agreed to issue, for  no
consideration,  additional shares of Class A common stock in number necessary to
maintain the 36% ownership interest in Telecom of the holders of Class A  common
stock.
 
    Under  the Purchase  Agreement, the  individual shareholders  of the Company
were required to place 5,153,778 shares of Common Stock in the Company in escrow
(the "Escrow Shares") to be released upon the completion of the then pending EMI
Asset acquisition  (see  Note 8),  Telecom's  attainment of  specific  operating
income  levels for the years 1997 through  1999 and the acquisition of interests
in a specified  number of FCC  license authorizations  by April 30,  2000. As  a
result  of  the consummation  of the  EMI Asset  acquisition, in  November 1995,
1,873,030 of the  Escrow Shares  of ART  were released.  The fair  value of  the
Escrow Shares released in 1995, amounting to $802,002, has been accounted for as
an  equity investment  in Telecom,  the effect of  which has  been recognized as
additional paid-in capital  in the  Company. Pursuant  to the  February 2,  1996
Reorganization,  the Escrow  Shares arrangement  was terminated  and all  of the
remaining Escrow Shares were  released to the stockholders  of the Company.  The
fair   value  of  the  remaining  Escrow  Shares  released,  in  the  amount  of
approximately $6.8 million,  will be  accounted for  in the  same manner  during
1996.
 
B -- MERGER
 
    Under the terms of the Purchase Agreement, the Company and Telecom intend to
operate  both companies as a single enterprise and are committed to merge if and
when permitted by the FCC.
 
                                      F-14
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
2.  PURCHASE AGREEMENT, CONTINUED:
Concurrent with the Purchase Agreement, the Company and Telecom entered into  an
exclusive   20-year  services  agreement  (the  "Services  Agreement")  for  the
construction, development and operation of systems in the Company's markets (see
Note 6).
 
    On February 2, 1996, the Company, Telecom and their respective  shareholders
agreed  to an amendment and restatement of the Stockholders' Agreement providing
for (i) termination effective  on the closing of  a public share offering,  (ii)
amendment and restatement of the Certificate of Incorporation and reorganization
of  the capital structure of Telecom; (iii) the exchange of the Advent Notes and
one share of  ART Series A  Redeemable Preferred  Stock for shares  of Series  E
preferred  stock  of  Telecom (see  Note  4);  (iv) revision  of  provisions for
election of  directors;  (v) amendment  and  restatement of  ART's  registration
rights  agreements;  (vi)  release of  shares  escrowed in  connection  with the
original Stockholders' Agreement; and (vii)  approval of a definitive  agreement
to merge the Company and Telecom (the "Reorganization").
 
C -- AMENDED MERGER
 
    The  definitive merger  agreement, as entered  into on February  2, 1996 and
subsequently restated and  amended on  June 26, 1996,  (the "Merger  Agreement")
provides for the merger of a newly-formed wholly owned subsidiary of the Company
("Merger  Sub")  into  Telecom  (the "Merger")  subject  to  certain conditions,
including the receipt  of FCC approval.  Prior to the  Merger, each  outstanding
share  of Telecom's serial preferred  stock will be converted  into 13 shares of
Telecom's common stock. In the Merger, each outstanding share of common stock of
Telecom will be exchanged for the right to receive an equal number of shares  of
Common  Stock of the  Company. As a  result, Telecom will  become a wholly owned
subsidiary of the Company. The Merger  Agreement provides that if the Merger  is
not  consummated by May 13, 1997, the  shares of Telecom's common stock owned by
the Company will be surrendered to Telecom, and the Services Agreements is to be
revised to, among other revisions, extend the term to 40 years and provide for a
proportionate participation by the Company's stockholders in any dividends  paid
by  Telecom or the proceeds from any  sale of Telecom. The Merger Agreement also
provides for the  assignment of Telecom's  interests in all  of its  agreements,
including  the  various  services agreements,  employment  agreements, equipment
purchase agreements and  purchase option  agreements, to  the Company.  Further,
upon  the Merger, the holders of warrants  to purchase an aggregate of 2,302,136
shares of Telecom common stock will be entitled to purchase an equivalent number
of shares of Common Stock on the same terms. Employee stock options to  purchase
1,664,732  shares of Telecom's common stock will be converted into similar stock
options of the Company.
 
3.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
 
DEVELOPMENT STAGE ENTERPRISE
 
    The Company is  a development stage  enterprise as defined  in Statement  of
Financial  Accounting Standards No. 7,  "Accounting and Reporting by Development
Stage Enterprises." The  financial statements  have been prepared  on the  going
concern basis of accounting.
 
PROPERTY AND EQUIPMENT
 
    Property  and equipment is stated at  cost. Depreciation and amortization is
computed using the straight-line method over the estimated useful lives of three
years.
 
                                      F-15
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
3.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, CONTINUED:
INVESTMENTS
 
    The Company accounts for its 50% interest in the ART West joint venture  and
its 34% interest in Telecom under the equity method.
 
FCC LICENSES
 
    The   Company  has   obtained  radio   spectrum  rights   under  FCC  issued
authorizations and licenses throughout the United States by petitioning the  FCC
directly  and through the purchase of such  rights held by others. Such licenses
are issued for an initial term of six years and are renewable subject to  review
by  the FCC.  The costs  associated with  the acquisition  of such  licenses are
capitalized and  amortized  on  a  straight-line basis  over  a  40-year  period
beginning  upon commencement  of operations in  the related  market. The 40-year
period is based upon management's license renewal expectations.
 
RECOVERABILITY OF LONG-LIVED ASSETS
 
    The  recoverability   of  property   and  equipment   and  capitalized   FCC
authorizations  and  licenses is  dependent upon  the successful  development of
systems in  each of  the respective  markets, or  through sale  of such  assets.
Management  estimates that  it will recover  the carrying amount  of those costs
from cash flow generated by the systems once they have been developed.  However,
it  is reasonably  possible that such  estimate will  change as a  result of the
failure to develop the FCC authorizations  on a timely basis, or  technological,
regulatory or other changes.
 
    The  Company's policy  is to assess  annually any impairment  in value based
upon a comparison of  projected operating cash flows  from each market over  its
expected  period of operation, on an  undiscounted basis, to the carrying amount
of the property and equipment, licenses  and other capitalized costs related  to
the market.
 
FINANCING COSTS
 
    Direct  costs  associated with  obtaining  debt financing  are  deferred and
charged to interest expense  using the effective interest  rate method over  the
term  of the debt.  Direct costs associated with  obtaining equity financing are
deferred and charged  to additional  paid-in capital  as the  related funds  are
raised.  Deferred costs associated  with unsuccessful financings  are charged to
expense.
 
    Accumulated amortization  of deferred  financing  costs totaled  $44,376  at
December 31, 1995.
 
REVENUE RECOGNITION
 
    Revenue  from telecommunications  services are  recognized ratably  over the
period such services are provided.
 
    During 1994, the Company recognized  income from consulting fees  associated
with  the  application of  FCC licenses  on behalf  of third  parties, including
consulting fees of approximately $80,000 from Extended.
 
INCOME TAXES
 
    The Company  accounts  for  income  taxes  under  the  liability  method  of
accounting.  Under the liability method, deferred  taxes are determined based on
the differences between  the financial  statement and  tax bases  of assets  and
liabilities  at enacted tax rates in effect in the year in which the differences
are expected to reverse. Valuation  allowances are established, when  necessary,
to reduce deferred tax assets to the amounts expected to be realized.
 
                                      F-16
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
3.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, CONTINUED:
NET LOSS PER SHARE
 
    Historical  net loss per share is computed  based on the loss for the period
divided by the  weighted average number  of shares of  Common Stock  outstanding
during the period. Historical net loss per share and the weighted average number
of shares of Common Stock outstanding are as follows:
 
<TABLE>
<CAPTION>
                                                                                       FOR THE PERIOD
                                                           FOR THE YEARS ENDED        FROM AUGUST 23,
                                                              DECEMBER 31,             1993 (DATE OF
                                                      -----------------------------    INCEPTION) TO
                                                           1995           1994       DECEMBER 31, 1993
                                                      --------------  -------------  ------------------
<S>                                                   <C>             <C>            <C>
Net loss per share..................................  $         0.13  $        0.01    $     --
                                                      --------------  -------------  ------------------
                                                      --------------  -------------  ------------------
Weighted average number shares of Common Stock
 outstanding........................................      10,013,055      9,178,633         5,006,527
                                                      --------------  -------------  ------------------
                                                      --------------  -------------  ------------------
</TABLE>
 
    The  Securities and  Exchange Commission requires  that potentially dilutive
instruments issued within one year prior  to a proposed initial public  offering
at  exercise prices below the expected  initial public offering price be treated
as outstanding for all periods presented. Accordingly, an additional  21,638,550
shares  are reflected in the  weighted average number of  shares of Common Stock
outstanding in computing the unaudited pro forma net loss per share for the year
ended December 31, 1995.
 
USE OF ESTIMATES
 
    The  preparation  of  financial  statements  in  conformity  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions that  affect the  reported  amounts of  assets and  liabilities  and
disclosure  of contingent assets and liabilities as of the date of the financial
statements and  the  reported  amounts  of  revenues  and  expenses  during  the
reporting period. Actual results could differ from those estimates.
 
4.  NOTE RECEIVABLE FROM TELECOM AND CONVERTIBLE NOTES PAYABLE TO ADVENT:
    The   Company,  Telecom   and  several   entities  affiliated   with  Advent
International Corp. (collectively, "Advent"), entered into a securities purchase
agreement (the "Advent Purchase Agreement") dated November 13, 1995 under  which
Advent agreed to acquire a 10% interest in the combined entities of the Company,
Telecom  and certain specified affiliates. Pending  the merger of these entities
(see Note 2), the Company issued  promissory notes (the "Advent Notes") with  an
aggregate principal amount of $4,950,000 and one share of the Company's Series A
Redeemable Preferred Stock in exchange for $5,000,000 in cash.
 
    The  Advent  Notes carried  interest at  a rate  of 10%  per annum  and were
payable on demand at any  time on or after May  13, 1997. The Advent Notes  were
collateralized  by certain assets  of the Company and  Telecom. The Advent Notes
were convertible into that number of shares of preferred stock which represented
in the aggregate at least 10% of the fully diluted capital stock of the combined
entities described  above, as  defined  in the  Advent Purchase  Agreement.  The
Advent  Notes were convertible either (i) immediately prior to an initial public
offering with  aggregate gross  proceeds  of at  least  $10,000,000 or  (ii)  at
Advent's election.
 
    At December 31, 1995, the Company accrued interest expense of $66,542 on the
Advent   Notes,  which  has  been  included  in  accounts  payable  and  accrued
liabilities.
 
    On November  13, 1995,  the gross  proceeds of  $5,000,000 received  by  the
Company  from Advent  were transferred  to Telecom in  exchange for  a note with
terms equivalent to  the terms of  the Advent  Notes. On February  2, 1996,  the
Company,    Telecom   and   Advent   entered    into   an   exchange   agreement
 
                                      F-17
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
4.  NOTE RECEIVABLE FROM TELECOM AND CONVERTIBLE NOTES PAYABLE TO
ADVENT, CONTINUED:
under which the Advent Notes, including  accrued interest, and the one share  of
ART  Series  A Redeemable  Preferred  Stock held  by  Advent were  exchanged for
232,826 shares  of  Series  E preferred  stock  of  Telecom, and  the  note  was
canceled.  As a result,  the Advent Notes  were canceled and  Telecom became the
owner of the one share of the ART Series A Redeemable Preferred Stock.
 
5.  EQUITY INVESTMENTS:
 
A -- INVESTMENT IN ART WEST JOINT VENTURE
 
    On April 4,  1995, the Company  entered into an  agreement with Extended  to
form  ART West, a jointly controlled general partnership established to acquire,
develop, and operate  radio systems  using 38  GHz licenses  in certain  western
states  of the U.S. The ART West  joint venture will continue until December 31,
2055, unless  terminated earlier.  The  Company's initial  capital  contribution
consisted  of $255,000 in cash, FCC licenses  and related assets with a carrying
value of  approximately  $5,000, and  73,625  shares  of Common  Stock  of  ART.
Extended's  initial capital  contribution consisted  of $5,000  in cash  and FCC
licenses. The combined  systems are  collectively referred  to as  the ART  West
Systems.  Additionally, Extended received distributions  of $250,000 in cash and
the 73,625 shares of Common Stock contributed  by the Company to ART West. As  a
result  of these contributions and distributions, the Company and Extended share
equally in  the partnership  interests of  ART West.  The Company  recorded  its
investment  in ART West in  the amount of $285,000.  The excess of the Company's
share of  the underlying  net assets  of ART  West over  the Company's  recorded
investment will be amortized over the life of the ART West Systems.
 
    On  October 1, 1994,  ART entered into an  exclusive services agreement with
Extended, whereby  ART  is  responsible  for  the  construction,  operation  and
management  of Extended's telecommunications systems.  The term of the Agreement
is for  five years.  In connection  with  the formation  of ART  West,  Extended
assigned  its interest in the services agreement to ART West. Under the terms of
the services  agreement,  ART will  incur  all  costs and  expenses  related  to
construction, operation and management of the systems. As compensation, ART will
receive  all revenues generated  by the systems  after deducting certain related
direct expenses, less 45%  which is to  be paid to ART  West. ART's interest  in
this service agreement was subsequently assigned to Telecom (Note 6). An officer
of ART is also the President and a shareholder of Extended.
 
B -- ART WEST JOINT VENTURE ACQUISITION AND MANAGEMENT AGREEMENTS
 
    In  June  1996,  the  Company agreed  to  acquire  Extended's  50% ownership
interest in ART West for $6,000,000  in cash upon consummation of public  equity
and  debt offerings with aggregate net proceeds of $125.0 million to the Company
and receipt of FCC  approval. In addition, the  Company entered into a  ten-year
management  agreement  which,  effective  June 1,  1996,  replaces  the services
agreement referred to above  with an arrangement whereby  the Company agrees  to
construct, operate and manage the ART West Systems in exchange for a license fee
equal to 10% of recurring operating revenues.
 
C -- INVESTMENT IN TELECOM
 
    The Company acquired 4,420,000 shares of Class A common stock of Telecom, or
34%  of the outstanding  and issued shares, for  cash of $340  (see Note 2). The
Company also recorded $802,002 as an  investment in Telecom based upon the  fair
value  of  Escrow  Shares released  in  1995 (see  Note  2). The  excess  of the
Company's share  of the  underlying net  assets of  Telecom over  the  Company's
recorded  investment  will  be  amortized  over  the  estimated  useful  life of
Telecom's FCC licenses.
 
                                      F-18
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
5.  EQUITY INVESTMENTS, CONTINUED:
    The Company recognizes its proportionate share  of the losses of Telecom  in
excess of its investment to the extent of its funding and financial commitments.
During 1995, the Company recognized its proportionate share of Telecom's loss in
the  amount of  $1,013,885. Summarized financial  information for  Telecom as of
December 31, 1995 and for the period from March 28, 1995 (date of inception)  to
December 31, 1995 is as follows:
<TABLE>
<CAPTION>
                                                                                          DECEMBER 31,
                                                                                              1995
                                                                                         ---------------
<S>                                                                                      <C>
Total current assets...................................................................   $   1,418,590
Property and equipment, net............................................................       3,579,838
FCC licenses...........................................................................       4,226,821
Other assets...........................................................................         605,366
                                                                                         ---------------
  Total assets.........................................................................   $   9,830,615
                                                                                         ---------------
                                                                                         ---------------
Total current liabilities..............................................................   $   3,450,537
Note payable to EMI....................................................................       1,500,000
Note payable to ART....................................................................       5,000,000
Total stockholders' deficit............................................................        (119,922)
                                                                                         ---------------
  Total liabilities and stockholders' deficit..........................................   $   9,830,615
                                                                                         ---------------
                                                                                         ---------------
 
<CAPTION>
 
                                                                                         MARCH 28, 1995
                                                                                            (DATE OF
                                                                                          INCEPTION) TO
                                                                                          DECEMBER 31,
                                                                                              1995
                                                                                         ---------------
<S>                                                                                      <C>
Operating revenue......................................................................   $       5,793
Expenses...............................................................................       2,986,866
                                                                                         ---------------
Net loss...............................................................................   $   2,981,073
                                                                                         ---------------
                                                                                         ---------------
</TABLE>
 
6.  TELECOM SERVICES AGREEMENT:
    The  Company entered into an exclusive  Services Agreement with Telecom, for
the construction,  operation and  management  of the  FCC licenses  and  related
telecommunications  systems that are owned by ART  or for which ART has existing
services agreements. Under the Services Agreement, Telecom will incur all  costs
and  expenses related to construction, operation  and management of the systems.
As compensation,  Telecom will  receive all  revenues generated  by the  systems
after deducting certain related direct expenses, less 25% which is to be paid to
the Company. The Services Agreement is for a period of 20 years.
 
    Through  this Services Agreement, the Company  has assigned its interests in
other similar services agreements with ART West  (see Note 5) and DCT (see  Note
7). There have been no services provided through December 31, 1995 on any of the
services agreements.
 
7.  DCT AGREEMENTS:
 
SYSTEM PURCHASE AGREEMENT
 
    On  September  1,  1994, the  Company  entered  into an  agreement  with DCT
Communications, Inc.  ("DCT"),  in which  the  Company obtained  the  option  to
purchase  certain FCC licenses (the "Systems")  from DCT for $500,000 and shares
of ART Common Stock that represent 5% of its fully diluted equity as of the date
of transfer. The option is exercisable at  any time after December 31, 1995  and
up to the date
 
                                      F-19
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
7.  DCT AGREEMENTS, CONTINUED:
that  is three years after the FCC issues DCT's first license. At any time after
December 31, 1995,  DCT may require  that the Company  purchase the Systems  for
$50,000, plus reimbursement of certain costs defined in the agreement.
 
SERVICES AGREEMENT
 
    On  September  1,  1994,  the Company  entered  into  an  exclusive services
agreement with  DCT whereby  the Company  is responsible  for the  construction,
operation and management of DCT's Systems. The term of the Agreement is for five
years.  Under the terms  of the services  agreement, the Company  will incur all
costs and  expenses related  to construction,  operation and  management of  the
systems. As compensation, the Company will receive all revenues generated by the
systems after deducting certain related direct expenses, less 45% which is to be
paid to DCT.
 
CONSULTING AND LOAN AGREEMENT
 
    On  March 13, 1995, the Company entered into a consulting and loan agreement
(the "Consulting and  Loan Agreement"). Under  the terms of  the Consulting  and
Loan  Agreement, DCT agreed to  loan the Company $8,500,  bearing interest at 9%
per annum. The loan, including interest of $431, was due and paid on August  31,
1995.
 
DCT PRELIMINARY AGREEMENT
 
    On  April  25, 1996,  the  Company and  Telecom  entered into  a preliminary
agreement with DCT to acquire DCT's  interest in certain FCC authorizations  and
licenses  in exchange for $3.6  million in cash, subject  to the completion of a
definitive purchase agreement  and services agreement.  The definitive  purchase
agreement  will supersede and replace all  other existing agreements between DCT
and the Company. The  definitive purchase agreement must  be signed by June  28,
1996 and the closing of the transaction is subject to FCC approval.
 
8.  COMMITMENTS:
 
ACQUISITION OF ASSETS OF EMI
 
    On  April 4, 1995, the Company entered into a purchase option agreement with
EMI to acquire  EMI's interest  in certain 38  GHz radio  spectrum licenses  and
related  assets in the northeastern United States (the "EMI Assets") in exchange
for $3,000,000 in cash  and a three year  non-negotiable promissory note in  the
amount  of  $1,500,000. Pursuant  to  the Purchase  Agreement  (see Note  1), in
November, 1995,  the  Company assigned  its  rights and  obligations  under  the
purchase option agreement to Telecom. The FCC subsequently approved the transfer
of  the EMI licenses  and Telecom directly  acquired the EMI  Assets in November
1995. The Company  has also  issued a  guarantee to  EMI of  the obligations  of
Telecom under the promissory note.
 
TELECOM ONE OPTION
 
    On  May 25,  1995, the  Company entered into  an agreement  with TeleCom One
Incorporated ("TeleCom One") whereby the Company agreed to assist TeleCom One in
its applications for certain FCC  licenses (the "TeleCom One Agreement").  Under
the  terms  of the  TeleCom One  Agreement,  in exchange  for its  services, the
Company acquired options to purchase a 49% interest in each of the FCC  licenses
obtained  by TeleCom One at a purchase price of $.0133 per person covered by the
geographic license area. The  term of the TeleCom  One Agreement is five  years.
The Company has not exercised any of its options.
 
                                      F-20
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
8.  COMMITMENTS, CONTINUED:
EMPLOYMENT AND CONSULTING AGREEMENTS
 
    On  May 8,  1995, the  Company and  Telecom jointly  entered into consulting
agreements with two executive officers of the Company and Telecom, effective  as
of  January  1, 1995  and continuing  for a  term of  three years,  with minimum
payments aggregating approximately $170,000 annually. The costs associated  with
these  contracts have been recorded by Telecom  and no amounts have been charged
to the Company.
 
    On December  16, 1995,  one of  the executive  officers of  the Company  and
Telecom, previously a party to one of the consulting agreements described above,
entered into a full-time employment agreement. The employment agreement is for a
three-year term with an annual salary of $250,000 in the first year, $275,000 in
the  second year  and $300,000  in the  third year.  In addition,  the agreement
provides for a cash bonus of up to $100,000 for each year based upon achievement
of specific performance objectives. The costs associated with this contract have
been recorded by Telecom and no amounts have been charged to the Company.
 
    On July  11,  1995, the  Company  and  Telecom entered  into  an  employment
agreement,  as  amended January  8, 1996,  with  an officer  of the  Company and
Telecom. The  term of  the  agreement is  three years  at  an annual  salary  of
$160,000  in the  first year, $200,000  in the  second year and  $240,000 in the
third year. Options to purchase shares  of Telecom common stock were awarded  to
this officer equivalent to 2.5% of the outstanding capital stock of Telecom. The
agreement also provides for an engagement bonus of $17,000 upon execution of the
agreement  and  a  cash  bonus  of  up to  $100,000  for  each  year  based upon
achievement of specific performance objectives.  The costs associated with  this
contract  have been recorded by Telecom and  no amounts have been charged to the
Company.
 
    The Company and Telecom  have also entered  into employment agreements  with
other executives that provide for annual base salaries and cash bonuses based on
achievement  of specific performance goals. These contracts may be terminated at
any time by management.
 
FINANCING AGREEMENT
 
   
    During 1994, the Company entered  into an agreement with Southeast  Research
Partners  ("SERP"), a subsidiary  of Josephthal, Lyons &  Ross, a Florida broker
dealer, to procure additional financing for the Company in exchange for cash and
options to purchase capital stock of the Company. Pursuant to a letter agreement
dated July  12,  1995,  the Company  and  Telecom  paid SERP  $245,000  and  the
shareholders  of the Company granted SERP  options to purchase 313,612 shares of
the Company's  Common  Stock directly  from  the Founding  Stockholders  for  an
aggregate consideration of $210,000.
    
 
    As  of December 31, 1995, the Company and Telecom have accounted for the fee
of $245,000 as  part of  the financing  provided by  Landover and,  accordingly,
$175,000  has been recorded as deferred  financing costs related to the issuance
of the Advent Notes (See Note 4) and the balance of $70,000 has been  recognized
as  an offset  against the  proceeds from the  issuance of  the serial preferred
stock of Telecom.
 
9.  COMMON STOCK:
    On April 5, 1994, the Board of  Directors authorized a 5 for 1 stock  split.
Subsequently,  on April  5, 1995, the  Board of  Directors authorized a  1 for 5
reverse stock split and simultaneously issued an additional 4,049,398 shares  of
Common Stock.
 
    On  May 30, 1996, the Board of  Directors authorized a 29,450.16 for 1 stock
split, increased the number of authorized  shares of Preferred Stock and  Common
Stock to 10,000,000 and 100,000,000,
 
                                      F-21
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
9.  COMMON STOCK, CONTINUED:
respectively,  and  changed the  par value  per  share from  $.01 to  $.001. All
references to the number of shares and per share amounts of the Company's Common
Stock in the accompanying financial statements have been restated to reflect the
five for one stock split, the one for five reverse stock split and the 29,450.16
for 1 stock split, unless otherwise  indicated. All par value amounts have  been
restated to reflect the change in par value to $.001 per share.
 
10. INCOME TAXES:
    As  of  December 31,  1995  and 1994,  the  Company has  net  operating loss
carry-forwards for income tax purposes  of approximately $390,000 and  $134,000,
respectively,  which will expire  between 2008 and 2010.  Deferred tax assets of
approximately $130,000 and $46,000 at December 31, 1995 and 1994,  respectively,
principally  comprised of such net operating  tax loss carry-forwards, have been
offset in full by a valuation allowance.
 
11. RELATED PARTY TRANSACTIONS:
    On May 8, 1995, the Company and Telecom entered into a consulting  agreement
with  Landover as  a strategic and  financial consultant.  Telecom paid Landover
$70,000 for services under this agreement during 1995. The consulting  agreement
was terminated on November 13, 1995.
 
    On  November 13,  1995, the  Company and  Telecom entered  into a management
consulting agreement  with Landover  to  provide strategic  planning,  corporate
development and general management. Under the agreement, the Company and Telecom
will  pay Landover $35,000 per month for  an initial one year term, renewable by
the Company and Telecom for two additional one year terms. The aggregate expense
recognized by  Telecom under  this agreement  during 1995  amounted to  $70,000.
These  expenses have been recorded by Telecom  and no portion of such costs have
been charged  to the  Company. The  agreement also  provides that  in the  event
Landover  arranges financing, acquisitions or certain other transactions for the
Company and Telecom,  Landover will be  paid a fee  in accordance with  industry
standards.
 
    Pursuant  to the Purchase  Agreement, the Company  and Telecom paid Landover
$391,750 for expenses  in connection  with the Landover  Funding Commitment,  of
which  $250,000 has been capitalized as  deferred financing costs by the Company
and the balance of $141,750 has been charged to paid-in capital of Telecom.
 
    Telecom  has  funded  certain  expenses  and  investments  of  the  Company,
including  the Company's  investment in ART  West and payments  of financing and
other operating costs. The amounts funded by Telecom to date totaling  $805,803,
offset by accrued interest income of $67,123 related to the note receivable from
Telecom (see Note 4) have been included in the amount due to Telecom.
 
    In  1994,  the  Company shared  office  space with  a  law firm  in  which a
principal of the law firm was also one of the Founding Stockholders. The Company
paid rent in the amount of  $6,353 to the law firm  for the use of their  office
space.  The  law firm  also regularly  provides legal  services to  the Company.
During 1995  and  1994,  the  Company incurred  fees  of  $34,770  and  $74,550,
respectively, for such services.
 
                                      F-22
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
12. FAIR VALUES OF FINANCIAL INSTRUMENTS
    The  carrying amounts and fair values of the Company's financial instruments
at December 31 were as follows:
 
<TABLE>
<CAPTION>
                                                                          1995                      1994
                                                              ----------------------------  --------------------
                                                                CARRYING                    CARRYING     FAIR
                                                                 AMOUNT       FAIR VALUE     AMOUNT      VALUE
                                                              -------------  -------------  ---------  ---------
<S>                                                           <C>            <C>            <C>        <C>
Note receivable from Telecom................................  $   5,000,000  $   5,000,000     --         --
Notes payable...............................................      4,950,000      4,950,000  $  70,000  $  70,000
</TABLE>
 
    Note receivable from Telecom: The  carrying amounts reported in the  balance
sheet are a reasonable estimate of fair values.
 
    Notes   payable:  The  carrying  amounts   reported  in  the  balance  sheet
approximate fair values based upon  interest rates that are currently  available
to the Company for issuance of similar debt with similar terms and maturities.
 
                                      F-23
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
                   UNAUDITED INTERIM CONDENSED BALANCE SHEETS
                         AS OF MARCH 31, 1996 AND 1995
 
<TABLE>
<CAPTION>
                                                                                           1996           1995
                                                                                      --------------  ------------
<S>                                                                                   <C>             <C>
                                                      ASSETS
Current assets:
  Cash..............................................................................  $        5,970  $        255
                                                                                      --------------  ------------
      Total current assets..........................................................           5,970           255
Equity investments..................................................................       3,242,401
FCC licenses........................................................................           8,913
Property and equipment, net.........................................................           1,292         3,448
Other assets........................................................................          23,212        34,030
                                                                                      --------------  ------------
      Total assets..................................................................  $    3,281,788  $     37,733
                                                                                      --------------  ------------
                                                                                      --------------  ------------
 
                                  LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable and accrued liabilities..........................................  $        2,500  $      4,230
  Due to Telecom....................................................................         498,100
  Notes payable.....................................................................                       114,334
                                                                                      --------------  ------------
      Total current liabilities.....................................................         500,600       118,564
Redeemable Preferred Stock, $.01 par value; 1,000 shares authorized; 1 share issued
 and outstanding at March 31, 1996..................................................          44,930
                                                                                      --------------  ------------
Commitments and contingencies
 
Stockholders' equity (deficit):
  Common Stock, $.001 par value; 58,900,320 shares authorized; 10,013,055 and
   5,890,032 shares issued and outstanding..........................................          10,013         5,890
  Additional paid-in capital........................................................       7,783,889        90,246
  Deficit accumulated during the development stage..................................      (5,057,644)     (176,967)
                                                                                      --------------  ------------
      Total stockholders' equity (deficit)..........................................       2,736,258       (80,831)
                                                                                      --------------  ------------
        Total liabilities and stockholders' equity (deficit)........................  $    3,281,788  $     37,733
                                                                                      --------------  ------------
                                                                                      --------------  ------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-24
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
              UNAUDITED INTERIM CONDENSED STATEMENTS OF OPERATIONS
               FOR THE THREE MONTHS ENDED MARCH 31, 1996 AND 1995
 
<TABLE>
<CAPTION>
                                                                                               1996         1995
                                                                                           -------------  ---------
<S>                                                                                        <C>            <C>
Expenses:
  General and administrative.............................................................  $      24,939  $  40,878
  Depreciation and amortization..........................................................          2,595
  Interest expense, net..................................................................            671        875
                                                                                           -------------  ---------
      Total expenses.....................................................................         28,205     41,753
Equity loss on investment in Telecom.....................................................      3,626,570
                                                                                           -------------  ---------
      Net loss...........................................................................  $   3,654,775  $  41,753
                                                                                           -------------  ---------
                                                                                           -------------  ---------
Pro forma net loss per share.............................................................  $        0.12
                                                                                           -------------
                                                                                           -------------
Pro forma weighted average number of shares of Common Stock outstanding (unaudited)......     31,651,605
                                                                                           -------------
                                                                                           -------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-25
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
              UNAUDITED INTERIM CONDENSED STATEMENTS OF CASH FLOWS
               FOR THE THREE MONTHS ENDED MARCH 31, 1996 AND 1995
 
<TABLE>
<CAPTION>
                                                                                                1996          1995
                                                                                           --------------  ----------
<S>                                                                                        <C>             <C>
Cash flows from operating activities:
  Net loss...............................................................................  $   (3,654,775) $  (41,753)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Non-cash interest expense............................................................          69,347
    Depreciation and amortization........................................................           2,595
    Equity loss on investment in Telecom.................................................       3,626,570
  Changes in operating assets and liabilities:
    Accounts payable and accrued liabilities.............................................         (43,836)     (7,459)
                                                                                           --------------  ----------
      Net cash used in operating activities..............................................             (99)    (49,212)
                                                                                           --------------  ----------
Cash flows from financing activities:
  Proceeds from loan and note payable....................................................                      44,334
                                                                                           --------------  ----------
      Net cash provided by financing activities..........................................        --            44,334
                                                                                           --------------  ----------
      Net decrease in cash...............................................................             (99)     (4,878)
Cash, beginning of period................................................................           6,069       5,133
                                                                                           --------------  ----------
Cash, end of period......................................................................  $        5,970  $      255
                                                                                           --------------  ----------
                                                                                           --------------  ----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-26
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
           NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION:
 
THE COMPANY
 
    Advanced  Radio  Technologies  Corporation  ("ART"  or  the  "Company")  was
organized as a  Delaware corporation on  August 23, 1993,  to provide  broadband
wireless  digital telecommunications services to the domestic telecommunications
market.
 
BASIS OF PRESENTATION
 
    The unaudited interim  condensed financial statements  included herein  have
been  prepared by the Company. The  foregoing statements contain all adjustments
(consisting only of normal recurring adjustments)  which are, in the opinion  of
the  Company's management, necessary to present fairly the financial position of
the Company as of March 31, 1996 and 1995, and the results of its operations and
its cash flows for the three months ended March 31, 1996 and 1995.
 
    Certain information and footnote disclosures normally included in  financial
statements  have been condensed or omitted pursuant to the rules and regulations
of the Securities and Exchange Commission. These condensed financial  statements
should  be  read in  conjunction with  the Company's  December 31,  1995 audited
financial statements and notes thereto.
 
    The financial statements have  been prepared on the  going concern basis  of
accounting,   which  contemplates  realization  of  assets  and  liquidation  of
liabilities in  the  ordinary  course  of  business.  The  Company  has  limited
financial  resources,  incurred operating  losses since  inception and  does not
expect to recognize material  operating revenues until  the commencement of  its
commercial  services, which is anticipated to  occur in fiscal 1996. The Company
estimates that  revenues in  1996 will  not be  sufficient to  fund its  initial
operating  expenses  and  other  working  capital  needs,  including consulting,
service and purchase commitments. The Company's continued funding of its initial
operating  expenses,  working  capital  needs  and  contractual  commitments  is
dependent  upon  its  ability to  raise  additional financing.  The  Company and
Advanced Radio  Telecom Corp.  ("Telecom")  (see Note  2) have  engaged  various
investment  bankers to assist them in  raising financing through a public equity
and debt offering. There can be no  assurance that the Company and Telecom  will
be  successful in their effort to raise additional financing through this public
offering or, if available, that the Company  and Telecom will be able to  obtain
it  on  acceptable terms.  These conditions  raise  substantial doubt  about the
Company's ability to continue  as a going concern.  The financial statements  do
not  include  any  adjustments  that  might result  from  the  outcome  of these
uncertainties.
 
2.  STOCKHOLDERS' AGREEMENT:
    On February 2, 1996, the Company, Telecom and their respective  shareholders
agreed  to an amendment and restatement of the Stockholders' Agreement providing
for (i) termination effective  on the closing of  a public share offering,  (ii)
amendment and restatement of the Certificate of Incorporation and reorganization
of  the capital structure of Telecom; (iii) the exchange of the Advent Notes and
one share of  ART Series A  Redeemable Preferred  Stock for shares  of Series  E
preferred  stock  of  Telecom;  (iv)  revision  of  provisions  for  election of
directors;  (v)  amendment   and  restatement  of   ART's  registration   rights
agreements;  (vi) release  of shares  escrowed in  connection with  the original
Stockholders' Agreement; and (vii) approval of the definitive merger agreement.
 
    The definitive merger  agreement, as entered  into on February  2, 1996  and
subsequently  restated and  amended on June  26, 1996  (the "Merger Agreement"),
provides for the merger of a newly-formed wholly owned subsidiary of the Company
("Merger Sub")  into  Telecom  (the "Merger")  subject  to  certain  conditions,
including  the receipt  of FCC approval.  Prior to the  Merger, each outstanding
share of
 
                                      F-27
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
      NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS, CONTINUED
 
2.  STOCKHOLDERS' AGREEMENT: CONTINUED:
Telecom's serial preferred stock will be  converted into 13 shares of  Telecom's
common  stock. In the Merger  each outstanding share of  common stock of Telecom
will be exchanged for the right to  receive an equal number of shares of  Common
Stock of the Company. As a result, Telecom will become a wholly owned subsidiary
of  the  Company.  The Merger  Agreement  provides  that if  the  Merger  is not
consummated by May 13, 1997, the shares  of Telecom's common stock owned by  the
Company  will be  surrendered to  Telecom and  the Services  Agreement is  to be
revised to, among other revisions, extend the term to 40 years and provide for a
proportionate participation by the Company's stockholders in any dividends  paid
by  Telecom or the proceeds from any  sale of Telecom. The Merger Agreement also
provides for the  assignment of Telecom's  interests in all  of its  agreements,
including  the  various  services agreements,  employment  agreements, equipment
purchase agreements and  purchase option  agreements, to  the Company.  Further,
upon  the Merger, the holders of warrants  to purchase an aggregate of 2,302,136
shares of Telecom common stock will be entitled to purchase an equivalent number
of shares of Common Stock on the same terms. Employee stock options to  purchase
1,664,732  shares of Telecom's common stock will be converted into similar stock
options of the Company.
 
3.  NET LOSS PER SHARE
    Historical net loss per share is computed  based on the loss for the  period
divided  by the  weighted average number  of shares of  Common Stock outstanding
during the period. Historical net loss per share and the weighted average number
of shares of Common Stock outstanding are as follows:
 
<TABLE>
<CAPTION>
                                                                   FOR THE THREE MONTHS ENDED
                                                                           MARCH 31,
                                                                  ----------------------------
                                                                      1996           1995
                                                                  -------------  -------------
<S>                                                               <C>            <C>
Net loss per share..............................................  $         .37  $    --
                                                                  -------------  -------------
                                                                  -------------  -------------
Weighted average number shares of Common Stock outstanding......     10,013,055     10,013,055
                                                                  -------------  -------------
                                                                  -------------  -------------
</TABLE>
 
    The Securities and  Exchange Commission requires  that potentially  dilutive
instruments  issued within one year prior  to a proposed initial public offering
at exercise prices below the expected  initial public offering price be  treated
as  outstanding for all periods presented. Accordingly, an additional 21,638,550
shares are reflected in  the weighted average number  of shares of Common  Stock
outstanding  in computing  the unaudited  pro forma net  loss per  share for the
three months ended March 31, 1996.
 
4.  NOTES RECEIVABLE FROM TELECOM AND CONVERTIBLE NOTE PAYABLE TO ADVENT:
    On February  2,  1996, the  Company,  Telecom  and Advent  entered  into  an
exchange agreement under which the Advent Notes, including accrued interest, and
the  one share of ART's Series A  Redeemable Preferred Stock held by Advent were
exchanged for 232,826  shares of Series  E preferred stock  of Telecom, and  the
notes  payable  by the  Company to  Advent and  by Telecom  to the  Company were
canceled, the related interest forgiven, and Telecom became the owner of the one
share of ART Series A Redeemable Preferred Stock.
 
5.  INVESTMENTS:
    The Company accounts for its 50% interest in the ART West joint venture  and
its 34% interest in Telecom under the equity method.
 
    In  June  1996,  the  Company agreed  to  acquire  Extended's  50% ownership
interest in ART West for $6 million  in cash upon consummation of public  equity
and  debt offerings with aggregate  net proceeds of $125  million to the Company
and  receipt  of  FCC  approval.  In  addition,  the  Company  entered  into   a
 
                                      F-28
<PAGE>
                    ADVANCED RADIO TECHNOLOGIES CORPORATION
                         (A DEVELOPMENT STAGE COMPANY)
      NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS, CONTINUED
 
5.  INVESTMENTS: CONTINUED:
ten-year  management  agreement  which,  effective June  1,  1996,  replaced the
services agreement with ART West with an arrangement whereby the Company  agrees
to construct, operate, and manage the ART West systems in exchange for a license
fee equal to 10% of recurring operating revenues.
 
    During 1995, the Company recorded $802,002 as an investment in Telecom based
upon  the fair value of Escrow Shares released  in 1995, the effect of which was
recognized as additional paid-in  capital in the Company.  On February 2,  1996,
the  Company recorded an  additional $6,795,514 based  on the fair  value of the
remaining Escrow Shares released, which was accounted for in the same manner.
 
    The Company recognizes its proportionate share  of the losses of Telecom  to
the  extent of its  investment, funding and  financial commitments. During 1996,
the Company has recognized its proportionate  share of the losses of Telecom  in
the amount of $3,626,570.
 
6.  COMMCOCCC ASSET ACQUISITION
    During July 1996, the Company entered into an agreement with CommcoCCC, Inc.
("CommcoCCC")   to  acquire  CommcoCCC's   interests  in  certain   38  GHz  FCC
authorizations (the "CommcoCCC Assets") in  exchange for 16.5 million shares  of
Common  Stock. The  acquisition of  the CommcoCCC  Assets is  subject to various
conditions including (i)  minimum population coverage  of the authorizations  of
the  Company and CommcoCCC, (ii) receipt of final FCC and other approvals, (iii)
receipt by CommcoCCC of an opinion as to the tax-free nature of the  transaction
(iv)  the accuracy of representations and warranties except for breaches that do
not have  in  the  aggregate  a  material adverse  effect,  (v)  no  pending  or
threatened  material  litigation, (vi)  consummation of  public equity  and debt
offerings  on  terms  reasonably  satisfactory  to  CommcoCCC  and  (vii)  other
customary  closing conditions.  Pending the  completion of  the acquisition, the
Company has agreed to construct, manage and operate the CommcoCCC Assets.
 
    The Company has given  a stockholder ("Commco LLC")  of CommcoCCC an  option
(the "Option") to purchase FCC authorizations in specified market areas in which
the  Company will  have more than  one authorization. The  Option is exercisable
only in the event that the  CommcoCCC Acquisition is consummated and Commco  LLC
receives  authorizations  pursuant to  pending  applications covering  a minimum
specified population  and expires  nine  months after  the consummation  of  the
Common  Stock Offering.  The price of  authorizations to be  purchased under the
Option is based upon a formula that  considers the market price of Common  Stock
on the date of exercise.
 
    In  connection with the  agreement to acquire  the CommcoCCC Assets, certain
stockholders of CommcoCCC loaned the Company $3 million in cash in exchange  for
notes  due September 30, 1996 (the "CommcoCCC Notes") with interest at the prime
rate and received three year warrants to purchase 50,000 shares of Common  Stock
at  a price of $15  per share. The CommcoCCC Notes  are collateralized by all of
the assets of the Company and, if not paid in full when due, the unpaid  balance
is  convertible into Common Stock,  at the option of  each holder, at stipulated
per share prices based upon the timing of exercise.
 
7.  RELATED PARTY TRANSACTIONS
    Telecom has funded the payment of certain expenses of the Company, including
financing costs. The amounts  funded by Telecom during  the quarter ended  March
31,  1996 totaled $175,000.  The balance resulting  from the funding activities,
offset by  the  net  effect of  the  conversion  of the  Advent  Notes  and  the
cancellation  of the note receivable  from Telecom (Note 3),  is shown as due to
Telecom in the accompanying balance sheet.
 
                                      F-29
<PAGE>
                       REPORT OF INDEPENDENT ACCOUNTANTS
 
To the Board of Directors and Stockholders of
Advanced Radio Telecom Corp.:
 
    We  have audited  the accompanying balance  sheet of  Advanced Radio Telecom
Corp. (a development  stage company) as  of December 31,  1995, and the  related
statements  of operations, stockholders'  deficit and cash  flows for the period
from March 28, 1995  (date of inception) to  December 31, 1995. These  financial
statements   are   the   responsibility  of   the   Company's   management.  Our
responsibility is to express an opinion  on these financial statements based  on
our audit.
 
    We  conducted  our  audit  in accordance  with  generally  accepted auditing
standards. Those standards require that we plan and perform the audit to  obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also  includes
assessing  the  accounting principles  used  and significant  estimates  made by
management, as well as evaluating the overall financial statement  presentation.
We believe that our audit provides a reasonable basis for our opinion.
 
    In  our opinion, the financial statements  referred to above present fairly,
in all material respects, the financial position of Advanced Radio Telecom Corp.
as of December 31, 1995,  and the results of its  operations and its cash  flows
for  the period from March 28, 1995 (date of inception) to December 31, 1995, in
conformity with generally accepted accounting principles.
 
    The accompanying  financial  statements  have been  prepared  on  the  going
concern  basis  of  accounting,  which contemplates  realization  of  assets and
liquidation of liabilities in the ordinary  course of business. As described  in
Note  1, the Company has  a substantial working capital  deficit at December 31,
1995, has  incurred operating  losses since  inception and  does not  expect  to
generate significant operating revenues until fiscal 1996. The Company estimates
that  revenues  in 1996  will  not be  sufficient  to fund  its  initial capital
requirements, operating expenses and other  working capital needs. In  addition,
as  set  forth  in  Notes  8  and  2,  the  Company  has  significant  financial
commitments.  The   Company's  continued   funding   of  its   initial   capital
requirements,   operating  expenses,  working   capital  needs  and  contractual
commitments is  dependent  upon  its  ability  to  raise  additional  financing.
Management's  plans in  this regard  are discussed  in Note  1. These conditions
raise substantial  doubt about  the Company's  ability to  continue as  a  going
concern.  The financial  statements do  not include  any adjustments  that might
result from the outcome of these uncertainties.
 
                                          COOPERS & LYBRAND L.L.P.
 
New York, New York
April 26, 1996, except for Note 2B
as to which the date is June 26, 1996
 
                                      F-30
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                                 BALANCE SHEET
                               DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                           ASSETS
<S>                                                                              <C>
Current assets:
  Cash and cash equivalents....................................................  $   627,585
  Due from ART (Note 12).......................................................      738,680
  Other current assets.........................................................       52,325
                                                                                 -----------
    Total current assets.......................................................    1,418,590
Property and equipment, net (Note 5)...........................................    3,579,838
FCC licenses (Note 4)..........................................................    4,226,821
Equipment and other deposits (Note 8)..........................................      284,012
Deferred financing costs.......................................................      321,354
                                                                                 -----------
      Total assets.............................................................  $ 9,830,615
                                                                                 -----------
                                                                                 -----------
 
                           LIABILITIES AND STOCKHOLDERS' DEFICIT
Current liabilities:
  Accounts payable and accrued liabilities (Note 6)............................  $ 3,450,537
                                                                                 -----------
      Total current liabilities................................................    3,450,537
Note payable to ART (Note 7)...................................................    5,000,000
Note payable to EMI (Note 4)...................................................    1,500,000
                                                                                 -----------
      Total liabilities........................................................    9,950,537
                                                                                 -----------
Commitments and contingencies (Notes 1, 8, 12 and 14)
Stockholders' deficit (Note 9):
  Serial preferred stock, $.001 par value, 488,492 shares issued and
   outstanding.................................................................          488
  Class A common stock, $.001 par value, 7,779,135 shares issued and
   outstanding.................................................................        7,779
  Class B common stock, $.001 par value, 7,512,076 shares issued and
   outstanding.................................................................        7,512
  Additional paid-in capital...................................................    2,845,372
  Deficit accumulated during the development stage.............................   (2,981,073)
                                                                                 -----------
      Total stockholders' deficit..............................................     (119,922)
                                                                                 -----------
        Total liabilities and stockholders' deficit............................  $ 9,830,615
                                                                                 -----------
                                                                                 -----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-31
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENT OF OPERATIONS
             FOR THE PERIOD FROM MARCH 28, 1995 (DATE OF INCEPTION)
                              TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
Operating revenue..............................................................  $    5,793
<S>                                                                              <C>
                                                                                 ----------
Expenses:
  General and administrative expenses (Notes 8, 9 and 10)......................   2,706,336
  Market development expenses..................................................     191,693
  Depreciation and amortization................................................       5,306
  Interest expense, net (Notes 4 and 7)........................................      83,531
                                                                                 ----------
    Total expenses.............................................................   2,986,866
                                                                                 ----------
      Net loss.................................................................  $2,981,073
                                                                                 ----------
                                                                                 ----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-32
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                       STATEMENT OF STOCKHOLDERS' DEFICIT
             FOR THE PERIOD FROM MARCH 28, 1995 (DATE OF INCEPTION)
                              TO DECEMBER 31, 1995
<TABLE>
<CAPTION>
                                        COMMON STOCK                             PREFERRED STOCK
                                    --------------------  -------------------------------------------------------------
SHARES                               CLASS A    CLASS B    SERIES A     SERIES B     SERIES C     SERIES D      TOTAL
- ----------------------------------  ---------  ---------  -----------  -----------  -----------  -----------  ---------
<S>                                 <C>        <C>        <C>          <C>          <C>          <C>          <C>
Issuance of common stock to ART
 for cash.........................  4,420,000
Issuance of common stock to
 Landover and affiliates for
 cash.............................    260,000  8,320,000
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................                           332,091                                            332,091
  Series B........................                                         82,318                                82,318
  Series C........................                                                       5,402                    5,402
Issuance of Series D preferred
 stock for cash...................                                                                   61,640      61,640
Shares issued to reflect
 anti-dilution adjustments........  3,099,135                  2,852        4,189                                 7,041
Redemption of common stock from
 Landover.........................              (807,924)
                                    ---------  ---------  -----------  -----------       -----   -----------  ---------
Balance at December 31, 1995......  7,779,135  7,512,076     334,943       86,507        5,402       61,640     488,492
                                    ---------  ---------  -----------  -----------       -----   -----------  ---------
                                    ---------  ---------  -----------  -----------       -----   -----------  ---------
 
<CAPTION>
SHARES
- ----------------------------------
<S>                                 <C>            <C>              <C>
Issuance of common stock to ART
 for cash.........................
Issuance of common stock to
 Landover and affiliates for
 cash.............................
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................
  Series B........................
  Series C........................
Issuance of Series D preferred
 stock for cash...................
Shares issued to reflect
 anti-dilution adjustments........
Redemption of common stock from
 Landover.........................
Balance at December 31, 1995......
</TABLE>
<TABLE>
<CAPTION>
                                                                               PAR VALUE
                                    -----------------------------------------------------------------------------------------------
                                          COMMON STOCK                                   PREFERRED STOCK
                                    ------------------------  ---------------------------------------------------------------------
AMOUNTS                               CLASS A      CLASS B     SERIES A      SERIES B       SERIES C       SERIES D        TOTAL
- ----------------------------------  -----------  -----------  -----------  -------------  -------------  -------------  -----------
<S>                                 <C>          <C>          <C>          <C>            <C>            <C>            <C>
Issuance of common stock to ART
 for cash.........................   $   4,420
Issuance of common stock to
 Landover and affiliates for
 cash.............................         260    $   8,320
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................                             $     332                                                 $     332
  Series B........................                                           $      82                                          82
  Series C........................                                                          $       5                            5
Issuance of Series D preferred
 stock for cash...................                                                                         $      62            62
Shares issued to reflect
 anti-dilution adjustments........       3,099                         3             4                                           7
Serial preferred stock issuance
 costs............................
Redemption of common stock from
 Landover.........................                     (808)
Investment by ART as a result of
 the release of escrow shares.....
Accrued stock option
 compensation.....................
Net loss..........................
                                                                                                   --
                                    -----------  -----------       -----           ---                           ---         -----
Balance at December 31, 1995......   $   7,779    $   7,512    $     335     $      86      $       5      $      62     $     488
                                                                                                   --
                                                                                                   --
                                    -----------  -----------       -----           ---                           ---         -----
                                    -----------  -----------       -----           ---                           ---         -----
 
<CAPTION>
 
                                    ADDITIONAL
                                      PAID-IN     ACCUMULATED
AMOUNTS                               CAPITAL       DEFICIT        TOTAL
- ----------------------------------  -----------  -------------  -----------
<S>                                 <C>          <C>            <C>
Issuance of common stock to ART
 for cash.........................  $    (4,080)                $       340
Issuance of common stock to
 Landover and affiliates for
 cash.............................       (7,560)                      1,020
Issuance of preferred stock to
 limited partnerships affiliated
 with Landover for cash:
  Series A........................    1,006,268                   1,006,600
  Series B........................      880,618                     880,700
  Series C........................      112,695                     112,700
Issuance of Series D preferred
 stock for cash...................    1,999,938                   2,000,000
Shares issued to reflect
 anti-dilution adjustments........       (3,106)
Serial preferred stock issuance
 costs............................     (229,814)                   (229,814)
Redemption of common stock from
 Landover.........................   (1,999,192)                 (2,000,000)
Investment by ART as a result of
 the release of escrow shares.....      802,002                     802,002
Accrued stock option
 compensation.....................      287,603                     287,603
Net loss..........................                $(2,981,073)   (2,981,073)
 
                                    -----------  -------------  -----------
Balance at December 31, 1995......  $ 2,845,372   $(2,981,073)  $  (119,922)
 
                                    -----------  -------------  -----------
                                    -----------  -------------  -----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-33
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                            STATEMENT OF CASH FLOWS
             FOR THE PERIOD FROM MARCH 28, 1995 (DATE OF INCEPTION)
                              TO DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
Cash flows from operating activities:
<S>                                                                              <C>
  Net loss.....................................................................  $(2,981,073)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Depreciation and amortization..............................................        5,306
    Non-cash compensation expense..............................................    1,089,605
    Changes in operating assets and liabilities:
      Deposits.................................................................       (4,012)
      Accounts payable and accrued liabilities.................................      567,290
      Other current assets.....................................................      (52,325)
                                                                                 -----------
        Net cash used in operating activities..................................   (1,375,209)
                                                                                 -----------
Cash flows from investing activities:
  Acquisition of EMI licenses and property and equipment.......................   (3,023,971)
  Additions to property and equipment..........................................     (621,364)
  Advances to ART..............................................................     (738,680)
  Deposits on equipment........................................................     (280,000)
                                                                                 -----------
        Net cash used in investing activities..................................   (4,664,015)
                                                                                 -----------
Cash flows from financing activities:
  Proceeds from issuance of common stock.......................................        1,360
  Proceeds from issuance of serial preferred stock.............................    4,000,000
  Stock issuance costs.........................................................     (208,814)
  Proceeds from issuance of note payable to ART................................    5,000,000
  Advances from Landover and affiliates........................................      175,000
  Payments on advances from Landover and affiliates............................     (175,000)
  Redemption of common stock...................................................   (2,000,000)
  Additions to deferred financing costs........................................     (125,737)
                                                                                 -----------
        Net cash provided by financing activities..............................    6,666,809
                                                                                 -----------
          Net increase in cash and cash equivalents and balance at end of
           period..............................................................  $   627,585
                                                                                 -----------
                                                                                 -----------
Supplemental cash flow information:
  Non-cash financing and investing activities:
    Additions to property and equipment........................................  $ 2,666,630
    Issuance of promissory note payable to EMI.................................    1,500,000
    Accrued stock issuance costs...............................................       21,000
    Accrued deferred financing costs...........................................      195,617
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-34
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                         NOTES TO FINANCIAL STATEMENTS
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION:
 
THE COMPANY
 
    Advanced  Radio  Telecom Corp.  ("Telecom"),  formerly named  Advanced Radio
Technology Ltd., was incorporated in Delaware as a subsidiary of Advanced  Radio
Technologies  Corporation  ("ART") on  March 28,  1995,  to develop,  market and
deliver broadband  telecommunication  and information  services  throughout  the
United States. The Company's business objective is to organize and finance local
operating  facilities,  establish  strategic  alliances  with  other businesses,
acquire new  wireless  telecommunications  technologies,  and  market  broadband
wireless services to telecommunications service providers and end users.
 
    Telecom  was organized by ART 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") (see Note 4).
Under the terms of a purchase agreement between Telecom, Landover and ART  dated
April  21, 1995 (the  "Purchase Agreement"), Landover  was obligated to purchase
$7.0 million of securities of Telecom. Pursuant to the Purchase Agreement and  a
stockholders'  agreement between Telecom, ART  and their respective shareholders
dated May 8, 1995  (the "Stockholders' Agreement"), Telecom  and ART will  merge
once  approval from the  Federal Communications Commission  (the "FCC") has been
granted. On February 2, 1996, Telecom  and ART entered into a definitive  merger
agreement  (the "Merger  Agreement") providing for  a merger of  Telecom and ART
(the "Merger"). (See Note 2).
 
INITIAL CAPITALIZATION
 
    As its initial capitalization,  Telecom issued 8,320,000  shares of Class  B
common  stock  to  Landover  and  260,000 shares  of  Class  A  common  stock to
consultants to Landover, for aggregate cash consideration of $1,020. Such shares
of Class  B common  stock  and Class  A common  stock  represented 64%  and  2%,
respectively,  of the total  number of shares  of capital stock  of Telecom then
outstanding. Concurrently, Telecom  issued 4,420,000  shares of  Class A  common
stock,  representing 34% of the total number  of shares of capital stock, to ART
for $340. The number of shares of Class A and Class B common stock issued at the
initial capitalization of Telecom shown above give effect to the 13 for 1  stock
split  but are prior to  the issuance of anti-dilutive  shares (see Note 9). All
references to number  of shares of  common stock  and per share  amounts in  the
accompanying  financial statements and  footnotes have been  restated to reflect
the 13 for 1 stock split unless otherwise indicated.
 
    Under the  Purchase Agreement,  Landover agreed  to invest  or cause  to  be
invested  $7.0  million in  Telecom and  its  affiliates (the  "Landover Funding
Commitment"). In consideration for this $7.0 million investment, Telecom  agreed
to  issue  serial  preferred stock,  the  number  of shares  of  which  would be
designated by Landover.
 
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.  Telecom has limited  financial
resources,  has incurred operating losses since inception and does not expect to
generate significant operating revenues until the commencement of its commercial
services, which is anticipated to occur  in fiscal 1996. Telecom 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  set  forth in  Notes  8 and  2.  Telecom's funding  of  its initial
operating  expenses,  working  capital  needs  and  contractual  commitments  is
dependent upon its ability to raise additional
 
                                      F-35
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
1.  FORMATION OF THE COMPANY AND BASIS OF PRESENTATION, CONTINUED:
financing.  Telecom and  ART have engaged  various investment  bankers to assist
them in raising  financing through  a public equity  and debt  offering of  ART.
There  can be no assurance that Telecom and ART will be successful in its effort
to raise additional  financing through  these offerings or,  if available,  that
Telecom  and ART will be able to obtain it on acceptable terms. These conditions
raise substantial doubt about Telecom'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.  REORGANIZATION AND PENDING MERGER WITH ART:
 
A -- MERGER
 
    Under the terms of the Purchase Agreement, Telecom and ART intend to operate
both companies as a single  enterprise and were committed  to merge if and  when
permitted  by the FCC.  Concurrent with the Purchase  Agreement, Telecom and ART
entered into an exclusive 20-year services agreement (the "Services  Agreement")
for  the construction, development and operation  of systems in ART markets (see
Note 8).
 
    On February 2, 1996, Telecom,  ART 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 (see  Note 9); (iii)  the exchange  of the Advent
Notes and one  share of ART  Series A  Redeemable Preferred Stock  for Series  E
preferred  stock  of  Telecom (see  Note  7);  (iv) revision  of  provisions for
election of directors; (v) amendment  and restatement of Telecom's  registration
rights  agreements;  (vi)  release of  shares  escrowed in  connection  with the
original  Stockholders'  Agreement  (see  Note  9);  and  (vii)  approval  of  a
definitive agreement to merge ART and Telecom (the "Reorganization").
 
B -- 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 ART
("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 ART. As a result, Telecom will become a wholly owned  subsidiary
of  ART. The Merger Agreement provides that  if the Merger is not consummated by
May 13,  1997,  the shares  of  Telecom's common  stock  owned by  ART  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 ART'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 ART. 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  ART
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
ART.
 
                                      F-36
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
3.  SIGNIFICANT ACCOUNTING POLICIES:
 
DEVELOPMENT STAGE ENTERPRISE
 
    Telecom 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.
 
CASH AND CASH EQUIVALENTS
 
    Telecom  considers all  highly liquid  investments purchased  with remaining
maturities of three months or less to be cash equivalents.
 
PROPERTY AND EQUIPMENT
 
    Property and equipment is stated at cost. Depreciation and amortization  are
computed  using the straight-line method over  the estimated useful lives of the
related assets as  follows: wireless  transmission equipment -  5 years;  office
furniture and equipment - 3 years.
 
FCC LICENSES
 
    Telecom  has  obtained  radio  spectrum  rights  under  FCC  issued licenses
throughout the United States through the purchase of such rights held by  others
and  by petitioning the  FCC directly. 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 amounts of those assets
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,  technological,
regulatory or other changes.
 
    Telecom'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, FCC licenses and other capitalized costs related to  the
market.
 
FINANCING COSTS
 
    Direct  costs associated  with obtaining  equity financing  are deferred and
charged to additional paid-in  capital as the related  funds are raised.  Direct
costs  associated with obtaining debt financing are deferred and amortized using
the effective interest rate method commencing when the related funds are raised.
Deferred costs associated with unsuccessful financings are charged to expense.
 
REVENUE RECOGNITION
 
    Revenue from  telecommunications services  are recognized  ratably over  the
period such services are provided.
 
                                      F-37
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
3.  SIGNIFICANT ACCOUNTING POLICIES, CONTINUED:
INCOME TAXES
 
    Telecom  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.
 
NET LOSS PER SHARE
 
    Net loss per share  of $0.19 is  computed based on the  loss for the  period
from  March 28,  1995 (date of  inception) to  December 31, 1995  divided by the
weighted average number of shares of common stock outstanding of 15,919,596.
 
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.
 
CONCENTRATION OF CREDIT RISKS
 
    Telecom   places  its  temporary  cash   investments  with  major  financial
institutions. At December 31, 1995, the Company's temporary cash investments are
principally placed  in  one entity.  Other  financial instruments  which  expose
Telecom  to potential credit risk include the  amount due from ART (Note 12) and
deposits on equipment (Note 8).
 
4.  ACQUISITION OF ASSETS OF EMI:
    On April 4, 1995, ART 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 $3.0
million in cash and a three year non-negotiable promissory note in the amount of
$1.5 million. Pursuant to the terms of the Purchase Agreement, in November 1995,
ART assigned its rights and obligations under the EMI purchase option  agreement
to  Telecom. The FCC subsequently approved the  transfer of the EMI licenses and
Telecom directly purchased the EMI Assets  in November 1995. The total  purchase
price, including expenses, was allocated to the acquired assets as follows:
 
<TABLE>
<S>                                                              <C>
Property and equipment.........................................  $  297,150
FCC licenses...................................................   4,226,821
                                                                 ----------
                                                                 $4,523,971
                                                                 ----------
                                                                 ----------
</TABLE>
 
    The  promissory note issued by Telecom, with  a guarantee by ART, is payable
in quarterly installments of  principal of $187,500  beginning January 1,  1997.
Interest is payable quarterly at a major commercial bank's prime rate plus 2.0%,
or 10.5% as of December 31, 1995.
 
    On  November 8, 1995 Landover advanced $175,000 to Telecom to fund a portion
of the initial payment  to EMI. Telecom  repaid such advance  later in the  same
month.
 
                                      F-38
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
5.  PROPERTY AND EQUIPMENT:
 
PROPERTY AND EQUIPMENT COMPRISE:
 
<TABLE>
<S>                                                              <C>
Wireless transmission equipment................................  $3,496,905
Office furniture and equipment.................................      88,239
                                                                 ----------
                                                                  3,585,144
Accumulated depreciation.......................................      (5,306)
                                                                 ----------
                                                                 $3,579,838
                                                                 ----------
                                                                 ----------
</TABLE>
 
    As  of December 31, 1995, excluding the property and equipment acquired from
EMI (Note 4), the wireless transmission equipment acquired to date has not  been
placed into service.
 
6.  ACCOUNTS PAYABLE AND ACCRUED LIABILITIES:
 
ACCOUNTS PAYABLE AND ACCRUED LIABILITIES COMPRISE:
 
<TABLE>
<S>                                                              <C>
Accrued interest payable.......................................  $   20,712
Salaries and other employee related costs......................     267,091
Trade accounts payable.........................................     496,104
Wireless transmission equipment payable........................   2,666,630
                                                                 ----------
                                                                 $3,450,537
                                                                 ----------
                                                                 ----------
</TABLE>
 
7.  NOTE PAYABLE TO ART:
    ART,   Telecom  and  several  entities  referred  to  as  the  Advent  Group
("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  ART,  Telecom  and  certain  specified
affiliates.  Pending  the merger  of  these entities  (see  Note 2),  ART issued
promissory notes  (the "Advent  Notes") with  an aggregate  principal amount  of
$4,950,000  and  one  share of  ART's  Series  A Redeemable  Preferred  Stock in
exchange for $5.0 million 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 ART  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  $10.0 million  or (ii) at
Advent's election.
 
    On November 13,  1995, the gross  proceeds of $5.0  million received by  ART
from  Advent  were transferred  to Telecom  in  exchange for  a note  with terms
equivalent  to  the  terms  of  the   Advent  Notes.  In  connection  with   the
Reorganization  on February  2, 1996,  ART, 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, the note
was canceled, and  Telecom became the  owner of the  one share of  ART Series  A
Redeemable Preferred Stock.
 
                                      F-39
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
8.  COMMITMENTS:
 
EQUIPMENT PURCHASE AGREEMENT
 
    On  August 11, 1995, Telecom entered  into an agreement to purchase wireless
transmission equipment from a vendor. Under the terms of the agreement,  Telecom
is  obligated  to purchase  a specified  number  of wireless  transmission units
between August 11, 1995  and December 31, 1998,  subject to termination upon  90
days  advance notice by either  party. Telecom's initial non-cancelable purchase
order amounts to $13,260,000. Through  December 31, 1995, Telecom has  purchased
and paid for $522,812 of equipment under this contract. In addition, Telecom has
made  a $280,000  deposit under  this agreement which  is to  be applied against
future purchases after Telecom  has purchased a  specified amount of  equipment,
which is expected to occur in 1996.
 
    Telecom  currently  purchases  the  majority  of  its  wireless transmission
equipment from this vendor.  Any reduction or interruption  in supply from  this
vendor  could have a material adverse effect on Telecom until alternative supply
sources are established.  Telecom does  not manufacture,  nor does  it have  the
capability  to manufacture, any of the wireless transmission equipment necessary
to  provide  its  services.  Although  there  are  a  limited  number  of  other
manufacturers  who have, or are developing,  equipment that would meet Telecom's
requirements, there can be no assurance  that such equipment would be  available
to  Telecom on comparable terms or on  terms more favorable to those included in
its current arrangements. Moreover, a change  in vendors could cause a delay  in
Telecom's  ability to provide its services,  which would affect future operating
results adversely.
 
SERVICES AGREEMENTS
 
    Under the Services Agreement, Telecom  has agreed to construct, operate  and
manage 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 ART.
 
    Telecom,  through its Services  Agreement with ART,  has two other exclusive
services agreements, one with ART West, a  joint venture in which ART has a  50%
ownership  interest, and one with DCT Communications, Inc. ("DCT"). The terms of
these two services agreements  are substantially identical to  the terms in  the
Services  Agreement between ART and Telecom, except that the services agreements
are for five  years and compensation  to the  Company is based  on all  revenues
generated  by the systems after deducting  certain related direct expenses, less
45% which is  paid to ART  West and DCT.  There have been  no services  provided
under these agreements through December 31, 1995. One of the officers of Telecom
is the President and a shareholder of ART's joint venture partner in ART West.
 
    On  April 24, 1996,  Telecom entered into a  services agreement with TeleCom
One on terms  substantially identical  to the  terms of  the Services  Agreement
between  ART and Telecom,  except that compensation  to Telecom is  equal to all
revenues generated by the  systems, after deducting  certain expenses, less  10%
which is paid to TeleCom One.
 
    Under  the services agreements  described above, title  to the system assets
purchased by Telecom  and used  to provide  services in  the respective  markets
remains with Telecom upon termination of the services agreements.
 
                                      F-40
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
8.  COMMITMENTS, CONTINUED:
EMPLOYMENT AND CONSULTING AGREEMENTS
 
    On  May 8, 1995, Telecom and  ART jointly entered into consulting agreements
with two executive  officers of  Telecom, effective as  of January  1, 1995  and
continuing  for  a  term  of  three  years,  with  minimum  payments aggregating
approximately $170,000 annually. The aggregate expense incurred by Telecom under
these consulting agreements through December 31, 1995 amounted to $166,750.
 
    On December 16, 1995, one of the executive officers of 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.
 
    On July 11, 1995, Telecom entered  into an employment agreement, as  amended
February  2, 1996, with an officer of Telecom.  The term of the agreement is for
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 common
stock were awarded to this officer equivalent to 2.5% of the outstanding capital
stock  of Telecom (see Note  10). 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.
 
    Telecom has 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, ART entered into an agreement with Southeast Research Partners
("SERP"), a subsidiary of Joesephthal, Lyons & Ross, a Florida broker dealer, to
procure additional  financing  for ART  in  exchange  for cash  and  options  to
purchase  capital stock of  ART. Pursuant to  a letter agreement  dated July 12,
1995, ART and  Telecom paid SERP  $245,000 and the  shareholders of ART  granted
SERP  options to purchase 313,644  shares of ART Common  Stock directly from the
shareholders of ART for an aggregate consideration of approximately $210,000.
 
    As of December  31, 1995,  ART and  Telecom have  accounted for  the fee  of
$245,000 as part of the financing provided by Landover and, accordingly, $70,000
has  been recognized as an offset against  the proceeds from the issuance of the
Serial preferred stock of Telecom  (see Note 9) and the  balance as part of  the
deferred  financing costs recorded by ART in connection with the issuance of the
Advent Notes (See Note 7).
 
                                      F-41
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
8.  COMMITMENTS, CONTINUED:
LEASES
 
    Telecom and ART  have entered  into operating  leases for  office space  and
antenna  sites which  expire between  1997 and  2001. Lease  expense amounted to
$16,044 for 1995. The costs associated  with these leases have been recorded  by
Telecom  and no amounts  have been charged  to ART. Future  annual minimum lease
payments as of December 31, 1995 are as follows:
 
<TABLE>
<S>                                                              <C>
1996...........................................................  $  363,079
1997...........................................................     352,480
1998...........................................................     302,727
1999...........................................................     297,417
2000 and thereafter............................................      25,825
                                                                 ----------
                                                                 $1,341,528
                                                                 ----------
                                                                 ----------
</TABLE>
 
9.  STOCKHOLDERS' DEFICIT:
    At December  31,  1995,  the Certificate  of  Incorporation  authorized  the
issuance  of  20,000,000  shares  of  stock of  all  classes,  divided  into (i)
10,000,000 shares  of  common  stock,  $0.001 par  value  per  share,  of  which
7,000,000 shares are designated as Class A common stock and 3,000,000 shares are
designated  as  Class B  common stock  and (ii)  10,000,000 shares  of preferred
stock, $0.001 par  value per  share of which  451,513 shares  are designated  as
Series  A preferred stock,  113,663 shares are designated  as Series B preferred
stock, 7,297 shares are designated as Series C preferred stock and 61,640 shares
are designated as Series D preferred stock, before giving effect to the 13 for 1
stock split discussed below.  Pursuant to the Reorganization  (see Note 2),  the
Certificate of Incorporation was amended and restated on February 2, 1996 to (i)
convert  each share of  Class A common stock  and Class B  common stock into one
share of common stock,  par value $0.001 per  share, (ii) change the  authorized
capital  stock of the Corporation to 70,000,000  shares of stock of all classes,
(iii) change the authorized  common stock to 60,000,000  shares, (iv) amend  the
terms  of the preferred stock  and each series thereof,  (v) provide for two new
series of preferred stock designated as "Series E preferred stock" and "Series F
preferred stock", and (vi) effect a 13 for 1 stock split of each share of common
stock issued and outstanding.
 
    The holders of Class A common stock had anti-dilution protection, but in all
other respects such shares were identical to the Class B common stock. Under the
anti-dilution provisions, additional shares of Class A common stock were issued,
for no  consideration, to  the holders  of the  Class A  common stock  upon  the
issuance  of serial preferred stock, so that the holders of Class A common stock
maintained their  36%  ownership  interest through  the  $7.0  million  Landover
Funding Commitment as set forth in the Purchase Agreement.
 
    Under  the  Purchase  Agreement,  the individual  shareholders  of  ART were
required to place 5,153,778 shares of Common Stock in ART in escrow (the "Escrow
Shares") to be released upon the completion of the pending EMI Asset acquisition
(see Note 4), 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 shares of the  Escrow
Shares  of ART were released. The related compensation of $802,002, based on the
then  current  fair  value  of  the  Escrow  Shares,  has  been  recognized   as
compensation  expense in 1995, the offset of  which has been accounted for as an
investment by ART. Pursuant to the  February 2, 1996 Reorganization, the  Escrow
Shares arrangement was
 
                                      F-42
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
9.  STOCKHOLDERS' DEFICIT, CONTINUED:
terminated  and  all  of  the  remaining  Escrow  Shares  were  released  to the
stockholders of  ART. The  related compensation  expense of  approximately  $6.8
million,  based  upon the  fair value  of  the remaining  Escrow Shares  will be
recognized in 1996.
 
    Each issuance of  serial preferred  stock pursuant to  the Landover  Funding
Commitment  is a separate  class and, as  a class, has  a liquidation preference
equal to  the aggregate  price paid  for such  class and  an ownership  interest
designated  by Landover at issuance. The  ownership interest of each outstanding
class of serial preferred stock was not to be diluted by subsequent issuances of
shares of other classes  of serial preferred stock  through the satisfaction  of
the  Landover  Funding  Commitment. As  a  result, additional  shares  of serial
preferred stock were issued  to the existing holders  upon the issuance of  such
other  shares so that each outstanding class maintained its designated aggregate
liquidation preference and aggregate ownership interest.
 
    Each share of  serial preferred stock  outstanding at December  31, 1995  is
convertible  into 13  shares of common  stock, subject  to certain anti-dilution
adjustments. The holders  of serial  preferred stock  have a  vote, and  receive
dividends  or distributions, equivalent to the  votes and amounts which would be
obtainable by them upon conversion of their shares into common stock.
 
    In partial satisfaction  of the  Landover Funding  Commitment, during  1995,
Telecom  issued 332,091  shares of  Series A  preferred stock,  82,318 shares of
Series B preferred stock and 5,402 shares  of Series C preferred stock to  three
separate  limited partnerships of which an  affiliate of Landover is the general
partner, for aggregate cash consideration of $2.0 million.
 
    On November 9,  1995, Telecom  issued 61,640  shares of  Series D  preferred
stock  for cash of $2.0 million. The Series D preferred stock purchase agreement
provided that in the  event that Telecom  and ART on a  combined basis, did  not
achieve an equity valuation of $225.0 million, as defined, on or before November
1,  1997, the holders of the Series D preferred stock had the option to purchase
additional shares of serial preferred stock for $0.001 per share up to a maximum
of 1.33%  of  the  then outstanding  capital  stock  of Telecom.  The  Series  D
preferred  stock purchase  agreement was  amended February  2, 1996  whereby the
option to purchase additional serial preferred stock was replaced with an option
to purchase 400,634 shares  of Telecom common stock  directly from Landover  for
$0.001  per share in the event Telecom  does not attain certain equity valuation
objectives.
 
    On November  13,  1995, the  Advent  Group executed  a  securities  purchase
agreement  with ART  and Telecom.  As a result  of the  exchange agreement dated
February 2, 1996, Advent received 232,826 shares of Series E preferred stock  of
Telecom (see Note 7).
 
    The  serial  preferred  stock  transactions  described  above  satisfied the
Landover Funding Commitment. As a  result, the anti-dilution protection for  the
Class  A common stock and serial preferred  stock terminated. As the actual cash
proceeds received  were in  excess  of Landover's  $7.0 million  commitment,  on
November 13, 1995, Telecom used the proceeds from the sale of Series D preferred
stock to redeem 807,924 shares of Class B common stock held by Landover.
 
    The  Series E and F preferred stock  (see Note 14) are senior in liquidation
preference to the Series A, B, C  and D preferred stock. The Series D  preferred
stock  is senior in  liquidation preference to  the Series A,  B and C preferred
stock. At any time on or after November  13, 2000, the Series E and F  preferred
stock  may be redeemed  at the option  of the holders  of such stock  at a price
equal to the liquidation amount plus all accrued and unpaid dividends.
 
                                      F-43
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
10. STOCK OPTION PLANS:
    On July 22, 1995,  Telecom adopted the 1995  Stock Option Plan (the  "Plan")
that  provides  for  option  grants  to  employees,  directors  and  independent
consultants of Telecom. Telecom  has reserved 2,500,000  shares of common  stock
for  issuance under the Plan. Options granted  to employees may be designated as
incentive stock options ("ISO's") or non-qualified stock options ("NQSO's"),  as
defined  by  the  Internal  Revenue  Service.  Options  granted  to  independent
consultants and other non-employees may only be designated NQSO's.
 
    The exercise price of options  granted under the Plan  may not be less  than
100%  of the fair market value of the common stock on the grant date. Generally,
options will be exercisable for a term  that will not exceed ten years from  the
date of grant.
 
    Under  the Plan,  options to  purchase an  aggregate of  817,232 and 235,000
shares of common stock were granted to employees of Telecom on July 22, 1995 and
December 29, 1995,  respectively, at an  option price of  $.5907 and $1.652  per
share,  respectively. The difference  between the exercise  price of the options
issued at $.5907 and the deemed fair value of common stock of $1.20 per share as
determined on the measurement date,  is recognized as compensation expense  over
the respective vesting period. The options vest at various dates during a 5-year
period.  At  December 31,  1995,  361,785 options  were  vested and  Telecom has
recognized compensation expense of $287,603  during 1995. At December 31,  1995,
unearned  stock option compensation expense amounted  to $210,339. There were no
options exercised or canceled during 1995.
 
    On February 15, 1996, options to purchase an aggregate of 145,000 shares  of
common  stock were granted to  employees of Telecom under  the Plan at an option
price of $3.94 per share.
 
    On April 24, 1996, Telecom adopted the 1996 Non-Employee Directors Automatic
Stock Option Plan (the "Directors Plan"), subject to shareholder approval, 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
an initial public offering,  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.
 
    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
Telecom's 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. Telecom  expects to  continue accounting  for employee  stock
compensation awards using current accounting requirements.
 
11. INCOME TAXES:
    As  of December  31, 1995, Telecom  has net operating  loss carryforwards of
approximately $1.9 million to  offset future taxable  income for Federal  income
tax  purposes which  will expire in  2010. Deferred tax  assets of approximately
$741,000, principally comprised  of such net  operating tax loss  carry-forwards
and temporary differences arising from compensation expense related to the stock
option plans have been offset in full by a valuation allowance.
 
                                      F-44
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
12. RELATED PARTY TRANSACTIONS:
    On  May 8, 1995,  Telecom and ART  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, Telecom and  ART entered into a management  consulting
agreement with Landover to provide strategic planning, corporate development and
general  management. Under the agreement, Telecom  will pay Landover $35,000 per
month for  an initial  one  year term,  renewable by  Telecom  and ART  for  two
additional  one year  terms. The aggregate  expense under  this agreement during
1995 amounted to $70,000, which amount is  payable as of December 31, 1995.  The
agreement   also  provides  that  in  the  event  Landover  arranges  financing,
acquisitions or certain other transactions for Telecom, it will be paid a fee by
Telecom in accordance with industry standards.
 
    Pursuant to the Purchase Agreement,  Telecom and ART paid Landover  $391,750
for  expenses  in  connection with  the  Landover Funding  Commitment,  of which
$141,750 has been charged  to paid-in capital by  Telecom and $250,000 has  been
capitalized as deferred financing costs by ART.
 
    An  executive  and shareholder  of ART  is a  principal in  a law  firm that
regularly provides legal services to Telecom.  During the period from March  28,
1995 through December 31, 1995, Telecom incurred $237,538 for such services.
 
    Telecom  has funded certain expenses and investments of ART, including ART's
investment in ART West and payments of financing and other operating costs.  The
amounts funded by Telecom to date totalling $805,803, offset by accrued interest
of $67,123 related to the note payable to ART (see Note 7) have been included in
the amount due from ART.
 
13. FAIR VALUES OF FINANCIAL INSTRUMENTS:
    The  carrying amount and  fair values of  Telecom's financial instruments at
December 31, 1995 were as follows:
 
<TABLE>
<CAPTION>
                                                                              CARRYING         FAIR
                                                                               AMOUNT          VALUE
                                                                            -------------  -------------
<S>                                                                         <C>            <C>
Cash and cash equivalents.................................................  $     627,585  $     627,585
Long-term notes payable...................................................      6,500,000      6,500,000
</TABLE>
 
    Cash and cash equivalents: The carrying amount reported in the balance sheet
approximates fair value.
 
    Long-term notes payable: The carrying  amount approximates fair value  based
upon interest rates that are currently available to Telecom for issuance of debt
with similar terms and maturity.
 
14. SUBSEQUENT EVENTS:
 
- -- AMERITECH FINANCING
 
    On  February 2, 1996, Telecom sold 48,893 shares of Series F preferred stock
for an  aggregate  purchase  price  of $2.5  million  to  Ameritech  Development
Corporation  ("Ameritech").  In  addition,  Telecom  entered  into  a  strategic
distribution agreement with Ameritech  Corp., the parent  of Ameritech, and,  as
partial  consideration, granted warrants to Ameritech  to purchase up to 877,136
shares of common stock from Telecom at  a price of $0.01 per share,  exercisable
on  February 2, 1996 through February 2,  2006. The Series F preferred stock and
warrants are collectively referred to as the Ameritech Securities. The strategic
distribution agreement provides for Ameritech to be the principal distributor of
Telecom's services  within  five midwestern  states.  Telecom incurred  fees  of
$150,000 in connection with this transaction.
 
                                      F-45
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                    NOTES TO FINANCIAL STATEMENTS, CONTINUED
 
14. SUBSEQUENT EVENTS, CONTINUED:
    Under  the  terms  of  the  securities  purchase  agreement  with Ameritech,
Ameritech is  entitled to  a put  option to  require Telecom  to repurchase  the
Ameritech  Securities if the Department of Justice finds that this investment is
in violation of restrictions  under the Modification of  Final Judgement in  the
United  States vs. AT&T Civil Action  82-0192 ("MFJ"). Telecom would be required
to repurchase the  Ameritech Securities at  a purchase price  equal to the  fair
market value on the date it is determined that the investment is in violation of
the MFJ.
 
- -- BRIDGE FINANCING
 
    On  March 8, 1996, Telecom issued in  a private placement of $5.0 million of
two year, 10% notes (the "Bridge Notes")  and five year warrants to purchase  up
to  an aggregate  of 1,100,000 shares  of common stock  at a price  of $6.25 per
share (the "Bridge Warrants") to certain holders of serial preferred stock.  The
Bridge Warrants are exercisable on March 8, 1996 through March 8, 2001.
 
- -- EQUIPMENT FINANCING
 
    On  April  24,  1996,  the  Board  of  Directors  approved  the  adoption of
resolutions necessary  to  complete a  $2,445,000  equipment financing  for  the
purchase of wireless transmission equipment.
 
- -- RESEARCH AND DEVELOPMENT ARRANGEMENTS
 
    On  January 26, 1996, Telecom entered into a preliminary agreement to invest
from $700,000 to $1.0 million in an entity in which an executive of Telecom is a
director and a shareholder. The preliminary agreement provides for the entity to
perform research and  development of  wireless transmission  equipment in  which
Telecom  will receive  a right  of first  refusal on  production capacity  and a
license fee in exchange for its investment.
 
    On March 13, 1996,  Telecom issued a  letter of intent to  a third party  to
provide  Telecom  with specific  technology  consulting in  connection  with the
development of wireless transmission equipment. The aggregate amount to be  paid
pursuant  to  the letter  of intent  totals  $90,000. The  letter of  intent was
executed in connection with  an agreement currently  under negotiations for  the
development and manufacture of wireless transmission equipment.
 
- -- SOFTWARE LICENSE AGREEMENT
 
    On  March 29, 1996,  Telecom entered into a  software license agreement (the
"Software License  Agreement").  The terms  of  the Software  License  Agreement
provide  for licensed software and hardware for Telecom's network management and
maintenance support services.  The Software  License Agreement  provides for  an
initial   software  license  fee  of  approximately  $2,000,000  and  an  annual
maintenance support fee of approximately  $300,000 per year. An initial  payment
of  $250,000 for  the software  license fee  was payable  upon execution  of the
agreement with  the balance  payable in  monthly installments  of principal  and
interest commencing January 1, 1997.
 
- -- DCT PRELIMINARY AGREEMENT
 
    On April 25, 1996, Telecom and ART entered into a preliminary agreement with
DCT  (the "DCT Preliminary Agreement") to  acquire DCT's interest in certain FCC
authorizations and  licenses in  exchange  for $3.6  million  in cash.  The  DCT
Preliminary  Agreement is  subject to  the completion  of a  definitive purchase
agreement and services agreement (see Note 8). The definitive purchase agreement
will supersede and replace all  other existing agreements between Telecom,  ART,
ART's  shareholders and DCT. The definitive purchase agreement must be signed by
June 28, 1996 and the closing of the transaction is subject to FCC approval.
 
                                      F-46
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
                   UNAUDITED INTERIM CONDENSED BALANCE SHEET
                                 MARCH 31, 1996
 
<TABLE>
<CAPTION>
                                           ASSETS
<S>                                                                             <C>
Current assets:
  Cash and cash equivalents...................................................  $  3,018,191
  Due from ART................................................................       498,100
  Other current assets........................................................        61,226
                                                                                ------------
    Total current assets......................................................     3,577,517
Property and equipment, net...................................................     6,379,603
FCC licenses..................................................................     4,226,821
Equipment and other deposits..................................................       344,417
Investment in ART.............................................................        44,930
Deferred financing costs......................................................       681,692
                                                                                ------------
      Total assets............................................................  $ 15,254,980
                                                                                ------------
                                                                                ------------
 
                            LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable and accrued liabilities....................................  $  4,211,017
                                                                                ------------
      Total current liabilities...............................................     4,211,017
Bridge Notes..................................................................     3,983,082
Note payable to EMI...........................................................     1,500,000
                                                                                ------------
      Total liabilities.......................................................     9,694,099
                                                                                ------------
Commitments and contingencies
Stockholders' equity:
  Serial preferred stock, $.001 par value, 920,951 shares issued and
   outstanding................................................................           921
  Class A common stock, $.001 par value, 18,114,135 shares issued and
   outstanding................................................................        18,114
  Additional paid-in capital..................................................    19,189,302
  Deficit accumulated during the development stage............................   (13,647,456)
                                                                                ------------
      Total stockholders' equity..............................................     5,560,881
                                                                                ------------
        Total liabilities and stockholders' equity............................  $ 15,254,980
                                                                                ------------
                                                                                ------------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-47
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
              UNAUDITED INTERIM CONDENSED STATEMENT OF OPERATIONS
                   FOR THE THREE MONTHS ENDED MARCH 31, 1996
 
<TABLE>
<CAPTION>
Operating revenue.............................................................  $     9,620
<S>                                                                             <C>
                                                                                -----------
Expenses:
  General and administrative..................................................    8,889,364
  Market development..........................................................    1,150,063
  Research and development....................................................      419,418
  Depreciation and amortization...............................................       86,684
  Interest expense, net.......................................................      130,474
                                                                                -----------
    Total expenses............................................................   10,676,003
                                                                                -----------
      Net loss................................................................  $10,666,383
                                                                                -----------
                                                                                -----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-48
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
    UNAUDITED INTERIM CONDENSED STATEMENT OF STOCKHOLDERS' EQUITY (DEFICIT)
                   FOR THE THREE MONTHS ENDED MARCH 31, 1996
<TABLE>
<CAPTION>
                                                                           PREFERRED STOCK
                             COMMON    ---------------------------------------------------------------------------------------
SHARES                       STOCK      SERIES A     SERIES B     SERIES C     SERIES D     SERIES E     SERIES F      TOTAL
- -------------------------  ----------  -----------  -----------  -----------  -----------  -----------  -----------  ---------
<S>                        <C>         <C>          <C>          <C>          <C>          <C>          <C>          <C>
Balance at December 31,
 1995....................  15,291,211     334,943       86,507        5,402       61,640                               488,492
Issuance of Series E
 preferred stock.........                                                                     232,826                  232,826
Shares issued to reflect
 anti-dilution
 adjustments.............   2,822,924     120,607       28,172        1,961                                            150,740
Issuance of Series F
 preferred stock.........                                                                                   48,893      48,893
                           ----------  -----------  -----------       -----   -----------  -----------  -----------  ---------
Balance of March 31,
 1996....................  18,114,135     455,550      114,679        7,363       61,640      232,826       48,893     920,951
                           ----------  -----------  -----------       -----   -----------  -----------  -----------  ---------
                           ----------  -----------  -----------       -----   -----------  -----------  -----------  ---------
 
<CAPTION>
 
                                                                        PAR VALUE
                           ---------------------------------------------------------------------------------------------------
                                                                           PREFERRED STOCK
                             COMMON    ---------------------------------------------------------------------------------------
AMOUNTS                      STOCK      SERIES A     SERIES B     SERIES C     SERIES D     SERIES E     SERIES F      TOTAL
- -------------------------  ----------  -----------  -----------  -----------  -----------  -----------  -----------  ---------
<S>                        <C>         <C>          <C>          <C>          <C>          <C>          <C>          <C>
Balance at December 31,
 1995....................  $   15,291   $     335    $      86    $       5    $      62                             $     488
Issuance of Series E
 preferred stock.........                                                                   $     233                      233
Shares issued to reflect
 anti-dilution
 adjustments.............       2,823         121           28            2                                                151
Issuance of Series F
 preferred stock and
 warrants in exchange for
 cash and the Strategic
 Distribution Agreement
 net of expenses of
 $150,000................                                                                                $      49          49
Value ascribed to the
 Bridge Warrants.........
Investment by ART as a
 result of the release of
 escrow shares...........
Accrued stock option
 compensation............
Net loss.................
                           ----------  -----------  -----------       -----   -----------  -----------  -----------  ---------
Balance at March 31,
 1996....................  $   18,114   $     456    $     114    $       7    $      62    $     233    $      49   $     921
                           ----------  -----------  -----------       -----   -----------  -----------  -----------  ---------
                           ----------  -----------  -----------       -----   -----------  -----------  -----------  ---------
 
<CAPTION>
 
SHARES
- -------------------------
<S>                        <C>          <C>            <C>
Balance at December 31,
 1995....................
Issuance of Series E
 preferred stock.........
Shares issued to reflect
 anti-dilution
 adjustments.............
Issuance of Series F
 preferred stock.........
 
Balance of March 31,
 1996....................
 
                           ADDITIONAL
                             PAID-IN     ACCUMULATED
AMOUNTS                      CAPITAL       DEFICIT        TOTAL
- -------------------------  -----------  -------------  -----------
<S>                        <C>          <C>            <C>
Balance at December 31,
 1995....................  $ 2,845,372   $(2,981,073)  $  (119,922)
Issuance of Series E
 preferred stock.........    4,672,953                   4,673,186
Shares issued to reflect
 anti-dilution
 adjustments.............       (2,974)
Issuance of Series F
 preferred stock and
 warrants in exchange for
 cash and the Strategic
 Distribution Agreement
 net of expenses of
 $150,000................    3,402,951                   3,403,000
Value ascribed to the
 Bridge Warrants.........    1,050,000                   1,050,000
Investment by ART as a
 result of the release of
 escrow shares...........    6,795,514                   6,795,514
Accrued stock option
 compensation............      425,486                     425,486
Net loss.................                (10,666,383)  (10,666,383)
                           -----------  -------------  -----------
Balance at March 31,
 1996....................  $19,189,302   $(13,647,456) $ 5,560,881
                           -----------  -------------  -----------
                           -----------  -------------  -----------
</TABLE>
 
    The accompanying notes are an integral part of the financial statements
 
                                      F-49
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
              UNAUDITED INTERIM CONDENSED STATEMENT OF CASH FLOWS
                   FOR THE THREE MONTHS ENDED MARCH 31, 1996
 
<TABLE>
<CAPTION>
Cash flows from operating activities:
<S>                                                                             <C>
  Net loss....................................................................  $(10,666,383)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Depreciation and amortization.............................................        86,684
    Non-cash interest expense.................................................        34,726
    Non-cash compensation expenses............................................     7,221,000
    Non-cash market development expense.......................................     1,053,000
    Changes in operating assets and liabilities:
      Deposits................................................................        (8,901)
      Accounts payable and accrued liabilities................................       881,492
      Other current assets....................................................       (60,405)
                                                                                ------------
        Net cash used in operating activities.................................    (1,458,787)
                                                                                ------------
Cash flows from investing activities:
  Additions to property and equipment.........................................    (3,050,607)
                                                                                ------------
        Net cash used in investing activities.................................    (3,050,607)
                                                                                ------------
Cash flows from financing activities:
  Proceeds from issuance of serial preferred stock............................     2,500,000
  Preferred stock issuance costs..............................................      (150,000)
  Proceeds from issuance of Bridge Notes and Bridge Warrants..................     5,000,000
  Payments of ART deferred finance costs......................................      (175,000)
  Additions to deferred financing costs.......................................      (275,000)
                                                                                ------------
        Net cash provided by financing activities.............................     6,900,000
                                                                                ------------
          Net increase in cash and cash equivalents...........................  $  2,390,606
          Cash and cash equivalents, beginning of period......................       627,585
                                                                                ------------
          Cash and cash equivalents, end of period............................  $  3,018,191
                                                                                ------------
                                                                                ------------
Supplemental cash flow information:
  Non-cash financing and investing activities:
    Additions to property and equipment.......................................  $  2,477,264
    Value ascribed to the Ameritech Strategic Distribution Agreement reflected
     as paid-in capital.......................................................     1,053,000
    Accrued deferred financing costs..........................................        85,338
    Exchange of Advent Notes and ART Notes for Series E preferred stock, net
     of deferred financing costs..............................................     4,673,186
</TABLE>
 
    The accompanying notes are an integral part of the financial statements.
 
                                      F-50
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
           NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS
 
1.  THE COMPANY AND BASIS OF PRESENTATION:
 
THE COMPANY
 
    Advanced  Radio  Telecom Corp.  ("Telecom"),  formerly named  Advanced Radio
Technology Ltd., was incorporated in Delaware as a subsidiary of Advanced  Radio
Technologies  Corporation  ("ART") on  March 28,  1995,  to develop,  market and
deliver broadband  telecommunication  and information  services  throughout  the
United States.
 
BASIS OF PRESENTATION
 
    The  condensed financial  statements included  herein have  been prepared by
Telecom. The foregoing  statements contain all  adjustments (consisting only  of
normal recurring adjustments) which are, in the opinion of management, necessary
to present fairly the financial position of Telecom as of March 31, 1996 and the
results  of its operations and  its cash flows for  the three months ended March
31, 1996.
 
    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 Telecom's  audited financial statements and
notes thereto included elsewhere herein.
 
    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.  Telecom has limited  financial
resources,  has incurred operating losses since inception and does not expect to
generate material operating  revenues until the  commencement of its  commercial
services,  which is anticipated to occur  in fiscal 1996. Telecom 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. Telecom's  funding  of  its  initial  operating  expenses,  working
capital needs and contractual commitments is dependent upon its ability to raise
additional financing. Telecom and ART have engaged various investment bankers to
assist  it in raising financing through a public equity and debt offering. There
can be no  assurance that  Telecom will  be successful  in its  effort to  raise
additional financing through this public offering or, if available, that Telecom
will  be  able  to  obtain  it  on  acceptable  terms.  These  conditions  raise
substantial doubt about Telecom'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.  REORGANIZATION AND PENDING MERGER WITH ART:
    On February 2, 1996, Telecom,  ART 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 Series E preferred stock of
Telecom; (iv) revision of  provisions for election  of directors; (v)  amendment
and  restatement of  Telecom'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  ART  and  Telecom (the
"Reorganization").
 
    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  ART
("Merger  Sub")  into  Telecom  (the "Merger")  subject  to  certain conditions,
including the receipt of FCC approval.  Upon the Merger, each outstanding  share
of  Telecom's  serial  preferred  stock  will be  converted  into  13  shares of
Telecom's common stock and each outstanding
 
                                      F-51
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
     NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS, CONTINUTED
 
2.  REORGANIZATION AND PENDING MERGER WITH ART: CONTINUED:
share of common stock of Telecom will  be exchanged for the right to receive  an
equal  number of shares of Common Stock of ART. As a result, Telecom will become
a wholly owned  subsidiary of  ART. The Merger  Agreement provides  that if  the
Merger  is not consummated by May 13, 1997, the shares of Telecom's common stock
owned by ART will be surrendered  to Telecom for nominal consideration, 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 ART'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
ART.  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  ART 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 ART.
 
3.  NET LOSS PER SHARE:
    Net  loss per  share of $0.59  is computed based  on the loss  for the three
months ended March 31, 1996 divided by the weighted average number of shares  of
common stock outstanding of 18,114,135.
 
4.  AMERITECH FINANCING:
    On  February 2, 1996, Telecom sold 48,893 shares of Series F preferred stock
for an  aggregate  purchase  price  of $2.5  million  to  Ameritech  Development
Corporation  ("Ameritech").  In  addition,  Telecom  entered  into  a  strategic
distribution agreement with Ameritech  Corp., the parent  of Ameritech, and,  as
partial  consideration, granted warrants to Ameritech  to purchase up to 877,136
shares of common stock from Telecom at  a price of $0.01 per share,  exercisable
on  February 2, 1996 through February 2, 2006. Telecom has recorded the value of
$1,053,000  ascribed  to   the  strategic  distribution   agreement  as   market
development  expense  in the  first quarter  of 1996.  Telecom incurred  fees of
$150,000 in connection with this transaction.
 
5.  NOTE PAYABLE TO ART:
    In connection with the Reorganization on February 2, 1996, ART, 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, the notes payable by ART to Advent and by Telecom to
ART were canceled, the related interest  forgiven, and Telecom became the  owner
of the one share of ART Series A Redeemable Preferred Stock.
 
6.  COMMITMENTS:
 
DCT PRELIMINARY AGREEMENT
 
    On April 26, 1996, Telecom and ART entered into a preliminary agreement with
DCT  (the "DCT Preliminary Agreement") to  acquire DCT's interest in certain FCC
authorizations and  licenses in  exchange  for $3.6  million  in cash.  The  DCT
Preliminary  Agreement is  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 Telecom, ART, ART's
shareholders and DCT. The definitive purchase  agreement must be signed by  June
28, 1996 and the closing of the transaction is subject to FCC approval.
 
                                      F-52
<PAGE>
                          ADVANCED RADIO TELECOM CORP.
                         (A DEVELOPMENT STAGE COMPANY)
     NOTES TO UNAUDITED INTERIM CONDENSED FINANCIAL STATEMENTS, CONTINUTED
 
7.  FINANCINGS:
 
BRIDGE FINANCING
 
    On  March 8, 1996, Telecom  issued in a private  placement $5,000,000 of two
year, 10% notes (the "Bridge Notes") and five year warrants to purchase up to an
aggregate of 1,100,000 shares of common stock at a price of $6.25 per share (the
"Bridge Warrants")  to certain  holders of  serial preferred  stock. The  Bridge
Warrants are exercisable on March 8, 1996 through March 8, 2001.
 
EQUIPMENT FINANCING
 
    On  April 29, 1996,  Telecom completed a  $2,445,000 equipment financing for
the purchase of  wireless transmission  equipment. Telecom  issued a  $2,445,000
promissary  note, payable  in 24  monthly installments  of $92,694  with a final
payment of  $642,305  due April  29,  1998.  In connection  with  the  equipment
financing,  Telecom issued five year warrants to  purchase up to an aggregate of
325,000 shares of  common stock  of Telecom. Telecom  paid $225,000  in fees  to
stockholders of Telecom to guarantee the equipment financing.
 
8.  ESCROW SHARES:
    Pursuant  to the  February 2, 1996  Reorganization, the terms  of the Escrow
Shares arrangement were terminated and all  of the remaining Escrow Shares  were
released  to  the  stockholders  of ART.  The  related  compensation  expense of
$6,795,514, based upon the  then estimated fair value  of the Escrow Shares  was
recognized, the offset of which was accounted for as an investment in Telecom by
ART.
 
9.  COMMCOCCC ASSET ACQUISITION
    During  July  1996,  ART  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
ART Common Stock. The acquisition of the CommcoCCC Assets is subject to  various
conditions  including (i) minimum  population coverage of  the authorizations of
ART 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) 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,  ART  has  agreed to
construct, manage and operate the CommcoCCC Assets.
 
    At the closing  of the  acquisition, ART  will give  a stockholder  ("Commco
LLC")  of CommcoCCC an  option (the "Option") to  purchase FCC authorizations in
specified market areas in which ART  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 ART Common Stock on the date of exercise.
 
    In  connection with the  agreement to acquire  the CommcoCCC Assets, certain
stockholders of CommcoCCC loaned  ART $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 ART Common  Stock
at  a price of $15  per share. The CommcoCCC Notes  are collateralized by all of
the assets of  ART and,  if not paid  in full  when due, the  unpaid balance  is
convertible  into ART Common Stock, at the option of each holder, stipulated per
share prices based upon the timing of exercise.
 
                                      F-53
<PAGE>
- -------------------------------------------
                                     -------------------------------------------
- -------------------------------------------
                                     -------------------------------------------
 
    NO  DEALER, SALES REPRESENTATIVE OR ANY  OTHER PERSON HAS BEEN AUTHORIZED TO
GIVE ANY INFORMATION  OR TO  MAKE ANY  REPRESENTATIONS IN  CONNECTION WITH  THIS
OFFERING  OTHER THAN THOSE CONTAINED IN THIS  PROSPECTUS, AND, IF GIVEN OR MADE,
SUCH INFORMATION  OR REPRESENTATIONS  MUST NOT  BE RELIED  UPON AS  HAVING  BEEN
AUTHORIZED  BY THE COMPANY OR ANY OF  THE UNDERWRITERS. THIS PROSPECTUS DOES NOT
CONSTITUTE AN  OFFER  TO  SELL, OR  A  SOLICITATION  OF AN  OFFER  TO  BUY,  ANY
SECURITIES OTHER THAN THE SHARES OF COMMON STOCK TO WHICH IT RELATES OR AN OFFER
TO,  OR A SOLICITATION OF, ANY PERSON IN ANY JURISDICTION WHERE SUCH AN OFFER OR
SOLICITATION WOULD BE UNLAWFUL. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR  ANY
SALE  MADE HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT
THERE HAS BEEN NO CHANGE IN THE AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF  OR
THAT  THE INFORMATION CONTAINED HEREIN  IS CORRECT AS OF  ANY TIME SUBSEQUENT TO
THE DATE HEREOF.
 
                            ------------------------
 
                               TABLE OF CONTENTS
                            ------------------------
 
   
<TABLE>
<CAPTION>
                                                    PAGE
                                                    -----
<S>                                              <C>
PROSPECTUS SUMMARY.............................           3
RISK FACTORS...................................           9
THE COMPANY....................................          21
USE OF PROCEEDS................................          22
DIVIDEND POLICY................................          22
CAPITALIZATION.................................          23
DILUTION.......................................          24
SELECTED HISTORICAL AND PRO FORMA FINANCIAL
 DATA..........................................          25
MANAGEMENT'S DISCUSSION AND ANALYSIS OF
 FINANCIAL CONDITION AND RESULTS OF
 OPERATIONS....................................          28
BUSINESS.......................................          34
MANAGEMENT.....................................          59
PRINCIPAL STOCKHOLDERS.........................          71
CERTAIN TRANSACTIONS...........................          73
DESCRIPTION OF CAPITAL STOCK...................          78
SHARES ELIGIBLE FOR FUTURE SALE................          80
DESCRIPTION OF CERTAIN INDEBTEDNESS............          82
UNDERWRITING...................................          84
LEGAL MATTERS..................................          85
EXPERTS........................................          85
AVAILABLE INFORMATION..........................          85
GLOSSARY.......................................          87
INDEX TO FINANCIAL STATEMENTS..................         F-1
</TABLE>
    
 
                            ------------------------
    UNTIL               , 1996 (25 DAYS AFTER THE DATE OF THIS PROSPECTUS),  ALL
DEALERS  EFFECTING  TRANSACTIONS IN  THE REGISTERED  SECURITIES, 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.
 
                                7,500,000 SHARES
 
                                     [LOGO]
 
                                  COMMON STOCK
 
                                ----------------
 
                                   PROSPECTUS
 
                                ----------------
 
                             MONTGOMERY SECURITIES
                              MERRILL LYNCH & CO.
                            DEUTSCHE MORGAN GRENFELL
 
                                           , 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, the NASD  filing fee and  the Nasdaq listing  fee, all of  the
amounts in the table below are estimated.
 
   
<TABLE>
<CAPTION>
Securities and Exchange Commission registration fee...................  $  26,767
<S>                                                                     <C>        <C>
NASD filing fee.......................................................
Nasdaq listing fee....................................................     50,000
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 Underwriting 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>
<C>        <S>                                                                               <C>
      1-1  Underwriting Agreement.**
      2-1  (a) Amended and Restated Certificate of Incorporation and Bylaws of
            Registrant.**
           (b) Amendment to Amended and Restated Certificate of Incorporation.**
           (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.**
      4-1  Specimen of Common Stock Certificate.(3)
      4-2  (a) Indenture.(3)
           (b) Specimen of Senior Discount Note. (See Exhibit 4-2(a)).(3)
      4-3  Form of Lock-Up Agreement.**
      4-4  (a) Form of Warrant Agreement.(2)
           (b) Specimen of Warrant Certificate. (See Exhibit 4-3(a)).(2)
      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.**
           (b) Steven D. Comrie, dated February 2, 1996.**
           (c) W. Theodore Pierson, Jr., dated May 8, 1995 and effective January 1, 1995.**
           (d) I. Don Brown, dated February 16, 1996.**
           (e) Charles Menatti, dated March 8, 1996.**
           (f) James D. Miller, dated February 1, 1996.**
           (g) Thomas A. Grina, dated April 26, 1996.(1)
     10-2  (a) Second Amended and Restated Certificate of Incorporation and By-laws of
            Telecom (filed as Exhibit 2-1 to the Registration Statement on Form S-1 of the
            Company dated May 2, 1996).**
           (b) Certificate of Incorporation of ART Merger Corporation (to become the
            Certificate of Incorporation of Telecom upon the completion of the Merger).**
     10-3  Form of Director Indemnification Agreement.**
</TABLE>
    
 
                                      II-4
<PAGE>
   
<TABLE>
<C>        <S>                                                                               <C>
     10-4  (a) Registrant's Equity Incentive Plan, as amended.**
           (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.**
     10-6  Stock Option Agreements.
           (a) Comrie Non-Qualified Stock Option Agreement.**
           (b) Comrie Incentive Stock Option Agreement.**
     10-7  Management Consulting Agreement with Landover Holdings Corporation, dated
            November 13, 1995.**
     10-8  (a)ART West Joint Venture Agreement dated April 4, 1995, with Extended
              Communications, Inc.**
           (b)Put/Call Agreement dated October 1, 1994, with Extended Communications,
              Inc.**
           (c)Services Agreement dated October 1, 1994, with Extended Communications,
              Inc.**
           (d)Amendment dated April 4, 1995 to the Put/Call Agreement dated October 1,
            1994, with Extended Communications, Inc.**
           (e)Asset Purchase Agreement dated June 24, 1996 with Extended Communications,
              Inc.**
           (f) Management Agreement dated June 1, 1996 with ART West Partnership.**
     10-9  (a)Put/Call Agreement dated September 1, 1994 with DCT Communications, Inc.**
           (b)Services Agreement dated September 1, 1994 with DCT Communications, Inc.**
           (c)Term Sheet dated April 26, 1996 with DCT.**
           (d) Purchase Agreement with DCT dated July 1, 1996.**
           (e) Amendment to Services Agreement dated June 1996 with DCT.**
    10-10  (a)Asset Purchase Agreement dated April 4, 1995 with EMI Communications
              Corporation.**
           (b)$1,500,000 Nonnegotiable and Nontransferable Promissory Note.**
           (c)Maintenance Agreement dated November 14, 1995 with EMI Communications
              Corporation.**
           (d)Agreement dated November 14, 1995 with EMI Communications Corporations.**
    10-11  38 GHz Radio Links Purchase Agreement dated August 11, 1995 with P-Com, Inc.+
    10-12  (a)Agreement dated May 25, 1995 with Telecom One.+**
           (b) Services Agreement dated April 24, 1996 with Telecom One.**
           (c) Asset Purchase Agreement and Management Agreement with Telecom One dated
            June 27, 1996.**
    10-13  Agreement dated April 25, 1996 with GTE.**
    10-14  Software License Agreement dated March 29, 1996 with GTE.**
    10-15  Agreement dated July 12, 1995 with Southeast Research Partners, Inc.**
    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.**
    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.**
    10-18  (a)Purchase Agreement dated April 21, 1995 with Landover Holdings Corporation.**
           (b)Letter Agreement dated May 8, 1995 with the Demetrees, Telecom and Landover
              Holdings Corporation.**
           (c)Letter Agreement dated November 13, 1995 with Telecom, E2-2 Holdings, L.P.
            and the Demetrees.**
    10-19  Restated and Amended Stockholders' Agreement dated February 2, 1996 with Telecom
            and the stockholders of each of Telecom and the Company.**
    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.**
    10-21  Services Agreement dated May 8, 1995 with Telecom.**
</TABLE>
    
 
                                      II-5
<PAGE>
   
<TABLE>
<C>        <S>                                                                               <C>
    10-22  Option Agreement dated February 2, 1996 with Telecom.**
    10-23  (a)Securities Purchase Agreement dated November 13, 1995 with Telecom, Vernon
              Fotheringham, W. Theodore Pierson, Jr., the stockholders of Telecom named
              therein and the Advent Partnerships.**
           (b)Exchange Agreement dated February 2, 1996 with Telecom and the Advent
              Partnerships.**
    10-24  (a)Securities Purchase Agreement dated February 2, 1996 with Telecom and
              Ameritech Development Corporation ("Ameritech"), including letter of
              intent.**
           (b)Warrant issued on February 2, 1996 to Ameritech.**
           (c)Put/Call Agreement dated February 2, 1996 with Ameritech.**
    10-25  Strategic Distribution Agreement dated April 29, 1996 with Ameritech.**
    10-26  Restated and Amended Merger Agreement and Plan of Reorganization dated June 26,
            1996 between the Company and Telecom.**
    10-27  (a)$2,445,000 Promissory Note in favor of CRA, Inc. ("CRA").**
           (b)Security Agreement with CRA (including UCC-1 Financing Statement).**
           (c)Indemnity Agreement.**
           (d) Form of Indemnity Warrant.**
    10-28  Memorandum of Terms of Development and Procurement Agreement with American
            Wireless with Extension Agreement dated April 25, 1996.**
    10-29  (a)Purchase Agreement dated April 26, 1996 with Harris Corporation Farinon
              Division ("Harris") (confidential treatment requested for certain terms).(1)
           (b)PCS Marketing Agreement dated April 26, 1996 with Harris (confidential
              treatment requested for certain terms).(1)
    10-30  Form of Subscription Agreement dated March 8, 1996, including Forms of Bridge
            Note and Bridge Warrant.**
    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.**
           (c) Form of Note issued to Columbia Capital Corporation.**
           (d) Form of Warrant issued to Commco, L.L.C.**
           (e) Form of Warrant issued to Columbia Capital Corporation.**
           (f) Option Agreement dated July 3, 1996 with Commco, L.L.C.**
           (g) Security Agreement dated June 27, 1996 with Columbia Capital Corporation.**
           (h) Form of Noncompetition Agreement with CommcoCCC.**
           (i) CommcoCCC Management Agreement dated July 3, 1996.**
           (j) Right of First Offer Agreement dated July 3, 1996.**
           (k) Engagement Letter with Montgomery Securities dated May 23, 1996.**
    10-32  Letter of Intent dated April 29, 1996 with Helioss Communications Inc.**
    10-33  Letter of Intent dated March 26, 1996 with Advantage Telecom, Inc.
    10-34  Consulting Agreement dated March 1, 1996 with Trond Johannesen.
       11  Computation of Pro Forma Net Loss Per Share of Common Stock.**
       12  Computation of Ratio of Earnings to Fixed Charges.(1)
       21  Subsidiaries of the Registrant.**
    23(a)  Consent of the Registrant's Independent Accountants.
    23(b)  Consent of the Registrant's Counsel.*
       25  Form T-1 Statement of Eligibility of The Bank of New York under the Trust
            Indenture Act of 1939.
</TABLE>
    
 
- ------------------------
 * To be filed by amendment.
** Previously filed.
+ Confidential treatment requested for the deleted portions of this document.
(1) Filed  with the Registration Statement on Form  S-1 of the Company dated May
    15, 1996 (SEC Reg. No. 333-03735) ("Unit Registration Statement").
   
(2) Filed with Amendment  No. 1  to Unit  Registration Statement  dated July  3,
    1996.
    
   
(3) Filed with Amendment No. 2 to Unit Registration Statement.
    
 
                                      II-6
<PAGE>
ITEM 17.  UNDERTAKINGS.
 
    Insofar as indemnification for liabilities under the Act may be permitted to
directors,  officers and  controlling person of  the Registrant  pursuant to the
foregoing provisions, or otherwise, the Registrant has been advised that in  the
opinion  of  the Commission  such indemnification  is  against public  policy as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification  against such  liabilities (other  than the  payment by  the
Registrant  of expenses incurred  or paid by a  director, officer or controlling
person of  the Registrant  in the  successful  defense of  any action,  suit  or
proceeding)  is  asserted by  such director,  officer  or controlling  person in
connection with the securities being registered, the Registrant will, unless  in
the opinion of its counsel the matter has been settled by controlling precedent,
submit  to  a  court  of  appropriate  jurisdiction  the  question  whether such
indemnification by it is against public policy as expressed in the Act and  will
be governed by the final adjudication of such issue.
 
    The  undersigned Registrant hereby undertakes to provide the Underwriters at
the closing  specified  in  the  Underwriting  Agreement  certificates  in  such
denomination  and registered  in such names  as required by  the Underwriters to
permit prompt delivery to each purchaser.
 
    The undersigned Registrant hereby undertakes that:
 
        (1) For  purposes  of  determining  any liability  under  the  Act,  the
    information  omitted  from the  form  of prospectus  filed  as part  of this
    Registration Statement in reliance upon Rule 430A and contained in a form of
    prospectus filed by  the Registrant pursuant  to Rule 424(b)(1)  or (4),  or
    497(h)  under  the Act  shall  be deemed  to  be part  of  this Registration
    Statement as of the time it was declared effective.
 
        (2) For the purposes  of determining any liability  under the Act,  each
    post-effective  amendment that contains a form of prospectus shall be deemed
    to be  a  new Registration  Statement  relating to  the  securities  offered
    therein, and the offering of such securities at that time shall be deemed to
    be the initial bona fide offering thereof.
 
    The undersigned Registrant hereby undertakes:
 
        (1)  To file, during any period in which offers or sales are being made,
    a post-effective amendment to this Registration Statement;
 
            (i) To include any  prospectus required by  Section 10(a)(3) of  the
       Act;
 
           (ii)  To reflect in the prospectus  any facts or events arising after
       the effective  date of  the Registration  Statement (or  the most  recent
       post-effective   amendment  thereof)   which,  individually   or  in  the
       aggregate, represent a fundamental change in the information set forth in
       the Registration Statement;
 
           (iii) To include any material information with respect to the plan of
       distribution not previously  disclosed in the  Registration Statement  or
       any material change to such information in the Registration Statement;
 
        (2)  That, for the  purpose of determining any  liability under the Act,
    each such post-effective amendment shall be deemed to be a new  registration
    statement  relating to the  securities offered therein,  and the offering of
    such securities at that  time shall be  deemed to be  the initial bona  fide
    offering thereof.
 
   
        (3)  To remove from registration by  means of a post-effective amendment
    any  of  the  securities  being  registered  which  remain  unsold  at   the
    termination of the offering.
    
 
                                      II-7
<PAGE>
                                   SIGNATURES
 
   
    Pursuant  to the requirements of the  Securities Act of 1933, the Registrant
has duly caused this  Amendment to this Registration  Statement to be signed  on
its  behalf by  the undersigned,  thereunto duly authorized  in the  City of New
York, State of New York, on      , 1996.
    
 
                                          Advanced Radio Technologies
                                          Corporation
 
   
                                          By:         /s/ THOMAS A. GRINA
    
 
                                             -----------------------------------
   
                                                       Thomas A. Grina
    
   
                                                EXECUTIVE VICE PRESIDENT AND
                                                   CHIEF FINANCIAL OFFICER
    
 
   
<TABLE>
<C>                                                     <S>                                        <C>
                      SIGNATURES                                          TITLE                         DATE
- ------------------------------------------------------  -----------------------------------------  --------------
 
                 /s/ VERNON L. FOTHERINGHAM*
     -------------------------------------------        Chairman, Chief Executive Officer and          , 1996
                Vernon L. Fotheringham                   Director
 
                /s/ W. THEODORE PIERSON, JR.*
     -------------------------------------------        Executive Vice President, General Counsel      , 1996
               W. Theodore Pierson, Jr.                  and Director
 
                      /s/ MATTHEW C. GOVE*
     -------------------------------------------        Director                                       , 1996
                   Matthew C. Gove
 
                       /s/ THOMAS A. GRINA
     -------------------------------------------        Executive Vice President and Chief             , 1996
                   Thomas A. Grina                       Financial Officer
 
                       /s/ THOMAS A. GRINA
     -------------------------------------------
        * By Thomas A. Grina, attorney-in-fact
</TABLE>
    
 
                                      II-8
<PAGE>
                               INDEX TO EXHIBITS
 
   
<TABLE>
<CAPTION>
EXHIBITS                                          DESCRIPTION                                           PAGE
- ----------  ----------------------------------------------------------------------------------------  ---------
<C>         <S>                                                                                       <C>
       1-1  Underwriting Agreement.**
       2-1  (a) Amended and Restated Certificate of Incorporation and Bylaws of Registrant.**
            (b) Amendment to Amended and Restated Certificate of Incorporation.**
            (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.**
       4-1  Specimen of Common Stock Certificate.
       4-2  (a) Indenture.(3)
            (b) Specimen of Senior Discount Note. (See Exhibit 4-2(a)).(3)
       4-3  Form of Lock-Up Agreement.**
       4-4  (a) Form of Warrant Agreement.(2)
            (b) Specimen of Warrant Certificate. (See Exhibit 4-3(a)).(2)
       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.**
            (b) Steven D. Comrie, dated February 2, 1996.**
            (c) W. Theodore Pierson, Jr., dated May 8, 1995 and effective January 1, 1995.**
            (d) I. Don Brown, dated February 16, 1996.**
            (e) Charles Menatti, dated March 8, 1996.**
            (f) James D. Miller, dated February 1, 1996.**
            (g) Thomas A. Grina, dated April 26, 1996.(1)
      10-2  (a) Second Amended and Restated Certificate of Incorporation and By-laws of Telecom
             (filed as Exhibit 2-1 to the Registration Statement on Form S-1 of the Company dated
             May 2, 1996).**
            (b) Certificate of Incorporation of ART Merger Corporation (to become the Certificate of
             Incorporation of Telecom upon the completion of the Merger).**
      10-3  Form of Director Indemnification Agreement.**
      10-4  (a) Registrant's Equity Incentive Plan, as amended.**
            (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.**
      10-6  Stock Option Agreements.
            (a) Comrie Non-Qualified Stock Option Agreement.**
            (b) Comrie Incentive Stock Option Agreement.**
      10-7  Management Consulting Agreement with Landover Holdings Corporation, dated November 13,
             1995.**
      10-8  (a)ART West Joint Venture Agreement dated April 4, 1995, with Extended Communications,
               Inc.**
            (b)Put/Call Agreement dated October 1, 1994, with Extended Communications, Inc.**
            (c)Services Agreement dated October 1, 1994, with Extended Communications, Inc.**
            (d)Amendment dated April 4, 1995 to the Put/Call Agreement dated October 1, 1994, with
               Extended Communications, Inc.**
</TABLE>
    
<PAGE>
   
<TABLE>
<CAPTION>
EXHIBITS                                          DESCRIPTION                                           PAGE
- ----------  ----------------------------------------------------------------------------------------  ---------
            (e)Asset Purchase Agreement dated June 24, 1996 with Extended Communications, Inc.**
<C>         <S>                                                                                       <C>
            (f) Management Agreement dated June 1, 1996 with ART West Partnership.**
      10-9  (a)Put/Call Agreement dated September 1, 1994 with DCT Communications, Inc.**
            (b)Services Agreement dated September 1, 1994 with DCT Communications, Inc.**
            (c)Term Sheet dated April 26, 1996 with DCT.**
            (d) Purchase Agreement with DCT dated July 1, 1996.**
            (e) Amendment to Services Agreement dated June 1996 with DCT.**
     10-10  (a)Asset Purchase Agreement dated April 4, 1995 with EMI Communications Corporation.**
            (b)$1,500,000 Nonnegotiable and Nontransferable Promissory Note.**
            (c)Maintenance Agreement dated November 14, 1995 with EMI Communications Corporation.**
            (d)Agreement dated November 14, 1995 with EMI Communications Corporations.**
     10-11  38 GHz Radio Links Purchase Agreement dated August 11, 1995 with P-Com, Inc.+
     10-12  (a)Agreement dated May 25, 1995 with Telecom One.+**
            (b) Services Agreement dated April 24, 1996 with Telecom One.**
            (c) Asset Purchase Agreement and Management Agreement with Telecom One dated June 27,
             1996.**
     10-13  Agreement dated April 25, 1996 with GTE.**
     10-14  Software License Agreement dated March 29, 1996 with GTE.**
     10-15  Agreement dated July 12, 1995 with Southeast Research Partners, Inc.**
     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.**
     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.**
     10-18  (a)Purchase Agreement dated April 21, 1995 with Landover Holdings Corporation.**
            (b)Letter Agreement dated May 8, 1995 with the Demetrees, Telecom and Landover Holdings
               Corporation.**
            (c)Letter Agreement dated November 13, 1995 with Telecom, E2-2 Holdings, L.P. and the
               Demetrees.**
     10-19  Restated and Amended Stockholders' Agreement dated February 2, 1996 with Telecom and the
             stockholders of each of Telecom and the Company.**
     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.**
     10-21  Services Agreement dated May 8, 1995 with Telecom.**
     10-22  Option Agreement dated February 2, 1996 with Telecom.**
     10-23  (a)Securities Purchase Agreement dated November 13, 1995 with Telecom, Vernon
               Fotheringham, W. Theodore Pierson, Jr., the stockholders of Telecom named therein and
               the Advent Partnerships.**
            (b)Exchange Agreement dated February 2, 1996 with Telecom and the Advent Partnerships.**
     10-24  (a)Securities Purchase Agreement dated February 2, 1996 with Telecom and Ameritech
               Development Corporation ("Ameritech"), including letter of intent.**
</TABLE>
    
<PAGE>
   
<TABLE>
<CAPTION>
EXHIBITS                                          DESCRIPTION                                           PAGE
- ----------  ----------------------------------------------------------------------------------------  ---------
            (b)Warrant issued on February 2, 1996 to Ameritech.**
<C>         <S>                                                                                       <C>
            (c)Put/Call Agreement dated February 2, 1996 with Ameritech.**
     10-25  Strategic Distribution Agreement dated April 29, 1996 with Ameritech.**
     10-26  Restated and Amended Merger Agreement and Plan of Reorganization dated June 26, 1996
             between the Company and Telecom.**
     10-27  (a)$2,445,000 Promissory Note in favor of CRA, Inc. ("CRA").**
            (b)Security Agreement with CRA (including UCC-1 Financing Statement).**
            (c)Indemnity Agreement.**
            (d) Form of Indemnity Warrant.**
     10-28  Memorandum of Terms of Development and Procurement Agreement with American Wireless with
             Extension Agreement dated April 25, 1996.
     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.**
     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.**
            (c) Form of Note issued to Columbia Capital Corporation.**
            (d) Form of Warrant issued to Commco, L.L.C.**
            (e) Form of Warrant issued to Columbia Capital Corporation.**
            (f) Option Agreement dated July 3, 1996 with Commco, L.L.C.**
            (g) Security Agreement dated June 27, 1996 with Columbia Capital Corporation.**
            (h) Form of Noncompetition Agreement with CommcoCCC.**
            (i) CommcoCCC Management Agreement dated July 3, 1996.**
            (j) Right of First Offer Agreement dated July 3, 1996.**
            (k) Engagement Letter with Montgomery Securities dated May 23, 1996.**
     10-32  Letter of Intent dated April 29, 1996 with Helioss Communications Inc.**
     10-33  Letter of Intent dated March 26, 1996 with Advantage Telecom, Inc.
     10-34  Consulting Agreement dated March 1, 1996 with Trond Johannesen.
        11  Computation of Pro Forma Net Loss Per Share of Common Stock.**
        12  Computation of Ratio of Earnings to Fixed Charges.(1)
        21  Subsidiaries of the Registrant.**
     23(a)  Consent of the Registrant's Independent Accountants.
     23(b)  Consent of the Registrant's Counsel.*
        25  Form T-1 Statement of Eligibility of The Bank of New York under the Trust Indenture Act
             of 1939.(3)
</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
    15, 1996 (SEC Reg. No. 333-03735) ("Unit Registration Statement").
 
(2) Filed with Amendment No. 1 to Unit Registration Statement.
   
(3) Filed with Amendment No. 2 to Unit Registration Statement.
    

<PAGE>

                                     [LOGO]
NUMBER                     ADVANCED RADIO TELECOM -TM-                   SHARES
ART
                          ADVANCED RADIO TELECOM CORP.

COMMON STOCK                                 SEE REVERSE FOR CERTAIN DEFINITIONS

              INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE
                                                               CUSIP 007540 10 1
This Certifies that



is the owner of


 FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK, $.001 PAR VALUE PER SHARE,
 OF

- ------------------------- ADVANCED RADIO TELECOM CORP. -------------------------

transferable on the books of the Corporation by the holder hereof in person
or by duly authorized attorney upon surrender of this certificate properly 
endorsed. This certificate is not valid until countersigned by the Transfer 
Agent and registered by the Registrar.

     WITNESS the facsimile seal of the Corporation and the facsimile signatures
of its duly authorized officers.


     Dated:



                                                        /s/
          CHAIRMAN                   [SEAL]                  SECRETARY

COUNTERSIGNED AND REGISTERED
 CONTINENTAL STOCK TRANSFER & TRUST COMPANY
           Jersey City, NJ
           TRANSFER AGENT AND REGISTRAR,
BY

                      AUTHORIZED OFFICER

<PAGE>
                          ADVANCED RADIO TELECOM CORP.

     The Corporation shall furnish without charge to each stockholder who so
requests a statement of the powers, designations, preferences and relative,
participating, optional or other special rights of each class of stock of the
Corporation or series thereof and the qualifications, limitations or
restrictions of such preferences and/or rights. Any such requests may be 
addressed to the Corporation or its Transfer Agent.

     The following abbreviations, when used in the inscription on the face of
this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations.
<TABLE>
<CAPTION>
<S>                                          <C>
TEN COM   -    as tenants in common          UNIF GIFT MIN ACT -            Custodian
TEN ENT   -    as tenants by the                                ------------         ------------
               entireties                                          (Cust)               (Minor)
JT TEN    -    as joint tenants                                 under Uniform Gifts to Minors
               with right of                                    Act
               survivorship and                                  ------------------------------
               and not as tenants            UNIF TRF MIN ACT -      Custodian (until age      )
               in common                                        ------                   -----
                                                                (Cust)
                                                                         under Uniform Transfers
                                                                ---------
                                                                (Minor)
                                                                to Minors Act
                                                                             ------------------
                                                                                   (State)
</TABLE>

     Additional abbreviations may also be used though not in the above list

FOR VALUE RECEIVED, _______________________Hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE

/                                     /

<TABLE>
<CAPTION>
<S>                     <C>
- --------------------------------------------------------------------------------------------------------------------------------
                       (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

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

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

                                                                                                                          Shares
- --------------------------------------------------------------------------------------------------------------------------
of the common stock represented by the within Certificate, and do hereby irrevocably constitute and appoint

                                                                                                                        Attorney
- ------------------------------------------------------------------------------------------------------------------------
to transfer the said stock on the books of the within named Corporation with full power of substitution in the premises.

Dated
       ------------------------------

                                                         X
                                                          ----------------------------------------------------------------------
                                                         X
                                                          ----------------------------------------------------------------------
                                                NOTICE:  THE SIGNATURE(S) TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME(S) AS
                                                         WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR WITHOUT
                                                         ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER
Signature(s) Guaranteed
By
   -----------------------------------------------------------------------
THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH
MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM) PURSUANT
TO S.E.C. RULE 17 Ad-15.
</TABLE>

<PAGE>

                  VOTING TRUST AGREEMENT AND IRREVOCABLE PROXY
                  --------------------------------------------



          AGREEMENT, made this        day of July, 1996, among Landover Holdings
Corp. ("LHC"), Kimberly Zimmerman ("KZ") and Zachary Tyler Zimmerman Trust (the
"Z Trust"), each a stockholder of Advanced Radio Technologies Corporation (the
"Company") or Advanced Radio Telecom Corp. ("Telecom"), each a corporation
organized and existing under the laws of the State of Delaware, and Laurence S.
Zimmerman ("Zimmerman"), who controls LHC, and Vernon L. Fotheringham, Andrew I.
Fillat and Mark C. Demetree, who are hereinafter called the Trustees.

          WHEREAS, the Company has agreed to a merger of its subsidiary (the
"Merger") with Telecom, subject only to approval by the Federal Communications
Commissions ("FCC"); and 

          WHEREAS, the Company will change its name to Advanced Radio Telecom
Corp. after the Merger; and 

          WHEREAS, the Company is preparing to make an underwritten initial
public offering (the "IPO") of its Common Stock, par value $0.001 per share (the
"Common Stock") and, in connection therewith, the Company and LHC deem it to be
in the best interests of the Company and its stockholders that the Company
obtain a listing of the Common Stock on the Nasdaq National Market ("Nasdaq") in
order to improve the liquidity and marketability of the Common Stock; and

          WHEREAS, after giving effect to the Merger, LHC owns 8,068,581 shares,
KZ owns 100,000 shares and the Z Trust owns 100,000 shares (collectively, the
"Current Shares") of the Common Stock including (i) 7,954,250 shares of Common
Stock issuable upon consummation of the Merger in exchange for shares of Telecom
Common Stock (the "ART Shares") and (ii) 37,500 shares of Common Stock issuable
upon exercise of warrants, but (iii) not including 294,487 shares, 1,375,699
shares, 5,276,440 shares and 95,719 shares of Common Stock, issuable upon
consummation of the Merger, held by E1 Holdings, L.P., E2 Holdings, L.P., E2-2
Holdings, L.P., respectively, each a limited partnership which is controlled by
LHC but which will dissolve on consummation of the Merger; and

          WHEREAS, in order to assist the Company to obtain such listing, LHC,
KZ and Z Trust have agreed to enter into this Agreement and deposit (i) the
Current Shares, (ii) any other shares of Common Stock that may hereafter be
acquired or beneficially owned by LHC or its affiliates, including without
limitation any shares of Common Stock issuable upon execution of warrants, and
(iii) any rights, warrants or options to purchase, or other securities
convertible into, Common Stock, (collectively, the "LHC Securities") into the
trust created hereby; and

          WHEREAS, in order for the Trustees to act hereunder the Company has
agreed to indemnify the Trustees for any costs relating to their services
hereunder; and

<PAGE>

          WHEREAS, 400,634 of the Current Shares, issuable upon consummation of
the Merger, (the "Option Shares") are held by Pierson & Burnett L.L.P. (the
"Escrow Agent") pursuant to an escrow agreement (the "Escrow Agreement") subject
to an option agreement, each dated February 2, 1996 among LHC, the holders of
Series D Preferred Stock of the Company, and, in the case of the Escrow
Agreement, the Escrow Agent; and

          WHEREAS, in the interests of all the stockholders of the Company, the
parties hereto are desirous of creating a trust;

          NOW THEREFORE the parties hereby agree as follows:

          1.        (a)  LHC shall forthwith, and from time to time in the
future if LHC acquires additional LHC Securities, indorse in blank and assign
and deliver to the Trustees all certificates for the LHC Securities (other than
the Option Shares) and shall do all things necessary for the transfer of the LHC
Securities (other than the Option Shares) to the Trustees on the books of the
Corporation.

                    (b)  LHC shall use its best efforts to cause the Escrow
Agreement to be amended to provide that any Option Shares that may be otherwise
released to LHC under the Escrow Agreement shall be assigned and delivered to
the Trustees, indorsed in blank, as LHC Securities subject to this Voting Trust
Agreement and Irrevocable Proxy.

          2.        (a)  The Trustees shall hold the LHC Securities so
transferred to them in trust hereunder for the benefit of LHC, under the terms
and conditions set forth herein.

                    (b)  Notwithstanding any provision hereof, LHC shall have
the right to sell, assign, transfer or pledge any or all of the LHC Securities
to third parties and the Trustees shall use their reasonable efforts to cause
any LHC Securities so sold, assigned, transferred or hypothecated to be
transferred promptly to the purchaser, assignee, transferee or pledgee thereof. 
LHC Securities sold, assigned, transferred or hypothecated to an affiliate of
LHC shall remain in trust hereunder subject to the terms of this Agreement.  LHC
Securities sold or transferred to third parties not affiliated with LHC shall be
released from the trust upon such sale or transfer.  A third party shall be
deemed "affiliated" if such third party is controlled by, controls or under
common control with LHC, Zimmerman or a member of the immediate family of
Zimmerman or has made substantial business investments of any nature in any
entity with LHC, Zimmerman or a member of the immediate family of Zimmerman. 
The term "substantial business investments" refers to investments by a third
party comprising more than 5% of the equity or debt of a company, partnership or
joint venture in which LHC, Zimmerman or an affiliate of LHC or Zimmerman has an
investment of at least 5%.

          3.        The Trustees shall surrender to the proper officers of the
Company for cancellation all certificates of stock which shall be assigned and
delivered to them as hereinbefore provided, 

                                       -2-
<PAGE>

and in their stead shall procure new certificates to be issued to them as
Trustees under this Agreement.

          4.        (a)  The Trustees shall have only the powers set forth in
this Agreement.

                    (b)  With respect to all LHC Securities held in trust by the
Trustees hereunder, LHC shall retain the entire economic and beneficial
ownership rights therein, including without limitation the right to receive
dividends and distributions on the LHC Securities and the right to direct the
Trustees in any order whatsoever to sell, assign, transfer, encumber or grant
any option therein to or in favor of any person other than LHC or an affiliate
of LHC or agree to do any such thing, except that the Trustees shall have the
exclusive and absolute right in respect of such LHC Securities to vote, assent
or consent the LHC Securities at all times during the term of this Agreement,
including without limitation the right to vote at any election of directors and
in favor of or in opposition to any resolution, any dissolution, liquidation,
merger or consolidation of the Company, any sale of all or substantially all the
Company's assets, any issuance or authorization of securities, or any action of
any character whatsoever which may be presented at any meeting or require the
consent of stockholders of the Company.  In exercising the Trustees' powers and
duties hereunder, the Trustees shall at all times vote, assent or consent in
respect of any action as follows:  (i) if the matter concerned is the election
of directors, then the Trustees shall vote, consent or assent the whole number
of shares held by the trust created hereunder for each director by multiplying
the number of votes held by the trust (including cumulative votes, if
applicable) by a fraction, the numerator of which is the number of votes cast by
stockholders other than the trust or LHC (the "Nonaffiliated Votes") for the
director and the denominator of which is the number of Nonaffiliated Votes cast
for all directors who have been nominated and are participating in the election
of directors; (ii) where the matter under Delaware law or the Certificate of
Incorporation or the Bylaws of the Company requires at least an absolute
majority of all outstanding shares of common stock of the Company in order to be
effected, then the Trustees shall vote, assent or consent all of the LHC
Securities in favor of or in opposition to such matter as the majority of all
Nonaffiliated Votes are cast; and (iii) on all other matters, the Trustees shall
at all times vote, assent or consent all of the LHC Securities in the identical
proportions in favor of or in opposition to such matter as Nonaffiliated Votes
are cast.  If any calculation of votes under the preceding sentence would
require a fractional vote, the Trustees shall vote the next lower number of
whole shares.  The Trustees shall use all reasonable commercial efforts to
ensure, with respect to the LHC Securities held in trust by the Trustees
hereunder, that the LHC Securities are counted as being present for the purposes
of any quorum required for stockholder action of the Company and to vote, assent
or consent as set forth above.

                                       -3-
<PAGE>

                    (c)  The Trustees may vote, assent or consent with respect
to all the LHC Securities held hereunder in person or by such person or persons
as it may from time to time select as their proxy provided that the Trustees
shall at all times do so in conformity with the provisions of Section 4(b)
hereof.

                    (d)  The Trustees shall have no authority to sell or
otherwise dispose of or to pledge, encumber or hypothecate, any of the stock
deposited pursuant to the provisions of this Agreement, unless directed to do so
by LHC as provided in Section 2(b) above. 

          5.        The Trustees shall not be liable for any vote cast, or
consent given by them, or for any other action hereunder taken or omitted by
them hereunder, in good faith, or in the absence of gross negligence or willful
misconduct.  The Trustees shall not be liable in acting on any notice, request,
consent, certificate, instruction, or other paper or document or signature
reasonably believed to be genuine and to have been signed by the proper party.
The Trustees may consult with legal counsel (reasonably competent for the
purpose) and any act or omission undertaken by the Trustees in good faith in
accordance with the opinion of such legal counsel shall not result in any
liability of the Trustees.

          6.        The Trustees shall collect and receive all dividends that
may accrue upon the shares of stock subject to this trust, and shall distribute
the same to LHC, except that dividends payable in stock of the Company shall be
held in trust as additional LHC Securities hereunder.

          7.        In the event of any Trustee ceasing to serve as a director
of the Company, dying or resigning or refusing or becoming unable to act (any of
which is deemed incapacity), the surviving or other Trustees or Trustee shall
appoint a Trustee or Trustees from among the directors of the Company to fill
the vacancy or vacancies, and any person so appointed shall thereupon be vested
with all the duties, powers, and authority of a Trustee hereunder as if
originally named herein.  No successor Trustee shall be liable for actions or
omissions of the Trustees or any other successor Trustee.

          8.        This Agreement and the trust created herein shall be
effective upon completion of the Merger and shall terminate (a) if the IPO fails
to close by September 1, 1996 or (b) upon the earlier to occur of (i) the death
of Laurence S. Zimmerman ("Zimmerman"), (ii) the later of August 31, 2006 or the
cash repayment in full of the Company's Senior Discount Notes due 2006,
(iii) the sale of all the LHC shares and (iv) prior to August 31, 2006 in the
event that a business combination occurs in which (A) the Senior Discount Notes
are repaid in full in cash, (B) holders of ART Common Stock receive common
equity securities in the new company representing less than 50% of the voting
power of the new company, (C) less than half of the directors of the new company
on a going-forward basis are former ART directors, and (D) LHC's equity
represents less than 5% of the voting power of the new company.  However,
notwithstanding any of the foregoing, this Agreement shall not 

                                       -4-
<PAGE>

terminate if its continued existence were required by a third party regulatory
agency, for example, as a condition to continued listing of the Company's (or
any acquiring company's) equity securities on the Nasdaq National Market System
or other principal trading market for such equity securities.  Upon the
termination of this Agreement the Trustees shall assign and transfer to LHC or
its designee(s) all the LHC Securities remaining in trust hereunder.

          9.        The Company and its stockholders are hereby expressly made
third party beneficiaries of this Agreement, and accordingly this Agreement may
not be amended without the prior written consent of the Company, acting by
unanimous vote of its Board of Directors, and approval of the Company's
stockholders acting by a two thirds vote.

          10.       The Trustees are expressly authorized to incur and pay such
reasonable expenses and charges, to employ and pay such agents, attorneys and
counsel, and to incur and pay such other charges and expenses as the Trustees
may deem reasonably necessary and proper for administering this Agreement.  The
Company, a party to this Agreement solely for purposes of this Section 10 agrees
to reimburse the Trustees for any such expenses and charges.

          11.       (a)  All of the covenants and agreements contained in this
Agreement shall be binding upon, and inure to the benefit of, the respective
parties and their successors, assigns, heirs, executors, administrators and
other legal representatives, as the case may be.
          
                    (b)  This Agreement, and the rights of the parties hereto,
shall be governed by and construed in accordance with the laws of the State of
Delaware.

                    (c)  This Agreement may be executed in one or more
counterparts, each of which will be deemed an original but all of which together
shall constitute one and the same instrument.

                    (d)  If any provision of this Agreement shall be declared
void or unenforceable by any court or administrative board of competent
jurisdiction, such provision shall be deemed to have been severed from the
remainder of the Agreement and this Agreement shall continue in all respects to
be valid and enforceable.

                    (e)  Whenever the context of this Agreement shall so
require, the use of the singular number shall include the plural and the use of
the gender shall include all genders.

                                       -5-
<PAGE>

          IN WITNESS WHEREOF, the subscribers have hereunto set their hands and
seals, and set opposite their respective signatures the number of shares held by
them respectively, and the Trustees, in token of their acceptance of the trust
hereby created, have hereunto set their hands and seals.



TRUSTEES:                               ______________________________
                                        Vernon L. Fotheringham
       
                                        ______________________________
                                        Andrew I. Fillat

                                        ______________________________
                                        Mark C. Demetree


LHC:                                    LANDOVER HOLDINGS CORPORATION
       

                                        By:___________________________
                                             Laurence S. Zimmerman    

KZ:                                     ______________________________
                                        Kimberly Zimmmerman


Z Trust:                                ZACHARY TYLER ZIMMERMAN TRUST


                                        By:___________________________
                                             Kimberly Zimmerman, Trustee


THE COMPANY (a party to this
Agreement solely for purposes
of Section 10 hereof):        ADVANCED RADIO TECHNOLOGIES
                                        CORPORATION


                                        By:___________________________


                                        -6-




<PAGE>



                      TRUSTEE INDEMNIFICATION AGREEMENT



      This Agreement is made as of the ____ day of ________, 1996 by and between
Advanced Radio Telecom Corp., a Delaware corporation (the "Corporation"), and
, (the "Indemnitee").

      The Indemnitee has in the past, is currently, and may in the future serve
as a director of the Corporation and has served, is serving or may serve at the
request of the Corporation as a trustee under a certain Voting Trust Agreement
and Irrevocable Proxy, dated  , 1996 (the "Trust Agreement") between Landover
Holdings Corporation and the trustees named therein.

      The Certificate of Incorporation of the Corporation provides for the
indemnification of the officers and directors of the Corporation to the fullest
extent authorized by law, including Section 145(f) of the General Corporation
Law of the State of Delaware, as the same exists or may hereafter be amended or
supplemented (the "Delaware Corporation Law").  Section 145(f) of the Delaware
Corporation Law specifically provides that the indemnification provisions
contained therein are not exclusive, and thereby contemplates that contracts may
be entered into between the Corporation and the members of its Board of
Directors with respect to indemnification of such directors.

      The Indemnitee has indicated his concern that the indemnities available
under the Corporation's Certificate of Incorporation may not be adequate to
protect him against the risks associated with his service to under the Trust
Agreement, and the Indemnitee may not be willing to serve or to continue to
serve as a trustee thereunder unless the Corporation is otherwise able to
indemnify the Indemnitee.

      In order to induce the Indemnitee to agree to continue to serve as a
trustee under the Trust Agreement and in consideration of the Indemnitee's
continued service after the date hereof, the parties hereby agree as follows:

      1.    If the Indemnitee was or is made a party or is threatened to be made
a party or is involved in any action, suit or proceeding, whether civil,
criminal, administrative or investigative (the "proceeding"), by reason of the
fact that he or a person for whom he is the legal representative is or was a
trustee under the Trust Agreement, whether the basis of such proceeding is an
alleged action in an official capacity as a director or as such trustee, the
Corporation shall indemnify and hold harmless the Indemnitee to the fullest
extent authorized by the Delaware General Corporation Law, as the same exists or
may hereafter be amended, against all costs, expenses, liabilities, judgments
and losses (including attorneys' fees, judgments, fines, excise taxes or
penalties under the Employee Retirement Income Security Act of 1974, as amended)
and amounts paid or to be paid in settlement of any proceeding, reasonably
incurred or suffered by 

<PAGE>



the Indemnitee in connection therewith.

      2.    The Corporation shall (within 15 days of written request therefor by
the Indemnitee) pay to the Indemnitee all costs and expenses (including, but not
limited to, attorneys', accountants', investment or other advisor and expert
witness fees) incurred by the Indemnitee or reasonably anticipated to be
incurred by the Indemnitee in defending any such proceeding in advance of its
final disposition; PROVIDED, HOWEVER, that the payment of such expenses in
advance of the final disposition of such proceeding shall be made only if the
request therefor by the Indemnitee is accompanied by a written undertaking,
signed by him, in favor of the Corporation to repay all amounts so advanced if
it should be ultimately determined by a court of competent jurisdiction that the
Indemnitee is not entitled to be indemnified under Section 145 of the Delaware
General Corporation Law.

      3.    If the Corporation does not respond to a written claim for any
payment (including advancement of expenses) under this Agreement within fifteen
days of having received such a claim, it shall be deemed to have waived any
right to refuse to pay such claim under this Agreement.  In addition, if a claim
under this Agreement is not paid by the Corporation, or on its behalf, within
thirty days after a written claim has been received by the Corporation, the
claimant may at any time thereafter bring suit against the Corporation and the
Corporation shall have the burden of proving that the Indemnitee is not entitled
to payment under this Agreement.  If successful in whole or in part, the
claimant shall be entitled to be paid also all expenses (including attorneys'
fees and expenses) of prosecuting such claim together with interest at the rate
of 12% per annum from the date the expenses were paid by the Indemnitee.

      4.    In the event of payment to the Indemnitee under this Agreement, the
Corporation shall be subrogated to the extent of such payment to all of the
rights of recovery of the Indemnitee (and his executors, administrators, and
heirs), who shall execute all documents and take all actions reasonably
requested by the Corporation to implement such right of subrogation.

      5.    The Corporation shall not be liable under this Agreement to make any
payment in satisfaction of adjudged liabilities assessed against the Indemnitee:

            (a)   for which payment is actually made to the Indemnitee under a
      valid and collectible insurance policy maintained by the Corporation,
      except in respect of any excess beyond the amount of payment under such
      insurance;

            (b)   based upon liability for a claim arising from a final
      adjudication by a court of competent jurisdiction that the Indemnitee is
      liable to the Corporation; provided that if and to the extent that the
      Court of Chancery of the State of Delaware or the court in which such
      action or suit giving rise 


                                     -2-
<PAGE>



      to such adjudication of liability was brought shall determine upon 
      application that, despite the adjudication of liability but in view of 
      all the circumstances of the case, the Indemnitee is fairly and 
      reasonably entitled to indemnity for such expenses as such court shall 
      deem proper, the Corporation shall indemnify the Indemnitee for such 
      expenses;

            (c)   based upon or attributable to the Indemnitee or any member of
      his immediate family having been finally adjudged to have gained in fact
      any personal profit or advantage to which he was not legally entitled;

            (d)   for an accounting for profits made from the purchase or sale
      by the Indemnitee of securities of the Corporation within the meaning of
      Section 16(b) of the Securities Exchange Act of 1934 and amendments
      thereto or similar provisions of any state statutory law or common law;

            (e)   on account of the Indemnitee's conduct which is finally
      adjudged to have been knowingly fraudulent, deliberately dishonest or
      willful misconduct; or

            (f)   for which indemnification under this Agreement is determined
      by a final adjudication of a court of competent jurisdiction to be
      unlawful and violative of public policy.

      6.    Within a reasonable time after receipt by the Indemnitee of notice
of the commencement of any proceeding, the Indemnitee will, if a claim in
respect thereof is to be made against the Corporation under this Agreement,
notify the Corporation of the commencement thereof; but the omission so to
notify the Corporation will not relieve the Corporation from any liability which
it may have to the Indemnitee otherwise than under this Agreement.  With respect
to any such action, suit or proceeding as to which the Indemnitee notifies the
corporation of the commencement thereof;

            (a)   the Corporation will be entitled to participate therein at its
      own expense;

            (b)   Except as otherwise provided below, to the extent that it may
      wish, the Corporation jointly with any other indemnifying party similarly
      notified will be entitled to assume the defense thereof, with counsel
      satisfactory to the Indemnitee.  After notice from the Corporation to the
      Indemnitee of its election so to assume the defense thereof, the
      Corporation will not be liable to the Indemnitee under this Agreement for
      any legal or other expenses subsequently incurred by the Indemnitee in
      connection with the defense thereof other than reasonable costs of
      investigation or as otherwise provided below.  The Indemnitee shall have
      the right to employ his counsel in such action, suit or proceeding, but
      the fees and expenses of such counsel incurred after notice from the
      corporation of its assumption for the defense thereof shall be at the
      expense of the Indemnitee unless (i) the 

                                     -3-
<PAGE>


      employment of counsel by the Indemnitee has been authorized by the 
      Corporation, (ii) the Indemnitee shall have concluded, in his sole 
      discretion, that there may be a conflict of interest between the 
      Corporation and the Indemnitee in the conduct of the defense of such 
      action or (iii) the Corporation shall not in fact employed counsel to 
      assume the defense of such action, in each of which cases the fees and 
      expenses of counsel shall be at the expense of the corporation.  The 
      Corporation shall not be entitled to assume the defense of any action, 
      suit or proceeding brought by or on behalf of the Corporation or as to 
      which the Indemnitee shall have made the conclusion provided for in 
      (ii) above; and

            (c)   the Corporation shall not be liable to indemnify the
      Indemnitee under this Agreement for any amounts paid in settlement of any
      action or claim effected without its written consent.  The Corporation
      shall not settle any action or claim without the Indemnitee's written
      consent.  Neither the Corporation nor the Indemnitee shall unreasonably
      withhold its or his consent to any proposed settlement.

      7.    All agreements and obligations of the Corporation contained herein
shall continue during the period the Indemnitee is serving in any of the
capacities referred to in Section 1 hereof and shall continue thereafter so long
as the Indemnitee or his executors, administrators, or heirs could be subject to
any possible claim or threatened, pending or completed proceeding by reason of
the fact that the Indemnitee was serving in any of such capacities.

      8.    (a)   Any notice or other communication under this Agreement shall
be in writing and shall be deemed given when delivered personally or mailed by
certified mail, return receipt requested, to the parties as follows:


            IF TO THE CORPORATION:

            Advanced Radio Telecom Corp.
            500 108th Avenue NE
            Suite 2600
            Bellevue, Washington  98004

            WITH A COPY TO:

            Hahn & Hessen LLP
            350 Fifth Avenue
            New York, New York  10118
            Attn:  James Kardon



                                     -4-
<PAGE>



            IF TO THE INDEMNITEE:

            __________________________
            c/o   Advanced Radio Telecom Corp.
            500 108th Avenue NE
            Suite 2600
            Bellevue, Washington  98004


or to such other address or person as any party hereto may specify by notice to
the other.

            (b)   The waiver by any party and the breach of any of the
provisions of this Agreement shall not operate or be construed as a waiver of
any subsequent breach hereof.

            (c)   This Agreement shall be binding upon and inure to the benefit
of the parties and their respective successors, assigns, legal representatives,
executors, administrators and heirs.

            (d)   This Agreement shall be governed by and construed in
accordance with the internal laws of the State of Delaware without regard to
conflict of law provisions.

            (e)   Each of the parties hereto submits to the jurisdiction of a
United States District Court of the Southern District of New York or, if such
Court lacks subject matter jurisdiction, to the jurisdiction of the Chancery
Court of the State of Delaware with respect to any disputes, directly or
indirectly, to any matter of interpretation of this Agreement or the respective
rights or obligations of each of the parties hereto (whether or not any such
party is otherwise subject to the jurisdiction or venue of either such Court).
Each of the parties specifically waives any objection which it may otherwise
have to the jurisdiction or venue of any such Courts and acknowledges that
service of process may be made by mailing a copy thereof in accordance with the
provisions of subsection (a) above.

            (f)   Each of the provisions of this Agreement is a separate and
distinct agreement and independent of all others, so that if any provision
hereof shall be held to be invalid or unenforceable for any reason, such
invalidity or enforceability shall not affect the validity or enforceability of
any other provisions hereof.  This Agreement is being entered into pursuant to
Section 145(f) of the Delaware the Corporation Law and as such is intended to be
supplemental to any other rights to indemnification available to the Indemnitee
and is not intended to be restricted by the provisions of clauses (a) and (b) of
such Section 145.  Nothing herein shall be deemed to diminish or otherwise
restrict the Indemnitee's right to indemnification under any provision of the
Certificate of Incorporation or By-laws of the Corporation.



                                     -5-
<PAGE>



            (g)   No amendment, modification, termination or cancellation of
this Agreement shall be effective unless in writing and signed by both parties
hereto.

      9.    The Indemnitee agrees that he will reimburse the Corporation for all
reasonable expenses paid by the Corporation in defending any civil or criminal
action, suit or proceeding against him in the event and only to the extent that
it shall ultimately be determined by a court of competent jurisdiction or in
arbitration between the Corporation and the Indemnitee in accordance with rules
of the American Arbitration Association that he was not entitled to be
indemnified by the Corporation for such expenses under the provisions of the
Delaware the Corporation Law, this Agreement or otherwise at the time the
expenses were advanced.

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

                                    ADVANCED RADIO TELECOM CORP.


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


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


                                     -6-

<PAGE>

                                VOTING AGREEMENT

          This Voting Agreement (the "Agreement") is made as of the ____ day of
July, 1996 by and between Landover Holdings Corp. ("LHC") and Advanced Radio
Technologies Corporation, a Delaware corporation (the "Company").

                                    RECITALS

          WHEREAS, the Company has agreed to a merger of its subsidiary (the
"Merger") with Advanced Radio Telecom Corp. ("Telecom"), subject only to
approval by the Federal Communications Commissions ("FCC"); and 

          WHEREAS, the Company will change its name to Advanced Radio Telecom
Corp. after the Merger; and 

          WHEREAS, the Company is preparing to make an underwritten initial
public offering (the "IPO") of its Common Stock, par value $0.001 per share (the
"Common Stock") and, in connection therewith, the Company and LHC deem it to be
in the best interests of the Company and its stockholders that the Company
obtain a listing of the Common Stock on the Nasdaq National Market ("Nasdaq") in
order to improve the liquidity and marketability of the Common Stock; and

          WHEREAS, LHC is controlled by Laurence S. Zimmerman ("Zimmerman"); and

          WHEREAS, after giving effect to the Merger, LHC owns 8,068,581 shares
and affiliates of LHC, including the wife and a family trust of Zimmerman (the
"LHC Affiliates"), own 200,000 shares (collectively, the "Current Shares"), of
the Common Stock, including (i) 7,954,250 shares of Common Stock issuable upon
consummation of the Merger in exchange for shares of Telecom Common Stock (the
"ART Shares") and (ii) 37,500 shares of Common Stock issuable upon exercise of
warrants, but (iii) not including 294,487 shares, 1,375,699 shares, 5,276,440
shares and 95,719 shares of Common Stock, issuable upon consummation of the
Merger, held by E1 Holdings, L.P., E2 Holdings, L.P., E2-2 Holdings, L.P.,
respectively, each a limited partnership which is controlled by LHC but which
will dissolve on consummation of the Merger; and

          WHEREAS, in order to assist the Company to obtain such listing and for
other consideration, LHC has agreed to enter into, and to cause the LHC
Affiliates to enter into, a Voting Trust Agreement and Irrevocable Proxy (the
"Voting Trust and Proxy"), dated the date hereof, with Mark C. Demetree, Andrew
I. Fillat, and Vernon L. Fotheringham (the "Trustees") and deposit (i) the
Current Shares, (ii)any other shares of Common Stock that may hereafter be
acquired or beneficially owned by LHC, including without limitation any shares
of Common Stock issuable upon exercise of warrants, and (iii) any rights,
warrants or options to purchase, or other securities convertible into, Common
Stock 

<PAGE>

(collectively, the "LHC Securities") into the trust created thereby; and

          WHEREAS, the Voting Trust and Proxy provides that the Trustees shall
vote the LHC Securities in the manner specified therein; and

          WHEREAS, in order for the Trustees to act hereunder the Company has
agreed to indemnify the Trustees for any costs relating to their services
hereunder; and

          WHEREAS, 400,634 of the Current Shares, issuable upon consummation of
the Merger, (the Option Securities") are held by Pierson & Burnett, L.L.P. (the
"Escrow Agent") pursuant to an escrow agreement (the "Escrow Agreement") subject
to an option agreement, each dated February 2, 1996 among LHC, the holders of
Series D Preferred Stock of the Company, and, in the case of the Escrow
Agreement, the Escrow Agent;

          NOW, THEREFORE, in consideration of the mutual covenants contained
herein, LHC and the Company hereby agree as follows:

          1.   EFFECTIVENESS.  This Agreement and the Voting Trust and Proxy
shall become effective upon the effective date of registration statement for the
IPO.

          2.   EXECUTION OF VOTING TRUST AND PROXY.  LHC hereby agrees that in
the event the Voting Trust and Proxy terminates by reason of the incapacity (as
defined therein) of each Trustee, LHC will execute a voting trust and
irrevocable proxy, substantially in the form and with the effect of the Voting
Trust and Proxy, appointing another person or entity reasonably acceptable to
the Board of Directors of the Company to act in the same capacity as the
Trustees under the Voting Trust and Proxy.

          3.   TERMINATION OF AGREEMENT.  Notwithstanding the provisions of
paragraph 2 above, this Agreement shall terminate (a) if the IPO fails to close
by September 1, 1996 or (b) upon the earlier to occur of (i) the death of
Zimmerman), (ii) the later of August 31, 2006 or the cash repayment in full of
the Company's Senior Discount Notes due 2006 (the "Senior Discount Notes"),
(iii) the sale or transfer to third parties not affiliated with LHC of all the
LHC Securities and (iv) prior to August 31, 2006 in the event that a business
combination occurs in which (A) the Senior Discount Notes are repaid in full in
cash, (B) holders of ART Common Stock receive common equity securities in the
new company representing less than 50% of the voting power of the new company,
(C) less than half of the directors of the new company on a going-forward basis
are former ART directors, and (D) LHC's equity represents less than 5% of the
voting power of the new company.  However, notwithstanding any of the foregoing,
this Agreement shall not terminate if its continued existence is required by a
third party regulatory agency, for example, as a condition to continued listing
of the 

                                       -2-
<PAGE>

Company's (or any acquiring company's) equity securities on the Nasdaq National
Market System or other principal trading market for such equity securities.

          4.   REPRESENTATIONS OF LHC.  LHC hereby represents and warrants to
the Company that LHC (a) owns and has the right to vote the LHC Securities
(except that the ART Shares can be voted prior to the Merger only on Telecom
matters), (b) has full power to enter into this Agreement and (c) will not take
any action inconsistent with the purposes and provisions of this Agreement.

          5.   SALE OF LHC SECURITIES.  No provision of this Agreement or the
Voting Trust and Irrevocable Proxy shall in any way limit right or ability of
LHC or the LHC Affiliates to sell, transfer, assign or pledge any or all of the
LHC Securities to a third party; except that LHC, the LHC Affiliates and
Zimmerman will enter into any lock-up agreements requested by the underwriters
of the IPO and entered into by other principal stockholders of the Company; and
provided that LHC Securities sold, assigned, transferred or hypothecated to an
affiliate of LHC shall remain in trust under the terms of the Voting Trust and
Irrevocable Proxy.  LHC Securities sold or transferred to third parties not
affiliated with LHC shall be released from the trust under such sale or
transfer.  For purposes of this Agreement, a third party shall be deemed
"affiliated" if such third party is controlled by, controls or under common
control with LHC, Zimmerman or a member of the immediate family of Zimmerman or
has made substantial investments of any nature with LHC, Zimmerman or any member
of the immediate family of Zimmerman.  The term "substantial business
investments" refers to investments by a third party comprising more than 5% of
the equity or debt of a company, partnership or joint venture in which LHC,
Zimmerman or an affiliate of LHC or Zimmerman has an investment of at least 5%.

          6.   IRREVOCABLE PROXY.  LHC hereby notifies the Company that it has
granted to the Trustees an irrevocable proxy pursuant to the provisions of the
Delaware General Corporation Law to vote, or to execute and deliver written
consents or otherwise act with respect to, all LHC Securities as fully, to the
same extent and with the same effect as the undersigned might or could do under
any applicable laws or regulations governing the rights and powers of
stockholders of a Delaware corporation.  LHC hereby affirms that this proxy is
given as a condition of this Agreement and to improve the liquidity and
marketability of the Common Stock and as such is coupled with an interest and is
irrevocable.  It is further understood by LHC that this proxy may be exercised
by the Trustees for the period set forth in paragraph 3 above unless sooner
terminated in accordance with the provisions of the Agreement and the Voting
Trust and Proxy.

          7.   TERMINATION OF MANAGEMENT CONSULTING AGREEMENT.  The Management
Consulting Agreement, dated as of November 13, 1996, between the Company and LHC
shall terminate upon consummation of the IPO, and LHC shall receive at the
closing of 

                                       -3-
<PAGE>

the IPO all amounts otherwise due through November 13, 1996 at the rate of
$35,000 per month as provided in such agreement.

          8.   CONFIDENTIALITY.  The Company, acting by a majority of its
directors, may from time to time, in its discretion, invite Zimmerman to attend
meetings of the Board of Directors; provided that Zimmerman enters into the
Confidentiality Agreement in the form attached hereto as Exhibit A as such
agreement may be amended from time to time in accordance with its terms (the
"Confidentiality Agreement").  LHC hereby guarantees Zimmerman's performance
under the Confidentiality Agreement.

          9.   THE TRUSTEES.  The Trustees are expressly authorized to incur and
pay such reasonable expenses and charges, to employ and pay such agents,
attorneys and counsel, and to incur and pay such other charges and expenses as
the Trustees may deem reasonably necessary and proper for administering this
Agreement. The Company agrees to reimburse the Trustees for any such expense and
charges.

          10.   ENFORCEABILITY; VALIDITY.  LHC expressly agrees that this
Agreement shall be specifically enforceable in any court of competent
jurisdiction in accordance with its terms.

          11.  GENERAL PROVISIONS.

               (a)  Except as provided in paragraph 3 above, all of the
covenants and agreements contained in this Agreement shall be binding upon, and
inure to the benefit of, the respective parties and their successors, assigns,
heirs, executors, administrators and other legal representatives, as the case
may be.

               (b)  This Agreement, and the rights of the parties hereto, shall
be governed by and construed in accordance with the laws of the state of
Delaware.

               (c)  This Agreement may be executed in one or more counterparts,
each of which will be deemed an original but all of which together shall
constitute one and the same instrument.

               (d)  If any provision of this Agreement shall be declared void or
unenforceable by any court or administrative board of competent jurisdiction,
such provision shall be deemed to have been severed from the remainder of the
Agreement and this Agreement shall continue in all respects to be valid and
enforceable.

               (e)  Whenever the context of this Agreement shall so require, the
use of the singular number shall include the plural and the use of any gender
shall include all genders.

               (f)  The Company and its stockholders are hereby expressly made
third party beneficiaries of this Agreement, and 

                                       -4-
<PAGE>

accordingly this Agreement may not be amended without the prior written consent
of the company, acting by unanimous vote of its Board of Directors, and approval
of the Company's stockholders acting by a two thirds vote.

          IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

LANDOVER HOLDINGS CORP.            ADVANCED RADIO TECHNOLOGIES
                                   CORPORATION


By:_______________________         By:_________________________
   Laurence S. Zimmerman,             Name:
   President                          Title:




758790


                                       -5-

<PAGE>

                            CONFIDENTIALITY AGREEMENT
                            -------------------------

          AGREEMENT entered into as of _____________, 1996 by and between
Laurence S. Zimmerman ("Zimmerman"), residing at 11 East 68th Street, New York,
New York 10021, and Advanced Radio Telecom Corp. and Advanced Radio Technologies
Corporation (collectively, the "Company"), located at 500 108th Ave., N.E.,
Suite 2600, Bellevue, Washington 98004.

          WHEREAS, the Company by action of a majority of its directors in their
sole discretion may from time to time invite Zimmerman as an observer to
meetings of its Board of Directors and provide to him information concerning the
Company; and

          WHEREAS, in connection therewith, the Company may, in its sole
discretion, disclose to Zimmerman and his affiliates,   consultants, attorneys
and advisors (collectively, "Representatives") certain material confidential
information relating to the Company's business, performance and prospects,
including, without limitation, the Company's books and records, the Company's
trade secrets, the Company's operational practices, the identity of the
Company's customers, the Company's plans and information concerning potential
and actual acquisitions, dispositions and business combinations, the identity of
the Company's affiliates, any of the Company's customers confidential
information, the identity of the Company's suppliers and prospective suppliers,
the identity of the Company's creditors and financial backers, the Company's
know how, the Company's designs, the Company's inventions, the Company's
methods, the Company's processes, the Company's techniques and skills (whether
devised, developed or used by or for the Company), the Company's estimating and
costing procedures and the cost and gross prices charged by the Company for its
products and services, the prices or other consideration charged to or required
of the Company by any of its suppliers or potential suppliers and the Company's
sales and promotional policies (hereinafter referred to collectively as
"Confidential Information"); and

          WHEREAS, the Company has adopted a policy concerning insider trading
in the form attached hereto as Appendix 1 (as amended by the Company in its
discretion from time to time and provided promptly in writing to Zimmerman, the
"Insider Trading Policy");

          NOW, THEREFORE, the parties hereto agree as follows:

          1.   Zimmerman (i) shall not disclose Confidential Information (ii)
shall keep such information confidential and (iii) shall not use Confidential
Information for any purpose that reduces the benefits the Company may derive
from that information; provided, however, that Zimmerman may disclose
information contained in the Confidential Information to Representatives;
provided further that such Representatives will be informed by Zimmerman of this
Agreement and any such Representative (other than counsel) will agree in writing
to treat any such Confidential Information in accordance with the 

<PAGE>

terms and conditions of this Agreement, including without limitation complying
with the Insider Trading Policy.  Nothing in this Agreement shall impinge on or
restrict Zimmerman's ability to consult with counsel.  Notwithstanding any other
provisions of this Agreement, this Agreement shall not operate to preclude
Zimmerman or his Representatives from disclosing any of the Confidential
Information or any information relating to their opinion, judgment or
recommendations concerning the Company developed after receipt of the
Confidential Information, if Zimmerman or his Representatives are compelled (by
deposition, interrogatory, request for documents, subpoena, civil investigatory
demand or similar process) to do so.  Zimmerman hereby agrees to notify the
Company promptly if he or his Representatives are compelled to disclose
information in such circumstances, so that the Company may seek a protective
order or other appropriate remedy.  The Company hereby agrees to pay in full,
and to advance payment for, any expenses, including legal fees, relating to
steps taken by the Company or taken by Zimmerman or his Representatives at the
request of the Company to seek a protective order or other remedy.

          2.   If at any time the Company shall so request, Zimmerman will
promptly deliver to the Company all written Confidential Information and will
cause all copies thereof to be returned or destroyed.  Zimmerman will confirm
such return or destruction in writing to the Company.

          3.   The term "Confidential Information" does not include information
which:

                      (i)     is in or subsequently comes into the public domain
               other than as a result of a disclosure by Zimmerman or the
               Representatives in breach of this Agreement; or 

                      (ii)    is otherwise legally acquired by Zimmerman from a
               third party not in breach of any confidentiality obligation to
               the Company; or

                      (iii)   is disclosed by the Company to Zimmerman, his
               Representatives or to any third party on a non-confidential
               basis; or 

                      (iv)    is brought to the Company by Zimmerman or his
               Representatives; or

                      (v)     is not information which would generally be
               expected to be Confidential Information and has not been
               expressly identified to Zimmerman or his Representatives by one
               of the Company's directors, or officers, representatives or
               agents as "Confidential Information".

For purposes of clause (v) above, the following are among the information
generally expected to be Confidential Information:  

                                      - 2 -
<PAGE>

financial reports, projections, business plans or acquisition plans.

          4.   Zimmerman agrees that, during times when he is in possession of
Confidential Information, he is subject to and will comply with all the terms of
the Insider Trading Policy.  The Company agrees to give Zimmerman notice of all
actions and determinations by the Company pursuant to the Insider Trading
Policy.

          5.   Zimmerman shall indemnify and hold the Company harmless from and
against any and all losses, liabilities, damages, deficiencies, costs or
expenses resulting from (a) the breach by Zimmerman of this Agreement, (b) the
disclosure by any Representative (whether or not intentional, negligent or
otherwise) of any Confidential Information disclosed to the Representative
directly or indirectly by Zimmerman, (c) the use by Zimmerman or his
Representatives of the Confidential Information for any purpose that reduces the
benefits the Company may derive from that information and (d) any and all
actions, suits, proceedings, claims, remands, assessments, judgments, costs and
expenses (including attorneys' fees) incident to any of the matters set forth in
this Section 5, including those incurred in connection with actions brought to
recover from Zimmerman pursuant to this Section 5.  However, Zimmerman shall not
be required to indemnify or hold harmless the Company against any or all losses,
liabilities, damages, deficiencies, costs or expenses resulting from the gross
negligence or willful misconduct of the Company or any of its directors,
officers or employees.


          6.   Except for the obligations set forth in Section 7 below, all
obligations hereunder shall expire on the second anniversary of the last date on
which Zimmerman attends a Board meeting of the Company or receives Confidential
Information from the Company.

          7.   Zimmerman agrees that he will not, and will use his best efforts
to ensure that persons employed or retained as consultants by him or members of
his immediate family will not, serve as directors, officers, employees or
consultants of ART during the term of the Voting Agreement, dated the date
hereof, between the Company and Landover Holdings Corporation.  The Company and
its stockholders are hereby expressly made third party beneficiaries of this
Agreement, and accordingly, this Section 7 may not be amended without the prior
written consent of the Company, acting by unanimous vote of its Board of
Directors, and approval of the Company's stockholders acting by a two thirds
vote.

          8.   Nothing in this Agreement shall operate to preclude or restrict
Zimmerman or his Representatives from providing to third parties information
(other than Confidential Information), including but not limited to investment,
acquisition or merger opportunities, that Zimmerman or his Representatives also
have provided to the Company.  

                                      - 3 -
<PAGE>

          9.   This Agreement sets forth the entire understanding of the parties
with respect to the subject matter hereof and supersedes and replaces all prior
discussions, writings or understandings between the parties on such matter.

          10.  Zimmerman recognizes that a breach of this Agreement may cause
irreparable harm to the Company and accordingly, without limiting any other
remedies available in equity or at law, agrees to the granting of injunctive
relief to prevent a breach or the continuing breach of this Agreement.

          11.  (a)    All of the covenants and agreements contained in this
Agreement shall be binding upon, and inure to the benefit of, the respective
parties and their successors, assigns, heirs, executors, administrators and
other legal representatives, as the case may be.

               (b)    This Agreement, and the rights of the parties hereto,
shall be governed by and construed in accordance with the laws of the State of
Delaware.

               (c)    This Agreement may be executed in one or more
counterparts, each of which will be deemed an original but all of which together
shall constitute one and the same instrument.

               (d)    If any provision of this Agreement shall be declared void
or unenforceable by any court or administrative board of competent jurisdiction,
such provision shall be deemed to have been severed from the remainder of the
Agreement and this Agreement shall continue in all respects to be valid and
enforceable.

               (e)    Whenever the context of this Agreement shall so require,
the use of the singular number shall include the plural and the use of the
gender shall include all genders.

          IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first above written.

                              ADVANCED RADIO TELECOM CORP.


                              By:___________________________
                                 Title:

                              ADVANCED RADIO TECHNOLOGIES
                              CORPORATION


                              By:___________________________
                                 Title:


                              ______________________________
                              Laurence S. Zimmerman

                                      - 4 -



<PAGE>

                         ADVANCED RADIO TELECOM CORP.
                            STOCK OPTION AGREEMENT

     THIS AGREEMENT, made and entered into as of the ______ day of __________
199_ between ADVANCED RADIO TELECOM CORP., a Delaware corporation (herein 
called the "Corporation"), and _________________, (herein called the 
"Optionee").

                                WITNESSETH:

     WHEREAS, under the terms and conditions hereinafter stated, the 
Corporation hereby grants to the Optionee on the date hereof (the "Date of
Grant") pursuant to the Corporation's Restated Equity Incentive Plan (as 
amended from time to time, the "Plan") an option (the "Option") to purchase
_________ shares of the Corporation's common stock, $.001 par value per 
share ("Common Stock") at an exercise price of $_____ per share, subject to 
adjustment as provided in the Plan (the "option price").

     NOW, THEREFORE, the Corporation and the Optionee agree as follows:

     1. DEFINITIONS.  All capitalized terms not otherwise defined herein have 
the meanings given to them in the Plan.

     2. TERM.  The term of the Option shall commence on ______________, 199_ 
and shall terminate at 5:00 P.M., P.S.T., on _______________ ("Expiration 
Date").

     3. EXERCISE.  The Option may be exercised in whole or in part in 
accordance with the following schedule: up to __________ shares upon and 
after the Date of Grant, and up to an additional __________ shares upon and 
after the first, second, third and fourth anniversary of the Date of Grant, 
for an aggregate of ____________ shares. The method for exercise described in 
this Paragraph shall be the sole method of such exercise. The Optionee may 
exercise the Options by delivery to the Corporation of written notice 
accompanied by payment of the option price as provided in the Plan. The 
Option shall be considered exercised on the date the notice and payment are 
delivered to the President of the Corporation or deposited in the mail, as 
the case may be.

     4. TRANSFERABILITY OF OPTIONS.  The Option shall not be transferable by 
the Optionee other than by will or under the laws of descent and 
distribution. The Option shall be exercisable during the lifetime of the 
Optionee only by the Optionee, the Optionee's guardian or the Optionee's 
legal representative.

     5. TERMINATION OF AFFILIATION.  If Optionee cease to be an employee of 
the Corporation while an Option remains outstanding and unexercised, then the 
Option term shall terminate and the Option shall cease to be outstanding in 
accordance with the Plan. In no event, however, may any Option be exercised 
after the Expiration Date of such Option.

<PAGE>

     6. REQUIREMENTS OF LAW.  The Corporation shall not be required to sell 
or issue Common Stock under the Option if the issuance of such Common Stock 
would constitute a violation by the Optionee or the Corporation of any 
provisions of any state or federal law, rule or regulation. In addition, in 
connection with the Securities Act of 1933 (as now in effect or hereafter 
amended), upon exercise of the Option, the Corporation shall not be required 
to issue such Common Stock unless the Corporation has received evidence 
satisfactory to it to the effect that the Optionee will not transfer such 
shares except pursuant to a registration statement in effect under such Act, 
or unless an opinion of counsel to the Corporation has been received by the 
Corporation to the effect that such registration is not required. Any 
determination in this connection by the Corporation shall be final, binding 
and conclusive. In the event the shares issuable on exercise of the Option 
are not registered under the Securities Act of 
1933, the Corporation may imprint the following legend or any other legend 
which counsel for the Corporation considers necessary or advisable to comply 
with the Securities Act of 1933:

           "The shares of stock represented by this certificate have not
        been registered under the Securities Act of 1933 or under the 
        securities laws of any state and may not be sold or transferred except
        upon such registration or upon receipt by the Corporation of an
        opinion of counsel satisfactory to the Corporation, in form and 
        substance satisfactory to the Corporation, that registration is not
        required for such sale or transfer."

        The Corporation may, but shall in no event be obligated to, register 
any securities covered hereby pursuant to the Securities Act of 1933 (as now 
in effect or as hereafter amended); and in the event any shares are so 
registered the Corporation may remove any legend on certificates representing 
such shares. The Corporation shall not be obligated to take any other 
affirmative action in order to cause the exercise of the Option or the 
issuance of shares pursuant thereto to comply with any state or federal law, 
rule or regulation.

     7. NO RIGHTS AS STOCKHOLDER.  Except as otherwise provided in the Plan, 
the Optionee shall have no rights as a stockholder with respect to Common 
Stock covered by the Option until the date of issuance to the Optionee of a 
stock certificate for such Common Stock.

     8. EMPLOYMENT OBLIGATION.  The granting of the Option shall not impose 
upon the Corporation any obligation to employ or become affiliated with or 
continue to employ or be affiliated with the Optionee. The right of the 
Corporation to terminate the employment of or its affiliation with the 
Optionee or any other person shall not be diminished or affected by reason of 
the fact that the Option has been granted to the Optionee.

                                     -2-

<PAGE>

     9. WITHHOLDING AND REPORTING.  The Corporation's obligation to deliver 
shares of Common Stock or to make any payment upon the exercise of the Option 
shall be subject to applicable federal, state and local tax withholding and 
reporting requirements.

    10. SUBJECT TO PLAN.  The Option is subject to  all the terms, 
conditions, limitations and restrictions contained in the Plan, as amended 
from time to time, which shall be controlling in the event of any conflicting 
or inconsistent provisions.

   12. INTERPRETATION OF AGREEMENT; GOVERNING LAW.  The Option granted 
pursuant hereto is intended to be an "incentive stock option" within the 
meaning of the Internal Revenue Code of 1986, as amended. This Agreement 
shall be construed and enforced in accordance with, and governed by, the laws 
of the State of Washington.

                                       ADVANCED RADIO TELECOM CORP.


                                       By:    ______________________________
                                       Name:  ______________________________
                                       Title: ______________________________

        The optionee hereby acknowledges that he has received and reviewed a 
copy of the Plan and accepts and agrees to be bound by all terms and 
conditions hereof and thereof.


___________________________________

Date: _____________________






<PAGE>

[LOGO]                                              AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.


                                                                   THE AGREEMENT
AGREEMENT BETWEEN THE PARTIES                                          SECTION 1

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






                                 SECTION 1


                       AGREEMENT BETWEEN THE PARTIES














- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 1


<PAGE>


[LOGO]                                              AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.


                                                                   THE AGREEMENT
AGREEMENT BETWEEN THE PARTIES                                          SECTION 1

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

1.0    GENERAL

       As used herein, the term "Seller" shall refer to P-Com, Inc. (hereinafter
       P-Com) and the term "Buyer" shall refer to Advanced Radio Technology
       Limited (hereinafter ART). The terms and conditions of sale contained 
       herein constitute a legal and binding agreement ("Agreement") between 
       the parties and apply to all of Buyer's purchase orders. If any provision
       of this Agreement is held to be invalid or unenforceable, in whole or in
       part, the remaining provisions shall be enforceable, in whole or in part,
       the remaining provisions shall be enforceable to the maximum extent
       possible under law.

2.0     TERM OF AGREEMENT/TERMINATION

        The effective date of this agreement is the date of the execution of 
        the agreement and will expire on December 31, 1998.

3.0     TERMS

        Invoices shall be due and payable within thirty (30) days (Net 30) 
        from the date of invoice. All Payments shall be made in U.S. dollars.

4.0     BASIS OF PRICING

        By executing this agreement, Buyer agrees to purchase and P-Com agrees 
        to sell, in accordance with this proposal, seven thousand five hundred 
        (7,500) radio links between the date of execution of this agreement and 
        December 31, 1998, and take shipment of those systems in that time
        frame. Applicable pricing will be per Schedule A.

        ART will accept shipment of a minimum of three hundred (300) links for 
        shipment prior to June 30, 1996 and submit payment in accordance with 
        the terms of the Agreement.

        Buyer agrees to accept shipment as per the shipment schedule (See 
        Schedule D) and appropriate release notices delivered by Buyer.


- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 2


<PAGE>

[LOGO]                                              AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.


                                                                   THE AGREEMENT
AGREEMENT BETWEEN THE PARTIES                                          SECTION 1

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


        Pricing is quoted as "fixed" prices based on the quantity of radio 
        equipment actually purchased by Buyer. Pricing is not inclusive of
        freight, nor any applicable taxes.

5.0     SPARES

        Seller agrees to provide, at no additional charge during the warranty 
        period, emergency spares replacement to Buyer such that P-Com will ship
        a replacement ODU and/or IDU, within two (2) business days of receiving
        notice from Buyer, to replace a unit that failed in the field. Buyer
        will be required to ship the failed unit to P-Com within 15 days
        otherwise P-Com will bill Buyer for the replacement unit. (Note, See
        Article 11 for responsibility of freight costs.)

6.0     DOCUMENTATION

        P-Com will supply up to 10 Operations and Maintenance Manuals per 
        licensed geographic area of Buyer's operations when each area begins 
        service/operations and orders a minimum of 10 links, at no additional
        cost. No additional Operation and Maintenance Manuals or documentation
        is understood to be required.

7.0     SHIPMENT

        Subsequent to the shipment of the initial One hundred & Fifty (150) 
        links before December 31, 1995, P-Com will commit to ship on a weekly
        basis beginning in 1996, given that the shipment schedule (Schedule D)
        for a particular month is agreed upon at least 90 days prior to the
        month in which shipments are expected to begin (eg., January 1, 1996 for
        April 1996 shipments).

        P-Com is willing to vary the weekly shipments to ART in any given 
        month with reasonable notice (i.e., 30 days) in order to cooperate
        with ART in satisfying its customers. P-Com is willing to adjust the
        scheduled monthly shipments given 90 days advance notice (eg., January
        1, 1996 for April, 1996 shipments) for a change in shipments of up to
        plus or minus 10%. Changes in shipments of greater than plus or minus
        10% minus 30% will require 120 days notice. Changes in shipments of


- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 3


<PAGE>

[LOGO]                                              AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.


                                                                   THE AGREEMENT
AGREEMENT BETWEEN THE PARTIES                                          SECTION 1

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


        greater than plus or minus 30% will require 150 days notice, subject 
        to mutual agreement of the parties.

8.0     WARRANTY

        P-Com will extend our normal warranty from 12 months to a warranty 
        period or of 24 months from date of shipment to Buyer, provided Buyer 
        accepts shipment of 300 links by June 30, 1996 and an additional 600
        links by December 31, 1996. Seller will provide additional warranty
        coverage for an additional charge of three per cent (3%) of the cost of
        the equipment for each additional 12 months of coverage desired, up to a
        maximum of 3 additional years. Buyer is to notify, and pay, P-Com 12
        months in advance should they elect to purchase the extended warranty.

        Buyer has Until December 31, 1996 an option to purchase extended 
        warranty for equipment purchased prior to that time. For equipment 
        purchased after December 31, 1996. Buyer must purchase the extended 
        warranty at the same time purchase order is placed. Terms of the said 
        extended warranty will be per Article 11. Limited warranty.

9.0     PRICING COMMITMENT

        Seller shall not sell equipment to any North American customer, or to 
        any customer for the intended usage in North America, unless such
        customer is purchasing greater aggregate quantities under similar terms
        and conditions, under similar product configurations as the equipment
        included in this proposal, unless also notifying Buyer in writing of the
        improved terms and conditions and offering said improved terms and
        conditions to Buyer. This Article will be applicable once ART purchases
        a minimum of 2,500 links within a 12 month period.


- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 4

<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Agreement Between the Parties                                        SECTION 1

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

10.0  TERMINATION

      Either party may, by ninety (90) days prior written notice to the other 
      party, terminate this Agreement. In the event Buyer terminates the 
      agreement, Buyer agrees to take delivery and pay for all units in 
      Schedule D for the 90 days following the notice of termination. In the 
      event the Seller terminates the agreement, the Buyer has the option to 
      place additional purchase orders at the prices set forth in Schedule A 
      for all units in Schedule D during the 120 day period following the 
      effective date of the termination. Upon termination, Schedules A & D 
      related to price and delivery would be subject to change. All other 
      applicable provisions of the Agreement will remain in force.

11.0  LIMITED WARRANTY

      Seller warrants to BUYER or the actual purchaser of the equipment, in 
      the event the equipment is re-sold by the BUYER, that the products will 
      be substantially free from defects in material and workmanship for 
      twenty-four (24) months after delivery to Buyer, and will comply with 
      the performance specifications referred to in Schedule F hereto. 
      Products purchased from Seller which do not comply with the warranty 
      and are returned to the Seller during such period will be repaired or 
      replaced at Seller's option, at no cost to Buyer. During the warranty 
      period, the Seller and Buyer pay for freight one direction. Should the 
      field failures exceed 1.5% of the accumulative purchased amount of IDUs & 
      ODUs the Seller shall pay inbound and outbound freight for those 
      returned and repaired items. For out of warranty repairs Buyer shall pay 
      all inbound and outbound freight charges and all costs of repair or 
      replacement. Buyer may return faulty products after having been issued 
      by Seller a Return Material Authorization (RMA). Seller will not 
      unreasonably withhold issuance of RMA. The RMA number will be issued 
      after Buyer's consultation with Seller. Items returned to Seller must 
      be shipped in the original container or equivalent packaging to insure 
      against damage in transit. The above warranty does not extend to any 
      Product that is modified or altered, is not maintained in accordance 
      with Seller's reasonable maintenance recommendations, is operated in a 
      manner other than that specified by Seller, or is subjected to


- ------------------------------------------------------------------------------
Aug. 7, 1995                                                            Page 5
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Agreement Between the Parties                                        SECTION 1

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

      abuse, misuse, accident, disaster, alterations, neglect or other 
      improper treatment. Seller and Buyer will make good faith 
      determinations as to the exercise of any cause of alleged defect. 
      Buyer's sole remedy with respect to any warranty or defect is stated 
      above. Seller neither assumes nor authorizes any other person to assume 
      for Seller any other liability in connection with the sale of products 
      under this Agreement.

12.0  LIMITATION OF LIABILITY

      NOTWITHSTANDING ANYTHING ELSE IN THIS AGREEMENT OR OTHERWISE, SELLER 
      WILL NOT BE LIABLE UNDER ANY PROVISION OF THIS AGREEMENT OR UNDER ANY 
      CONTRACT, NEGLIGENCE, STRICT LIABILITY OR OTHER LEGAL OR EQUITABLE 
      THEORY (A) FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES, OR (B) FOR COST 
      OF PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES.

13.0  DEFAULT AND CANCELLATION

      If Buyer becomes bankrupt or insolvent, or files or has filed against 
      it any petition in bankruptcy, or makes an arrangement for the benefit 
      of its creditors, or suffers a receiver or similar party to be 
      appointed, or fails to make payment for goods received or fails to 
      fulfill purchase commitments, the Seller shall be entitled to cancel 
      this Agreement without judicial intervention or declaration of default 
      of Buyer and without prejudice to any right or remedy which shall have 
      accrued or shall thereafter accrue to Seller. Either Party shall have 
      45 days after written notice to correct any identified defaults.

14.0  MODIFICATION/WAIVER

      No addition to, deletion from, or modification of any of the provisions 
      of this Agreement shall be binding upon the Parties unless acknowledged 
      in writing and accepted by the Party to be bound.

15.0  NOTICES


- ------------------------------------------------------------------------------
Aug. 7, 1995                                                            Page 6
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Agreement Between the Parties                                        SECTION 1

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

      Any notice contemplated by or made pursuant to this Agreement shall be 
      in writing and shall be deemed delivered on the date of delivery if 
      delivered personally or by facsimile, or five (5) days after mailing if 
      placed in the U.S. mail, postage prepaid, registered or certified mail, 
      return receipt requested, addressed to Buyer or Seller (as the case may 
      be) at the address shown on the reverse side hereof, or such other 
      address as shall be designated by at least ten (10) days prior written 
      notice.

16.0  GOVERNING LAW

      This contract shall be governed by Delaware law as applied to contracts 
      entered into by Delaware residents within the state of Delaware and to 
      be performed within the state of Delaware without regard to applicable 
      principles of conflict of laws.

17.0  REVENUE SHARING

      Once ART purchases link 300, P-Com agrees to partially finance 
      additional equipment in the form of a subsidy in return for receiving a 
      share of the revenue on the equipment shipped from link 301 forward, 
      subject to the provisions of schedule L.

18.0  EXHIBITS

      The exhibits listed herein are made part of this agreement.

                        Schedule A     Pricing
                        Schedule B     Standard Configuration
                        Schedule C     Auxiliary Equipment Pricing
                        Schedule D     Delivery
                        Schedule E     Ship in Place Criteria
                        Schedule F     Radio Technical Information
                        Schedule G     NMS Programs
                        Schedule H     Standards
                        Schedule J     Quality
                        Schedule K     Training
                        Schedule L     Revenue Sharing


- ------------------------------------------------------------------------------
Aug. 7, 1995                                                            Page 7
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Agreement Between the Parties                                        SECTION 1

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

                               SIGNATORY PAGE

IN WITNESS WHEREOF, the parties hereto have executed this legally binding 
Agreement.

Per this Agreement, the initial order is for 900 links, non-cancelable, to be 
purchased and delivered per Schedule A and Schedule D. The initial order will 
take the form of a Master Purchase Order with a value of $13,260,000 to be 
provided to P-Com upon execution of this Agreement.


P-COM, INC.                              ADVANCED RADIO TECHNOLOGY CORPORATION



/s/ PIER ANTONIUCCI           8/11/95    /s/ STEVEN D. COMRIE           8/11/95
- -------------------------------------    --------------------------------------
Signature                     Date       Signature                      Date


PIER ANTONIUCCI                          STEVEN D. COMRIE
- -------------------------------------    --------------------------------------

EXECUTIVE V.P.                           PRESIDENT
- -------------------------------------    --------------------------------------

3175 S. Winchester Boulevard             1200 19th Street
Campbell, CA 95008                       Suite 560
                                         Washington, D.C. 20036


- ------------------------------------------------------------------------------
Aug. 7, 1995                                                            Page 8
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Terms and Conditions                                                 SECTION 2

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




                                 SECTION 2



                           TERMS and CONDITIONS






- ------------------------------------------------------------------------------
Aug. 7, 1995                                                            Page 1
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Terms and Conditions                                                 SECTION 2

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

1.  ASSIGNMENT:  This Agreement shall accrue to the benefit of and be binding 
upon the parties hereto, any purchaser and any successor entity into which 
any such person shall have been merged or consolidated or to which any such 
person shall have sold or transferred all or substantially all its assets. 
Buyer may assign its rights and/or obligations under this Agreement to one or 
more Buyer Affiliates, provided such Buyer Affiliates agree to be bound by 
all of the terms and conditions hereof. This Agreement shall not otherwise be 
assigned by either party without the prior written consent of the other 
party. The parties agree that any consent to a requested assignment shall not 
be unreasonably withheld. Should Buyer assign this Agreement to any entity or 
person, Seller may request commercially reasonable assurance of payment by 
the assignee, prior to any shipment thereto. Should Buyer assign this 
Agreement to any Buyer's Customer, Buyer agrees and understands that pricing 
contained herein shall not transfer. Buyer agrees not to assign this 
Agreement to any entity which is not credit worthy or to an established 
competitor of Seller (i.e. a supplier of radio equipment for use in the 23 
GHz and higher spectrum). For purposes of this Agreement, purchase orders by 
Buyer's affiliates shall be deemed to be a purchase orders of Buyer for 
purposes of Schedule B, and Buyer affiliates shall be entitled to the rights 
of Buyer here under with respect to purchases made pursuant to such purchase 
orders.

2.  MANUFACTURED SPECIFICATIONS:  Seller shall manufacture equipment proposed 
herein to the agreed upon Specifications and shall notify Buyer in the event 
any future changes in component parts or design have a material impact on the 
agreed upon Specifications. Seller agrees to provide one hundred and twenty 
(120) days advance notice to Buyer of any such changes. Seller agrees to make 
any reasonable changes and modifications in the equipment if requested by 
Buyer at a price to be mutually agreed upon at that time.

3.  CONFORMITY WITH LAW:  Seller is a commercial manufacturer/supplier and 
complies with all applicable Federal and State laws.

4.  NEW FEATURES AND/OR EQUIPMENT:  Seller agrees to make new Equipment, 
features, functions, and capabilities available to the Buyer at then 
reasonable prices and on reasonable terms to be mutually agreed upon. Seller 
agrees that future equipment will be compatible with equipment purchased 
hereunder on a like-for-like basis. Hot-standby equipment will not be covered 
under this provision.


- ------------------------------------------------------------------------------
AUG. 7, 1995                                                            Page 2
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Terms and Conditions                                                 SECTION 2

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

5.  BANKRUPTCY:  In the event of Seller's bankruptcy or otherwise ceasing to 
do business, Seller agrees to permit Buyer to have Seller's subcontractors 
manufacture the Equipment provided by this Agreement. Seller agrees to make 
best efforts to ensure that Buyer obtains Seller's pricing from 
subcontractors and has access to and the right to use Seller's source codes 
software, engineering designs and specifications as well as technical 
information for use by Buyer only in connection with the manufacture, testing 
and use of the Equipment. Seller and Buyer will reach mutual agreement with 
respect to escrow arrangements to insure Buyer's access to source codes and 
software in such event.

6.  INDEMNIFICATION:  Seller will indemnify Buyer and hold Buyer harmless 
from and against any liability, damage, loss, expense, claim or judgment 
arising from injury to any person or damage to any property however caused, 
whether by Seller's sole or concurrent negligence or otherwise, arising from 
the sale, resale, repair, replacement or use of any products shipped pursuant 
to any order resulting from this Agreement up to a maximum of three million 
dollars ($3 M) per occurrence. Seller further agrees to indemnify and hold 
Buyer harmless from any and all expenses, losses, royalties, and damages 
including court costs and attorney's fees resulting from the bringing of such 
suit or proceedings including settlement or decree of judgment entered 
therein, unless it arises from an action by Buyer.

Seller will indemnify and hold Buyer harmless from and against any liability, 
damage, loss, expense, including reasonable attorney fees, claim or judgment 
arising from or brought against Buyer or its agents or vendors for alleged 
patent, trademark or copyright infringement, as well as for alleged unfair 
competition resulting from similarity in design or appearance of Equipment 
provided per this Agreement up to a maximum of three million dollars ($3M) 
per occurrence. The Seller may be represented by and actively participate 
through its own counsel in any such suit or proceedings.

7.  EQUIPMENT AND FACTORY INSPECTION:  Seller agrees to permit Buyer, and 
Buyer's Affiliates, Major Customers, Financing/Leasing Sources, the 
opportunity to inspect the Equipment as it is built and the Seller's premises 
and the premises of the Seller's contractors, to ensure that adequate quality 
control is provided by the Seller. Buyer must provide Seller with no less 
than ten (10) business days advance notice of all visits. Seller will 
coordinate all visits with Seller's contractors. All visits will be made 
during regular business hours. At Buyer's request Buyer shall be entitled to 
inspect equipment prior to shipment;


- ------------------------------------------------------------------------------
AUG. 7, 1995                                                            Page 3
<PAGE>


[LOGO]                                               AGREEMENT BETWEEN PARTIES
                                                  A.R.T. LIMITED & P-COM, INC.

                                                                 The Agreement
Terms and Conditions                                                 SECTION 2

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

provided, however, that Buyer's inspection shall be made within a reasonable 
period to enable Seller to satisfy scheduled shipment date.

8.   LIABILITY INSURANCE:  Seller agrees to maintain adequate product 
liability, employee related and business insurance with reputable insurance 
companies. Seller shall agree to list Buyer as an additional insured under 
Seller's liability insurance policies during the term hereof and for two 
years thereafter.

9.   PRODUCT CERTIFICATION:  Seller agrees to obtain and maintain the 
applicable and necessary safety and FCC certifications for usage of the 
Equipment to be provided per this Agreement.

10.  EQUIPMENT NAME:  Buyer must receive prior approval from Seller before 
attaching, affixing, or placing any Buyer name or insignia onto Seller's 
Equipment. Such approval shall not be unreasonably withheld. In no event will 
Seller's name (P-Com, Inc.) and or logo be removed from the Equipment.

11.  PARTS AND REPLACEMENT:  Seller agrees to maintain a satisfactory parts 
and replacement inventory for five (5) years after shipment of Equipment. 
Seller agrees to provide repair and return services and have in place a 
procedure for such services.

12.  CONTRACT TERMS:  Seller is a commercial supplier and recognizes standard 
commercial contract terms and conditions. Seller will reasonably cooperate 
with and assist Buyer in connection with satisfying contract terms of Buyer's 
customers.

13.  GRATUITIES:  Seller and Buyer shall agree that no gratuities or similar 
payments have been made or received in connection with this Agreement.

14.  WORK STOPPAGE:  Seller agrees to notify Buyer of any potential work 
stoppages or any other event which could impact product flow to Buyer.


- ------------------------------------------------------------------------------
AUG. 7, 1995                                                            Page 4
<PAGE>

[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                   A.R.T. LIMITED & P-COM, INC.

                                                                  The Agreement
Terms and Conditions                                                  SECTION 2
- -------------------------------------------------------------------------------

15. SHIPPING, TITLE, TAXES: Shipping terms are F.O.B. Factory, title and risk 
to pass only upon shipment to Buyer. Seller to invoice Buyer upon shipment of 
Equipment. Buyer shall pay all freight charges, applicable state and federal 
sales and excise taxes. Buyer shall designate the manner of shipping. Seller 
shall arrange and coordinate shipments. The Buyer agrees to provide a 
California resale certificate or appropriate document if it is determined 
taxes are not applicable.

16. SUBCONTRACT MANUFACTURING: Seller may freely select its subcontractors 
subject only to the subcontractor meeting the requirements of the Seller. 
Seller shall notify Buyer of a significant change of subcontractor.

17. TECHNICAL SUPPORT: Seller agrees to provide telephone technical 
assistance to Buyer 24 hours a day at no charge for the first one hundred 
(100) hours should Buyer purchase a minimum of nine hundred (900) links 
during the first 18 months of the Agreement. Subsequent technical assistance 
will be provided at a rate of seventy dollars ($70) per hour with a one (1) hour
minimum. Seller's personnel agree to follow Buyer's and Buyer's customer's 
plant rules given that Seller has been advised in advance of the rules.

18. ENGLISH LANGUAGE: Seller agrees to provide all shipping and technical 
materials in connection with this Agreement in English.

19. PACKAGING: Seller agrees to cooperate with Buyer to ensure that the 
Equipment is packaged appropriately for handling by one individual and in a 
method that avoids breakage. Seller reserves the right to charge Buyer for 
additional labor and/or materials required beyond Seller's standard 
procedures.

20. MATERIAL OWNERSHIP: Seller shall own all specifications, drawings and 
technical material prepared by it. Buyer shall own all specifications, 
drawings and technical material prepared by it.

21. LIENS: Seller shall provide and ship all Equipment free of all liens and 
encumbrances of any nature.

22. INVOICES: Seller shall prepare separate invoices for each shipment of 
Equipment. Invoices shall be issued to Buyer promptly upon shipment.


- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 5

<PAGE>

[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                   A.R.T. LIMITED & P-COM, INC.

                                                                  The Agreement
Terms and Conditions                                                  SECTION 2
- -------------------------------------------------------------------------------

23. DISCLOSURES: Any disclosures concerning this Agreement shall require the 
mutual consent of the Seller and Buyer, except as may be required to comply 
with securities laws and in connection with relevant government agency 
communications. Notwithstanding the foregoing, either party shall be entitled 
to disclose this agreement and the terms hereof to its financing sources.

24. NETWORK MANAGEMENT SYSTEM: Seller is developing (and will continue to 
develop) a Network Management System based on the Hewlett Packard Open View 
Architecture for use as an operating system for the Equipment ("Seller's 
NMS") which it anticipates will be completed on or before December 31, 1995. 
Seller's NMS shall perform to the specification referred to on Schedule I. 
Seller agrees to license Seller's NMS to Buyer at commercially reasonable 
rates reflecting the cost of its development, such rates to be mutually 
agreed upon between the parties. Seller agrees to work cooperatively with the 
Buyer in interfacing the Seller's NMS with the Network Management System 
utilized or developed by Buyer for use in operating the Equipment provided, 
however, that Seller shall be entitled to charge Buyer for such service at 
the rate of seventy ($70) dollars for each hour of time spent by Seller's 
technical staff in connection therewith.

- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 6

<PAGE>

[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                   A.R.T. LIMITED & P-COM, INC.
REF: US-PCN-296
                                                                         REV. 4
                                                                       EXHIBITS
Pricing                                                              SCHEDULE A
- -------------------------------------------------------------------------------




                                   SCHEDULE A


                                 RADIO PRICING



- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 1

<PAGE>

[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                   A.R.T. LIMITED & P-COM, INC.
REF: US-PCN-296
                                                                         REV. 4
                                                                       EXHIBITS
Pricing                                                              SCHEDULE A
- -------------------------------------------------------------------------------


                           389 GHZ RADIO EQUIPMENT


The proposed non-protected radio equipment is the Tel-Link 38. The link 
pricing listed below consists of two ODU's and two IDU's which allow for 4T1 
radio capacity including two 1' antenna's. Link Manager Port. and NMS 
service channel. Equipment operates at -48VDC. The Belden 9913 coaxial cable 
used to interconnect the ODU and IDU is not included.


                                    TABLE 1

CUMULATIVE QUANTITY LEVEL       LINK LIST PRICE      ART LINK PRICE      % DISC.
- -------------------------       ---------------      --------------      -------

                                   [CONFIDENTIAL]

Upon execution of this Agreement Buyer agrees to provide a master purchase 
order reflecting the initial 900 links being purchased. The first 50 links 
are to be shipped on or before September 31, 1995, at the initial link price 
of [CONFIDENTIAL]. The next 100 links are to be shipped on or before December 
31, 1995, at the initial link price of [CONFIDENTIAL] Links 151-300 will ship 
on or before June 30, 1996, at the initial link price of [CONFIDENTIAL] Links 
301-900 will be billed per Schedule A and shipped in accordance with Buyer 
shipping notices, but in no event later than December 31, 1996, and as 
indicated in Schedule D. The balance of the purchases are to take place 
pursuant to purchase orders of Buyer and shipping instructions issued by 
Buyer in accordance with the Agreement.

Buyer agrees to provide an [CONFIDENTIAL] of [CONFIDENTIAL] of [CONFIDENTIAL] 
Buyer will pay invoices in full upon receipt in accordance with the 
Agreement. [CONFIDENTIAL]


- -------------------------------------------------------------------------------
AUG 7, 1995                                                              Page 2


<PAGE>

[LOGO]                                                 Agreement Between Parties
                                                    A.R.T. LIMITED & P-Com, Inc.

REF: US-PCN-296                                                            REV.4
                                                                        EXHIBITS
Pricing                                                               Schedule A
- --------------------------------------------------------------------------------


In addition, once ART purchases link [CONFIDENTIAL] to be
settled as follows:

During the course of the purchase of links [CONFIDENTIAL]

These pricing levels are valid for all purchase orders released to P-Com through
December 31, 1998.  In the event ART does not take delivery of 900 links by
December 31, 1996 and does not issue a master purchase order prior to December
31, 1996 for an additional 2,500 links with scheduled delivery during 1997 per
Schedule D, P-Com has the right to terminate the Agreement and receive all
outstanding moneys due within thirty (30) days thereafter.  Further, in the
event ART does not issue purchase orders, purchase and take delivery of a
minimum of 2500 additional links in each of calendar years 1998 and 1999, then
P-Com has the right to terminate the Agreement and receive all outstanding
moneys due within thirty (3) days thereafter.  In the event P-Com terminates the
Agreement as indicated above, all scheduled delivery commitments, against
outstanding purchase orders would be fulfilled by P-Com and accepted by ART.

As noted above, ART will accept shipment of one hundred fifty (150) links for
shipment prior to December 31, 1995, and submit payment in accordance with the
terms of the Agreement.

Seller agrees to ship in accordance with the purchase orders and shipping
instructions delivered by Buyer, provided no purchase order shall contain any
provisions that contradict or supersede the provisions set forth in the
Agreement between the Parties.

Pricing is quoted as "fixed" prices based on the quantity of radio equipment
actually purchased by Buyer.  Pricing is not inclusive of freight, nor any
applicable taxes.






- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 3

<PAGE>

[LOGO]                                                 Agreement Between Parties
                                                    A.R.T. LIMITED & P-Com, Inc.

REF:  US-PCN-296                                                           REV.1
                                                                        EXHIBITS
Pricing                                                               Appendix 1
- --------------------------------------------------------------------------------







                                      APPENDIX 1


                                       PRICING













- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>

[LOGO]                                                 Agreement Between Parties
                                                    A.R.T. LIMITED & P-Com, Inc.

REF:  US-PCN-296                                                           REV.1
                                                                        EXHIBITS
Pricing                                                               Appendix 1
- --------------------------------------------------------------------------------



                                38 GHz Radio Equipment

The proposed non-protected radio equipment is the Tel-Link 38.  The link pricing
listed below consists of two ODU's and two IDU's which allow BT1 and DS3 radio
capacity, as applicable, also includes two 1' antenna's.  Link Manager Port, and
NMS service channel.  Equipment operates at -48VDC.  The Belden 9913 coaxial
cable used to interconnect the ODU and IDU is not included.


                                       Table 2
- --------------------------------------------------------------------------------
                                  BT1 Non-Protected
- --------------------------------------------------------------------------------
Cumulative                  Link                ART
Quantity Level           List Price          List Price          % Disc.
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                                   [CONFIDENTIAL]

                                       Table 3
- --------------------------------------------------------------------------------
                                  1DS3 Non-Protected
- --------------------------------------------------------------------------------
Cumulative                 Link                ART
Quantity Level           List Price          List Price          % Disc.
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                                   [CONFIDENTIAL]

- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2

<PAGE>

[LOGO]                                                 Agreement Between Parties
                                                    A.R.T. LIMITED & P-Com, Inc.

REF:  US-PCN-296                                                           REV.1
                                                                        EXHIBITS
Pricing                                                               Appendix 1
- --------------------------------------------------------------------------------


Once the Buyer issues the Seller a purchase order in accordance with the
agreement inclusive of 8DS1 and/or DS3 radio links, [CONFIDENTIAL].  All 4DS1
radio links will carry the [CONFIDENTIAL]; all 8DS1 radio links will carry the
[CONFIDENTIAL] and all 1DS3 radio links will carry the [CONFIDENTIAL].

                                   [CONFIDENTIAL]

                                       Table 4
- --------------------------------------------------------------------------------
                         Links purchased / Debit calculation
- --------------------------------------------------------------------------------
   Link Version              Basic               Factor             Actual
                        Credit / Debit                          Credit / Debit 
    4DS1                      
    8DS1                           [CONFIDENTIAL]
    1DS3                      








- --------------------------------------------------------------------------------
Aug 7                                                                     Page 3


<PAGE>

[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                       EXHIBITS
Equipment Configuration                                              SCHEDULE B
- -------------------------------------------------------------------------------


                                  SCHEDULE B

                            STANDARD CONFIGURATION


- -------------------------------------------------------------------------------
Aug 7, 1995                                                              Page 1

<PAGE>

[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                       EXHIBITS
Equipment Configuration                                              SCHEDULE B
- -------------------------------------------------------------------------------


The Tel-Link Series Radio terminal (38 GHz), as described in the P-Com 
Applications Handbook and as proposed to ART, is equipped with the following 
capabilities:

                                     4DS1 TERMINAL
                   -  38 GHz ODU equipped for 4T1's
                   -  Basic IDU equipped with 4T1's (without Keypad)
                   -  2 FSK Modulation
                   -  -48v Power Input
                   -  Link Manager Port
                   -  DB25 100 Ohm Connector for T1 Connectivity
                   -  Alarm Relays
                   -  NMS Service Channel 
                   -  Front Only Connectors (No connectors on the back)
                   -  30cm antenna


                                     8 DS1 TERMINAL
                   -  38 GHz ODU equipped for 8T1's
                   -  Basic IDU equipped with 8T1's (without Keypad)
                   -  4 FSK Modulation
                   -  -48v Power Input
                   -  Link Manager Port
                   -  DB25 100 Ohm Connector for T1 Connectivity
                   -  Alarm Relays
                   -  NMS Service Channel 
                   -  Front Only Connectors (No connectors on the back)
                   -  30cm antenna


                                     1 DS3 TERMINAL
                   -  38 GHz ODU equipped for (1) DS3
                   -  Basic IDU equipped with (1) DS3 (without Keypad)
                   -  4 FSK Modulation
                   -  -48v Power Input
                   -  Link Manager Port
                   -  75 Ohm BNC Connector for DS3 Connectivity
                   -  Alarm Relays
                   -  NMS Service Channel 
                   -  Front Only Connectors (No connectors on the back)
                   -  30cm antenna


The optional equipment available with the Tel-Link Series Radio equipment is 
detailed in Schedule C.


- -------------------------------------------------------------------------------
Aug 7, 1995                                                              Page 2


<PAGE>


[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296                                                           Rev. 1
                                                                       EXHIBITS
Equipment Options                                                    SCHEDULE C
- -------------------------------------------------------------------------------


                                  SCHEDULE C

                          AUXILIARY EQUIPMENT PRICING


- -------------------------------------------------------------------------------
Aug 7, 1995                                                              Page 1

<PAGE>


[LOGO]                                                AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296                                                           Rev. 1
                                                                       EXHIBITS
Equipment Options                                                    SCHEDULE C
- -------------------------------------------------------------------------------


The pricing offered for the standard configuration is based upon a 
streamlined platform that does not accommodate all options. Group 1, lists 
the options that will require the use of the Enhanced IDU which is also 
listed in Group 1. Group 2 items can be used directly with the standard radio 
package. Group 3 lists specialty items that can be provided but that will 
require special clarification.

EQUIPMENT                                    LIST PRICE      ART PRICE % DISC.*
- ---------------------------------------      ----------      --------- --------

GROUP 1
Enhanced IDU (additional price)                

Data Service Channel (per radio)               

FEC (per radio)                               

Point to Point Orderwire (per radio)          

Protection Kit:
MHSB Protection Kit #1 (per terminal)                    [CONFIDENTIAL]
     Two Antenna Application
MHSB Protection Kit #2 (per terminal)          
     Single Antenna Application

GROUP 2
2' Antenna (per radio)                          

Remote Mounting Kit (per radio)               

Link Manager Software:                       

GROUP 3
Network Management Software:                   To be determined, based upon
                                               ART's requirements


- -------------------------------------------------------------------------------
Aug 7, 1995                                                              Page 2



<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296                                                            REV.2
                                                                        EXHIBITS
Delivery Schedule                                                     SCHEDULE D
- --------------------------------------------------------------------------------







                                      SCHEDULE D


                                  EQUIPMENT DELIVERY













- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296                                                            REV.2
                                                                        EXHIBITS
Delivery Schedule                                                     SCHEDULE D
- --------------------------------------------------------------------------------




Following is the shipment schedule for P-Com Tel-Link 38 radio equipment to ART,
subject to the provisions of Article 7 of Section 1.


    SHIPMENT DATE                           QUANTITY OF RADIO LINKS

    On or Before September 31, 1995          50, plus
    On or Before December 31, 1995          100

    SHIPMENT DATES CALENDAR YEAR 1996       QUANTITY OF RADIO LINKS

    January                                 25 
    February                                25
    March                                   25
    April                                   25
    May                                     25
    June                                    25
    July                                    50
    August                                  75
    September                               100
    October                                 100
    November                                125
    December                                150

ANNUALIZED FOR 1995/1996                    900

CALENDAR YEAR 1997

    January                                 250
    February                                250
    March                                   250
    April                                   250
    May                                     250
    June                                    250

    July, 1997                              360 per month
    through December 1998




- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296                                                                 
                                                                        EXHIBITS
Ship in Place Criteria                                                SCHEDULE E
- --------------------------------------------------------------------------------








                                      SCHEDULE E


                                SHIP IN PLACE CRITERIA











- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296                                                                 
                                                                        EXHIBITS
Ship in Place Criteria                                                SCHEDULE E
- --------------------------------------------------------------------------------



For cases where Seller has received purchase orders with agreed scheduled
delivery dates from Buyer but has not received "SHIP TO" instructions, Seller
will "ship-in-place" as of the last day of the month for which shipment was
scheduled.

In such cases, the following criteria shall apply:

         1. The Buyer will be invoiced against the purchase order and Buyer
         shall pay in accordance with the invoice.

         2. The Seller will transfer the equipment to a bonded storage
         facility, and title to the goods shall pass to the Buyer.

         3. A ship-in-place fully satisfies the contract commitment for
         delivery.

         4. Buyer will be invoiced at the Sellers cost, which shall not exceed
         commercially reasonable storage fees and insurance costs, and said
         amount will be added to the freight bill.

Upon receipt of ship to instructions, Seller agrees, as agent for the Buyer, to
arrange shipment thereof in accordance with the provisions of Article 15 of
Terms and Conditions (Section 2).








- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2

<PAGE>

                                                       Agreement Between Parties
[P-COM LOGO]                                        A.R.T. LIMITED & P-Com, Inc

REF: US-PCN-296
                                                                        EXHIBITS
Technical Specification                                               SCHEDULE F
- --------------------------------------------------------------------------------






                                   SCHEDULE F


                           RADIO TECHNICAL INFORMATION


Set forth herein are the typical performance specifications of the Tel-Link 38,
referred to in Article 11 of the Agreement prepared with respect to the
Agreement.









- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>

1.0  TECHNICAL INFORMATION

     1.1  INTERFACES

          P-Com is continuously evolving new products and features.  Please note
          the following:

          AVAILABLE INTERFACES ARE:
               1E1, 2E1 and 4E1
               1DS1 and 4DS1
               3x64 kb/s

          FUTURE INTERFACES MAY INCLUDE:
               8DS1 and 16DS1
               34 Mb/s & 45 Mb/s
               10Mb E-Net

     1.2  RADIO SPECIFICATIONS

          In addition to the radio specifications listed below, refer to the
          product data sheets in the appendix.  The following specifications
          relate to the Tel-Link Series 38GHz radio.

          A)   Frequency Response:

               38.6 GHz to 40.0 GHz

          B)   Output power and adjustments:

               Typical:       +17 dBm

               Output power is software controlled and is adjusted locally from
               the radio control panel on the IDU.  Adjustments can also be made
               remotely by computer.  Transmitter power can be software
               controlled over a range of 25 dB down from maximum output power.

          C)   Modulation Technique:

               P-Com employs 2-FSK modulation.


- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2

<PAGE>

          D)   Interface Line Code:

               AMI or B8ZS, field selectable.

          E)   Radiation pattern and dispersion:

               Seller to provide as requested.

          F)   BER back to back:

               10(-11) or better.

          G)   BER at -30 dBm RCL, -50 dBm RCL, -60 dBm RCL:
               will be 10(-11) or better.

               BER applies to all RCLs listed above.

          H)   Receiver type and sensitivity:

               Type:          Dual conversion.
               Sensitivity:

               BER 10(-6)               -78 dBm

               BER 10(-3)               -81 dBm

          I)   Transmitter type

               Type:                    2-FSK modulated IDU and Upconverted
                                        ODU.
               Typical Stability:       PLUS OR MINUS 0.0005%

          J)   Noise characteristics:

               Receiver:      13 dB

          K)   Tuning range and steps:

               Range:         350 MHz
               Steps:           5 MHz


- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 3

<PAGE>

          L)   Channel bandwidth and spacing:

               Bandwidth:     1DS1, 5 MHz, 4DS1, 15 MHz
               Spacing:       700 MHz

          M)   DS1, CEPT1 and 2 masks:

               Fully compliant with CCITT G.703.

          N)   Antenna Characteristics:

               Antennas are FCC Category A rated.

          O)   Co-channel and multi path rejection:

               Co-channel is 21 dB for one decade BER degradation referenced to

               1x10(-6)   BER.  This applies to all data rates.

               Due to the narrow beamwidth and short path application of 38GHz,
               multipath perturbations are not a concern.

     1.3  ANTENNA CHARACTERISTICS

          A)   Wind resistance and survivability:

               Windloading for both the 1-foot and 2-foot antennas is:
                    Operational:   112 mph
                    Survival:      157 mph

          B)   Echo return loss:

               Return loss if 10 dB.

          C)   Range using 1ft and 2ft antennae:

               The propagation range of 38 GHz frequencies is controlled by the
               instantaneous rain rate.  Typically, path lengths are 5 to 7
               kilometers or less.

          D)   Insertion loss (nominal):


- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 4
<PAGE>


[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                        EXHIBITS
Technical Specification                                               Schedule F
- --------------------------------------------------------------------------------

                   P-Com's patented antenna flange design eliminates losses in
                   the connection between the ODU and the antenna.  A direct
                   coupling is made between the ODU and the antenna eliminating
                   the need for waveguide, connectors or flex-twist.

              E)   Vertical and horizontal polarizations (field):

                   P-Com mounts are designed to allow for both vertical and
                   horizontal polarity orientation.  In addition, the ODU and
                   antenna can be oriented for either right-hand or left-hand
                   mounting.  All orientations are selected in the field.

              F)   Mounts (i.e. customization available):

                   The P-Com mount will accommodate 1.75" to 4.5" O.D. pipe
                   mounts, left- and right-hand orientation, and vertical or
                   horizontal polarization.  The ODU can also be mounted
                   remotely from the antenna using the optional P-Com Remote
                   Installation Kit.

                   If ART has additional mounting requirements, P-Com will
                   gladly discuss any customized requirements and work with ART
                   to meet those requirements.

              G)   Gain Rx + Tx:

                   The antenna gain is:

                        12": 37.5 dBi
                        24": 44.0 dBi


         1.4. PERFORMANCE CHARACTERISTICS:

              MTBF - Engineering objective:

              An MTBF of 10 years or greater is expected through prediction
              calculations.  The predictions are based on accurate types and
              quantities of parts, failure rates for actual stress levels,
              circuit redundancies, cycling effects and environment.


- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 5

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                        EXHIBITS
Technical Specification                                               Schedule F
- --------------------------------------------------------------------------------

              In addition to MTBF, MTTR is also a critical consideration.  P-
Com's MTTR, once a technician has arrived at site, is typically 20 minutes or
less.

         1.5  MECHANICAL:

              A)   Dimensions of both antenna and indoor unit:

                   Outdoor Unit(ODU):       10" dia., 8" depth
                   Antenna, 1 foot:         12' dia., 4" depth
                   Indoor Unit (IDU):       3.5" x 19" x 10.5"

              B)   Weight of both units:

                   Outdoor Unit(ODU):       10 lbs.
                   Indoor Unit(IDU):         8 lbs.

              C)   Type cable, fire retardant, Teflon available:

                   Type: RG8, Beldon 9913 recommended.
                   Only one cable is required.
                   Various cable coatings are available to 
                   accommodate installation requirements to meet 
                   building codes.  The cable is not provided with the 
                   radio equipment.

              D)   RF connection at antenna:

                   N-type female connector on the ODU.  Requires N-type
                   male connector for cable.

              E)   Shipping weight and container size:

                   IDU:                17.5 lb; 10.5" x 18" x 24.5"
                   ODU:                19.0 lb; 16.5" x 15.5" x 16.5"
                   Antenna (12")       17.5 lb; 28.0" x 18.0" x 12.0"
                   Antenna (24")       40.0 lb; 29.0" x 29.0" x 16.0"

              F)   Connection at customer interface:

                   DS1:      DB25, 100 ohm balanced
                   
                   E1:       BNC, 75 ohm unbalanced; or,

- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 6

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                        EXHIBITS
Technical Specification                                               Schedule F
- --------------------------------------------------------------------------------

                                DB25, 120 ohm balanced

              G)   Maximum distance between antenna unit and interface
                   module.  System is self equalizing.

                   Maximum distance: 1000 feet

              H)   Equalization at digital interface.  Self equalization.

                   The radio is equipped with an LBO that is software
                   controlled and field adjustable via a laptop computer
                   equipped with P-Com Link Manager software.


         1.6  ENVIRONMENTALIST:

              A)   Heat dissipation:

                   ODU:      Typical 23 Watts (78.64 Btu/hr)
                             Maximum 30 Watts (102.56 Btu/hr)

                   IDU & ODU System:
                             4DS1:     Typical 40 Watts (136.77 Btu/hr)


                   The low power consumption of the radio equipment
                   equates to a low heat dissipation.

              B)   Maximum and minimum ambient temperatures for antenna
                   unit and digital unit.

                   Outdoor Unit:       -30 DEG.C to +60 DEG.C
                   Indoor Unit:        -10 DEG.C to +55 DEG.C

              C)   Maximum and minimum relative humidity for both units.

                   Outdoor Unit:       Up to 100% (all weather operation)
                   Indoor Unit:        95% at +55 Deg.C

              D)   EMR rating:

                   P-Com's radio equipment has been designed and tested to the
                   highest and most stringent of international EMC/EMI


- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 7

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                        EXHIBITS
Technical Specification                                               Schedule F
- --------------------------------------------------------------------------------


                   standards.  Both the IDU and ODU are sealed enclosures
                   providing maximum EMC screening protection.  The use of
                   double-screened coaxial cable between the "N" type connector
                   terminations ensures maximum EMC performance.

                   There are no oscillators in the IDU or ODU operating in the
                   1.8 GHz frequency range and there are no receive IF
                   frequencies operating in the 1.8 GHz frequency range. 
                   Therefore, the equipment will perform to full specification
                   and will not have any adverse affect on co-located 1.8 GHz
                   PCN equipment.

              The following tests were conducted and passed:

              Conducted emissions:     150kHz  - 30 MHz, average peak.
              Radiated emissions:      30 MHz - 1 GHz, 3m and 10m ranges.

              Test Categories and standards included:

              CATEGORY                      STANDARD
              --------                      --------
              Emissions (conducted)         CISPR-22
              Emissions (radiated)          EN55022 DIN VDE 0876
              Immunity (conducted)          IEC 801-4
              Immunity (radiated)           IEC 801-3

              E)   Engineered effect of ESD practical experience.

                   The equipment has been designed to the highest and most
                   stringent of international ESD standards, IED 801-2
                   (equivalent to EN 55101-2).

                   The P-Com equipment consists of sealed and shielded units
                   that protect it from ESD.  There is no requirement for
                   opening these units for maintenance or repair.

                   P-Com's radio equipment is installed in Cellular, PCN and
                   Telco environments.  No problems have been reported.



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 8




<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Technical Specification                                               SCHEDULE F
- --------------------------------------------------------------------------------


      1.7  POWER:

           A)   Range of voltage input:

                -48VDC    Range -38.4 to -62.4VDC

           B)   Power consumption:

                Typical (Non-protected)  4DS1:40W

           C)   Ripple tolerance:

                50mV p-p

           D)   Surge tolerance and protection:

                Compliant with ETSI pr ETS 300.132



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 9

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Network Management                                                    SCHEDULE G
- --------------------------------------------------------------------------------



                                      SCHEDULE G


                                  NETWORK MANAGEMENT



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>


[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Network Management                                                    SCHEDULE G
- --------------------------------------------------------------------------------


                      P-COM'S NETWORK MANAGEMENT SYSTEM SUPPORT


GENERAL

P-Com's Network Management System (NMS) provides the customer with a modem
efficient and open way to monitor and control P-Com's radio systems.

The radios on the network (or clusters of radios) are daisy-chained or 
otherwise interconnected in order to create one network.  Connections between 
radios can be accomplished directly or through secondary data lines.  P-Com's 
approach to Network Management provides a very open approach to creating 
different topologies to support any possible scenario.  The following 
description will include the standard NMS support inside the radio, the Link 
Manager, and the Extended Link Manager.  P-Com's Network Mediator, P-Com's 
Network card, Network Supervisor, and a complete Network Management System 
are projects currently planned but may or may not be under current 
development.

RADIO SUPPORT

The network is developed based on the advanced monitor and control features that
are part of the radio.  Some of these features are:

      -  IDU and ODU alarms internally monitored and serialized

      -  Four way bridge for star and daisy chain configuration.

      -  Physically connected with RS-232/422 asynchronous up to 9600 baud
         protocols.

      -  Object oriented P-Com protocol that allows access to local and remote
         sites.

      -  Up to 8 external alarms can be monitored

      -  5 relay contacts that can be configured to close on any radio event.

      -  Full radio configuration, diagnostics and link performance (G.821)
         supported through the network.

      -  Error detection protocol and error recovery.

      -  Multiple radio architecture capable of monitoring up to 4095
         terminals.

      -  Optional NMS card for special applications.



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2

<PAGE>


[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Network Management                                                    SCHEDULE G
- --------------------------------------------------------------------------------


LINK MANAGER

The Link Manager is a PC program running under Microsoft Windows.  The Link
Manager controls a single link (local and remote).  Link Manager is connected to
the radio using the standard computer port either directly or through a modem. 
See Addendum A for additional details.  The Link Manager provides the following
functionality:

      -  PC based application running Microsoft Windows using menus and action
         buttons.

      -  Fully controls the radio link (unprotected or protected).

      -  Link Set-up (frequency, power, bit rate, ID...)

      -  Link Alarm Display (current, history)

      -  Lines Status (alarms, enable...)

      -  Loop back Diagnostics Support

      -  Relay Configuration Set-up

      -  Inventory Display (serial numbers, versions)

EXTENDED LINK MANAGER

Extended Link Manager (ELM) is based on the same Link Manager technology, but
connects to the radios via the NMS port.  ELM allows the user to select which
radio is addressed at any time.  The connection can be accomplished either
directly or via a modem.



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 3

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Network Management                                                    SCHEDULE G
- --------------------------------------------------------------------------------


                            OPTIONAL P-COM NMS PROGRAMS


NETWORK MEDIATOR

The Network Mediator is an external unit that can be installed next to a radio
or a cluster of radios at a hub.  The Network Mediator serves as a translator
between P-Com's protocol and the controlled radios.  The main characteristics of
the mediator are:

      -  Physically self contained in a 1U shelf with its own power supply

      -  Able to communicate and monitor multiple daisy chained radios

      -  Able to communicate via Ethernet using SNMP to a higher NMS.

      -  Supports automatic polling of all the controlled radios.

      -  Able to store 24 hours of polled information.

      -  Able to send commands received on the Ethernet to the selected radio.

NETWORK CARD

The network card is an add on to the radio that allows the radio to communicate
with the network management system directly over Ethernet using SNMP.  The card
is installed inside the radio and maintains the SNMP agent for the radio.  This
card can be used with other customized protocols.

NETWORK SUPERVISION SYSTEM

The network Supervision System is based on HP OpenView software running on a PC
with Windows.  This system can monitor multiple P-Com radios daisy chained using
the NMS radio provisions.  The radios could be at one site, or separated as
long, as the NMS service channel is extended.  The main characteristics of the
Network Supervision System are:

      -  PC-Based running Microsoft Windows.

      -  Multi-Level network map with zooming.

      -  Network graphical alarm summary, allows status check based on colors.

      -  Network logging of events and display filters allowing examination of
         alarm history.



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 4

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Network Management                                                    SCHEDULE G
- --------------------------------------------------------------------------------


                            OPTIONAL P-COM NMS PROGRAMS


NETWORK MANAGEMENT SYSTEM

The Network Management System is based on HP OpenView.  It is the same as the
Supervision System but also includes full control of the radio using an embedded
Link Manager element that can be launched on the NMS platform.

If the radios are connected using the Network Mediator, the radios can be polled
and managed by any standard SNMP Network Management System (such as HP
OpenView).

NETWORK MANAGEMENT SUMMARY

As you can see, P-Com has several network management options, and we are
prepared to work with ART to determine what option(s) will meet ART's
requirements.  P-Com can also modify its protocol to operate with existing
network management systems.

P-Com's approach is to be flexible and accommodating to insure that the
end-users receive the network management features and interface capabilities
desired to operate and maintain their networks.

It is recommended that P-Com and ART meet to discuss in detail ART's
requirements and how P-Com can accommodate them.



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 5

<PAGE>


[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Technical Specification                                               SCHEDULE H
- --------------------------------------------------------------------------------



                                      SCHEDULE H


                         STANDARDS & PRODUCT TYPE ACCEPTANCE



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>


[LOGO]                                                 AGREEMENT BETWEEN PARTIES
REF:  US-PCN-296                                     A.R.T. LIMITED & P-Com, Inc

                                                                        EXHIBITS
Technical Specification                                               SCHEDULE H
- --------------------------------------------------------------------------------


             P-Com meets or exceeds the following standards.  P-Com employs the
             leading industry standards in the design and manufacture of the
             Tel-Link Series radios.  P-Com's equipment has also been tested
             and certified by regulatory agencies in the United Kingdom, Italy
             and Germany.

             Following is a partial list of the standards employed:

                  FCC Part 21, 94,15        IEC 801-3, 801-4
                  AT&T TA 34, Pub 43802     CCIR Rec. 749
                  DTI MPT 1414              CCITT G.703, 823, 824, 842
                  ETSI pr ETS 300 197       BS 3192
                  BAPT 211 ZV 12/38GHz      CISPR-22
                  IEC 950, 65, 215          EN 55022 DIN VDE 0876

             P-Com is approved by certification testing labs in the U.K. (DTI)
             and in Germany (BZT), as well as being homologated or approved for
             service in the following countries:

                  APPROVED                  PENDING
                  --------                  -------
                  United States (FCC)       Hungary
                  Mexico                    France
                  Germany                   Belgium
                  United Kingdom            Spain
                  Australia                 Portugal
                  Czechoslovakia
                  Greece
                  Italy
                  Slovakia

             And in adhering to the worldwide demand for quality design and
             manufacturing processes, P-Com is ISO-9001 certified.

             After an extensive technical evaluation and quality audit, P-Com
             has finalized approval as an OEM supplier to:

                           AT&T,

                           Siemens, and

                           Harris Corporation, Farinon Division



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2

<PAGE>

[logo]                                               AGREEMENT BETWEEN PARTIES
                                                     A.R.T. LIMITED & P-COM, INC

REF: US-PCN-296
                                                                        EXHIBITS
QUALITY AND PRODUCT APPROVAL                                          SCHEDULE J
________________________________________________________________________________









                               SCHEDULE J


                                QUALITY










________________________________________________________________________________
Aug 7, 1995                                                               Page 1
<PAGE>
                                  [logo]
                            QUALITY ASSURANCE
                                 MANUAL







      [PICTURE]                                                     [PICTURE]
RESEARCH AND DEVELOPMENT                                        CUSTOMER SERVICE




                                       QUALITY
                                       SYSTEM




     [PICTURE]                                                     [PICTURE]
MANUFACTURING & TEST                                           SALES & MARKETING

<PAGE>
[logo] QUALITY ASSURANCE MANUAL                                   No: 03.70.001
                                                                  Rev:  E
                                                                  Date: 3-94
                                                                  Page: 1 of 18
________________________________________________________________________________




                      QUALITY ASSURANCE MANUAL


                        COPY CONTROL NO._____
     
                        / / UNCONTROLLED COPY

This QUALITY ASSURANCE MANUAL addresses the requirements of ISO 9001-1987 (BS 
5750: Part 1. EN29001-1987) and is the property of P-Com. Inc., and must be 
returned upon request.

This manual describes in outline form the organization and the quality related 
systems within the Company, and is intended to assist the recipient in 
understanding how the Company's Quality System works.

The Quality System outlined is enforced by seperate QUALITY ASSURANCE 
PROCEDURES that are considered confidential and may not be distributed outside 
the Company.

This manual in whole or part may not be copied without the written permission 
of the President of the Company.





                                                    P-Com, Inc.
                                                    3175 S. Winchester Boulevard
                                                    Campbell, CA  95008
                                                    U.S.A.
<PAGE>

[logo] QUALITY ASSURANCE MANUAL                                   No: 03.70.001
                                                                  Rev: E
                                                                  Date: 3-94
                                                                  Page: 2 of 18
________________________________________________________________________________


                             TABLE OF CONTENTS


ISO 9001 CROSS REFERENCE TABLE................................................3

ISO 9001 CROSS REFERENCE......................................................3

1.0 QUALITY POLICY STATEMENT..................................................4

2.0 APPLICABLE DOCUMENTS......................................................5

3.0 GLOSSARY..................................................................5

4.0 CORPORATE PROFILE.........................................................6

5.0 ORGANIZATION..............................................................7

6.0 MANAGEMENT RESPONSIBILITY.................................................8

7.0 QUALITY SYSTEM............................................................10

8.0 PROCEDURE SUMMARY.........................................................11

LOCATION MAP..................................................................17

RECORD OF REVISIONS...........................................................18
<PAGE>

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                               QUALITY ASSURANCE MANUAL
                                                                   NO: 03.70.001
                                                                   REV: E       
                                                                   DATE: 3-94   
                                                                   PAGE: 3 OF 18

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



                               ISO 9001 CROSS REFERENCE
- --------------------------------------------------------------------------------
 ISO 9001                                          QAM
  PARA                     REQUIREMENTS            PARA      PAGE     QAP #
- --------------------------------------------------------------------------------
 4.1.1     Quality Policy                         1.0        4
- --------------------------------------------------------------------------------
 4.1.2.1   Responsibility and Authority           5.0        7
- --------------------------------------------------------------------------------
 4.1.2.3   Management Representative              6.0        8
- --------------------------------------------------------------------------------
 4.1.3     Management Review                      8.1       11      03.70.002
- --------------------------------------------------------------------------------
 4.2       Quality System                         7.0       10
- --------------------------------------------------------------------------------
 4.3       Contract Review                        8.2       11      03.70.003
- --------------------------------------------------------------------------------
 4.4.1     Design Control                         8.3       11      03.70.004
- --------------------------------------------------------------------------------
 4.4.5     Design Verification                   8.3.5      12      03.70.004
- --------------------------------------------------------------------------------
 4.4.6     Design Changes                        8.3.6      12      03.70.004
- --------------------------------------------------------------------------------
 4.5       Document Control                       8.4       12      03.70.005
- --------------------------------------------------------------------------------
 4.6       Purchasing                             8.5       13      03.70.006
- --------------------------------------------------------------------------------
 4.7       Purchaser Supplied Product             8.6       13      03.70.007
- --------------------------------------------------------------------------------
 4.8       Product Identification and 
           Traceability                           8.7       13      03.70.008
- --------------------------------------------------------------------------------
 4.9       Process Control                        8.8       14      03.70.009
- --------------------------------------------------------------------------------
 4.10      Inspection and Testing                 8.9       14      03.70.010
- --------------------------------------------------------------------------------
 4.11      Inspection, Measuring and 
           Test Equipment                        8.10       14      03.70.011
- --------------------------------------------------------------------------------
 4.12      Inspection and Test Status            8.11       15      03.70.012
- --------------------------------------------------------------------------------
 4.13      Control of Non-Conforming Material    8.12       15      03.70.013
- --------------------------------------------------------------------------------
 4.13.1    Non-conformance Review and 
           Disposition                          8.12.1      15      03.70.013
- --------------------------------------------------------------------------------
 4.14      Corrective Action                     8.13       15      03.70.014
- --------------------------------------------------------------------------------
 4.15.1    Handling, Storage, Packaging and
           Delivery                              8.14       15      03.70.015
- --------------------------------------------------------------------------------
 4.16      Quality Records                       8.15        16     03.70.016
- --------------------------------------------------------------------------------
 4.17      Internal Quality Audits               8.16        16     03.70.017
- --------------------------------------------------------------------------------
 4.18      Training                              8.17       16      03.70.018
- --------------------------------------------------------------------------------
 4.19      Servicing                             8.18       16
- --------------------------------------------------------------------------------
 4.20      Statistical Techniques                8.19       16      03.70.019
- --------------------------------------------------------------------------------

<PAGE>

[LOGO]
                               QUALITY ASSURANCE MANUAL
                                                                   NO: 03.70.001
                                                                   REV: E       
                                                                   DATE: 3-94   
                                                                   PAGE: 4 OF 18
- --------------------------------------------------------------------------------


1.0 QUALITY POLICY STATEMENT

    It is the policy of P-Com, Inc., to provide the customer with products that
    conform to all aspects of generally accepted industrial standards and
    specified contract requirements.

    Quality is of vital importance to the Company and we totally commit to a
    Quality Assurance Management System that conforms to the requirements of
    ISO 9001:1987.

    All employees are responsible for quality, and are responsible for
    achieving the specified levels of quality at all stages of work that have
    an effect on the final quality of the product supplied.

    We undertake, by practical example and training, to ensure that each
    employee has a proper understanding of the quality function and it's direct
    relevance and significant contribution to our success.

1.1 MANAGEMENT CERTIFICATION

    I hereby certify that this QUALITY ASSURANCE MANUAL accurately describes
    the Quality Assurance Management System in use within P-Com. Inc., and
    encompasses the requirements of ISO 9001:1987.





President and CEO /s/ George P. Roberts          Date: 3/31/94
                 ---------------------------      ------------
                   George P. Roberts

<PAGE>

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                               QUALITY ASSURANCE MANUAL
                                                                   NO: 03.70.001
                                                                   REV: E       
                                                                   DATE: 3-94   
                                                                   PAGE: 5 OF 18
- --------------------------------------------------------------------------------


1.2 COMPANY CONTACTS

    All questions concerning P-Com's commitment to the contents of this QUALITY
    ASSURANCE MANUAL may be directed to either George Roberts, President and
    CEO, or Kenneth Bean, Quality Assurance Manager, by the following methods:

    Tel:      408-866-3666
    Fax:      408-866-3655
    Mail:     P-Com, Inc.
              3175 S. Winchester Boulevard
              Campbell, CA 95008
              U.S.A.


2.0 APPLICABLE DOCUMENTS

    ISO 9001: 1987 Quality Systems
    BS 5750 Part 1: 1987 Quality Systems
    EN 29001: 1987 Quality Systems
    ANSI/ASQC Q91 Quality Sytems
    QAP 03.70.002 Management Review - QAP 4.1
    QAP 03.70.003 Contract Review - QAP 4.3
    QAP 03.70.004 Design Control - QAP 4.4
    QAP 03.70.005 Document Control - QAP 4.5
    QAP 03.70.006 Purchasing - QAP 4.6
    QAP 03.70.007 Purchaser Supplied Product - QAP 4.7
    QAP 03.70.008 Product I.D. and Traceability - QAP 4.8
    QAP 03.70.009 Process Control - QAP 4.9
    QAP 03.70.010 Inspection and Testing - QAP 4.10
    QAP 03.70.011 Inspection, Measuring and Test Equipment - QAP 4.11
    QAP 03.70.012 Inspection and Test Status - QAP 4.12
    QAP 03.70.013 Control of Non-conforming Product - QAP 4.13
    QAP 03.70.014 Corrective Action - QAP 4.14
    QAP 03.70.015 Handling, Storage, Packaging and Delivery - QAP 4.15
    QAP 03.70.016 Quality Records - QAP 4.16
    QAP 03.70.017 Internal Quality Audits - QAP 4.17
    QAP 03.70.018 Training - QAP 4.18
    QAP 03.70.019 Statistical Techniques - QAP 4.20

3.0 GLOSSARY

    QUALITY: The totality of features and characteristics of the product that
    bear on its ability to satisfy stated or implied needs.

    QUALITY ASSURANCE MANAGEMENT SYSTEM: All the planned and systematic actions
    necessary to provide adequate confidence in the product to satisfy given
    requirements for quality.

<PAGE>

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                               QUALITY ASSURANCE MANUAL
                                                                   NO: 03.70.001
                                                                   REV: E       
                                                                   DATE: 3-94   
                                                                   PAGE: 6 OF 18
- --------------------------------------------------------------------------------


4.0 CORPORATE PROFILE

    P-Com Inc. was founded in August 1991, for the express purpose of
    developing, manufacturing and marketing millimeter wave radio products for
    the telecommunications industry. These prducts meet a critical need for
    high quality, cost effective, digital transmission in short distance
    applications. In general, the P-Com management team is dedicated to
    removing the gap that exists between the products that arre currently
    available and the needs of the market.

    P-Com millimeter wave radio products meet the crucial requirement of
    minimizing the customer's "cost of ownership". The design philosophy that
    governs all P-Com product development decisions is one that results in a
    product that is low in cost, high in reliability and simple to install and
    maintain. Given the competitive nature of the telecommunications service
    industry, these attributes play a key role in the successful and profitable
    operation of a customer's telecommunications network.

4.1 COMPANY MISSION

    To design, develop and manufacture high quality radio transmission products
    for the worldwide wireless telecommunications market.



                             [GRAPHIC OF WORLD MAP]


<PAGE>

[LOGO]
                            QUALITY ASSURANCE MANUAL
                                                                  No: 03.70.001
                                                                  Rev: E
                                                                  Date: 3-94
                                                                  Page: 7 of 18

- --------------------------------------------------------------------------------
<TABLE>
<CAPTION>

5.0  ORGANIZATION

     The Company organization and lines of authority are detailed in Figure 1.
       <S>               <C>                 <C>                           <C>                  <C>        <C>       <C>
                         -------------
                          BOARD OF 
                          DIRECTORS
                         -------------
                              /
                              /
                         -------------      ----------------
                          PRESIDENT &
                            CEO       ------ ADMINISTRATIVE
                         -------------      ----------------
                              /
          ------------------------------------------------------------------------------------------------------------------
          /                   /                                                /                     /        /            /
      ---------           -----------                                      ----------           ---------  --------- ------------
      MARKETING           ENGINEERING                                       OPERATIONS            QUALITY    FINANCE      CTD
       & SALES               VP                                               VP                ASSURANCE     VP     EXECUTIVE VP
      SENIOR VP                                                                                  MANAGER
      ---------           -----------                                      ----------           ---------  --------- ------------
          /                   /                                                /                     /     /          /Business
          /                   /                                                /                     /     /Controller/Development
          /                   /                                                /                     /     /----------/-----------
          /                   /                                                /                     /     /          /Advance
          /                   /                                                /                     /     /Accounting/Development
          /                   /                                                /                     /     /----------/-----------
          /                   /                                                /                     /     /Human     
          /                   /                                                /                     /     /Resources 
          /                   /                                                /                     /     /----------
          /                   /                                                /                     /     /Facilities
          /                   /                                                /                     /     /----------
          /                   /                                                /                     /
          /                   /                                                /                     --------------------------
    ---------           -----------------------------------          ----------------------------------------------           /
    /       /           /           /          /          /          /           /          /           /         /           /
- --------- -------- ----------  ----------- ---------  ----------- ---------- ----------  ---------  --------  ------------- -------
MARKETING  SALES     ??????      SYSTEMS   MICROWAVE  MECHANICAL  PROGRAM    PRODUCTION  MATERIALS  CUSTOMER  MANUFACTURING QUALITY
 MANAGER  DIRECTOR PROCESSING  ENGINEERING DIRECTOR   ENGINEERING MANAGEMENT  MANAGER     MANAGER    SERVICE  ENGINEERING ENGINEER-
                   DIRECTOR                          SUPERVISOR   MANAGER                                                   ING
- --------- -------- ----------  ----------- ---------  ----------- ---------- ----------  ---------  --------  ----------    -------
/MARKETING /APPLICATION /         /        /          /MECHANICAL /NEW PRODUCT /         /PURCH-  /RETURN &/ TEST       /  
/SUPPORT   /ENGINEERING /SOFTWARE /????    /????      /DESIGN     /INTRODUCTION/ASSEMBLY /ASING   /REPAIR  /ENGINEERING /INSPECTION
- ---------- /----------- /-------- /------- /--------- /----------  ----------- /-------- /------  /------- /----------- /----------
           /SALES       /HARDWARE /SYSTEM  /????      /PCB                     /TEST     /INVEN-  /SYSTEM  /PRODUCT      
           /SUPPORT     /         /DESIGN  /          /DESIGN                  /         /TORY    /CONFIG- /ENGINEERING 
           /            /         /        /          /                        /         /CONTROL /URATION /            
           /----------  /-------- /------- /--------- /----------              /---------/------- /--------/----------- 
                                  /????    /RADIO     /DRAFTING                /SYSTEM   /RECIEVING        /PRODUCT
                                  /DESIGN  /DESIGN    /                        /INTEGRA- /AND              /ENGINEERING
                                  /        /          /                        /TION     /SHIPPING         /            
                                  /--------/--------- /----------              /-------- /--------         /----------- 
                                                                                                           /COMOPONENT
                                                                                                           /ENGINEERING  
                                                                                                           /----------- 
                                                                                                           /DOCUMENT        
                                                                                                           /CONTROL     
                                                                                                           /            
                                                                                                           /----------- 
                                                                                                           /???? 
                                                                                                           /
                                                                                                           /------------
                                                            Figure 1
</TABLE>

<PAGE>

[LOGO] COM QUALITY ASSURANCE MANUAL                        NO: 03.70.001
                                                           REV:  E
                                                           DATE: 3-94
                                                           PAGE: 8 OF 16

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

6.0    MANAGEMENT RESPONSIBILITY

       The Company's organization is designed to provide effective direction,
       communication and management to meet the requirements defined in the
       Quality Policy Statement.

6.1    PRESIDENT AND CHIEF EXECUTIVE OFFICER (CEO)

       The President and CEO holds responsibility within the Company to
       formulate, in association with the key Executives, overall Company
       policy.  He is responsible for the development and implementation of
       strategies for the control of all aspects of the business through
       designated Company personnel.  The President shall be deputized Quality
       Assurance Manager in his absence.

6.2    EXECUTIVE VICE PRESIDENT AND CHIEF TECHNICAL OFFICER (CTO)

       Reporting to the President of the Company, the Executive Vice-President
       has overall responsibility for the introduction of advanced technologies
       into the product, business development and strategic business alliance
       activities.

6.3    QUALITY ASSURANCE MANAGER

       The Quality Assurance Manager is the management representative reporting
       to the President and is responsible for ensuring full implementation and
       maintenance of the ISO 9001 quality system and the internal auditing
       required to verify its effectiveness.  In addition to these
       responsibilities, he has issuing and revision control of the Company's
       Quality Assurance Manual and related Quality Assurance Procedures
       (QAP's).

6.3.1  SENIOR QUALITY ENGINEER

       The Senior Quality Engineer reporting to the Quality Assurance Manager
       develops and initiates standards and methods for inspection, testing, and
       evaluation of materials and products.  The Senior Quality Engineer also
       directs Inspectors engaged in product inspection and tabulating data
       concerning materials product, or process quality and reliability.  In
       addition, duties include maintaining the procedures for disposition of
       non-conforming materials and product in conjunction with appropriate
       corrective action follow-up.

6.4    VICE PRESIDENT (V.P.), OPERATIONS

       Reporting to the President of the Company, the Operations V.P. is
       responsible for organizing and introducing the product manufacturing
       strategy and manufacturing control systems combined with providing
       services and facilities for the Company's operation.

6.4.1  PROGRAM MANGER

       Reporting to the Operations V.P. the Program Manager is responsible for
       providing technical support for other Company functions and creating a
       MASTER DESIGN SCHEDULE to satisfy the MARKET REQUIREMENTS SPECIFICATION
       and the business objectives as defined by senior management.  The
       Program Manager also identifies critical issues and expediting
       improvements through staff meetings and design reviews with
       consideration to estimated parts and labor costs.

<PAGE>

[LOGO] COM QUALITY ASSURANCE MANUAL                           NO: 03.70.001
                                                              REV:  E
                                                              DATE: 3-94
                                                              PAGE: 9 OF 16

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

6.4.2  PRODUCTION MANAGER

       Reporting to the Operations V.P. the Production Manager prepares
       operational schedules and coordinates manufacturing activities to ensure
       production and quality of products.  Other responsibilities include
       planning production operations, establishing priorities and sequences
       for manufacturing products.

6.4.3  MATERIALS MANAGER

       Reporting to the Operations V.P. the Materials Manager is responsible
       for directing and coordinating the purchasing and distribution of
       components for the design and manufacture of products, capital
       equipment, and liaison with arranging contracts with suppliers and  
       sub-contractors.

6.5    SENIOR VICE PRESIDENT (VP), MARKETING & SALES

       Reporting to the President of the Company, the Marketing V.P. is
       responsible for developing the customer base and obtaining sales orders
       through marketing and sales strategy action plans.  Other
       responsibilities include communicating the Company's corporate image in
       the market place while defining the market requirements for use by
       design engineering.  He also provides technical publications, operations
       manuals, training materials and seminars for existing or potential
       customers.

6.5.1  MARKETING MANAGER

       Reporting to the Marketing & Sales V.P., the Product Marketing Manager
       is responsible for: a) product definition to Engineering based upon
       customer inputs, competitive research.  Industry standards and cost
       targets, b) corporate and product promotional literature, trade shows,
       public relations, customer demonstrations/presentations and sales
       support (assistance in proposal generation).

6.5.2  DIRECTOR OF SALES

       Reporting to the Marketing & Sales V.P., the Director of Sales is
       responsible for expanding the customer base, developing the Marketing
       Plan, obtaining sales orders, and meeting the revenue objectives of the
       corporation.  Other responsibilities include ensuring customer
       satisfaction, relaying customer requests for product improvement and
       customer support functions of the corporation.  The Director of Sales
       acts as a liaison between the customer and the corporation.

6.6    VICE PRESIDENT (V.P.), FINANCE/CONTROLLER

       Reporting to the President of the Company, the Finance V.P. is
       responsible for preparation of the Company's assets.  Other
       responsibilities include management of Human Resources and
       Administrative functions.

6.7    VICE PRESIDENT (V.P.), ENGINEERING

       Reporting to the President, the Engineering V.P. is responsible for
       planning, budgeting, and managing the technical resources for the
       Company.  Responsibilities also include technical direction for the
       Company, and organizing the engineering team to insure the technical
       integrity of products developed and that the requirements as defined by
       Marketing are satisfied.

6.7.1  DIRECTOR, MICROWAVE ENGINEERING

       Reporting to the Engineering V.P., the Microwave Engineering Director is
       responsible for managing a team of design engineers, technicians and
       consultants that provide all the microwave circuit designs and
       associated system interfaces including all the required documentation
       and control procedures.

<PAGE>

[LOGO] COM QUALITY ASSURANCE MANUAL                           NO: 03.70.001
                                                              REV:  E
                                                              DATE: 3-94
                                                              PAGE: 10 OF 16

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

6.7.2  DIRECTOR, SIGNAL PROCESSING (SP) ENGINEERING

       Reporting to the Engineering V.P., the SP Engineering Director is
       responsible for managing a team of design engineers, technicians and
       consultants that provide all the SP electronic circuit designs and
       associated system interfaces including all the required documentation and
       control procedures.

7.0    QUALITY SYSTEM

       The Quality System within the Company is based on a four tier
       documentation system composed of the following:

       *    Level 1, Quality Assurance Manual
       *    Level 2, Quality Assurance Procedures (QAP's)
       *    Level 3, Company Standards and Procedures
       *    Level 4, Industrial Standards and Database

7.1    LEVEL 1

       The QUALITY ASSURANCE MANUAL describes in outline form the Management's
       organization and the quality related systems in operation within the
       Company to meet the requirements of ISO 9001: 1987.  It assists the
       customer in making as assessment of our ability to meet the specified
       quality assurance requirements.

7.2    LEVEL 2

       The systems outlined in the QUALITY ASSURANCE MANUAL are enforced by
       separate QUALITY ASSURANCE PROCEDURES (QAP'S) which describe the
       operational procedures of the related systems and define the responsible
       personnel and the objective evidence generated for substantiation.

       The QAP's are confidential to the Company and not for general
       distribution.  However, at the discretion of the Company President, they
       may be made available for review by the customer.

7.3    LEVEL 3


       The QAP's are supported by a number of related non-product design
       documents such as COMPANY STANDARDS AND PROCEDURES that contain detail
       describing the administrative system, such as how to conduct a Design
       Review meeting.

       Separate from Company Standards and Procedures are the product design
       documents describing tasks or work instructions that are in direct
       support of the product, such as a Test Procedure.

       Both non-product design and product design documents are confidential to
       the Company and are not for general distribution.  However, at the
       discretion of the Company President, they may be made available for
       review by the customer.

7.4    LEVEL 4

       Level four documents are industrial engineering standards, design rules
       or Customer documents that form reference materials as a database
       supporting Internal COMPANY STANDARDS AND PROCEDURES.

<PAGE>

[logo] QUALITY ASSURANCE MANUAL                                   NO: 03.70.001
                                                                  REV:  E
                                                                  DATE:3-94
                                                                  PAGE: 11 OF 18
- --------------------------------------------------------------------------------

8.0     PROCEDURE SUMMARY
- -------------------------

        This following sections give a brief overview of each QAP that 
        describes in detail the operational procedures of the related systems in
        support of ISO 9001 : 1987.  Next to each QAP title the corresponding 
        document number is given in parenthesis as applicable.

8.1     MANAGEMENT REVIEW - QAP 4.1 (03.70.002)

        It is company policy that the Quality System is reviewed by the 
        President every six months. The meeting is chaired by the Presidents,
        and attended by the Vice Presidents, the Quality Assurance
        Manager, and any other personnel deemed necessary.

        The agenda includes a review of actions taken from previous meetings,
        results of Internal Quality Audits, Non-conformance Reports, customer
        complaints and overall effectiveness of the Quality System.

        The minutes of the meeting and relevant documentation are retained by 
        the Quality Assurance Manager.

8.2     CONTRACT REVIEW - QAP 4.3 (03.70.003)

        It is the policy of P-Com to document all inquiries, quotations, 
        contracts, bid proposals, purchase orders and associated area.

        This documentation is reviewed to establish that requirements can be
        achieved and that all contracts and specifications are adequately
        defined.  Deviations are resolved with the customer before processing
        and amendments to requirements are documented.

8.3     DESIGN CONTROL - QAP 4.4 (03.70.004)

8.3.1   GENERAL

        P-Com has established STANDARDS AND PROCEDURES for control and 
        verification of the product design to ensure that all specified
        contract requirements are satisfied.

8.3.2   DESIGN AND DEVELOPMENT PLANNING

        The MARKETING REQUIREMENT SPECIFICATION is used by the Program Manager
        to create a MASTER DESIGN SCHEDULE for the design project.  Additional
        planning schedules are produced containing planning information for 
        engineers and personnel from other functions.  These are regularly 
        reviewed, documented and the information circulated to all appropriate 
        groups within the company.

        QUALITY PLANS are written describing how the quality requirements of 
        contract are achieved.

        The Engineering V.P. has overall responsibility for the product design 
        function and assigns design and verification activities to the 
        Engineering Directors.  The design resources consist of teams of 
        specialist engineers and technicians with the necessary capital 
        equipment.

8.3.3   DESIGN INPUT
        
        The MARKETING REQUIREMENT SPECIFICATION and the specific customer 
        contracts are the source documents for the design input requirements.
   
        Technical engineering specifications are developed for the procuct
        and for defined subdivisions of the product.  Detail requirements
        are refined during the design process.
<PAGE>
[logo] QUALITY ASSURANCE MANUAL                                   NO: 03.70.001
                                                                  REV:  E
                                                                  DATE: 3-94
                                                                  PAGE: 12 of 18
________________________________________________________________________________

8.3.3   CON'T

        This Product Design Specification defines the functionality of the 
        product system and identifies the regulatory, customer specific, 
        marketing, product safety, and engineering requirements.

8.3.4   DESIGN OUTPUT

        During the design process acceptance criteria are established for all
        appropriate product systems and sub-systems.

        Design calculations, system analysis, drawings, process instructions,
        test procedures, specifications, user manuals, etc., are generated as 
        design outputs.

8.3.5   DESIGN VERIFICATION

        Design reviews are regularly held to control all aspects of the design 
        process and are part of the MASTER DESIGN SCHEDULE.

        Verification that the design meets the specified contract requirements 
        is conducted at various levels of product system.  Testing against 
        defined acceptance criteria and qualification programs are carried out.

8.3.6   DESIGN CHANGES

        P-Com has STANDARDS AND PROCEDURES for the documentation and recording
        of design changes.  The engineering Change Order (ECO) system provides
        the method to evaluate, approve, and incorporate design changes into 
        product documentation.

8.3.7   Product Release

        P-Com has Standards and Procedures defining the requirements for a 
        uniform method of releasing a product and its technical documentaion
        manufacturing.  The system also provides the method of controlling 
        documentation during the engineering development cycle and construcion 
        of breadboard and/or prototype product.

8.4     DOCUMENT CONTROL -QAP 4.6 (03.70.005)

8.4.1   Document Approval and Issue

        P-Com operated Standards and procedures for the registration, issue of 
        all product design documents and non product documents including the
        Quality Manual, Quality Assurance Procedures, Company Standards, 
        Procedures and database.
         
        The Document Control department ensures that only the applicable issues
        of documents are used and obsolete documents are removed.

8.4.2   Document Change and Modification

        Company Standards and Procedures provide for the initiation, 
        evaluation, approval and implementation of all documentation changes.
        The Document Control department maintains a log of all proposed and 
        approved ECO's for product design documents.  Approval Sheets for 
        changes of non product design documents are alos maintained within 
        Document Control.
 <PAGE>

[logo] QUALITY ASSURANCE MANUAL                                   No: 03.70.001
                                                                  Rev: E
                                                                  Date: 3-94
                                                                  Page: 13 of 18
________________________________________________________________________________

8.5     PURCHASING - QAP 4.6 (.03.70.005)

8.5.1   General
        
        All purchasing resisted activities are conducted under controlled 
        conditions which provide for objective assessment of all suppliers and 
        ensure that purchasing information is correct before release to the 
        supplier.

8.6.2   Assessment of Suppliers/Subcontractors

        It is Company policy that, wherever possible, purchased material and 
        subcontracted service are obtained from a company approved source.

        The Company maintains lists of approved sources and carries out 
        supplier/sub-contractor evaluations to ensure conformance with
        requirements.  Products pruchased from non-approved sources are 
        identified to the cutomer.

8.5.3   Purchasing Date

        All purchasing documents clearly describe the material and sub-
        contractor services ordered.  Purchase orders are reviewed and approved
        before release.

8.5.4   Verification of Purchased Product/Service
 
        When contractually specified by the customer.  Quality Assurance 
        requirements may be verified at P-Com by the customer.  It is 
        Company policy to provide for and assist those customers who require
        such verification.

8.6     PURCHASER SUPPLIED PRODUCT - QAP 4.7 (03.70.007)

        Purchaser Supplied product in this type of industry is typically 
        equipment and/or documentation supplied to P-Com for design and 
        production related work.  The Marketing Manager is responsible for the 
        care and control of documentation and the Quality Assurance Manager
        is responsible for equipment.

8.7     PRODUCT IDENTIFICATION AND TRACEABILITY -QAP 4.8 (03.70.008)

        Components, printed circuit assemblies (PCA's), modules, and top 
        assemblies used to produce the product shall be assigned unique part 
        numbers.  All of these shall be physically marked with their 
        corresponding part numbers and revision where practical using a  
        permnent method.  In the case of purchased off the shelf components
        and size limitations, the storage or handling container shall be 
        marked with the corresponding part number and revision.

        PCA's, modules, and top assemblies used to produce the product are 
        assigned and indelibly marked with serial numbers.  Records of the 
        serial numbers used for the final product assembly are maintained.

        Components are excluded from individual serail number assignments 
        except when deemed necessary by the Design department for critical 
        applications requiring source lot traceability.  These components are
        identified on pruchase documentation such as Source Control Drawings 
        and Specification Control Documents, drawings/schematics, and Bills of
        Material.
<PAGE>
[logo] QUALITY ASSURANCE MANUAL                                   No: 03.70.001
                                                                  Rev:  E
                                                                  Date: 14 of 18
________________________________________________________________________________


8.8     PROCESS CONTROL - QAP 4.9 (03.70.009)

        General

        The company ensures that the procedures that control the planning
        and operation of the manufacturing process are implemented.  This is 
        accomplished through documented work instructions and appropriate 
        equipment for process, assembly and test.

8.8.1   Special Processes

        There are no special processes

8.9     INSPECTION AND TESTING - QAP 4.10 (03.70.10)

8.9.1   Receiving Inspection and Testing

        All incoming materials are checked for compliance with the purchase 
        order detail.  Any damaged or incorrect materials are identified, 
        segregated and processed using formal control procedures incoming 
        material released for urgent purposed is identified and recorded in 
        accordance with formal positive recall procedures.

8.9.2   In-process Inspection and Testing 

        At defined states of the process and assembly operation, the product 
        is identified, inspected and tested to establish conformance to 
        documented specified requirements.

8.9.3   Final Inspection and Test Records

        All inspection records are retained for manufactured products 
        indicating acceptance to defined criteria.

8.10    INSPECTION, MEASURING AND TEST EQUIPMENT - QAP 4.11 (03.70.011)

        The Company operates a system for ensuring that inspection, measuring 
        and test equipment used to determine the conformance of product to 
        contract specified requirements are periodically calibrated serviced
        and adjusted to maintain the accuracy to required limits.

        Calibration system and records maintained in compliance to applicable 
        national standards.

   

<PAGE>

[LOGO] QUALITY ASSURANCE MANUAL                                  No: 03.70.001
                                                                 Rev: E
                                                                 Date: 3-94
                                                                 Page: 15 of 18
- -------------------------------------------------------------------------------

8.11          INSPECTION AND TEST STATUS - QAP 4.12 (03.70.012)

         The inspection and test status of product during the process and
         assembly stages of the operation is identified by unique routing card.

         A unique routing card is provided for each defined module, subassembly
         or product recording its progress through the manufacturing process
         and its conformance to inspection and tests performed.

         The Quality Assurance Manager is responsible for the release of
         conforming product.

8.12          CONTROL OF NON-CONFORMING PRODUCT - QAP 4.13 (03.70.013)

         Incoming material, work in progress, and finished product that does
         not conform to specified requirements is prevented from inadvertent
         use by identification, segregation and disposition in accordance with
         documented procedures.

8.12.1   NON-CONFORMANCE REVIEW AND DISPOSITION

         In the documented procedures, the Quality Engineer is responsible for
         the review of NON-CONFORMANCE REPORTS with other members of the
         Company Material Review Board to determine the appropriate disposition
         of non-conforming material and product.

         A DEVIATION AUTHORIZATION may be requested from the customer for non-
         conforming product that is proposed for use or repair.

8.13          CORRECTIVE ACTION - QAP 4.14 (03.70.014)

         The Company maintains documented procedures for the investigation and
         analysis of the cause for non-conforming material and product
         resulting in corrective actions to prevent recurrence.

8.14          HANDLING, STORAGE, PACKAGING AND DELIVERY - QAP 4.15 (03.70.015)

8.14.1   GENERAL

         Procedures for handling, storage, packaging and delivery of material,
         work in process and finished product are maintained by the Company.

         SPECIAL COMPANY STANDARDS AND PROCEDURES establish the minimum
         requirements for electrostatic discharge control where sensitive
         electronic parts, assemblies or products are manufactured, assembled,
         tested, serviced, handled, packaged or stored.

8.14.2   HANDLING

         The Company handles all materials in such a manner as to prevent
         damage, deterioration or loss.

8.14.3   STORAGE

         Secure storage areas are provided and COMPANY STANDARDS AND PROCEDURES
         control the receipt and issuing of materials.

         Lists of materials requiring special storage conditions, or having a
         limited shelf life are maintained and controls applied to conform with
         requirements.  The materials requiring special storage conditions are
         maintained in the appropriate environment and materials having limited
         shelf life are discarded in an approved manner when shelf life has
         expired.  MATERIAL SAFETY DATA SHEET regulations are applied for
         storage and handling of material.  Lists of such materials are
         maintained.

<PAGE>

[LOGO] QUALITY ASSURANCE MANUAL                                  No: 03.70.001
                                                                 Rev: E
                                                                 Date: 3-94
                                                                 Page: 16 of 18
- -------------------------------------------------------------------------------

8.14.4   PACKAGING

         COMPANY STANDARDS AND PROCEDURES control the marking and packaging
         of the product to ensure conformance to specified contract
         requirements.

8.14.5   DELIVERY

         After final inspection and test, documented procedures provide for the
         protection of the product in stores and during delivery to the
         customer.

         Delivery documentation is provided and instructions are carried out in
         accordance with specified contract requirements.

8.15          QUALITY RECORDS - QAP 4.16 (03.70.016)

         The quality records identified in the QUALITY ASSURANCE PROCEDURES are
         filed and maintained by the applicable department and are under the
         jurisdiction of the Quality Assurance Manager for demonstration of the
         Quality System effectiveness.

         The records are retained for a minimum of five years or for a period
         specified by customer contract.

8.16          INTERNAL QUALITY AUDITS - QAP 4.17 (03.70.017)

         All quality activities are subject to a planned and documented audit
         to verify compliance with the defined Quality System.

         Audits are conducted at predetermined intervals and are carried out by
         trained personnel under the control of the Quality Assurance Manager.

         The results of these audits are recorded and used to improve the
         effectiveness of the Quality System.

8.17          TRAINING - QAP 4.18 (03.70.018)

         The Company maintains procedures for identifying the training needs of
         all employees in performing assigned tasks and in increasing their
         quality awareness.

         Training records are held for each employee registering their
         education, experience and training requirements.

8.18          SERVICING

         The design philosophy of products manufactured by the Company
         precludes the need for regular maintenance.  Servicing procedures are
         therefore not required.

8.19          STATISTICAL TECHNIQUES - QAP 4.20 (03.70.019)

         The Company promotes the use of statistical tools and techniques in a
         systematic way to continually reduce variation in processes, products,
         and incoming materials.  The Quality Assurance Manager is the
         Statistical Coordinator for the Company.

<PAGE>
[LOGO] QUALITY ASSURANCE MANUAL                                  No: 03.70.001
                                                                 Rev: E
                                                                 Date: 3-94
                                                                 Page: 17 of 18
- -------------------------------------------------------------------------------

                             [MAP OF P-COM, INC. HEADQUARTERS]

<PAGE>

[LOGO] QUALITY ASSURANCE MANUAL                                  No: 03.70.001
                                                                 Rev: E
                                                                 Date: 3-94
                                                                 Page: 18 of 18
- -------------------------------------------------------------------------------

RECORD OF REVISIONS

- --------------------------------------------------------------------------------
REVISION DESCRIPTION                                       DATE      APPROVED
                                                                        BY
- --------------------------------------------------------------------------------
    1    Initial draft                                   10-12-92       KB

- --------------------------------------------------------------------------------
    2    Adds expanded Procedure Summary pages 8          11-06-92      KB
         through 14.
- --------------------------------------------------------------------------------
    3    Introduced modified front sheet, organization    12-17-92      KB
         chart, management responsibilities and
         procedure summary.
- --------------------------------------------------------------------------------
    A    Formal Release                                   01-08-93     K Bean

- --------------------------------------------------------------------------------
    B    Update 5.0, 6.0                                  10-20-93     K Bean

- --------------------------------------------------------------------------------
    C    Add ISO cross reference table and rewrite        11-18-93     K Bean
         para. 8.19
- --------------------------------------------------------------------------------
    D    Add QAP 4.20 to Applicable Documents             11-29-93     K Bean

- --------------------------------------------------------------------------------
    E    Correct address page 1 & para 1.2. Update        03-21-94     K Bean
         Location Map page 17.
- --------------------------------------------------------------------------------


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


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


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


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

<PAGE>


                             STANDARD/PROCEDURE APPROVAL


Standard/Procedure Number  03.70.001     Revision    E     Date  03-14-94
                          ----------------        ----------    ----------------

Standard/Procedure Title          Quality Assurance Manual
                       --------------------------------------------------------



As a minimum, the originator and the Director of the department issuing the
Standard/Procedure are the required approvals. For Company Standards, the
President must also approve.




Approvals:

/s/           3-14-94        /s/            3/21/94
- ----------------------       ----------------------
QA Manager      Date         President       Date

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.

REF:  US-PCN-296                                                           REV 1
                                                                        EXHIBITS
Training                                                              SCHEDULE K
- --------------------------------------------------------------------------------


         The P-Com Tel-Link Series radio is designed for ease of installation,
         operation, and maintenance, and as a result, minimal training is
         required.  P-Com's training consists of a two day course covering
         installation, operations and maintenance for up to a maximum of 10
         students per course to be held in P-Com's facilities.  The training
         cost will be waived for the first four (4) classes in the event that
         ART has purchased a minimum of 900 links and placed purchase orders
         for 2,500 additional links for delivery  by December 30, 1996.  For
         subsequent years, P-Com will continue to provide four (4) training
         classes per year free of charge should ART purchase a minimum of 2,500
         links in each of the subsequent calendar years.  Buyer will be
         retroactively charged $7,500 per training session performed in the
         event a minimum of 2,500 links are not purchased within a calendar
         year.

         Training classes will be scheduled at a mutually agreeable time and
         conducted at Seller's facilities.  Seller agrees to provide applicable
         and necessary training materials.


- --------------------------------------------------------------------------------
Aug 7, 1996                                                               Page 2

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.

REF:  US-PCN-296
                                                                        EXHIBITS
Revenue Sharing                                                       SCHEDULE L
- --------------------------------------------------------------------------------








                                      SCHEDULE L


                                   REVENUE SHARING






- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 1

<PAGE>

[LOGO]                                                 AGREEMENT BETWEEN PARTIES
                                                    A.R.T. LIMITED & P-COM, INC.

REF:  US-PCN-296
                                                                        EXHIBITS
Revenue Sharing                                                       SCHEDULE L
- --------------------------------------------------------------------------------


Following is the schedule for P-Com's equipment subsidy position and payment
schedule required by P-Com:

CUMULATIVE              SCHEDULE                 EQUIPMENT    P-COM
CITY LEVEL              "A" PRICE    CASH PRICE  SUBSIDY      MONTHLY ROYALTY
- ----------------         ---------   ----------  ---------    ---------------

                                                               0% of Revenue
                                                              20% of Revenue
                                                              20% of Revenue
                    [CONFIDENTIAL]                            20% of Revenue
                                                              20% of Revenue
                                                              20% of Revenue
                                                              20% of Revenue
                                                              20% of Revenue

Beginning with the shipment of link 301 P-Com will subsidize 20% of the
equipment cost (per Schedule A) and in return will receive 20% of the monthly
revenue generated from the link.  If the link is put in service generating $500
or more in monthly T1 revenue.  P-Com is to be paid the full price as indicated
in Schedule A and still receive 20% of the revenue generated from the link.

All other aspects of the Agreement stay the same with the exception of the
[CONFIDENTIAL].  That is, the cumulative pricing schedule which allows
for [CONFIDENTIAL] provision remain in the Agreement.  [CONFIDENTIAL]



- --------------------------------------------------------------------------------
Aug 7, 1995                                                               Page 2








<PAGE>

                                                      Amendment to Exhibit 10-11

    FIRST AMENDMENT TO AGREEMENT BETWEEN THE PARTIES

    THIS FIRST AMENDMENT TO AGREEMENT BETWEEN THE PARTIES (this "Amendment") is
entered into as of the 19th day of July, 1996 by and between P-Com, Inc. ("P-
Com") and Advanced Radio Technology Limited ("ART"), with reference to the
following facts:

    A.   P-Com and Art entered into that certain Agreement Between the Parties
dated as of August 11, 1995 (the "Purchase Agreement") for the purchase of radio
links.

    B.   P-Com and Art desire to amend the Agreement to clarify the original
intent of the parties with respect to revenue sharing and other items set forth
herein.

    NOW, THEREFORE, in consideration of the above recitals and for other
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged by all parties, the parties agree to amend the Purchase Agreement
as follows:

    1.   All capitalized terms used herein shall have the same meanings as are
set forth in the Purchase Agreement, unless otherwise indicated.

    2.   Paragraph 17.0 of Section 1 of the Purchase Agreement is hereby
deleted in its entirety and inserted in its place is the following:

         "REVENUE SHARING: In the event ART purchase 300 links, ART, in its
         sole discretion may agree to select the financing option presented on
         Schedule "L" attached hereto."

    3.   The second sentence of the first full paragraph of Schedule L,
commencing with: "If the Link is put in service generating..." is hereby deleted
in its entirety.

    4.   The following is hereby inserted after the word "concept" at the end
of the first sentence of the second full paragraph of Schedule L:

         "set forth in Schedule A of this Agreement.:

    5.   the signature block for ART set forth on the Signatory Page is hereby
amended to read "Advanced Radio Technology, Ltd."

    6.   P-Com hereby acknowledges, and consents to, the future assignment by
ART of its rights, interests and obligations under the Purchase Agreement to
Advanced Radio Technologies Corporation pursuant to a merger transaction
involving ART.


<PAGE>

    7.   The Purchase Agreement is modified, amended and supplemented only to
the extent set forth herein, and as so modified, amended and supplemented, shall
remain in full force and effect between ART, or its successor or assign, and P-
Com.  In the event of any conflict between the provision of this Amendment and
those of the Purchase Agreement, the terms of this Amendment shall prevail.

    8.   This Amendment may be executed in several counterparts, each or which
shall be deemed to be an original, and all of which together shall be deemed to
be one and the same instrument when each party has signed one such counterpart.

    IN WITNESS WHEREOF, P-Com and ART have executed this Amendment as of the
date first above written.


    P-COM:                                  ART:

    P-Com, Inc.                             Advanced Radio Telecom Corp.
                                            (f/k/a Advanced Radio
                                             Technology, Ltd.)

    By:___________________________

    Name:_________________________          By:___________________________

    Title:________________________          Name:_________________________

                                            Title:________________________


                                            Advanced Radio Technologies
                                            Corporation

                                            By:___________________________

                                            Name:_________________________

                                            Title:________________________

<PAGE>


                          MEMORANDUM OF TERMS

                                  RE

DEVELOPMENT AND PROCUREMENT AGREEMENT BETWEEN ART AND AMERICAN WIRELESS FOR
THE DEVELOPMENT OF LOW COST, HIGH CAPACITY 38 GHZ RECEIVER PROTOTYPES. THIS 
AGREEMENT INITIATES THE FIRST STEP IN THE DEVELOPMENT OF A METROPOLITAN AREA 
NETWORK SYSTEM FOR MILLIMETER WAVE SPECTRUM. THIS OFFER REMAINS OPEN UNTIL 
JANUARY 31, 1996.

This Memorandum of Terms is between American Wireless Corporation ("AWC") 
located at 3650 131st Ave. SE. Ste. 630 Bellevue, WA (phone 206-0603-9955)
and ART Corporation ("ART") at 500 105th Ave. NE ste. 2600, Bellevue, WA 
98004.

     WHEREAS ART has acquired authorizations at 38GHz in metropolitan markets 
     in the U.S.; and

     WHEREAS ART intends to develop and operate high data rate wireless 
     networks using the 38GHz licensed spectrum; and

     WHEREAS AWC intends to develop low cost 38 GHz digital radio technology, 
     an air interface which includes defining a network access protocol, and
     the system components to provide integration between the public and private
     networks.

     WHEREAS ART is desirous of demonstrating as soon as possible a 38 GHz 
     network using AWC's low cost, high capacity digital radio equipment and air
     interface; and 

     WHEREAS BOTH PARTIES intend to establish defacto industry standards 
     which are fundamental to the formation of millimeter wave broad band 
     metropolitan networks.

     NOW THEREFORE the parties hereto agree as follows:

1.0 PRODUCTS

     This agreement covers the development of receive-only, indoor and outdoor 
     digital radios for Metropolitan Area Applications. The preliminary specific
     product requirements are included in Appendix 1. The product requirements 
     may be altered from time to time by AWC: provided that


                                                                               1


<PAGE>


     AWC shall consult on such alterations with ART and shall exercise its 
     best efforts to accommodate ARTs desires and needs.

     The parties also agree that, if mutually agreed upon, products in 
     addition to the 38GHz receive-only product may be added to this agreement.

     This agreement establishes the procurements and royalty rights granted 
     to ART for the investment in prototype radio development.

2.0 PRODUCT OWNERSHIP

     American Wireless will own exclusively all inventions and intellectual 
     property created under this agreement (the Technology), subject to the 
     licensing arrangements set forth in section 7, and provided that AWC shall
     pay to ART during the term of this agreement, in consideration for ART's
     sponsorship and funding of the development of the product, a royalty on all
     sales in the U.S. of the product equal to 1.5% of the gross sales price,
     which payment shall be credited against ART's purchases form AWC so long 
     as ART continues to purchase products. Total Royalty payments shall not 
     exceed the total dollar amount of development funding under section 3.0 
     actually paid by ART multiplied by a factor of 1.429.

3.0 DEVELOPMENT FUNDING

     In consideration of AWC developing such products, and for the 
     consideration set forth in section 4, ART will fund $700,000 dollars in ten
     (10) monthly payments of $70,000 subject to the demonstration schedule
     stated in Appendix 2. The first payment will occur upon the signature of
     this agreement. The following nine payments will occur on the first Tuesday
     of the month following in which this agreement is signed.

     Should, at any time it become apparent that the development project will 
     not be completed on schedule and on or under budget, the parties may elect,
     through mutual agreement, to revise the budget and schedule, in which case
     ART shall fund the program on a fully burdened development cost basis not
     to exceed a total program investment of $1,000,000. In such event, if the
     parties are unable to agree on a revised budget and schedule, either party
     may terminate pursuant to section 8.0.


                                                                               2


<PAGE>


4.0 PROCUREMENT RIGHTS

     4.1 Provided that ART places the order set forth in section 5.2. ART 
     will be granted exclusive rights to procure the subject product as 
     outlined in appendix 1, that is marketed or sold for operation in U.S.
     markets owned or licensed by ART or where ART is operating or has executed
     an agreement to operate for a period of 18 months from the date of the
     first order.

     4.2 In addition to the exclusive procurement rights in section 4.1. ART 
     shall have the right of first offer ("RFO") to purchase all of the subject 
     product that is manufactured for sale in the U.S. during the Term of this 
     agreement at the lower of the Target Price or the most favorable pricing to
     any other customer of AWC. The RFO shall be exercised by ART within 30 days
     following certification of AWC as to the number and type of product units
     to be manufactured in the ninety day period that commences ninety days
     from the date of certification. ART shall also have the right of first
     offer to purchase follow-on or derivative 38GHz products, based on the
     Technology developed by AWC during the Term of this agreement. Pricing 
     for such follow-on products will be defined under a separate agreement.

5.0 PURCHASE OPTION

     5.1 In consideration of the development funding, ART will receive the 
     option to place an order covering first deliveries of the production
     product described in Appendix 1 at a price equal to AWC's fully burdened 
     cost-to-manufacture (not including non-recurring development costs) for the
     first 300 units. The target price for additional units shall be $1500. Both
     parties agree that, following completion of ART's purchase pursuant to
     section 5.3., the product price shall be established to be equivalent to
     market-based competitive prices for comparable products.

     5.2 To insure exclusivity, ART will place an order of not less than 300 
     units within 30 days after completion of the demonstration as defined by 
     Appendix 1 and listed as a major milestone in Appendix 2 and will place 
     total orders as described in paragraph 5.3 by the last business day of each
     quarter.

     5.3 Order minimums will be $500,000 for Q1: $1,000,000 for Q2: $1,500,000 
     for Q3; and $2,000,000 for Q4.


                                                                               3


<PAGE>


     5.4 Both parties agree to negotiate in good faith to provide a staged 
     procurement agreement for additional units of the subject receiver, subject
     to section 4.2, and for future components of the Metropolitan Area System 
     developed by AWC.

6.0 MANUFACTURING

     6.1 AWC retains all manufacturing rights, subject to section 7.0.

7.0 DEFAULT

     7.1 Should AWC not complete the development and successful demonstration 
     of products as described in Appendix 1 and in accordance with each of the 
     milestones in Appendix 2, as revised in accordance with section 3, AWC 
     will have nine (9) months to cure the default condition. Following the nine
     month cure period, if AWC remains in default, ART will be granted one of
     the following options:

     OPTION A:
     (1) AWC will refund ART the amount paid since the last successful 
     milestone over the following eight quarters and (2) will grant ART a 
     royalty-free license to use, manufacture or distribute the product based on
     the Technology developed through the last completed milestone, including
     all firmware and software for the term of this agreement.

     OPTION B:
     AWC will grant ART a 10% equity interest in AWC on a fully diluted basis, 
     assuming ART will commit to fund completion of the development in return
     for an additional equity interest based upon the percentage relationship
     between the additional funds from ART necessary to completion and the 
     fair market value ("FMV") of AWC at the time of the first investment of
     such additional funds, which FMV is conclusively deemed to be $10 million.

8.0 TERMINATION

     8.1 The relationship of the parties with regard to this agreement would 
     be terminable: (a) under the conditions described in section 3.0 (with
     regards to termination; (b) under the conditions described in section 7.0,
     where AWC remains in default after the nine month cure period. In such an
     event, AWC will grant ART a royalty-free license to use, manufacture or
     distribute the product based on the Technology developed through the last
     completed milestone, including all firmware and software for the term


                                                                               4


<PAGE>

ART/AWC HEADS OF AGREEMENT                                               1/24/96


    of this agreement.  In any event, all inventions and intellectual property
    developed under this agreement shall remain the sole property of AWC.

9.0 TERM

    9.1 The parties agreements shall be become effective on the date upon which
    a definitive agreement is executed and shall terminate on its fourth
    anniversary.  The parties shall negotiate a definitive agreement within
    thirty days of the date of this MOT to replace the MOT.  The MOT shall
    become null and void on the thirtieth day.

10.0 ENTIRE AGREEMENT / MODIFICATION.  This agreement constitutes the entire
agreement between the parties hereto and supersedes all prior representations,
agreements, understandings and arrangements, oral or written, between the
parties hereto with respect to the subject matter hereof.  This Agreement may
not be modified except by a writing that expressly refers to this Agreement and
is executed by all parties hereto.

IN WITNESS WHEREOF, the parties have duly executed this Agreement on the date
first written below.


Advance Radio Technologies Corp        American Wireless Corporation

By: /s/ STEVEN D. COMRIE               By: /s/ ROBERT B. FOSTER
   --------------------------------       --------------------------------

Title: President                       Title: President & CEO
     -----------------------------           -----------------------------

Date:  1/29/96                         Date:  1/26/96
    ------------------------------          ------------------------------

<PAGE>

ART/AWC HEADS OF AGREEMENT                                               1/24/96


APPENDIX 1. PRODUCT DESCRIPTION (INSERT 38 GHz DEVELOPMENT PLAN)

<PAGE>

ART/AWC HEADS OF AGREEMENT                                               1/24/96


APPENDIX 2. MILESTONE SCHEDULE


MONTH                             ACTIVITY/MILESTONE

5             Demonstration of 1.7 GHz IF converter for Indoor Radio

6             Demonstration of millimeter wave VCO and PLL Synthesizer for
              Outdoor Radio 1.7 GHz IF converter for Outdoor Radio

7             Demonstration of either the QPSK or QAM modem at bit rates
              exceeding 30 Mbps

9             Demonstration of either the Ethernet LAN or ATM application using
              either the Indoor or Outdoor Radio

<PAGE>

                         [ADVANCED RADIO TELECOM LETTERHEAD]

April 25, 1996


                                 AGREEMENT EXTENSION

Signature below by an authorized representative confirms agreement to extend the
existing Memorandum of Terms executed between American Wireless Corporation and
Advanced Radio Telecom Corporation until June 20, 1996.  Both parties agree to
finalize a definitive agreement prior to June 20, 1996.


Advanced Radio Telecom Corporation          American Wireless Corporation


/s/ CHRISTOPHER B. VILLANI             /s/ ROBERT FOSTER
- ------------------------------         ------------------------------
Christopher B. Villani                 Robert Foster


<PAGE>



                                  HARRIS CORPORATION
                                   FARINON DIVISION

                                  PURCHASE AGREEMENT


This Agreement is entered into this 26th day of April, 1996, by and between
Advanced Radio Telecom Corporation, a Delaware corporation with offices located
at 500 108th Avenue NE, Suite 2600, Bellevue, WA 98006 ("ART" or "Customer"),
and Harris Corporation, Farinon Division, a Delaware corporation, with offices
located at 330 Twin Dolphin Drive, Redwood Shores, CA 94065 ("Harris").

Whereas, Customer desires to purchase microwave transmission equipment, software
and services ("Products"), and

Whereas, Harris is willing to sell such Products to Customer upon the terms and
conditions as set forth herein and the various annexes attached hereto and
incorporated into this document,

Now, Therefore, in consideration of the mutual covenants set forth below, ART
and Harris, intending to be legally bound, hereby agree as follows:

1.  EFFECTIVE DATE; RELATED PCS MARKETING AGREEMENT; FINANCING COMMITMENT.

The Effective Date of this Agreement shall be the date of execution by the
parties, provided, however, that the rights and obligations of the parties
hereunder shall not become effective unless and until the parties have executed
a definitive marketing agreement ("PCS Marketing Agreement") for 38 GHz services
as contemplated by Version 5 of a Letter of Intent executed by ART and Harris
and dated February 22, 1996.

2.  SCOPE

Harris will furnish Products for Customer in accordance with the individual
Purchase Orders issued by Customer from time to time during the Term of this
Agreement based upon the prices provided in Annex A hereto.  The Products will
be provided in conformity with the terms, conditions, specifications and other
requirements of this Agreement and each Purchase Order will be governed by the
terms and conditions stated herein.

3.  PRICES/TAXES

All prices are exclusive of shipping and insurance charges which shall be billed
separately.  All prices are exclusive of all sales, use, excise, and other
taxes, duties or charges.  Unless evidence of tax exempt status is provided by
Customer, Customer shall pay, or upon receipt of invoice from Harris, shall
reimburse Harris for all such taxes or charges levied or imposed on Customer, or
required to be collected by Harris, resulting from this transaction or any part
thereof.

All prices are FOB Harris' Factory.  Unless instructed otherwise, Harris will
arrange for insurance and standard commercial shipping, the costs of which will 
be invoiced to the Customer.


                                                                               1

<PAGE>

Responsibilities regarding the export of items delivered under this Agreement
are detailed in ARTICLE 8.  Prior to delivery, Harris reserves the right to make
substitutions, modifications and improvements to the equipment and/or software
ordered, provided that such substitutions, modifications or improvements shall
not materially affect performance in the application originally agreed to with
Customer.

4.  PURCHASE FORECAST GOALS.

ART shall provide Harris with MicroStar and MicroStar Plus purchase forecasts,
which shall serve as a baseline to establish pricing levels outlined in Annex A.
ART's initial forecast is attached hereto as ANNEX B.  Unless otherwise agreed
by the parties, future forecasts shall be provided by ART on a quarterly basis.

5.  PAYMENT/FINANCING

Payment terms shall be determined on a per order basis and are subject to credit
review by Harris.

Late payments shall result in the assessment of a late charge equal to one and
one-half (1 1/2%) percent per month on any outstanding balance, or the maximum
amount of interest chargeable by law, whichever is less.

Customer shall remain liable for all payments regardless of the method of
payment or financing of this Agreement, unless otherwise agreed to in writing by
Harris.

Customer's payment obligations are particular hereto, and Customer has no right
of set-off against other Purchase Orders or other transactions between the
parties.

6.  WARRANTIES AND LICENSE

    a)   EQUIPMENT WARRANTY

Refer to Annex C for terms and conditions related to customer service and
equipment warranty:

Harris warrants that each product of its own manufacture shall, at the time of
delivery and for a period of twenty-four (24) months thereafter, be free from
defects in materials and workmanship and to conform to Harris' published
specifications.  Such warranty shall not include any consumable components to
which a specific manufacturer's guarantee applies.  If any Harris product shall
prove to be defective in materials or workmanship under normal intended usage,
operation and maintenance during the applicable warranty period as determined by
Harris after examination of the product claimed to be defective, then Harris
shall repair, replace or refund the purchase price of, at Harris' sole option,
such defective product, in accordance with procedures specified below, at its
own expense, exclusive, however, of the cost of labor by the Customer's own
employees, agents or contractors in identifying, removing or replacing the
defective part(s) of the product.  Replacement products may be new, refurbished
or remanufactured.  Returned replaced products shall become the property of
Harris.  Replacement products shall be warranted for the balance of the
unexpired portion of the returned products warranty.

In composite equipment assemblies and systems, which include equipment of such
other than Harris manufacture, Harris' responsibility under this warranty
provision for the non-Harris manufactured portion of the equipment shall be
limited to the other equipment manufacturer's standard warranty.  Provided,
however, that if the other manufacturer's standard warranty period


                                                                               2

<PAGE>

is of a shorter duration than the warranty period applicable to Harris'
manufactured equipment, then Harris shall extend additional coverage to such
other equipment manufacturer's warranty equal to the differential in time
between the expiration of the other manufacturer's warranty and the duration of
Harris' manufactured equipment warranty applicable to such order.  Harris shall
repair, replace or refund the purchase price of, at Harris' sole option, such
other manufacturer's defective part(s) within sixty (60) days after receipt of
such parts by Harris in accordance with the below specified procedures, at
Harris' own expense, exclusive, however, of cost of labor by the Customer's own
employees, agents or contractors in identifying, removing or replacing the
defective part(s) of the product.

A written authorization to return products to Harris under this warranty must be
obtained from a Harris representative prior to making shipment to Harris' plant,
and all returns shall be shipped freight prepaid.  Collect shipments will not be
accepted, but Harris will prepay return freight charges on repaired and replaced
products found to be actually defective.

The warranty provided herein does not cover damage, defects, malfunctions or
service failures caused by:

(1)  Customer's failure to follow Harris' environmental, installation, operation
or maintenance specifications or instructions;

(2)  Modifications, alterations or repairs made other than by Harris;

(3)  Customer's mishandling, abuse, misuse, negligence, or improper storage,
servicing or operation of the Equipment (including without limitation use with
incompatible equipment); or

(4)  Power failures, surges, fire, flood, accident, actions of third parties or
other like events outside Harris' control.  Repairs necessitated during the
warranty period by any of the foregoing causes may be made by Harris, and the
Customer shall pay Harris' standard charges for time and materials, together
with all shipping and handling charges arising from such repairs.

    b)   SOFTWARE WARRANTY AND LICENSE

    (1)  LICENSE.  Harris grants to Customer a non-exclusive, non-transferable
license to use the software and related documentation ("Software") provided
hereunder.  The Software may include software and documentation that are owned
by third parties and distributed by Harris under license from the owner.  If
Customer is a reseller of the software purchased under this agreement, this
license is assignable only to Customer's customer, subject to Harris' written
authorization and only if the end customer is bound in writing to the Terms and
Conditions of this license.  Customer shall retain a copy of such end Customer
Agreement for Harris' inspection.

    (2)  COPIES.  Customer shall not make any copies of the Software, except
for a single archival copy solely for internal purposes.

    (3)  CONFIDENTIALITY.  Customer shall maintain the confidentiality of the
Software and shall not sub-license, sell, rent, disclose, make available, or
otherwise communicate the Software to any other person, or use the Software
except as expressly authorized in writing by Harris.

    (4)  TITLE.  The Software and all copies thereof will at all times remain
the sole and exclusive property of Harris or its licensor, as applicable, and
Customer shall obtain no title to the Software.

    (5)  COPYRIGHT.  Customer shall reproduce all copyright notices and any
other


                                                                               3

<PAGE>

proprietary legends on any copy of the Software made by Customer.

    (6)  ALTERATION.  Customer shall not modify, disassemble, or decompile the
Software.

    (7)  MEDIA.  If Customer sells or otherwise disposes of Customer owned
media on which the software is fixed, such media must be erased before any sale
or disposal.

    (8)  WARRANTY.  Harris does not warrant that the operation of the Software
will be error free.  Harris will use reasonable efforts to correct any defects
reported to Harris in writing within twenty-four (24) months of the date of
shipment, exclusive of defects caused by physical defects in Software disks due
to mishandling, operator error or interfacing other systems not approved by
Harris.

    c)   LIMITATIONS

LIABILITY OF HARRIS FOR BREACH OF ANY AND ALL WARRANTIES HEREUNDER IS EXPRESSLY
LIMITED TO THE REPAIR, REPLACEMENT OR REFUND OF THE PURCHASE PRICE OF DEFECTIVE
PRODUCTS AS SET FORTH IN THIS SECTION, AND IN NO EVENT SHALL HARRIS BE LIABLE
FOR SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES BY REASON OF ANY BREACH OF
WARRANTY OR DEFECT IN MATERIALS OR WORKMANSHIP.  HARRIS SHALL NOT BE RESPONSIBLE
FOR REPAIR, REPLACEMENT, REFUND OF PURCHASE PRICE OF PRODUCTS WHICH HAVE BEEN
SUBJECTED TO NEGLECT, ACCIDENT OR IMPROPER USE, OR WHICH HAVE BEEN ALTERED BY
OTHER THAN AUTHORIZED HARRIS PERSONNEL.  THE FOREGOING WARRANTIES ARE IN LIEU OF
ALL OTHER WARRANTIES WHETHER ORAL, WRITTEN, EXPRESSED, IMPLIED, OR STATUTORY. 
IN PARTICULAR, THE IMPLIED WARRANTIES OF FITNESS FOR PARTICULAR PURPOSE AND
MERCHANTABILITY ARE HEREBY DISCLAIMED AND SHALL NOT BE APPLICABLE EITHER FROM
HARRIS OR ANY OTHER EQUIPMENT OR SOFTWARE MANUFACTURER, HARRIS' WARRANTY
OBLIGATIONS AND CUSTOMER'S REMEDIES THEREUNDER ARE SOLELY AND EXCLUSIVELY AS
STATED HEREIN.  IN NO CASE SHALL HARRIS BE LIABLE FOR INDIRECT KINDS OF DAMAGES,
INCLUDING BUT NOT LIMITED TO SPECIAL, INCIDENTAL, AND CONSEQUENTIAL DAMAGES, OR
LOSS OF CAPITAL, REVENUE, OR PROFITS. IN NO EVENT SHALL HARRIS' LIABILITY TO
CUSTOMER, OR ANY PARTY CLAIMING THROUGH CUSTOMER, BE IN EXCESS OF THE ACTUAL
SALES PRICE PAID BY CUSTOMER FOR ANY ITEMS SUPPLIED HEREUNDER.

7.  TITLE AND RISK OF LOSS

Risk of loss for all Equipment sold under this Agreement shall pass to Customer
at time of delivery as defined herein.  Customer grants to Harris a security
interest in the Equipment covered by this Agreement in the amount of the unpaid
balance of the purchase price until payment in full of the purchase price at
which time title in the Equipment will pass in accordance with the terms and
conditions set forth herein.  A financing statement may be filed with the
appropriate public authorities and Customer agrees to sign any such financing
statements or other documents tendered to it by Harris from time to time to
protect Harris' security interest.

8.  EXPORT AND RE-EXPORT RESTRICTIONS

Performance and delivery of the equipment, documents, services and Software sold
or delivered hereunder are subject to export control laws and regulations of the
United States and/or Canada, as applicable, and conditioned upon receipt of
required U.S. and/or Canadian Government licenses and approvals by Harris. 
Customers shall not export products or technical data delivered hereunder from
the United States or Canada without complying with regulations of the Bureau of
Export Administration of the United States Department of Commerce and/or the
Export Controls Division of the Canadian Department of Foreign Affairs and
International Trade, as applicable.  Customers shall not re-export the products
and technical data delivered hereunder from the country of delivery or to any
facility engaged in the design, development, stockpiling,


                                                                               4
       

<PAGE>

manufacturing or use of missile, chemical or biological weapons without fully
complying with the regulations of the above United States and/or Canadian
government agencies.

9.  EXCUSABLE DELAY

Harris shall be excused from performance under the Purchase Order and not be
liable to Customer for delay in performance attributable in whole or in part to
any cause beyond its reasonable control, including but not limited to, actions
or inactions of government whether in its sovereign or contractual capacity,
judicial action, war, civil disturbance, insurrection, sabotage, act of a public
enemy, labor difficulties or disputes, failure or delay in delivery by Harris'
suppliers or subcontractors, transportation difficulties, shortage of energy,
materials, labor or equipment, accident, fire, flood, storm or
other act of God, or Customer's fault or negligence.

In the event of an excusable delay, Harris shall make reasonable efforts to
notify Customer of the nature and extent of such a delay and Harris (i) will be
entitled to a schedule extension on at least a day-for-day basis, (ii) in the
event of Customer's fault or negligence, will be also entitled to an equitable
adjustment in the price of this contract.  Notwithstanding any other term
contained herein.  In the event an excusable delay occurs and continues for a
period of ninety (90) days or longer, ART shall have the right to immediately
terminate this Agreement or any Purchase Order given pursuant to the Agreement
without further liability to Harris.

10. TERM AND TERMINATION

This Agreement shall continue in effect for one (1) year from the date hereof at
which time it will terminate, unless terminated earlier pursuant to this Article
12.  Renewal is subject to mutual written agreement signed by both parties.

Cancellation of any Purchase Order hereunder will be accepted only upon the
specific written approval of Harris and is subject to standard Harris
cancellation charges of 25% if cancellations is received 30 days after receipt
of order from ART, provided however, that ART may cancel any Purchase Order
without the approval of Harris and without incurring cancellation charges if the
delivery of Products under such Purchase Order is delayed, or expected to be
delayed, by ninety (90) days or more from the original delivery date.

In the event that Customer shall become liquidated, dissolved, bankrupt or
insolvent, or shall take any action to be so declared, or shall suffer any such
action brought by another, Harris shall have the right to terminate this
Agreement and all Purchase Orders immediately and may stop shipment of any
Products in transit.

Either party may terminate this Agreement immediately upon notice in writing to
the other party:

    a)  if the other party shall breach any provision of this Agreement in any
material respect and such breach remains unremedied thirty (30) days after
notice thereof from the non-breaching party;

    b)  in the event that the other party breaches any material term, condition
or covenant of the PCS Marketing Agreement referenced in Section 1 above and the
other party fails to cure any default or breach within thirty (30) days of
receipt of written notice of such breach from the non-breaching party; or

    c)  in the event that the other party has caused the PCS Marketing
Agreement referenced in Section 1 above to be terminated.


                                                                               5

<PAGE>

    The right of termination provided herein is absolute and neither party
shall be liable to the other for damages or otherwise by reason of such
termination.

11. INFRINGEMENT INDEMNIFICATION

Customer agrees to promptly notify Harris in writing of any notice, suit, or 
any action against Customer based upon a claim that the Product infringes a 
U.S. patent, copyright, trademark, or trade secret of a third party.  Harris 
will defend at its expense any such action, except as excluded below, and 
shall have full control of such defense including all appeals and 
negotiations, and will pay all settlement costs, or damages awarded against 
Customer, but Harris shall not be liable to Customer for special, incidental, 
indirect or consequential damages.  In the event of such notice, suit or 
action, Harris will at its expense procure for the Customer the right to 
continue using the product, or modify the Product to render such 
non-infringing, or accept return and replace such with substantially 
equivalent non-infringing equipment, or accept return of the Product and 
refund or credit to Customer the amount of the original purchase price, less 
a reasonable charge for depreciation and damage.

The preceding agreements by Harris in this section shall not apply to any
Product or portion thereof manufactured to specifications furnished by or on
behalf of Customer, or to any infringement arising out of the use of the Product
in combination with other equipment or software not furnished by Harris, or to
use in a manner not normally intended, or to any patent, copyright, trademark or
trade secret in which Customer, or subsidiary or affiliate thereof, has a direct
or indirect interest, or if customer has not provided Harris with prompt notice,
authority, information and assistance necessary to defend the action.  The
foregoing states the entire liability of Harris for patent, copyright, trademark
and trade secret infringements by the Product or portion thereof.

The rights and obligations of the parties under this Section shall survive
termination of this Agreement.

12. TECHNICAL DATA AND INVENTION

Unless specifically agreed to by Harris and identified and priced in this 
contract as a separate item or items to be delivered by Harris (and in that 
event, except to the extent so identified and priced), the sale of goods 
hereunder confers on Customer no right in, license under, access to, or 
entitlement of any kind to any of Harris' technical data including but not 
limited to design, process technology, softare and drawings, or to Harris' 
inventions (whether or not patentable) irrespective of whether any such 
technical data or invention or any portion thereof arose out of work 
performed under or in the course of this contract, and irrespective of 
whether Customer has paid or is obligated to pay Harris for any part of the 
design and/or development of the goods.

Harris shall not be obliged to safeguard or hold confidential any data whether
technical or otherwise, furnished by Customer for Harris' performance of this
contract unless (and only to the event that) Customer and Harris have entered
into a separate written confidential agreement.

Customer shall not violate Harris' copyright of documents or software or
disclose Harris' confidential or proprietary data to others without Harris
written permission.

13. ASSIGNMENT

Neither party may assign this agreement in whole or in part without the prior
written consent signed by an officer of the other party.  Such consent shall not
be unreasonably withheld.


                                                                               6

<PAGE>

14. GOVERNING LAW, VENUE, AND JURISDICTION

This Agreement will be governed by and construed in accordance with the laws of
the State of California.  The parties agree that any action to enforce any
provision of this Agreement or arising out of or based upon this Agreement or
the business relationship between Harris and Customer will be brought in a local
or Federal court of competent jurisdiction in the State of California.

15. ENFORCEABILITY

If any provision of this Agreement shall be held to be invalid, illegal or
unenforceable, the validity, legality or enforceability of the remaining
provisions shall in no way be affected or impaired.

16. NOTICES

All notices shall be in writing and shall be delivered or sent by registered,
certified or express mail, return receipt requested, to the addresses indicated
in this Agreement or to such other addresses as the parties shall specify by
giving notice pursuant hereto.  A copy of all notices shall be sent to Harris
Corporation, Farinon Division, 330 Twin Dolphin Drive, Redwood Shores, CA 94065.
Attention:  Manager of Contracts, and to W. Theodore Pierson, Jr. Executive Vice
President and General Counsel, 1667 K Street, NW, Suite 801 Washington, DC
20006.

17. INDEMNIFICATION

    a)  INDEMNIFICATION OF ART BY HARRIS

Harris shall indemnify ART against, and hold ART harmless from all liabilities,
demands, claims, damages, losses, demands, costs, judgments and expenses
(including reasonable attorneys' fees) arising out of or in connection with
arising out of or relating to the installation, operation, or use of the
Products for personal injury or damage to tangible property, caused by the
negligent acts or omissions of Harris or Harris's employees, agents or invitees.
In no event shall ART's employees, agents or invitees be deemed to be employees,
agents or invitees of Harris.

    b)  INDEMNIFICATION OF HARRIS BY ART

ART shall indemnify Harris against, and hold Harris harmless from all
liabilities, demands, claims, damages, losses, demands, costs, judgments and
expenses (including reasonable attorneys' fees) to the extent they arise out of
or are in connection with or relate to the installation, operation, or use of
the Products for personal injury or damage to tangible property, caused by the
negligent acts or omissions of ART or ART's employees, agents or invitees.  In
no event shall Harris's employees, agents or invitees be deemed to be employees,
agents or invitees of ART.

    c)  DUTY TO NOTIFY AND ASSIST

If any claim arises to which the provisions of this Section may be applicable,
the party against whom such claim is made shall notify the other party
immediately upon learning of the claim.  If it appears that the other party may
be obligated to provide indemnification as a result of such claim, the other
party, in its discretion, may settle or compromise the claim


                                                                               7

<PAGE>

or retain counsel of its own choosing and control and prosecute the defense
against such claim.  In no event shall the party against whom the claim is
asserted have the right to pay, settle or compromise such claim without the
prior written consent of the party who may be obligated to indemnify under this
Section and the parties hereto agree that they will not unreasonably withhold
consent to such consent to payment, settlement or compromise.  The party against
whom the claim is asserted shall provide the other party such assistance as may
be reasonable in the defense and disposition of such claim.

The rights and obligations of the parties under this Section shall survive
termination of this Agreement.

18. LIMITATION OF LIABILITY

NOTWITHSTANDING ANY OTHER PROVISIONS OF THIS CONTRACT, UNDER NO CIRCUMSTANCES
SHALL HARRIS BE LIABLE TO CUSTOMER OR ANY THIRD PARTY CLAIMING UNDER CUSTOMER
FOR SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES, AS A RESULT OF A
BREACH OF ANY PROVISION OF THIS CONTRACT.

19. ENTIRE AGREEMENT

This Agreement supersedes all previous communications, transactions, and
understandings, whether oral, or written, and constitutes the sole and entire
agreement between the parties pertaining to the subject matter hereof.  No
modification or deletion of, or addition to these items shall be binding on
either party unless made in writing and signed by a duly authorized
representative of both parties.

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
by their duly authorized representatives as of the day and year first stated
above.


ADVANCED RADIO TELECOM CORPORATION


BY: /s/ Charles P. Menatti
   --------------------------------

NAME: Charles P. Menatti
     ------------------------------

TITLE: V.P. Bus. Dev.
- -----------------------------------


HARRIS CORPORATION
FARINON DIVISION

BY: /s/ J. Michael Slattery
   --------------------------------

NAME: J. Michael Slattery
     ------------------------------

TITLE: Division Controller
     ------------------------------

                                                                               8

<PAGE>










                                     ANNEX A


                                     PRICING

<PAGE>

                                                                          Page 1

                                     ANNEX A
                                     -------

                                     Pricing
                                     -------

                               38 GHz 8T1 products
                               -------------------


1.0  MicroStar 8T1.
     --------------


1.1  Pricing by annual purchased quantities.
     ---------------------------------------


     Prices for MicroStar 38, non-protected links, equipped with 8T1,
     integrated antenna and pole mounting gear.  The radios have built-in access
     ports for NMS, CIT and east & west connections.  Product documentation is
     included.  Prices are in US $ and are exclusive of sales taxes.

     The following table shows the gradual discounts related to annual volume
     purchased.  The prices are for 38 GHz 8T1 links.


      Annual            Price               Price
        Qty
      Serial        MicroStar 8T1       MicroStar 8T1
       Links            Link                Link
                    With 12" ant.       With 24" ant.


                  [CONFIDENTIAL]



1.2  Pricing methodology

     Pricing outlined in 1.1 are serial based for volumes achieve over a period
     of one year.

<PAGE>


                                                                         Annex A
                                                                          Page 2

                                     ANNEX A
                                     -------

                                     Pricing
                                     -------

                               38 GHz 8T1 products
                               -------------------

1.3  Options
     -------

1.31 Craft Interface Tool software.
     ------------------------------

     A multi-Site lisence will be provided to ART at [CONFIDENTIAL]. Harris will
     support ART on this product.  ART installation technicians will get their
     support through ART as opposed to direct support from Harris.

1.32 Antenna alignment tool kit.
     ---------------------------

     The antenna alignment tool kit consist of a removable Azimuth & Elevation
     adjustment mechanism.  Harris will supply ART with [CONFIDENTIAL] for every
     [CONFIDENTIAL] purchased under this agreement up to a maximum of 
     [CONFIDENTIAL] kits after which each kits will be sold at [CONFIDENTIAL].
     Any extra kits can be purchased at [CONFIDENTIAL] at any time.

1.4  Delivery
     --------

     Delivery of MicroStar radios will begin no later than June 30, 1996.

1.5  Extended Warranty
     -----------------

     Annual Repair Service Program (per link) ............  [CONFIDENTIAL]

<PAGE>

                                                                         Annex A
                                                                          Page 3
                                     ANNEX A
                                     -------

                                     Pricing
                                     -------

                               38 GHz DS3 products
                               -------------------

2.0  MicroStar Plus (DS3)
     --------------------

2.1  Pricing by annual purchased quantities
     --------------------------------------

     Prices for MicroStar Plus 38, DS3, non-protected link equipped with
     Integrated 9" CTS antenna and pole mounting gear.  The radios have built-in
     access ports for NMS, CIT and east & West connections.  MicroStar Plus
     provides a clear DS3 interface.  For T1 interfaces an external multiplexer
     is required.  Product documentation is included.  Prices are in US $ and
     are exclusive of sales taxes.


      Annual            Prices              Prices
        Qty        MicroStar Plus      MicroStar Plus
                         DS3                 DS3
      Serial         with 9" CTS        with 11" CTS
                       antenna             antenna
       Links          Per link            Per link

                   [CONFIDENTIAL]

     2.2  Pricing methodology

     Pricing outlined in 2.1 are serial based for volumes achieve over a period
     of one year.


<PAGE>

                                                                         Annex A
                                                                          Page 4
                                       ANNEX A

                                       PRICING


                                 38 GHz, DS3 PRODUCTS

2.3 OPTIONS

2.31 CRAFT INTERFACE TOOL SOFTWARE

    A multi-Site lisence will be provided to ART at [CONFIDENTIAL].  Harris will
    support ART on this product.  AT installation technicians will get their
    support through ART as opposed to direct support from Harris.

2.4 DELIVERY

    Delivery of the MicroStar Plus DS3 will begin no later than Jan. 15, 1997

2.5 EXTENDED WARRANTY

    Annual Repair Service Program (per link) ......... $ [CONFIDENTIAL]

<PAGE>

                                       ANNEX B

                                MINIMUM PURCHASE GOALS

                             FOR YEAR 1 OF THIS AGREEMENT


                                  QUARTERLY FORECAST



- --------------------------------------------------------------------------------
         MONTH          MICROSTAR 38 GHz, 8T1         MICROSTAR 38 GHz, DS3
       1996/1997                LINKS                         LINKS
- --------------------------------------------------------------------------------

          Q1                      50
- --------------------------------------------------------------------------------
          Q2                      50
- --------------------------------------------------------------------------------
          Q3                      50                           140
- --------------------------------------------------------------------------------
          Q4                      50                           135
- --------------------------------------------------------------------------------

Total for 12 month period        200                           275
- --------------------------------------------------------------------------------

<PAGE>

                                       ANNEX C

                                   CUSTOMER SUPPORT

<PAGE>

CUSTOMER SUPPORT                                  [HARRIS FARINON DIVISION LOGO]
- --------------------------------------------------------------------------------

THE FOREGOING WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES WHETHER ORAL,
WRITTEN, EXPRESSED, IMPLIED, OR STATUTORY.  IN PARTICULAR, THE IMPLIED
WARRANTIES OF FITNESS FOR PARTICULAR PURPOSE AND MERCHANTABILITY ARE HEREBY
DISCLAIMED AND SHALL NOT BE APPLICABLE EITHER FROM HARRIS FARINON OR ANY OTHER
EQUIPMENT MANUFACTURER.  HARRIS FARINON'S WARRANTY OBLIGATIONS AND BUYER'S
REMEDIES THEREUNDER ARE SOLELY AND EXCLUSIVELY AS STATED HEREIN.  IN NO CASE
SHALL HARRIS FARINON BE LIABLE FOR INDIRECT KINDS OF DAMAGES, INCLUDING BUT NOT
LIMITED TO SPECIAL, INCIDENTAL, AND CONSEQUENTIAL DAMAGES, OR LOSS OF CAPITAL,
REVENUE, OR PROFITS.  IN NO EVENT SHALL HARRIS FARINON'S LIABILITY TO BUYER, OR
ANY PARTY CLAIMING THROUGH BUYER, BE IN EXCESS OF THE ACTUAL SALES PRICE PAID BY
BUYER FOR ANY ITEMS SUPPLIED HEREUNDER.

REPAIR & EXCHANGE WARRANTY

Harris Farinon's warranty policy is as follows:

Repair Warranty              90 days
Exchange Warranty            90 days

and/or the remainder of the original product warranty period, whichever is
greater.

SERVICES OFFERED

Technical assistance from highly qualified Product Support engineers to resolve
technical questions/problems on the phone.

Field Service support to resolve equipment problems on site by highly
professional Field Service engineers.

Repair of equipment at our Repair & Return facilities in a timely and cost-
effective manner.

24-Hour emergency telephone support by highly qualified Product Support
engineers for traffic affecting or traffic threatening problems.

24-Hour emergency shipment of replacement parts on selected items to minimize
downtime.

PRODUCT TRAINING BY HIGHLY QUALIFIED INSTRUCTORS THAT MAXIMIZES PRODUCT
PERFORMANCE AND MINIMIZES MAINTENANCE COSTS.

<PAGE>


                                           [HARRIS FARINON DIVISION LOGO] HARRIS
                                                 FARINON DIVISION

CUSTOMER SUPPORT
- ----------------------------------------------------------------------------

CUSTOMER RESOURCE CENTER

Our Customer Resource Center (CRC) is staffed with factory trained and highly 
qualified Product Support engineers whose task is to provide telephone 
support to resolve complex customer equipment problems quickly and accurately 
in a customer oriented manner. Customers who completed product training given 
by Harris Farinon and are equipped with proper test equipment and spare parts 
will experience quick resolution of their equipment problems. CALL CRC AND 
SELECT 1 WHEN PROMPTED.

24-HOUR TECHNICAL ASSISTANCE

Technical support is available 24 hours per day, seven days a week. Product 
Support Engineers are available in the USA from 6:30am to 5pm PST, Monday 
through Friday, and 7:30am to 5:00pm EST in Canada. At all other times, our 
Product Support Engineers will return your call within 30 minutes whenever 
you have traffic affecting or traffic threatening situations. In the USA, 
call us at 1-800-227-8332 (415-594-3800) or fax to 415-594-3659. In Canada, 
call 1-800-465-4654 (514-421-8333) or fax to 514-421-3555. Please provide us 
with the following information when you call us.

1.  Your name, company and telephone number.
2.  Equipment type and Sales Order # or FWL # found at the bottom of the rack.
3.  Detailed description of the problem.

REPAIR AND RETURN

Harris Farinon repairs all its manufactured products as well as coordinates 
repairs on vendor items which are part of its systems. The standard repair 
turn around time for current production models is 5 working days upon receipt 
of the defective parts.

Repair charges and turn around time for OEM (vendor) items are set by Harris 
Farinon suppliers. Our close working relationships with our suppliers assure 
us of the best repair prices and turn around time. CALL 1-800-227-8332, AND 
SELECT 2 WHEN PROMPTED (210-561-7420) OR FAX REQUEST TO 210-561-7421 OR FOR 
CANADA CALL 1-800-465-4654 AND SELECT 2 WHEN PROMPTED (514-421-8333) OR FAX 
REQUEST TO 514-421-3555.


                                                                            17


<PAGE>


                                           [HARRIS FARINON DIVISION LOGO] HARRIS
                                                 FARINON DIVISION

CUSTOMER SUPPORT
- ----------------------------------------------------------------------------

RETURN MATERIAL AUTHORIZATION

Before sending in your equipment for repair, please call us at 1-800-227-8332 
and select 2 when prompted for a Return Material Authorization (RMA) first or 
FAX your request to 210-561-7421 or for Quebec province call 1-800-465-4654 
and select 2 or FAX your request to 514-421-3555. This will ensure that the 
repairs will be done in a timely manner and eliminate any delays due to 
incomplete information. Please provide us with the following information when 
you call us.

1.  Your name, company and telephone number.
2.  Equipment type, part number, serial # and FWL number found at the bottom 
    of the rack
3.  Detailed description of the problem.
4.  Purchase order number.
5.  Billing and shipping addresses.
6.  Any special return packing or shipping instructions.
7.  Customs clearance information if from overseas.

MODULE EXCHANGE

You may prefer to receive a replacement unit before you send your defective 
unit to us. Harris Farinon maintains an inventory of many different modules 
that can be shipped to you within 24 hours. Harris maintains product 
inventory so it can provide module exchange within 24 Hrs.

Emergency exchange is available with a 24 hour turn-around for current 
production models. Emergency exchanges are billed at actual exchange prices 
(zero for warranty units) plus $[CONFIDENTIAL] per unit regardless of warranty 
status. [CONFIDENTIAL]

All exchanged units must be returned to us within 20 calendar days (DOMESTIC) /
45 calendar days (INTERNATIONAL) from date of shipment to avoid getting 
invoiced for the difference between the exchange price and the list price.

The returned unit must match the product specification of the advance 
exchange unit like for like. CALL 1-800-227-8332, AND SELECT 2 WHEN PROMPTED 
(210-561-7420) OR FAX REQUEST TO 210-561-7421 OR FOR CANADA CALL 
1-800-475-4654 AND SELECT 2 WHEN PROMPTED (514-421-8333) OR FAX REQUEST TO 
514-421-3555.


                                                                            18


<PAGE>


                                           [HARRIS FARINON DIVISION LOGO] HARRIS
                                                 FARINON DIVISION

CUSTOMER SUPPORT
- ----------------------------------------------------------------------------


RESTOCKING CHARGE

An incremental charge, calculated as a percentage of the current list price, 
is invoiced as per the following table for exchanged units returned later 
than the 20 calendar days (DOMESTIC) / 45 calendar days (INT'L) from date of 
shipment:

     ------------------------------------------------------------------
         1- 45 days overdue         15% charge
        46-120 days overdue         45% charge
         > 120 days overdue         No returns accepted. Invoice    
                                    difference between the exchange 
                                    price and the list price.
    --------------------------------------------------------------------

EMERGENCY REPAIR

Emergency repair is available with a 24 hour turn around time for products 
that are of current production. Emergency repairs are billed at actual repair 
price (zero for warranty units) plus $[CONFIDENTIAL] per unit regardless of 
warranty status. Our normal shipping time is 4:00 PM unless special shipping 
instructions are requested. [CONFIDENTIAL]

EQUIPMENT DAMAGED DURING SHIPMENT

PLEASE CHECK FOR SHIPPING DAMAGE WHEN YOUR EQUIPMENT IS RECEIVED.

Inspect all cartons at the time of delivery. Visible damage should be brought 
to the attention of the carrier at once. In the event of concealed damage, 
keep the shipping container, packing material and equipment intact. It is 
your responsibility to file any claims for damage or loss with the carrier.

After the carrier has inspected the damaged material, contact Harris' Repair 
Administration Department to obtain a return authorization, then return the 
damaged equipment to Harris. Once repair costs including any and all 
associated freight costs have been established, you will be advised and these 
charges may be included in your claim. Harris will make every effort to 
expedite replacement of damaged goods that are the result of shipping damage.


                                                                            19


<PAGE>
                                           [HARRIS FARINON DIVISION LOGO] HARRIS
                                                 FARINON DIVISION

CUSTOMER SUPPORT
- ----------------------------------------------------------------------------

EVALUATION FEE

There is a $[CONFIDENTIAL] evaluation charge per unit if no problem is found 
and no repair is required. The evaluation fee will not be applied for 
warranty repairs.

NON-REPAIRABLE UNITS

Equipment which has been damaged due to customer negligence or which has 
parts removed will be repaired at prevailing flat repair fee or on a time and 
material basis whichever is higher regardless of the warranty status. Any 
equipment that is determined non-repairable will be returned to the customer. 
A $[CONFIDENTIAL] evaluation fee will be assessed. This fee will be credited 
if the customer purchase a replacement unit within 30 days.

RETURN FLIGHT

Harris Farinon prepays standard return freight back to our customers. Return 
freight back to customers on billable repairs is invoiced to the customers. A 
$[CONFIDENTIAL] handling charge is added in excess of freight charges for 
international shipments.

In-coming shipments should be sent DDU (delivered duty unpaid). Outgoing 
shipments will be sent EXW (EX Works). Service Center locations.

Customers are responsible for clearance and insurance of goods (except 
USA/Canada custom clearance).

The customer pays for shipping units to Harris Farinon for both warranty and 
out-of warranty repairs. Harris does not accept inbound shipments that are 
C.O.D. Special shipping requests may be subject to additional charge.

PLEASE MAKE SURE TO PACK THE UNIT IN SUCH A WAY AS TO PREVENT ELECTROSTATIC 
DISCHARGE AND PHYSICAL DAMAGE IN TRANSIT.

                                                                            20
<PAGE>
                                                 [HARRIS FARINON DIVISION LOGO]

CUSTOMER SUPPORT


ON-SITE FIELD SERVICE REPAIR

Harris Farinon factory trained Field Service engineers are available to 
perform on-site repairs on an as needed basis when telephone assistance can 
not be effectively rendered. The rate is $[CONFIDENTIAL] per hour portal to 
portal plus actual travel expenses with 20% mark-up (airline tickets, rental 
car, meals, lodging, etc.). Field service request during weekends and 
holidays will be billed at $[CONFIDENTIAL] per hour portal to portal.  All 
request for on-site assistance should be made to Customer Resource Center.  
Call the Customer Resource Center nearest you.

CUSTOMER TRAINING

Harris Farinon offers courses in microwave, lightwave and multiplex system 
operation designed to maximize product performance and minimize maintenance 
costs. Regular classes are held in our Redwood Shores, CA and 
Dollard-des-Ormteaux, Canada facilities. Special classes can be held at 
customer sites. Training is available for standard products. All other 
training requirements must be quoted by the Customer Training Department.

PRICES

Regular Scheduled Class at Harris      
Special Class at Harris                
Special Class at Customer Site (USA)   [CONFIDENTIAL]
Special Class at Customer Site         
(International)                        

*Farscan classes for six students maximum

ANNUAL REPAIR SERVICE PROGRAM (ARSP)

Our ARSP service will assure you that all your repairs will be covered for a 
minimal fee paid up front. Repairs will be processed immediately and 
unexpected large repair expenses will be avoided. Only Harris Farinon 
manufactured units are covered by the Annual Repair Service Program and the
antenna system as well as OEM equipment like the channel banks are excluded.
This warranty extension excludes any units deemed "irreparable" due to misuse 
or abuse of the units. Equipment must be in good operating condition prior to 
purchasing an annual repair service.

                                                                             21

<PAGE>

CUSTOMER SUPPORT                                  [HARRIS FARINON DIVISION LOGO]


SERVICE LOCATIONS

Our customer service representatives will ask you to ship your defective 
units after the RMA is given to you in one of the following locations:

Harris Farinon Division                    Harris Farinon Division
330 Twin Dolphin Drive                     5727 Farinon Drive
Redwood Shores, CA 94065-1421, USA         San Antonio, TX 78249, USA
Phone: 1-800-227-8332 or 415-594-3800      Phone: 1-800-227-8332 or 
                                           210-561-7420
Fax: 415-594-3621                          Fax: 210-561-7421

Harris Farinon Canada
3 Hotel-de-Ville
Dollard-des-Ormeaux, Quebec
Canada H9B 3G4
Phone: 1-800-465-4654 or 514-421-8333
Fax: 514-421-3555
Telex: 05-821893

                                                                             22

<PAGE>

[HARRIS FARINON DIVISION LOGO]


 HARRIS FARINON DIVISION & ADVANCED RADIO TELECOM
                    AGREEMENT ON
                      PUBLICITY

Pursuant to the PCS Marketing Agreement and Purchase Agreement between 
Advanced Radio Telecom Corporation and Harris Corporation, Farinon Division, 
signed on April 26, 1996; both parties agree that each party shall consult 
with the other before issuing any press release or otherwise making any 
statements to third parties with respect to the above agreements or the 
transactions and relationships contemplated in these agreements and shall not 
issue any press release or make any such statements prior to obtaining the 
written consent of the other party, which consent shall not be unreasonably 
withheld.



ADVANCED RADIO TELECOM CORPORATION

BY: /s/ Charles Menath
   -------------------------------
NAME:  Charles Menath
     -----------------------------
TITLE: V.P. Bus. Development
      ----------------------------

HARRIS CORPORATION, FARINON DIVISION

BY: /s/ J. Michael Slattery
   -------------------------------
NAME: J. Michael Slattery
      ----------------------------
TITLE: Division Controller
      ----------------------------




<PAGE>

                            CS MARKETING AGREEMENT

THIS PCS MARKETING AGREEMENT ("Agreement") is entered into as of the 26th day 
of April, 1996 by and between Advanced Radio Telecom Corporation, a Delaware 
corporation with offices located at 500 108th Avenue NE, Suite 2600, 
Bellevue, WA 98006 ("ART") and Harris Corporation. Farinon Division, a 
Delaware corporation, with offices located at 330 Twin Dolphin Drive, Redwood 
Shores, CA 94065 ("Harris").

WHEREAS ART and Harris wish to develop new business opportunities in the 
emerging Personal Communications Services ("PCS") marketplace for the 
provision of both 38 GHz services and equipment; and

WHEREAS ART has acquired authorizations at 38GHz in certain markets in the 
United States; and

WHEREAS Harris desires to include ART's 38GHz services Right-of-Use of its 38 
GHz frequencies and associated coordination services as well as installation 
and network monitoring, field services in conjunction with its sales of 38GHz 
equipment to the PCS marketplace;

WHEREAS Harris desires, as a secondary approach to direct sales of its 
microwave radio to promote ART's leased services to the PCS market.

NOW THEREFORE, in consideration of the premises and the mutual 
representations, warranties, covenants and agreements hereinafter set forth. 
ART and Harris, intending to be legally bound, hereby agree as follows:

1.0     EFFECTIVE DATE: RELATED SUPPLY AGREEMENT.  The Effective Date of this 
Agreement shall be the date of execution by the parties provided, however, 
that the rights and obligations of the parties hereunder shall not become 
effective unless and until the parties have executed a definitive supply 
agreement ("Purchase Agreement") for 38 GHz equipment as contemplated by 
Version 2 of a Letter of Intent executed by ART and Harris and dated February 
22, 1996.

2.0     TERM OF AGREEMENT, RENEWAL AND TERMINATION.  Subject to the 
provisions of Section 1.0 hereof, the term of this Agreement begins on the 
Effective Date and shall continue in effect for one (1) year from the 
Effective Date ("Initial Term"). The Agreement shall automatically renew 
after the Initial Term for successive periods of one (1) year (each 
successive period a "Renewal Term") unless one of the parties gives written 
notice not to renew no later than sixty (60) days prior to the scheduled date 
of expiration of the Initial Term or any subsequent Renewal Term. The parties 
acknowledge and agree that failure of either party to give notice of 
termination shall give rise to a conclusive presumption that the Agreement is 
to be renewed pursuant to this Section 2.0. A party may terminate this 
agreement:

     (a)  upon notice in writing delivered to the other party, in the event 
that the other party breaches any material term, condition or covenant hereof 
if the other party fails to cure any default or breach within thirty (30) 
days of receipt of written notice of such breach from the non-breaching party;
<PAGE>

     (b) upon notice in writing delivered to the other party, in the event 
that the other party breaches any material term, condition or covenant of the 
Purchase Agreement referenced in Section 1.0 above and the other party fails 
to cure any default or breach within thirty (30) days of receipt of written 
notice of such breach from the non-breaching party; or

    (c) upon notice in writing delivered to the other party in the event that 
the other party has caused the Purchase Agreement referenced in Section 1.0 
above to be terminated; or

    (d) at any time by providing ninety (90) days written notice to the other 
party.

    2.1 PROVISIONS OF TERMINATION FOR OPERATING FREQUENCIES: in the event of 
termination of this agreement under the terms and conditions outlined in 
section 2.0 all Right of Use of ART's frequencies purchased from Harris prior 
the effective date of the termination shall remain in effect for the time 
period agreed in section 3.0. Harris agrees, for the remaining period that 
the Right of Use is in effect, to pay to ART the annual coordination fees 
specified in section 5.2.

3.0 RIGHTS GRANTED TO HARRIS. During the Initial Term and any Renewal Term of 
this Agreement and subject to the terms and conditions of this Agreement, ART 
hereby grants to Harris a non-transferable non-exclusive right to use ("Right 
of Use") 38 GHz authorizations which ART owns or otherwise controls for a 
period not exceeding 10 years (as shown in Exhibit A attached hereto). Not 
withstanding the forgoing Harris may transfers to the PCS End User the rights 
contained in this paragraph provided that the PCS End User agrees in writing 
to the terms and conditions of this agreement that are applicable to it. The 
Right of Use granted to Harris hereunder shall be limited to Harris's 38 GHz 
equipment sales to the PCS market. Harris covenants and agrees that, during 
the term of this Agreement, it will not offer or promote alternate 38 GHz T1 
leased services from any other provider of 38 GHz service to any PCS accounts 
identified in Exhibit B hereto. In consideration for the grant of the Right 
of Use, Harris shall pay ART the fees identified in Section 5.1 hereof.

    3.1 COVENANT WITH RESPECT TO RIGHT OF USE. ART covenants and agrees to 
take all necessary action to comply with FCC rules and regulations governing 
the Right of Use granted to Harris hereunder. ART shall be responsible for 
resolving all regulatory and channel conflict issues concerning the Right of 
Use.

4.0 SERVICES PROVIDED BY ART.

   4.1 FREQUENCY COORDINATION. In addition to the Rights of Use granted to 
Harris under Section 3.0 hereof, ART shall also provide Harris with channel 
conflict assessment services ("Frequency Coordination") for links sold by 
Harris to the PCS market. Harris shall notify ART at least 15 working days 
prior to each shipment made under this agreement, and ART shall be solely 
responsible for Frequency Coordination and provide to Harris the frequency 
assignment within 5 business days of Harris notification to ART, including 
the assignment of the frequency to be used by the end-user and avoidance of 
channel conflicts. In consideration for these services, Harris shall pay ART 
the fees identified in Section 5.2 hereof.

   4.2 INSTALLATION AND NETWORKING MONITORING, FIELD SERVICE/RESTORAL. In 
addition to the Rights of Use granted to Harris under Section 3.0 hereof, ART 
shall also provide Harris installation and network monitoring field 
service/restoral services as defined in Exhibit E and Exhibit F, respectively 
hereto. In connection with the provision of such network monitoring, field 
service/ restoral and installation services. Harris shall provide ART with 
installation and workmanship standards training, as identified in Exhibit D 
hereto, at no charge to ART.


                                                2

<PAGE>

    4.3 LIMITED WARRANTY: ART warrants that the installation, Network 
Monitoring and Field Service/Restoral services to be provided by ART pursuant 
to this Agreement will be performed in a good and substantial workmanlike 
manner in accordance with the performance requirements hereunder, generally 
prescribed industry standards and when applicable, in accordance with 
manufacturers instructions and specifications. The warranty granted under 
Section 4.3 with respect to ART's Installation services shall be for a period 
of one (1) year from the date of Installation of any equipment.

    4.4 LIMITATION OF LIABILITY: OTHER THAN AS SET FORTH IN SECTION 4.3 
HEREIN. ART MAKES NO WARRANTIES OF ANY KIND WITH RESPECT TO THIS AGREEMENT 
WHETHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES 
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR CONFORMITY TO ANY 
REPRESENTATION OR DESCRIPTION, EXCEPT FOR CREDITS FOR OUTAGES AS DESCRIBED IN 
SECTION 11, ART SHALL NOT BE LIABLE FOR ANY CLAIM OF ANY KIND. INCLUDING, BUT 
NOT LIMITED TO ACTIONS, DAMAGES, DEMANDS JUDGMENTS, LOSSES, COSTS, EXPENSES, 
LIABILITIES, AND LOSS OF MONIES ARISING OUT OF THIS AGREEMENT OR THE 
PERFORMANCE THEREOF, WHETHER BASED ON CONTRACT, WARRANTY, TORT INCLUDING 
NEGLIGENCE, MISTAKE, ERROR, MISCONDUCT, INTERRUPTION, DELAY, DEFECT OR 
OTHERWISE OF ART, ITS EMPLOYEES, AGENTS, CONTRACTORS, OR SUB-CONTRACTORS, OR 
AFFILIATED COMPANIES, INCLUDING BUT NOT LIMITED TO SPECIAL INCIDENTAL, 
CONSEQUENTIAL, INDIRECT, EXEMPLARY OR PUNITIVE DAMAGES, LOSS OF REVENUE OR 
PROFIT, LOSS OF USE OF ANY PROPERTY, COST OF SUBSTITUTE PERFORMANCE, 
EQUIPMENT OR SERVICES, COST OF CAPITAL DOWNTIME COSTS AND CLAIMS OF THE 
CUSTOMER FOR DAMAGES.

    4.5 EFFECT OF TARIFFS: SERVICES SHALL BE PROVIDED BY ART TO HARRIS 
PURSUANT TO THE TERMS AND CONDITIONS SET FORTH HEREIN, AND IN THE APPLICABLE 
TARIFFS ON FILE WITH THE FEDERAL COMMUNICATIONS COMMISSION AND RELEVANT STATE 
UTILITY COMMISSIONS. THE TERMS AND CONDITIONS OF THOSE TARIFFS, AS AMENDED 
FROM TIME TO TIME, CONTROL THE PARTIES OBLIGATIONS NOTWITHSTANDING ANYTHING 
TO THE CONTRARY HEREIN.

5.0 FEES.

    5.1 INITIAL RIGHT OF USE FEE. Harris shall pay ART the following fee for 
every link sold with ART's 38 GHz frequency channels. Such fees shall be due 
and payable to ART within thirty (30) days of the date of receipt of invoice.


                        TABLE 1

ANNUAL QUANTITY PURCHASED     RIGHT OF USE FEE
   LICENSES-LINKS                 PER LINK
- -------------------------     -----------------


                  [CONFIDENTIAL]

                                                3

<PAGE>

    5.2 FREQUENCY COORDINATION FEE. Harris shall pay ART an annual fee of 
($[CONFIDENTIAL]) per link sold pursuant to this Agreement in consideration 
for ART's provision of Frequency Coordination services to PCS service 
providers who have purchased links from Harris. Such fees shall be due and 
payable to ART within thirty (30) days of the beginning of each service year 
applicable to each link. In order to facilitate the administration of the 
annual fees, on large accounts a specific annual service date for all links 
within their networks can be negotiated.

    5.3 INSTALLATION FEES: Harris shall pay ART the fees identified in table 
2 for each installation (as defined in the Exhibit E). ART shall bill Harris 
promptly following completion of an Installation, and such fees shall be due 
and payable to ART within 30 days of receipt of invoice.

    5.4 NETWORK MONITORING AND FIELD SERVICE/RESTORAL FEE: Fees for Network 
Monitoring services are identified in Table 3. Harris shall pay ART the fees 
identified in table 3 for each link (as defined in the Exhibit F), shall be 
billed to Harris on a monthly basis and are due and payable to ART within 
thirty (30) days of receipt of invoice. Cancellation fee of Network 
Monitoring services shall be payment up to the next anniversary date of this 
agreement, due thirty (30) days after such anniversary date. Field 
Service/Restoral will be based on links performance. A rate of $[CONFIDENTIAL]
Man Day plus materials will charged for Field Services/Restoral services. 
Minimum charge of one (1) "Man Day) should Field service/Restoral be 
requested.

    5.4 LIMITATIONS ON ART'S OBLIGATION TO MAINTAIN AND RESTORE. ART's 
obligations exclude each of the following: (i) Service, maintenance or 
restoral that would be unsafe or impractical because of alterations to the 
Equipment not approved by ART, or its connection to equipment or devices not 
furnished or approved by ART or which connection would for any reason render 
Service impossible; (ii) Service, maintenance or restoral involving Equipment 
located in an unsafe or hazardous environment; (iii) Service that cannot be 
restored because of elements external to the Equipment and not under the 
control of ART, including, but not limited to, adverse environmental 
conditions or inadequate power that are not within the manufacturer's or 
ART's specifications; (iv) maintenance or restoral resulting from any 
accident, neglect, alterations, improper use or misuse of the Equipment by 
personnel not under the control of ART; (v) maintenance or restoral in 
connection with relocation of any of the Equipment not approved by ART, and 
(vi) the inability of ART to access the premises of Harris or the Customer in 
order to perform maintenance and repair due to limitations or restrictions 
imposed by Harris or the Customer.





             TABLE 2-INSTALLATION FEE

    ANNUAL QUANTITY           INSTALLATION FEE
    INSTALLED LINKS               PER LINK
- -------------------------     -----------------

                  [CONFIDENTIAL]

                                                4

<PAGE>

   TABLE 3-MONTHLY NETWORK MONITORING FEE

   ANNUAL QUANTITY              FEE PER LINK
   INSTALLED LINKS                PER MONTH
- -------------------------     -----------------


                   [CONFIDENTIAL]


    5.5 PAYMENT TERMS. All payments due to ART hereunder shall be sent to 
ART's Bellevue office or to the address identified on the applicable invoice. 
In addition to any other remedies available to it. ART may impose, without 
further notice to Harris, a late payment charge of one and one-half percent 
(1.5%) per month (but not in excess of the lawful maximum) on any past due 
amounts. Harris also agrees that it shall pay all costs, including reasonable 
attorneys' fees, expended in collecting past due amounts.

6.0 BETA TRIALS. ART shall provide Harris Rights of Use and Frequency 
Coordination Services for a period of sixty (60) days without any obligation 
of Harris to pay a Rights of Use fee for the frequency channels solely for 
the purpose of conducting two (2) BETA trials, with each trial consisting of 
one Harris client and one link. The specific location of these trials shall 
be subject to the mutual agreement of ART and Harris. All costs associated 
with installation including but not limited to, site specific equipment and 
materials and field service during the BETA trial period shall be borne by 
Harris. ART shall bear its own personnel and travel-related costs associated 
with the site survey and installation in connection with the two BETA trials.

7.0 SALES FORECAST: Harris shall provide ART with 38 GHz radio link sales 
forecasts, which shall serve as a basis to establish pricing levels outlined 
in section 5.1. Harris' initial forecast is attached hereto as Exhibit C 
Unless otherwise agreed by the parties, future forecasts shall be provided by 
Harris on a quarterly basis.

8.0 RELATIONSHIP OF THE PARTIES: NO AGENCY OR PARTNERSHIP. Each party is an 
independent business entity and will perform its obligations hereunder as an 
independent contractor. It is agreed and understood that neither party is an 
agent, employee or legal representative of the other, and has no authority to 
bind the other in any way. Nothing in this Agreement shall be deemed to 
constitute ART and Harris as partners, joint ventures, or otherwise 
associated in or with the business of the other, and neither party shall be 
liable for the debts, accounts, obligations or other liabilities of the other 
party, its agents or employees. Neither party is authorized to incur debts or 
other obligations of any kind on the part of or as agent for the other except 
as may be specifically authorized herein.

9.0 INTELLECTUAL PROPERTY. Except as may be expressly authorized by this 
Agreement or by separate written agreement between the parties, nothing 
herein shall grant either party a license to use the trademarks, service 
marks or trade names of the other party, its affiliates and/or suppliers or 
licensers. All intellectual property shall remain the exclusive property of 
the party owning or controlling such intellectual property.


                                                5
<PAGE>

10.0 CONFIDENTIALLY AND NON-DISCLOSURE. In connection with this Agreement, 
each party may disclose or otherwise make available certain data or 
information to the other party, which data or information the disclosing 
party considers to be confidential and proprietary. As used herein, 
""Confidential Information,'' means any non-public information, including 
customer and vendor lists, business plans and proposals, financial 
information, marketing information, problem solving methods, implementation 
steps, know-how, technology, trade secrets and drawings and renderings 
related to each party's ongoing and proposed businesses, products and 
services (including installation and training services) which is being 
provided or which has been provided to the receiving party by the disclosing 
party, or which is obtained by the receiving party from its meetings and 
contacts with the disclosing party, or any information derived by receiving 
party from information so provided or obtained. Confidential Information 
includes all written or electronically recorded materials identified and 
marked as confidential or proprietary or which on their face appear to be 
confidential or proprietary, and oral disclosures of Confidential Information 
by the

disclosing party which are identified as confidential or proprietary at the 
time of such oral disclosure. Confidential Information does not include any 
of the following: (a) information that is in or becomes part of the public 
domain without violation of this Agreement by the receiving party; (b) 
information that was known to or in the possession of the receiving party on 
a non-confidential basis prior to the disclosure thereof to the receiving 
party by the disclosing party; (c) information that was developed 
independently by the receiving party's employees, which employees have had no 
access to the Confidential Information; (d) information that is disclosed to 
the receiving party by a third party under no obligation of confidentiality 
to the disclosing party and without violation of this Agreement by the 
receiving party; or, (e) is authorized by the disclosing party in writing for 
disclosure or release by the receiving party. The parties agree: (a) to treat 
and keep as confidential and proprietary all Confidential Information 
disclosed by the other party; (b) to advise each employee to whom any 
Confidential Information is to be made available of the confidential nature 
of such Confidential Information and of the terms of this Agreement; (c) to 
promptly return to the disclosing party (or its designees), upon the 
disclosing party's request, all Confidential Information and all copies 
thereof. The receiving party shall have discharged its obligation to 
safeguard the Confidential Information received hereunder only if it has 
exercised the same degree of care as it uses to protect its own proprietary 
information of like importance.

11.0 INDEMNIFICATION.

    11.1 INDEMNIFICATION OF ART BY HARRIS. Harris shall indemnify ART 
against, and hold ART harmless from all liabilities, demands, claims, 
damages, losses, demands, costs, judgments and expenses (including reasonable 
attorneys' fees) arising out of or in connection with this Agreement for 
personal injury or damage to tangible property, or in connection with the use 
or exercise by Harris of the Right of Use, caused by the negligent acts or 
willful omissions of Harris or Harris's employees, agents or invitees. In no 
event shall ART's employees, agents or invitees be deemed to be employees, 
agents or invitees of Harris.

    11.2 INDEMNIFICATION OF HARRIS BY ART. ART shall indemnify Harris against 
and hold Harris harmless from all liabilities, demands, claims, damages, 
losses, demands, costs, judgments and expenses (including reasonable 
attorneys' fees) arising out of or in connection with this Agreement for 
personal injury or damage to tangible property, or in connection with the use 
or exercise by Harris of the Right of Use, caused by the negligent acts or 
willful omissions of ART or ART's employees, agents or invitees. In no event 
shall Harris's employees, agents or invitees be deemed to be employees, 
agents or invitees of ART.


                                                6

<PAGE>

    11.3 DUTY TO NOTIFY AND ASSIST. If any claim arises to which the 
provisions of this Section may be applicable, the party against whom such 
claim is made shall notify the other party immediately upon learning of the 
claim. If it appears that the other party may be obligated to provide 
indemnification as a result of such claim, the other party, in its 
discretion, may settle or compromise the claim or retain counsel of its own 
choosing and control and prosecute the defense against such claim. In no 
event shall the party against whom the claim is asserted have the right to 
pay, settle or compromise such claim without the prior written consent of the 
party who may be obligated to indemnify under this Section, and the parties 
hereto agree that they will not unreasonably withhold consent to such consent 
to payment, settlement or compromise. The party against whom the claim is 
asserted shall provide the other party such assistance as may be reasonable 
in the defense and disposition of such claim.

NOTICES. All notices, demands or other communications which are required or 
may be given under this Agreement shall be given or made in writing, and 
shall be delivered personally or by overnight air courier or first class 
certified or registered mail, return receipt requested and postage prepaid to 
the persons and addresses listed below, or to such other persons and/or 
address as the party to whom notice is to be given has furnished to the other 
party. Each such notice, demand or other communication shall, simultaneously 
with its being delivered to the courier or messenger for delivery or placed 
in the mail, be sent by facsimile or comparable electronic means. All notices 
and other communications hereunder shall be deemed to have been given: (a) on 
the date of delivery if personally delivered or, if not delivered on a 
business day, the first business day thereafter; (b) on the first business 
day after the date sent if sent by overnight air courier; or (c) on the fifth 
business day after the date sent if sent by mail.

If to ART:                   If to Harris:
Steven D. Comne              Don Fenn
President                    Contracts Manager
500-108th Ave NE, Ste 2600   330 Twin Dolphin Drive
Bellevue, WA 98004           Redwood Shores, CA 94065
206-688-8700                 415-594-3000

Copy to:
W. Theodore Pierson, Jr.
Executive Vice President and General Counsel
1667 K Street, NW, Ste 801
Washington, DC 20006
202-466-5278


13.0 SURVIVAL. It is expressly agreed that the provisions of Sections 5, 10, 
11, 12, 17 and 18 shall survive any termination of this Agreement and shall 
be and remain valid, binding and enforceable after any such termination 
according to their terms.


14.0 ASSIGNMENT; BINDING EFFECT. Neither party shall assign or transfer any 
of its rights or obligations hereunder without the prior written consent of 
the other party hereto. Any attempted assignment without written consent will 
be void. This Agreement shall inure to the benefit of and shall be binding 
upon the successors and assigns of the parties.


15.0 SEVERABILITY. If any portion of this Agreement is held to be invalid by 
a court of competent jurisdiction, that provision shall become ineffective 
and unenforceable. The parties agree that such invalidity shall not affect 
the validity of the remaining portions of this Agreement, and further agree 
to substitute for the invalid provision a valid provision that most closely 
approximates the effect and intent of the invalid provision.


                                                7

<PAGE>

16.0 FORCE MAJEURE: NEITHER PARTY SHALL BE LIABLE FOR DELAYS IN PERFORMANCE 
OR FAILURE TO PERFORM. THIS AGREEMENT OR ANY OBLIGATIONS HEREUNDER, WHICH ARE 
ATTRIBUTABLE TO CAUSES BEYOND ITS REASONABLE CONTROL, INCLUDING BUT NOT 
LIMITED TO FIRE, FLOOD, EPIDEMIC, EARTHQUAKE, ENVIRONMENTAL DAMAGE, ACT OF 
GOD, LIGHTNING, PUBLIC POWER FAILURE OR SURGE, EXPLOSION, STRIKE OR OTHER 
LABOR DISPUTE, RIOT OR CIVIL DISTURBANCE, WAR OR ARMED CONFLICT, OR OTHER 
GOVERNMENTAL ORDER OR REGULATION, OR ORDER OF ANY COURT OF COMPETENT 
JURISDICTION, OR ANY OTHER SIMILAR OCCURRENCE NOT WITHIN ITS CONTROL.

17.0 GOVERNING LAW. The parties agree that this Agreement shall be 
interpreted and construed both as to performance and validity in accordance 
with and governed by the laws of the domestic laws of the State of Washington 
even if its choice of law provisions are in conflict with this requirement.

18.0 DISPUTE RESOLUTION; ARBITRATION. The parties agree that all disputes, 
claims or controversies between them arising out of or relating to this 
Agreement, and only if good faith attempt at resolution between parties 
fails, shall be settled by arbitration in accordance with the rules of the 
American Arbitration Association. Decisions of the arbitration panel shall be 
based upon Washington State law, and the site of such arbitration shall be in 
King County, Washington. The arbitration panel shall consist of three 
arbitrators, one arbitrator to be selected by each party and the third 
arbitrator to be selected by the other two arbitrators. Any decision rendered 
by the arbitration panel pursuant to this provision shall be concurred in by 
a majority of the members of the panel. Judgment may be entered by any court 
of competent jurisdiction. Arbitration pursuant to this section shall be the 
exclusive means of resolving any dispute, claim or controversy arising 
hereunder. Each party shall bear its own costs, including attorneys' fees, in 
connection with any proceeding brought under this Section.

19.0 REGULATORY APPROVAL. The rights and obligations of the parties hereunder 
are subject to any regulatory approvals which may be required, and this 
Agreement may be terminated by either party if any governmental or regulatory 
agency imposes rules or regulations affecting the relationship between the 
parties in a material way.

20.0 WAIVER OF BREACH. The failure to enforce or to require the performance 
at any time of any of the provisions of this Agreement by a party shall not 
be construed to be a waiver of any other provisions by that party, and shall 
not affect either the validity of this Agreement or any part hereof or the 
right of any party thereafter to enforce each and every provision of this 
Agreement.

21.0 EXECUTION IN COUNTERPARTS. This Agreement may be executed in any number 
of counterparts, each of which shall, when executed, be deemed to be an 
original, but all of which together shall constitute one and the same 
instrument.

22.0 PUBLICITY. Each party shall consult with the other before issuing any 
press release or otherwise making any statements to third parties with 
respect to this Agreement or the transactions and relationships contemplated 
hereby and shall not issue any press release or make any such statements 
prior to obtaining the written consent of the other party, which consent 
shall not be unreasonably withheld.

23.0 SECTION HEADINGS. The section and sub-section headings contained herein 
are for reference purposes only and shall not affect in any way the meaning 
or interpretation of any provision of this Agreement.


                                                8

<PAGE>

24.0 AUTHORITY. Each party represents and warrants that it has full power and 
authority to enter into and perform under this Agreement and that its 
delivery of this Agreement has been duly authorized by all necessary 
corporate or other action and that the person signing the Agreement on its 
behalf is duly authorized to do so. Each party further acknowledges that it 
has read and understands this Agreement and agrees to be bound by all of its 
terms, conditions and provisions.

25.0 ENTIRE AGREEMENT; MODIFICATION. This Agreement and all Exhibits, 
Appendices and Attachments hereto constitutes the entire agreement between 
the parties and supersedes all prior representations, agreements, 
understandings and arrangements, oral or written, between the parties with 
respect to the subject matter hereof. All Recitals, Background and Statements 
of Purpose are expressly excluded from this Agreement. This Agreement 
allocates the risks of loss among the parties, which allocation is reflected 
in the charges and terms and conditions set forth herein. This Agreement may 
not be released, discharged, amended or modified in any way except by a 
writing that expressly refers to this Agreement and is executed by all 
parties hereto IN WITNESS WHEREOF, the parties have duly executed this 
Agreement as of the date first above written.

Advance Radio Telecom Corporation            Harris Corporation


By: /s/ Charles Menath                       By: /s/ J. Michael Slattery
   --------------------------                   ---------------------------
Print                                        Print
Name: Charles Menath                         Name: J. Michael Slattery
     ------------------------                     -------------------------
Title: V.P. Bus. Development                 Title: Division Controller
      -----------------------                      ------------------------


                                                9
<PAGE>

                PCS MARKETING AGREEMENT
                 BETWEEN ART AND HARRIS
                    LIST OF EXHIBITS

Exhibit A    List of Authorizations under ART's Control at 38 GHz.

Exhibit B    List of Harris PCS Target Accounts.

Exhibit C    Harris Sales Forecast.

Exhibit D    Outline of Harris Training on Installation and Workmanship
             Standards.

Exhibit E    Definition of ART's Installation Services, Procedures and Schedule.

Exhibit F    Definition of ART's Network Monitoring Services and Procedures.


                                                10

<PAGE>

                             Exhibit A

          LIST OF AUTHORIZATION UNDER ART'S CONTROL AT 38GHZ


    MARKET                  CHANNELS      
    ------                  --------
1   Albany                  13            NY
2   Albany                  1,14          NY
3   Albuquerque             2             NM
4   Allentown               1,14          PA
5   Altoona                 1,14          PA
6   Anchorage               2             AK
7   Altanta                 1             GA
8   Austin                  2             TX
9   Baltimore               6             MD
10  Baltimore               1,14          MD
11  Baton Rouge             2             LA
12  Billings                1             MT
13  Binghamton              1,14          NY
14  Birmingham              4             AL
15  Boston (No.)            1,14          MA
16  Boston (So.)            1,14          MA
17  Bridgeport              1,14          NH
18  Buffalo                 10            NY
19  Buffalo                 1,14          NY
20  Canton                  2             OH
21  Charleston              4             SC
22  Charleston              1             WV
23  Chicago                 1             IL
24  Cincinnati              6             OH
25  Cleveland               1             OH
26  Columbus                6             OH
27  Corning                 1,14          NY
28  Dallas                  1             TX
29  Dayton                  6             OH
30  Denver                  1             CO
31  Des Moines              5             IA
32  Eugene                  3             OR
33  Eureka                  4             CA
34  Fairbanks               4             AK
35  Grand Rapids            7             MI
36  Greensboro              14            NC
37  Harris                  1,14          PA
38  Hartford                2             CT
39  Hartford                1,14          CT


                                                11

<PAGE>

                                  EXHIBIT A
                                   Page 2

40  Honolulu                4             HI
41  Houston                 1             TX
42  Huntington              2             WV
43  Indianapolis            2             IN
44  Jackson                 4             MS
45  Jackson                 14            MS
46  Juneau                  6             AK
47  Kansas City             1             MO
48  Kingston                1,14          NY
49  Knoxville               8             TN
50  Las Vegas               4             NV
51  Lincoln                 4             NE
52  Lorain                  1             OH
53  Louisville              6             KY
54  Madison                 2             WI
55  Memphis                 2             TN
56  Miami                   1             FL
57  Minneapolis             6             MN
58  Mobile                  8             AL
59  Nashville               12            TN
60  New Orleans             1             LA
61  New York - Long Island  1,14          NY
62  New York (Manhattan)    13            NY
63  New York (North)        1,14          NY
64  New York (South)        1,14          NY
65  Newark North            1,14          NJ
66  Newark South            1,14          NJ
67  Norfolk                 4             VA
68  Oklahoma City           1             OK
69  Ogden                   4             UT
70  Pensacola               3             FL
71  Philadelphia            1,14          PA
72  Phoenix                 1             AZ
73  Pittsburgh              1,14          PA
74  Portland                2             OR
75  Providence              1,14          RI
76  Reno                    1             NV
77  Richmond                4             VA
78  Rochester               2             NY
79  Rochester               1,14          NY


                                                12

<PAGE>

                                  EXHIBIT A
                                   Page 3

80  Sacramento              9             CA
81  Salt Lake City          1             UT
82  San Antonio             11            TX
83  San Diego               5             CA
84  San Jose                9             CA
85  Scranton                3             PA
86  Scranton                1,14          PA
87  Seattle                 1             WA
88  Shreveport              1             LA
89  Spokane                 4             WA
90  Springfield             1,14          MA
91  St. Louis               1             MO
92  Stamford                1,14          CT
93  Syracuse                1,14          NY
94  Tacoma                  1             WA
95  Trenton                 1,14          NJ
96  Tucson                  1             AZ
97  Utica-Rome              1,14          NY
98  Washington              6             DC
99  Washington              1,14          DC
100 White                   1,14          NY
101 Wichita                 3             KS
102 Wilmington              3             DE
103 Wilmington              1,14          DE
104 Worcester               1,14          MA
105 York                    1             PA


                                                13
<PAGE>

           EXHIBIT B
LIST OF HARRIS PCS TARGET ACCOUNTS
- ----------------------------------

1.        [CONFIDENTIAL]

2.

3.

4.

5.


                                                14

<PAGE>

           EXHIBIT C
     HARRIS SALES FORECAST
     ---------------------

           LINKS

1.     [CONFIDENTIAL]

2.

3.

4.

5.
    ______________________

          Total


                                                15

<PAGE>

                                  EXHIBIT D

     OUTLINE OF HARRIS TRAINING ON INSTALLATION AND WORKMANSHIP STANDARDS
     --------------------------------------------------------------------

COURSE NO:      VID-MIC-01

COURSE TITLE:   MICROSTAR[cad 176] INSTALLATION, MAINTENANCE AND OPERATION
                --------------------------------------------------

AUDIENCE: This course is designed for the technical personnel who have the 
responsibility of installing, operating and maintaining the Microstar.

COURSE DESCRIPTION: The course objective is to provide the skills and 
knowledge required to perform installation, operation and maintenance of the 
equipment so as to achieve a minimum of downtime. You will learn to use the 
proper procedures to eliminate equipment damage resulting from incorrect 
handling as well as how to relate the comprehensive documentation in the 
installation manual to actual equipment installation, operation and 
maintenance. You will also be taught how to isolate and replace faulty unit. 
Finally, you will learn performance monitoring techniques to maintain an 
initial level of system operation.

KEY TOPICS:

  / /  General Information
  / /  Fannon Publication And Drawing
  / /  Basic Digital background
  / /  Microstar Typical Application
  / /  Signal Flow
  / /  System Setup
  / /  Operation Fault Isolation
  / /  Unit Replacement
  / /  Maintenance

MEDIA: TR-MIC-01 is a three volume Video cassette Course, reinforced with 
detail product documentation.

   Videocassette Vol. 1   Microstar Theory of Operation        Duration: 25 min.

   Videocassette Vol. 2   Microstar Installation               Duration: 20 min.

   Videocassette Vol. 3   Microstar Maintenance and Operation  Duration: 30 min.

PERQUISITES:   Knowledge of the basic Telecommunication System

COURSE OUTLINE: Microstar Installation


                                                16

<PAGE>

                                   EXHIBIT D
                                     Page 2

RELATED COURSES:

    -TR-BASDIG   Basic Digital Telecommunication
    -TR-BASMIC   Basic Microwave Installation
    -TR-BASMOD   Basic Microwave Modulation
    -TR-DIG-1    Digital Telecommunication
    -TR-Mic-1    Microwave Installation
    -TR-MIC-02   Microstar System Design and Technical Support


                                                17
<PAGE>

                                   EXHIBIT D
                                     Page 3

COURSE NO:  TR-MIC-02


COURSE TITLE:  MICROSTAR SYSTEM DESIGN AND TECHNICAL SUPPORT
               ---------------------------------------------

AUDIENCE:  This course is designed for technical personnel who have the 
responsibility of designing Telecommunication System using Microstar and/or 
providing technical assistance to personnel installing, operating and 
maintaining the Microstar.

COURSE DESCRIPTION:  The course objective is to provide the skills and 
knowledge required to perform Network and System Design using the Microstar 
Radio Path Calculation basics, reliability calculation and Network Management 
consideration will be taught so as to achieve cost effective System Design. 
You will also learn how the Microstar functions in detail so that you become 
a product expert. This will enable you to provide Advanced Technical Support 
to installation, operation, and maintenance personnel.

KEY TOPICS:

 / / General Information
 / / Farinon Publication and Drawing
 / / Path Calculation
 / / Microstar Interconnectivity
 / / Theory of Operation
 / / System Installation
 / / Operation
 / / Maintenance
 / / Alarm Synopsis
 / / Diagnostics
 / / Network Management

MEDIA:  TR-MIC-02 is a combination of lecture, reinforcement with hands-on 
exercises using product documentation.

PREREQUISITES:  Knowledge of the basic digital technique and modulation 
technique and basic telecommunications background.

     Trainees will need basic knowledge of the following subjects:
       -Digital Communication Format (North American DS1,2,3 or CEPT E1,2,3)
       -Digital Modulation Techniques (QPSK, OQPSK, QPR, QAM, FSK)
       -Digital Telecommunications System (Backbone, SPUR, Networking)


                                                18

<PAGE>

                                   EXHIBIT D
                                     Page 4

DURATION:  2 day

COURSE OUTLINE:  Microstar System Design and Technical Support

RELATED COURSES
:
     -TR-BASDIG             Basic Digital Telecommunication
     -TR-BASMIC             Basic Microwave Installation
     -TR-BASMOD             Basic Microwave Modulation
     -TR-DIG-1              Digital Telecommunications
      VID-MIC-1             Microwave Installation


                                                19

<PAGE>

                                   EXHIBIT E

           DEFINITION OF ART'S INSTALLATION SERVICES AND PROCEDURES
           --------------------------------------------------------

STANDARD INSTALLATION:

     "Any installation where both radios are roof mounted, no coning boring 
     penetrations are necessary, access is unrestricted during normal 
     business hours, and the installation can be accomplished in one concurrent
     eight hour business man day."

     TYPICAL STANDARD INSTALLATION EQUIPMENT REQUIRED:

        1" antenna
        Standard Wall Pipe Mount
        ODU
        RG8 or RG11 cable (up to 100 feet)
        IDU (either wall-mount or rack-mount)
        75W Foresight power supply (either wall-mount or rack-mount)
        DB-25 10" cable terminated into a wirewrap block
        Standard installation parts kit (Miscellaneous hardware, nuts, bolts,
        etc.)

NON-STANDARD INSTALLATION:

     "Any installation that would require coring, long or difficult cable 
     runs, tower or rigging crews required to install the ODU, modifications to 
     mounting structures, restricted or limited access, and/or installation
     time beyond a concurrent eight hour business man day."

     TYPICAL NON-STANDARD INSTALLATION EQUIPMENT REQUIRED:

         2" Antenna
         Tripod or special tower mounts
         Additional RG8 or RG11 cable beyond 100 feet
         Protected power supplies
         DB-25 cable terminated into DSX panel
         Cabinets or weatherproof enclosures
         "Smart" jacks
         CSU/DSU



The installation fee as outlined in 5.3 Table 2 is inclusive of up to two (2) 
"Man Days" at eight (8) hours per each business day. At Harris' request ART 
shall perform Non-Standard installations or should additional days be 
required for Standard installations beyond two (2) "Man Days" a rate of 
$[CONFIDENTIAL] per man day plus reasonable incremental expenses will apply. 
Harris to provide all installation materials required at no-charge to ART

                                                20

<PAGE>

                                   EXHIBIT E
                                    Page 2

                             INSTALLATION SCHEDULE
                             ---------------------

INSTALLATION MILESTONES:

     1.   ART receives a request for service (RFS) from Harris. The RFS must
          include certain information necessary for the installation process,
          including but not limited to a Preliminary Site Survey.

     2.   Within 3 business days of receiving the RFS, ART will inform Harris
          if the RFS is incomplete, noting the additional information ART 
          requires.

     3.   Within 10 business days of receiving a completed RFS, ART will 
          complete a Detailed Site Survey, noting any issues, limitations or 
          exceptions with respect to the installation.

     4.   Harris will provide ART with an executed Service Order based on the
          Detailed Site Survey provided by ART. In order for the Service Order
          to be deemed complete, Harris must provide ART with satisfactory
          evidence of the necessary roof rights, including copies of leases,
          authorizations, agreements with landlords, and the like where
          applicable.

     5.   ART will complete Standard Installations within 15 business days of 
          receiving a complete, executed Service Order, or such later date as
          may be requested by Harris or its Customer and agreed to in writing
          by ART.

     6.   ART will complete Non-Standard Installations in accordance with a 
          schedule to be mutually agreed on among ART, Harris and the 
          Customer.


                                                21
<PAGE>

                                   EXHIBIT F

        ART'S DEFINITION OF NETWORK MONITORING SERVICES AND PROCEDURES
        --------------------------------------------------------------

NETWORK OPERATIONS CENTER

    The NOC operates on a seven (7) day twenty-four (24) hour basis to 
    monitor all circuits. The NOC provides continuous Supervisory Control and
    Data Acquisition (SCADA).

    The ART Network Operations Center (NOC) will provide the following services
    to ART customers per the fee schedule outlined.

        A.  Link alarm monitoring via OZBOX dial-up modem or customer call in.
        B.  Link performance monitoring.
        C.  Link performance monitoring.
        D.  Historical link performance data.
        E.  Remote link diagnosis.
        F.  Remote link restoral via the Network Monitoring System (NMS).  The
            NMS is the GET Worldwin system and described below.
        G.  Restoral of service if an ART Link failure occurs.
        H.  Initiate dispatch activities, as required.
        I.  Coordination and testing with associated NOC's if outage occurs but
            not due to an ART failure.

    Response Times & Procedures.

        The operational status of every ART circuit is tracked by a dedicated 
        OZBOX which continuously monitors the performance of the wireless link.

        The OZBOX automatically contacts ART's Network Operations Center when
        it detects a problem.

        A message is flashed on the Network Operator's screen informing him 
        of a problem.

            0-15 MINUTES:
            -------------
            The Network Operator then runs diagnostic routines in the OZBOX,
            attempting to determine the cause of the malfunction.

            (If a customer or user calls into ART's Network Operations Center
            with a performance problem, the same procedure is initiated -the
            Network Operator connects to the corresponding OZBOX to initiate
            diagnostic routines.)

            If the problem can be corrected remotely, the Network Operator will
            restore service.

            If the diagnosis can determine the problem is due to non-ART network
            equipment, the Network Operator will notify and coordinate with the 
            associated NOC which is responsible for the effected equipment. The
            ART Network Operations Center will continue to participate in the
            testing as appropriate.


                                                22

<PAGE>

                                   EXHIBIT F
                                    Page 2

            15-30 MINUTES:
            --------------
            If the problem requires on-site service, a dispatch will be issued
            within 30 minutes of our initial notification of the problem. At
            this point the customer is notified, and advised of the planned
            solution. An ART Field Service Technician will be dispatched if in
            the vicinity and IMMEDIATELY AVAILABLE.  Otherwise a GTE Field
            Service Technician will be dispatched.

            30 MINUTES TO 1 HOUR:
            --------------------
            The service technician will be on-site within 30 minutes, or have an
            ETA of when he will be on site. If the ETA exceeds 30 minutes for
            the dispatch, the problem will be escalated within both service
            organizations.

            1-4 HOURS:
            ----------
            The service technician will perform on-site diagnosis as
            appropriate, and swap all ART equipment with new equipment as
            required to restore service within 4 hours

WORLDWIN SYSTEM DESCRIPTION
- ---------------------------

The WorldWin products comprise a Service Fulfillment and Integrated Customer 
Contact File. Asset Management & Tracking, Network Operations NMS product and 
Project /Work Order Management. WorldWin is able to provide the following:

            Easily, quickly and with flexibility define services to be delivered
            to our customers.

            Manage network configuration, including automated provisioning of
            customer services.

            Monitor and maintain the operational integrity of our customer
            circuits, including fault and performance management, trouble
            ticketing/repair and work order management.

            Perform business support functions such as service order processing
            and customer management (billing, call records and sales quotes).

Worldwin will manage the business, services and network from a single 
integrated platform ART will deliver services, as well as unparalleled 
customer support on demand from any department work station. Simultaneous 
transmission of network information - Messages containing information 
(typically called Call Detail Record-CDR), performance, fault, alarm, or 
provisioning data can be sent in near real-time to other applications, i.e. 
"alarm records" to an output file on the NT Corporate Server.


                                                23

<PAGE>

                                                                   EXHIBIT 10-32
[ADVANTAGE TELECOM, INC. LETTERHEAD]


March 20, 1996

Mr. Vernon L. Fotheringham
CEO
Advanced Radio Telecom Corp.
Bellevue City Center
500 108th, Ave. NE
Suite 2600
Bellevue, Washington
98004

RE: LETTER OF INTENT FOR STRATEGIC VENTURE FOR FIXED TELECOMMUNICATIONS
OPERATIONS IN CANADA.

Dear Vern:

         This letter summarizes our recent conversation and constitutes a
Letter of Intent ("LOI") to enter into a binding Definitive Agreement on or
before September 14, 1996.  This LOI does not obligate the parties in any
respects other than (i) to negotiate in good faith to reach a Definitive
Agreement and (ii) not to take any action concerning the activities contemplated
herein without the other's concurrence.  All obligations under this LOI will
become null and void on the sooner of the execution of a Definitive Agreement
and or September 14, 1996.

         Advantage Telecom Inc. ("ATI") is a Canadian corporation, wholly owned
by Canadian citizens and is incorporated in the province of British Columbia
("BC") and with its principal place of business at 1535 Bramble Lane, Coquitlam,
B.C. V3E 2S7.  ATI has commenced the process to become authorized as a provider
of 38GHz services throughout Canada.  In view of Advanced Radio Telecom's
("ART") expertise in fixed wireless telecommunications in the United States and
its desire to enter the Canadian market, ATI wishes to form a Strategic Venture
with ART, which will be the means by which either party participates in the
provision of broadband fixed wireless or wired telecommunications within Canada.

         The initial endeavor of the Strategic Venture shall be obtaining
authorization to provide 38GHz services in all regions of Canada.  Subsequently,
depending upon demand, competition and the regulatory climate, the parties
intend to expand their services to encompass other fixed wireless frequencies
and hybrid wired/wireless broadband networks.

         As between ATI and ART, ART shall furnish all of the funds needed to
secure the appropriate licenses and commence operations, ART shall hold the
maximum amount of legal and beneficial interests and provide the maximum degree
of services permitted under Canadian law and ART shall operate the systems and
furnish all services to the Strategic Venture upon

                              Proprietary / Confidential

<PAGE>

reasonable and appropriate terms.  ART shall approve in advance all expenditure
and activities to be undertaken by ATI prior to the execution of a Definitive
Agreement.
ATI shall furnish ART with all relevant documents, including its incorporation
papers, and consult with ART no less than weekly concerning all relevant
developments and near term contacts and plans.  ATI, with ART's input shall
commence immediately the preparation of a business plan and a five year pro
forma income/expense projection.

         If these LOI terms meet with your approval, please so signify by
executing below.

Sincerely,

/s/ MIRIAM D. HAYWARD
Miriam D. Hayward
as President
Advantage Telecom, Inc.

ACCEPTED AGREED:    /s/ VERNON L. FOTHERINGHAM
Vernon L. Fotheringham
as CEO Advanced Radio Telecom Corp.

                              Proprietary / Confidential

<PAGE>
                              CONSULTING AGREEMENT


This Consulting Agreement (the "Agreement") is made and entered into effective
as of the 1st day of March, 1996, between Advanced Radio Telecom Corporation
(the "Company") and Trnd Johanssen (the "Consultant").

The Company, operating in the Information Technology and Communications
industry, is organized to deliver broadband, wireless services to business,
government and private customers.  The company is to date established in the
United States, intending to expand into world markets.

The Consultant has experience in the Information Technology and Communications
Industry.  He is an Appointment Representative of Caledonian European
Securities, Ltd., specializing in assisting upstart telecommunications companies
in their financing and strategic partnering activities.  The Consultant may act
in this role in parallel with this agreement, as and when agreed between the
Company and Caledonian European Securities, Ltd.  The Consultant is the Chairman
and sole shareholder of JEITO A/B, a Norwegian corporation currently applying
for broadband frequency license in Norway.

Now, therefore, in consideration of and for the mutual promises and covenants
contained herein, the parties agree as follows:

1. Purpose.  The Company hereby employs Consultant during the term specified
hereinafter to render such consulting services to the Company as described in
Section 3 hereof and such other consulting services as the Company and the
Consultant may from time to time agree ("Consulting Services"), upon the terms
and conditions as set forth herein.

2. Term.  This Agreement shall commence as of the effective date of this
Agreement and shall continue for a period of 24 months.

3. Extent of Consulting Services Provided.

(a)  During the term of this Agreement, Consultant will provide Company with
Consulting Services with respect to the Company's international expansion,
including, but not limited to the following:

     (i)  Acquisition of broadband frequency licenses from regulatory entities,
or from entities to whom licenses have already been issued.

     (ii) Formation of corporate entities to operate services based on the
acquired licenses.

     (iii) Identification of local operating partners for each corporate
entity formed.

<PAGE>

     (iv) Identifying and negotiating appropriate arrangements with commercial
or other private capital sources, including conventional sources such as bank
financing or other institutional asset based financing, and private equity or
mixed equity and debt placements.

(b)  In connection with rendering its advice hereunder, the Consultant and its
employees and agents shall, to the extent reasonably required in connection with
providing Consulting Services, be given access to the Company's offices,
premises and records.

(c)  The Consultant will, with respect to its Consulting Services, provide the
services of personnel with the requisite experience and skill to provide the
Consulting Services required and will furnish to the Company reasonable
information with respect to the identity and qualifications of the personnel
assigned to provide Consulting Services.

(d)  Consultant shall be available to provide Consulting Services for not less
than twelve (12) person/days per month during the term of this Agreement
("Minimum Consulting Services").
Consulting beyond twelve days per month will be in the interest of the
Consultant, as a substantial part of his compensation is potentially coming at
the successful completion of the project(s).

(e)  The Consultant will provide Consulting Services in a professional manner
and in accordance with the highest professional standards generally applicable
to comparable consulting services.  The Company acknowledges, however, that
advice given by the Consultant does not and will not constitute any guarantee or
other assurance as to the ability of the Company to realize the financial or
other objectives in connection with which the advice was given.

(f)  The Company acknowledges that the Consultant retains the right to provide
consulting advice to other parties.  Except as specifically provided herein with
respect to the confidentiality of proprietary information and non-competition
provision of the Company, nothing herein shall be construed to limit or restrict
the Consultant in conducting such business with respect to others, or in
rendering advice to others or conducting any other business.

(g)  Except as disclosed to the Company in writing, the Consultant is not a
member, an affiliate, or an affiliate of a member of:

     (i)  any institutional lender or investor, including, without limitation,
any commercial, investment or merchant bank, investment fund, leasing company or
other, comparable entity;

     (ii) any Information Technology and Communications industry firm;

     (iii)     any regulatory body or industry association connected with the
Company.

The Consultant will promptly inform the Company in writing of any change in the
information


<PAGE>

set forth in this Section 3(g).

4. Compensation.  Company agrees to pay the Consultant for the Minimum
Consulting Services hereunder the sum of six thousand five hundred United States
dollars (USD 6,500) for each month, payable on the 15th day of each month during
the term of this Agreement.

In any new corporation established with the assistance of the consultant, the
Consultant will be assigned 20% of the shares upon formation, and the Company
will be assigned 80%.  These shares will be the same class, and carry the same
privileges.  In the case of third parties investing in the new corporation(s),
the Consultant and the Company will dilute at the same rate.  The Company will
have a right of first refusal to the Consultant's shares, exercisable by notice
of 30 days of "bona fide" offer, except in transfers to wife or immediate family
members, or JEITO A/A (a company wholly owned by the Consultant).  In the case
of a share sale in the new corporation by the Company, the Consultant shall have
the right to require that his shares are sold on his behalf by the Company, as
part of the same transaction, and on equal terms as those of the Company.

5. Expenses.  Consultant shall be entitled to reimbursement by Company of such
reasonable, accountable out-of-pocket expenses as Consultant may incur in
performing Consulting Services under this Agreement.  Company has right to
require receipts for all expenditures.  Such reimbursements shall be in addition
to any fees otherwise earned by Consultant hereunder.  Any expense in excess of
two hundred fifty United States dollars (USD 250) in any calendar month for
which Consultant shall be entitled to reimbursement hereunder shall be approved
in advance by Company provided, however, that ordinary and necessary travel
expenses of Consultant need not be so approved, provided that travel itinerary
has been approved.  The Company shall pay consultant a fixed communications
(telephone, fax, e-mail, Internet, etc.) compensation of USD 1,950 per month,
or the actual itemized amount, whichever is higher.  This does not include
communications charges when traveling, which will be compensated in full.

6. Restriction on Use of Proprietary and Certain Other Information.

A. The parties agree to enter into a Confidentiality Agreement as supplied by
the Company or the Consultant on the effective date of this Agreement.
B. The parties agree not to engage in competing activities for fixed wireless
services in the countries named in Appendix A for the period of the Agreement
and 12 months after the termination of the Agreement.

7. Arbitration.  Any controversy or claim arising out of or relating to the
compensation to be paid by the Company or the services to be rendered by the
Consultant pursuant to the terms of this Agreement, or otherwise related to the
compliance by either party with its obligations hereunder, shall be settled by
binding arbitration in accordance with the rules of the American Arbitration
Association, any judgment on the award rendered by the arbitrator(s) may be
entered by any court having jurisdiction thereof.  Any part of this Agreement
may submit to arbitration any controversy or claim.


<PAGE>

8. Assignment.  This Agreement and the rights hereunder may not be assigned by
either party (except by operation of law, or to affiliates (owned or
controlled), parent or subsidiary) without the prior written consent of the
other party, but, subject to the foregoing limitation, this Agreement shall be
binding upon and inure to the benefit of the respective successors, assigns, and
legal representatives of the parties.

9. Notice.  Any notice or other communication between the parties hereto shall
be sufficiently given if sent by certified or registered mail, postage prepaid,
with a copy by electronic means, if to the Company addressed to it at

Advanced Radio Telecom Corporation
500 - 108th Avenue, NE, Suite 2600
Bellevue, WA 98004, USA
Att.: Mr. Vernon L. Fotheringham, Chairman and CEO
Tel: 1-206-688-8700
Fax: 1-206-688-0703

or if to the Consultant, addressed to it at

Trend Johannessen
Via Alesandro Volta, 15
1-20121, Milan, Italy
Tel.: 39-2-657-1033
Fax: 39-2-657-0016

or to such other address as shall hereafter be designated in writing by one
party to the other.  Such notice or other communication shall be deemed to be
given on the day sent.

10. Captions.  The headings of the sections of this Agreement are intended
solely for convenience of reference and are not intended and shall not be deemed
for any purpose whatever to modify or explain or place any construction upon any
of the provisions of this Agreement.

11.  Attorneys' Fees.  In the event any party shall institute an action to
enforce any rights hereunder, the prevailing party in such action shall be
entitled, in addition to any other relief awarded by the arbitrator(s) or the
Court, to such reasonable arbitration costs and attorney's fees as the
arbitrator(s) or the Court may award.

12.  Entire Agreement.  This Agreement constitutes the entire Agreement between
the parties hereto pertaining to the subject matter hereof and supersedes all
prior and contemporaneous agreements and understandings of the parties, and
there are no representations, warranties or other agreements between the parties
in connection with the subject matter hereof except as specifically set forth
herein.  No supplement, modification, amendment, waiver or termination of  this
Agreement shall be binding, unless executed in writing by the parties hereto. 
No waiver of any of the provisions of this Agreement shall have deemed or shall
constitute a 


<PAGE>

waiver of any provision hereof (whether or not similar), nor shall waiver
constitute a continuing waiver.

13.  Severability.  In the event that any provision of this Agreement shall be
held to be invalid, illegal, or unenforceable in any circumstances, the
remaining provisions shall nevertheless be construed as if the unenforceable
portion or portions were deleted.

14. Governing Law.  The parties hereby agree that this Agreement shall be
governed by the laws of the State of Washington.

In witness whereof, the parties hereto have executed this Agreement this day and
year first above written.


Advanced Radio Telecom Corporation                Trend Johannessen



___________________________________               ____________________________



Vernon L. Fotheringham, Chairman/CEO              Consultant



Date:______________________________               Date:______________________


<PAGE>

                                   Appendix A

                 Countries covered by clause 6, Non-corporation


Austria
Belgium
Denmark
Finland
France
Germany
Greece
Italy
Luxembourg
Netherlands
Norway
Portugal
Spain
Sweden
Switzerland
United Kingdom 

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


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