Document:

<PAGE>   1
                                                                   EXHIBIT 10.21

                              CONSULTING AGREEMENT

         The following represents the agreement between PennzEnergy Company
("PennzEnergy") and Brent Scowcroft ("Consultant") regarding consulting
services.

1.       Consultant will provide consulting services as requested by PennzEnergy
         during the period of June 1, 1999 through May 31, 2002. These
         consulting services will primarily relate to PennzEnergy's
         international projects and investments.

2.       In exchange for these services, PennzEnergy will pay a retainer in the
         total amount of $300,000, payable in twelve (12) equal quarterly
         installments of $25,000, due and payable on the first day of the months
         of June, September, December and March, with the initial installment
         payable on June 1, 1999 and the last installment payable on March 1,
         2002.

3.       In addition, PennzEnergy will either provide transportation and lodging
         or reimburse Consultant for necessary travel expenses incurred in
         connection with rendering consulting services pursuant to this
         agreement.

4.       While providing the consulting services contemplated by this agreement,
         Consultant will be acting as an independent contractor, and not as an
         employee of PennzEnergy under the meaning of any federal, state or
         local law.

5.       Consultant will be responsible for all taxes and other payments due any
         federal, state or local government agency with respect to the quarterly
         retainer payments paid to Consultant by PennzEnergy. PennzEnergy will
         not withhold taxes or other amounts from the quarterly retainer
         payments and will not provide any worker's compensation, insurance or
         other benefits pursuant to this consulting agreement.

                                      129
<PAGE>   2
6.       Either party may terminate this agreement at any time upon written
         notice; however, Consultant will be entitled to reimbursement for
         travel expense incurred in connection with consulting services
         performed prior to receipt of the written notice and the retainer will
         not be subject to refund to the extent one or more quarterly
         installments have been paid prior to termination. In the event of
         termination by PennzEnergy, any quarterly installment(s) not previously
         paid will become due and payable within 30 days following notice of
         termination.

Agreed to this 17th day of May, 1999.

/s/ James L. Pate                                    /s/ Brent Scowcroft
------------------------------------                 -------------------
By: James L. Pate                                    Brent Scowcroft
Title: Chairman of the Board                         900 Seventeenth St., N.W.
                                                     Suite 500
                                                     Washington, DC 20006

                                      130<PAGE>   1

                                                                    EXHIBIT 10.5

     "***" Confidential portions of this Agreement have been omitted and filed
     separately with the Securities and Exchange Commission under a Confidential
     Treatment Request, pursuant to Rule 24b-2 of the Securities Exchange Act of
     1934, as amended.

Frank Hosea
Senior Vice President
Video Operations
Nucentrix Broadband Networks, Inc.
200 Chisholm Place, Suite 200
Plano, Texas 75075

RE: Amendment to SFU Agreement

Dear Frank:

Reference is made to that certain SFU Agreement made as of April 5, 1998, as
amended from time to time (the "SFU Agreement"), by and between Heartland
Wireless Communications, Inc. and DIRECTV, Inc. The parties wish to amend the
terms of the SFU Agreement as described below, effective as of December 1, 1999
(except as otherwise set forth below).

1.   The name of the party, Heartland Wireless Communications, Inc., shall be
     changed to Nucentrix Broadband Networks, Inc.

2.   All references to DSS System shall be changed to DIRECTV System.

3.   Section E(2) of the Agreement shall be deleted in its entirety and replaced
     with the following:

     "Company hereby agrees and acknowledges that, in order to receive the
     Subsidy as set forth herein, Company must either (a) sell such DIRECTV
     System to Qualifying Subscribers or (b) provide such DIRECTV System through
     a rent, lease, rent-to-own or lease-to-own model to Qualifying Subscribers
     who subscribe to both DIRECTV programming and Company's cable programming
     services. In addition, the rent, lease, rent-to-own or lease-to-own
     model/arrangement must be in compliance with any and all applicable
     federal, state and local laws, statutes, codes, rules, regulations,
     ordinances or otherwise."

4.   The following shall be added as new Section C(3):

     "Company shall not represent that DIRECTV Programming Packages may be
     obtained on any different terms or rates, shall not impose additional or
     different terms and shall not offer customers any discount, rebate, or
     other material benefits in consideration for subscribing to them, except as
     expressly authorized by DIRECTV

<PAGE>   2

     in writing. Notwithstanding any failure by a Qualifying Subscriber (as
     defined below) to pay his/her rent or lease free, if any, of a DIRECTV
     System, Company shall not disconnect or otherwise attempt to disconnect any
     Qualifying Subscriber's DIRECTV Programming Package without the prior
     written consent of DIRECTV."

5.   Effective as of August 29, 1999, Exhibit B shall be amended such that the
     Percentage of DIRECTV Programming Package Revenue Per Calendar Month
     (Continuing Service Fee) shall be "***" for all DIRECTV Programming
     Packages.

Except as set forth herein, all terms of the SFU Agreement shall remain
unmodified and in full force and effect. Kindly acknowledge your agreement to
the foregoing terms by signing in the space provided below.

                                       Sincerely,

                                       DIRECTV, INC.

                                       By: /s/ James B. Arnold
                                           -------------------------------------
                                               James B. Arnold

AGREED, ACCEPTED AND ACKNOWLEDGED:

Nucentrix Broadband Networks, Inc.

By: /s/ Frank Hosea
    -------------------------------
Name:
     ------------------------------
Title:
      -----------------------------
Date: 12/3/99
     ------------------------------<PAGE>   1

                                                                   EXHIBIT 10.16

                                MASTER AGREEMENT

                                      AMONG

                    HEARTLAND WIRELESS COMMUNICATIONS, INC.,
                            CS WIRELESS SYSTEMS, INC.

                                       AND

                           CAI WIRELESS SYSTEMS, INC.

                          DATED AS OF DECEMBER 2, 1998

<PAGE>   2

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                            Page
                                                                                                            ----

<S>                                                                                                          <C>
Preamble......................................................................................................1

Section 1 - Defined Terms.....................................................................................2

Section 2 - CS Wireless Common Stock..........................................................................4

Section 3 - Transfers of Assets and Leases of Spectrum Rights at the Stage I Closing..........................5

Section 4 - Cancellation of Heartland Long-Term Note and Related Transactions at the
     Stage II Closing.........................................................................................6

Section 5 - Stage I and Stage II Closing Dates................................................................7

Section 6 - FCC Cooperation and Related Spectrum Matters......................................................7

Section 7 - Conditions to All of the Parties' Obligations.....................................................8

Section 8 - Representations and Warranties of the Parties....................................................12

Section 9 - Covenants of All of the Parties..................................................................19

Section 10 - Covenants of Heartland..........................................................................20

Section 11 - Covenants of CS Wireless........................................................................21

Section 12 - Releases and Indemnification....................................................................23

Section 13 -  Termination....................................................................................24

Section 14 - Further Assurances..............................................................................25

Section 15 - No Waiver.......................................................................................25

Section 16 - Miscellaneous...................................................................................25
</TABLE>

                                       i

<PAGE>   3

Exhibits

Exhibit A - Resignation of Heartland Directors and Heartland Independent
              Director
Exhibit B - CS Wireless FCC Assets Spectrum Lease
Exhibit C - Heartland FCC Assets Spectrum Lease
Exhibit D - Amendment to BTA Lease and Option Agreement
Exhibit E - BTA Lease and Option Agreement
Exhibit F - Form of CS Wireless Senior Noteholder Consent

Schedules

3(a)(i) -   Customer Premises Equipment
3(a)(ii) -  CS Wireless FCC Assets
3(b) -      Heartland FCC Assets
4(a)(i) -   CS Leases
4(a)(ii) -  Radcliffe Non-FCC Assets
4(b)(i) -   Heartland Leases
4(b)(ii) -  Portsmouth Non-FCC Assets
8(a)(ii) -  Title to Heartland Assets
8(a)(v) -   Heartland Compliance with Laws
8(a)(vi) -  Heartland leased FCC Assets
8(a)(vii) - Heartland Litigation
8(a)(x) -   Condition of Portsmouth Non-FCC Assets
8(b)(ii) -  Title to CS Wireless Assets and Leases
8(b)(v) -   CS Compliance with Laws
8(b)(vi) -  Construction Completion Dates
8(b)(vii) - CS Wireless Litigation
8(b)(x) -   Condition of CPE and Radcliffe Non-FCC Assets 8(c)(iii)
              - CAI Litigation

                                       ii

<PAGE>   4

                                MASTER AGREEMENT

     Master Agreement dated as of the 2nd day of December, 1998 (this
"Agreement") by and among Heartland Wireless Communications, Inc., a Delaware
corporation having its principal place of business located at 200 Chisholm
Place, Suite 200, Plano, Texas 75075 ("Heartland"), CAI Wireless Systems, Inc.,
a Connecticut corporation having its principal place of business located at 18
Corporate Woods Boulevard, Third Floor, Albany, New York 12211 ("CAI") and CS
Wireless Systems, Inc., a Delaware corporation having its principal place of
business located at 1101 Summit Avenue, Plano, Texas 75074 ("CS Wireless").

                                 R E C I T A L S

     WHEREAS, the parties hereto are parties to that certain Participation
Agreement (as defined herein), pursuant to which each of Heartland and CAI
contributed wireless cable assets or the stock of entities owning wireless cable
assets to CS Wireless in exchange for CS Common Stock (as defined herein); and

     WHEREAS, in connection with the consummation of the transactions
contemplated by the Participation Agreement, Heartland received 3,578,834 shares
of CS Wireless Common Stock, which amount was subsequently increased to
3,836,035 shares of CS Wireless Common Stock as a result of the issuance by CS
Wireless to Heartland of an additional 257,201 shares of CS Wireless Common
Stock in satisfaction of that certain true-up obligation owed to Heartland under
Section 9.6(a) of the Participation Agreement; and

     WHEREAS, in connection with the consummation of the transactions
contemplated by the Participation Agreement, CS Wireless issued to Heartland the
Heartland Long-Term Note (as defined herein) in the principal amount of
$15,000,000, which promissory note matures on February 21, 2006; and

     WHEREAS, there is $2,335,276.00 outstanding on the Heartland Long-Term Note
as of November 30, 1998; and

     WHEREAS, simultaneously with the consummation of the transactions
contemplated by the Participation Agreement, the parties hereto entered into
that certain Stockholders' Agreement (as defined herein), which agreement
requires, among other things, that Heartland and CAI vote their shares of CS
Wireless Common Stock in favor of a board of directors comprised of four members
designated by CAI and three members designated by Heartland, and that
significant decisions affecting CS Wireless requires the approval of at least
70% of the directors of CS Wireless so that neither CAI nor Heartland can
unilaterally make significant decisions affecting CS Wireless; and

     WHEREAS, the parties have disagreed about various matters regarding the
operations, valuation, governance and future of CS Wireless; and

     WHEREAS, with due regard to their respective fiduciary duties to various
constituencies including the respective stockholders and creditors of CS
Wireless, CAI and Heartland, the parties wish to terminate Heartland's ongoing
participation in the governance of CS Wireless on a basis that

<PAGE>   5

after prolonged negotiation, investigation and consultation with advisors, the
parties believe to be fair and in the best interests of the parties and their
respective constituents while ensuring that the future operations of Heartland
and CS Wireless and their respective successors can be separated without
unnecessary disruption to either party; and

     WHEREAS, CAI desires to purchase from Heartland and Heartland desires to
sell to CAI all of the 3,836,035 shares of CS Wireless Common Stock owned by
Heartland, on and subject to the terms and conditions set forth herein; and

     WHEREAS, CS Wireless desires to assign and transfer to Heartland certain
MDS-1 channels, all assets relating to the Radcliffe, Iowa market, WCS Spectrum
in 19 markets and certain other equipment, and Heartland desires to assign and
transfer to CS Wireless any and all ownership and leasehold interests in MMDS
and MDS channels in the Portsmouth, New Hampshire market, including, but not
limited to, the MMDS E Group and MDS H1 - 3 channels, together with any and all
assets used by Heartland in the Portsmouth market; and

     WHEREAS, the parties hereto desire to cooperate with each other with
respect to proposed two-way use of their MMDS, MDS and ITFS spectrum in
contiguous and adjacent markets, including, but not limited to, reaching an
agreement with respect to a comprehensive two-way frequency utilization plan,
cooperation with respect to the implementation of such, timely provision of
requisite interference consent agreements and such other actions as may be
consistent with supporting each other's necessary or desirable filings at the
FCC (as defined herein) in connection with two-way applications; and

     WHEREAS, the parties hereto desire to settle certain claims they have
against each other; and

     WHEREAS, the parties shall continue to own and lease spectrum rights in
contiguous and adjacent markets, the value of which rights would be materially
adversely affected absent agreement with respect to interference and related
uses arising out of the contemplated two-way applications of such spectrum.

     NOW, THEREFORE, in consideration of the foregoing and the mutual agreements
contained herein, each of the parties hereto agree as follows.

     Section 1. Defined Terms. As used in this Agreement, the following terms
shall have the respective meanings set forth below:

     "Bankruptcy Code" means the United States Bankruptcy Code, as heretofore
and hereafter amended, and as codified as 11 U.S.C. Sections 101 et seq.

     "BTA" means Basic Trading Area, as such term is used by the FCC to denote
geographic areas in connection with the public auction of available spectrum in
the Multipoint and/or Multichannel Distribution Service.

     "BTA Lease and Option Agreement" means that certain BTA Lease and Option
Agreement

                                       2

<PAGE>   6

dated October 31, 1997 by and between CS Wireless and Heartland.

     "CPE" means Customer Premises Equipment listed on Schedule 3(a)(i) attached
hereto.

     "Communications Act" means the Communications Act of 1934, as amended, 47
U.S.C. Sections 151 et seq.

     "CS Leases" means the spectrum leases listed on Schedule 4(a)(i) attached
hereto.

     "CS Senior Notes" means $400,000,000 aggregate principal amount of Series B
11-3/8% Senior Notes due 2006 of CS Wireless Systems, Inc.

     "CS Wireless Common Stock" means the common stock, par value $.001 per
share, of CS Wireless.

     "CS Wireless FCC Assets" means the FCC licenses owned by CS Wireless and
listed on Schedule 3(a)(ii) attached hereto.

     "Encumbrance" shall have the meaning given to such term in Section 8(a)(i).

     "FCC Approvals" shall have the meaning given to such term in Section 3(b).

     "Governmental Authority" means (a) the government of (i) the United States
of America or any State or other political subdivision thereof, or (ii) any
jurisdiction in which any party hereto or any of such party's subsidiaries
conducts all or any part of its business, or which has jurisdiction over any
properties of any party hereto, as the case may be, or (b) any entity exercising
executive, legislative, judicial, regulatory or administrative functions of, or
pertaining to, any such government.

     "Heartland FCC Assets" means the FCC licenses owned by Heartland and listed
on Schedule 3(b) attached hereto.

     "Heartland Leases" means the spectrum leases listed on Schedule 4(b)(i)
attached hereto.

     "Heartland Long-Term Note" means that certain Subordinated Promissory Note
dated February 23, 1996 and issued by CS Wireless to Heartland in the principal
amount of $15,000,000.

     "Hosea" means Frank H. Hosea.

     "Participation Agreement" means the Participation Agreement dated as of
December 12, 1995 by and among CAI, Heartland and CS Wireless, as amended by
Amendment No. 1 to the Participation Agreement dated as of February 23, 1996
among the parties thereto.

     "Portsmouth Non-FCC Assets" means all assets owned by Heartland and used in
connection with the operation of the channels pursuant to the Heartland FCC
Assets and Heartland Leases, including, without limitation, the assets listed on
Schedule 4(b)(ii) attached hereto.

                                       3

<PAGE>   7

     "Radcliffe Non-FCC Assets" means all assets owned by CS Wireless and used
in connection with the Radcliffe, IA wireless cable system, including, without
limitation, the assets listed on Schedule 4(a)(ii) attached hereto.

     "Securities Act" means the Securities Act of 1933, as amended.

     "Services Agreement" means that certain Administrative Services Agreement
dated as of February 23, 1996 by and between Heartland and CS Wireless.

     "Stage I Closing" shall have the meaning given to such term in Section
5(a).

     "Stage I Closing Date" shall have the meaning given to such term in Section
5(a).

     "Stage I Transactions" shall have the meaning given to such term in Section
5(a).

     "Stage II Closing" shall have the meaning given to such term in Section
5(b).

     "Stage II Closing Date" shall have the meaning given to such term in
Section 5(b).

     "Stage II Transactions" shall have the meaning given to such term in
Section 5(b).

     "Stockholders' Agreement" means that certain Stockholders' Agreement dated
as of February 23, 1996 by and among CS Wireless, CAI and Heartland.

     Section 2. CS Wireless Common Stock.

     (a) At the Stage I Closing (as defined below), Heartland shall sell,
assign, transfer, convey and deliver to CAI, and CAI shall purchase, accept and
assume from Heartland, all of Heartland's right, title and interest in and to
3,836,035 shares of CS Wireless Common Stock owned by Heartland, which shares
represent the entire equity interest in CS Wireless owned by Heartland as of the
date hereof.

     (b) The parties hereto agree that upon the consummation of the Stage I
Transactions (as defined below), Heartland shall cease to have any equity
interest in CS Wireless and the Stockholders' Agreement shall, without further
action by the parties, permanently and irrevocably lapse and terminate with no
further force or effect, and each of the parties thereto shall be relieved of
their obligations thereunder, with the same force and effect and as if the
parties had never entered into such agreement. Upon such Stage I Closing, the
resignation of each of the Heartland Directors and the Heartland Independent
Director (as such terms are defined in the Stockholders' Agreement) from the
Board of Directors of CS Wireless, in the form attached hereto as Exhibit A,
shall become immediately effective without further action by the parties;
provided, however, that any indemnification obligations of CS Wireless to each
of the Heartland Directors, the Heartland Independent Directors and Hosea under
CS Wireless' certificate of incorporation, by-laws, contracts, insurance
policies (to the extent applicable) or otherwise existing as of the date hereof
shall survive such resignation, and CS Wireless expressly agrees to assume any
such indemnification obligation in any bankruptcy proceeding filed by or against
CS Wireless.

                                       4

<PAGE>   8

     Section 3. Transfers of Assets and Leases of Spectrum Rights at the Stage I
Closing.

     At the Stage I Closing:

     (a) CS Wireless shall, in partial satisfaction of the Heartland Long-Term
Note, which shall cease to accrue interest from and after the Stage I Closing
Date:

          (i) sell, assign, transfer, convey and deliver to Heartland, Heartland
     shall purchase, accept and assume from CS Wireless, all of CS Wireless'
     right, title and interest in and to the CPE listed on Schedule 3(a)(i);

          (ii) lease to Heartland, and Heartland shall lease from CS Wireless
     all of CS Wireless' right, title and interest in and to the CS Wireless FCC
     Assets. The CS Wireless FCC Assets shall be leased pursuant to the Lease
     Agreement set forth as Exhibit B attached hereto. Within ten (10) business
     days of the signing of this Agreement, CS Wireless and Heartland together
     shall file with the FCC the necessary applications for the consent of the
     assignment of the CS Wireless FCC Assets; and

          (iii) pay Heartland Three Hundred Sixty-six Thousand and 00/100
     Dollars ($366,000.00), payable in immediately available funds by wire
     transfer in accordance with written wire transfer instructions previously
     delivered by Heartland to CS Wireless;

     (b) Heartland shall lease to CS Wireless, and CS Wireless shall lease from
Heartland all of Heartland's right, title and interest in and to the Heartland
FCC Assets. The Heartland FCC Assets shall be leased pursuant to the Lease
Agreement set forth as Exhibit C attached hereto. Within ten (10) business days
of the signing of this Agreement, CS Wireless and Heartland together shall file
with the FCC the necessary applications for the consent of the assignment of the
Heartland FCC Assets (such consent, together with the consent of the FCC
contemplated by Section 3(a)(ii) above, the "FCC Approvals");

     (c) CAI shall pay Heartland One Million Five Hundred Thirty-four Thousand
and 00/100 Dollars ($1,534,000.00), payable in immediately available funds by
wire transfer in accordance with written wire transfer instructions previously
delivered by Heartland to CAI; and

     (d) Heartland and CS Wireless shall execute and deliver an amendment to the
BTA Lease and Option Agreement in the form attached hereto as Exhibit D, which
amendment shall correct certain ground elevation parameters of Heartland's
Sherman, Texas market to reflect a previously proposed or licensed facility and
correct certain operating parameter of CS Wireless' Fort Worth, Texas market.

The parties acknowledge that it is impracticable for Heartland to inspect, test
and select the CPE before the Stage I Closing. Accordingly, CS Wireless shall
make the CPE available for inspection by Heartland representatives during normal
business hours and Heartland shall inspect, test and select the CPE on or before
the Stage II Closing. CS Wireless shall make available for inspection at CS
Wireless' offices or warehouse facilities the CPE listed on Schedule 3(a)(i) at
the following locations:

                                       5

<PAGE>   9

     (Model 8607 BN55) Scientific Atlanta                  San Antonio
     converter boxes (with remote)

     (Model 5508 W or WP) Tocom converter boxes            Dallas
     (with remote)

     (Cal Amp 2040\011 or PacMono 3191i                    Dallas
     or 3192i) Dipoles, PCS filtered and tested

In the event that CS Wireless does not make available for delivery to Heartland
on or before the Stage II Closing the CPE listed on Schedule 3(a)(i), CS
Wireless shall immediately pay to Heartland cash in an amount equal to the
difference between $354,000 and the value (as established pursuant to Schedule
3(a)(i)) of the CPE made available for delivery at the Stage II Closing.

For a period of One Hundred Eighty (180) days following the earlier of the (i)
Stage II Closing or (ii) the date on which Heartland accepts a unit of CPE made
available by CS Wireless, Heartland shall have the right to return such unit of
CPE which is not in good working order for the purpose for which it was
intended. Upon timely receipt of any returned unit, CS Wireless shall
immediately (i) pay to Heartland cash in an amount equal to the value of such
item as established in Schedule 3(a)(i) or (ii) repair or replace such unit. If
CS Wireless elects to repair or replace such unit, Heartland shall have a period
of Forty-five (45) days to determine whether such repaired or replacement unit
is in good working order for the purpose for which it was intended. Except as
provided herein, CS Wireless hereby disclaims all warranties, express or
implied, including without limitation any warranties under the UCC or otherwise
implied by law. CS Wireless shall use all reasonable commercial efforts to
assist Heartland in enforcing the terms of any manufacturer's warranty
applicable to any unit of CPE delivered to Heartland pursuant to the terms
hereof.

     Section 4. Cancellation of Heartland Long-Term Note and Related
Transactions at the Stage II Closing.

     At the Stage II Closing:

     (a) CS Wireless shall sell, assign, transfer, convey and deliver to
Heartland, and Heartland shall purchase, accept and assume from CS Wireless, all
of CS Wireless' right, title and interest in and to the CS Wireless FCC Assets,
the lessee's interest under the CS Leases and the Radcliffe Non-FCC Assets;

     (b) Heartland shall sell, assign, transfer, convey and deliver to CS
Wireless, and CS Wireless shall purchase, accept and assume from Heartland, all
of Heartland's right, title and interest in and to the Heartland FCC Assets, the
lessee's interest under the Heartland Leases and the Portsmouth Non-FCC Assets;

     (c) CS Wireless shall pay Heartland One Hundred Thousand and 00/100 Dollars
($100,000.00), payable by wire transfer in immediately available funds in
accordance with written

                                       6

<PAGE>   10

wire instructions previously delivered by Heartland to CS Wireless; and

     (d) Heartland shall cancel the Heartland Long-Term Note and deliver such
cancelled promissory note to CS Wireless.

     CS Wireless acknowledges and agrees that Heartland shall not assume any
liabilities, obligations or commitments of CS Wireless or any affiliates thereof
relating to or arising out of the operation of the CS Wireless FCC Assets, the
CS Leases or Radcliffe Non-FCC Assets prior to the Stage II Closing Date
including, without limitation, any liabilities associated with employees arising
prior to the Stage II Closing Date who are hired by Heartland from and after the
Stage II Closing Date.

     Heartland acknowledges and agrees that CS Wireless shall not assume any
liabilities, obligations or commitments of Heartland or any affiliate thereof
relating to or arising out of the operation of the Heartland FCC Assets,
Heartland Leases or Portsmouth Non-FCC Assets prior to the Stage II Closing
Date.

     Section 5. Stage I and Stage II Closing Dates.

     (a) The sale and transfer of the CS Wireless Common Stock by Heartland to
CAI, and the sale and transfer of the CPE, the cash payments by each of CS
Wireless and CAI to Heartland contemplated under Section 3, the lease from CS
Wireless to Heartland of the CS Wireless FCC Assets and the lease from Heartland
to CS Wireless of the Heartland FCC Assets (collectively, the "Stage I
Transactions") shall occur at the offices of Heartland, 200 Chisholm Place,
Suite 200, Plano, Texas 75075, at 11:30 a.m., at a closing (the "Stage I
Closing") on December 2, 1998, or at such other time as the parties hereto may
agree (the "Stage I Closing Date").

     (b) The sale and transfer of the CS Wireless FCC Assets, the CS Leases, the
Radcliffe Non-FCC Assets, the Heartland FCC Assets, the Heartland Leases and the
Portsmouth Non-FCC Assets, the cash payment by CS Wireless to Heartland
contemplated under Section 4 and the cancellation and delivery of the Heartland
Long-Term Note (collectively, the "Stage II Transactions") shall occur at the
offices of Heartland, 200 Chisholm Place, Suite 200, Plano, Texas 75075, at
11:30 a.m., at a closing (the "Stage II Closing") on January 30, 1999 or, if
later, 3 business days after receipt of the final FCC Approvals, or at such
other time as the parties hereto may agree (the "Stage II Closing Date").

     Section 6. FCC Cooperation and Related Spectrum Matters. As a material
inducement to each of the parties to enter into this Agreement and as additional
consideration for the transactions contemplated by Sections 2, 3 and 4 above,
the parties hereto agree as follows:

     (a) The parties hereto will cooperate with each other to the maximum extent
possible in agreeing to enter into interference agreements requested by the
other party that are necessary to facilitate the FCC's grant of applications
filed or sponsored by the other party, as more fully described in Article V of
the BTA Lease and Option Agreement, dated October 31, 1997 by and between
Heartland and CS Wireless and their affiliates (hereinafter the "BTA Lease and
Option Agreement"), which agreement is attached hereto as Exhibit D and
incorporated herein by this

                                       7

<PAGE>   11

reference. Heartland and CS Wireless hereby expressly agree to abide by the BTA
Lease and Option Agreement, and that the BTA Lease and Option Agreement,
together with this Agreement, supersedes any other agreements to the contrary;
provided, however, that neither Heartland nor CS Wireless shall be required to
breach any pre-existing agreements with third parties as a result of this
Agreement, or pay monetary or other consideration not otherwise due.

     (b) (i) With respect to markets in which Heartland and CS Wireless have
contiguous or adjacent interests, including, without limitation, Dallas and Fort
Worth, Texas, Heartland and CS Wireless agree to give high priority to resolving
issues surrounding CS Wireless' developmental application for two-way authority
in Dallas/Fort Worth, Texas and to cooperate in an expeditious manner so as to
permit the other party to file two-way transmission applications in such markets
during the first FCC filing window (with priority given to CS Wireless'
Dallas/Fort Worth market) to (A) agree on a comprehensive two-way frequency
utilization plan, (B) implement such plan and (C) provide the other party with
requisite interference consent agreements in support of such party's two-way
applications, as long as such applications meet each party's mutually agreed
upon technical parameters, consistent with FCC rules.

          (ii) Notwithstanding anything to the contrary, CS Wireless and
     Heartland agree that the preferred use of the MDS-1 and MDS-2 channels, as
     well as the WCS Spectrum, shall be for upstream transmissions, and that
     both parties will take all reasonable and appropriate steps to accommodate
     the other party's applications for and the use of such spectrum so long as
     such applications meet the mutually agreed upon technical parameters,
     consistent with FCC rules.

     (c) Notwithstanding anything in the FCC's rules to the contrary, for
purposes of this Agreement, the interference protection criteria applicable to
the WCS Spectrum shall be governed by the FCC rules in 47 C.F.R. Part 21, as
such rules are amended from time to time, applicable to MMDS spectrum licensed
pursuant to BTA authorizations. For example, the maximum power flux density
application to the WCS Spectrum shall be equal to or less than - 73 dbw/m2 at
the BTA or partitioned service area boundary(ies), or as otherwise provided in
any successor rule or regulation of the FCC for MMDS spectrum licensed pursuant
to BTA authorizations.

     (d) Heartland hereby acknowledges its obligation to cooperate with CS
Wireless in resolving a dispute with the licensee of the G group channels in
Grand Rapids, Michigan, Call Sign WLS-950, including, but not limited to,
assigning the lease to CS Wireless on an expeditious basis and permitting CS
Wireless to negotiate and execute an excess capacity lease agreement directly
with the licensee. Notwithstanding anything to the contrary, nothing in this
Section 6(d) shall require Heartland to pay any amount of consideration to the
licensor of such channels or to CS Wireless, or to expend any other amounts
related to such channels, including, without limitation, construction, tower
lease, engineering, legal or other fees.

     Section 7. Conditions to All of the Parties' Obligations.

     (a) The respective obligations of Heartland, CAI and CS Wireless to
consummate the Stage I Transactions, as appropriate, are subject to the
fulfillment prior to or on the Stage I Closing Date of the following conditions
(each of which may be waived in whole or in part by the party

                                       8

<PAGE>   12

being benefitted thereby in its sole discretion):

          (i) Representations and Warranties. The representations and warranties
     of Heartland, CAI and CS Wireless contained in this Agreement shall be
     complete and correct in all material respects when made and at the Stage I
     Closing Date.

          (ii) Compliance. Each of Heartland, CAI and CS Wireless shall have
     performed and complied in all material respects with all agreements and
     conditions contained in this Agreement required to be performed or complied
     with by each of them prior to or on the Stage I Closing Date.

          (iii) Compliance Certificates. Each of Heartland, CAI and CS Wireless
     shall have delivered to the other an Officer's Certificate dated the Stage
     I Closing Date, certifying (A) that the conditions specified in subsections
     (i) and (ii) of this Section 7(a), solely as such conditions relate to the
     certifying party, have been fulfilled, (B) as to resolutions adopted by the
     Board of Directors of Heartland, CAI and CS Wireless, as the case may be,
     which certificate shall have attached thereto a copy of such resolutions,
     and (C) as to such other corporate proceedings relating to the
     authorization, execution and performance of the transactions contemplated
     hereby.

          (iv) Board Authorizations. The Board of Directors of each of
     Heartland, CAI and CS Wireless shall have approved this Agreement and the
     transactions contemplated hereby, and shall have authorized, empowered and
     directed any or all of their corporate officers to execute and deliver this
     Agreement and such agreements, certificates, instruments and other
     documents and to take any and all other actions that may be deemed
     necessary or desirable by the officer taking such action to give effect to
     this Agreement and the transactions contemplated hereby.

          (v) Transactions Permitted under Applicable Law. On the Stage I
     Closing Date, the Stage I Transactions contemplated by this Agreement shall
     (A) be permitted by the laws and regulations of each jurisdiction or
     Governmental Authority, including, without limitation, the FCC, to which
     Heartland, CAI or CS Wireless or any of their respective affiliates, as the
     case may be, is subject, and (B) not violate any applicable law or
     regulation.

          (vi) Certain Proceedings and Regulatory Matters. At the Stage I
     Closing, none of the parties hereto shall be subject to any judgment, writ,
     order, decree or injunction of any court of competent jurisdiction which
     restrains, enjoins or otherwise prohibits the consummation of the Stage I
     Transactions, nor shall there be pending any suit, action, investigation,
     inquiry or other proceeding by any person (including, without limitation,
     any Governmental Authority) that (A) seeks injunctive or other relief or
     remedies in connection with such transactions or that makes consummation of
     the Stage I Transactions subject to significant uncertainty, (B) could
     prevent or make illegal the consummation of the Stage I Transactions
     contemplated hereby, or (C) imposes or would be reasonably expected to
     impose any remedy, condition or restriction on a party hereto which, in its
     reasonable judgment, is material and adverse to such party.

                                       9

<PAGE>   13

          (vii) Third Party Authorization, Consent, etc. All required
     authorizations, consents, approvals or waivers of any third party,
     including, without limitation, consents of Governmental Authorities, if
     any, and any lender to any of the parties hereto, in connection with the
     transactions contemplated hereby shall have been obtained, including,
     without limitation, the consent of the holders of at least a majority of
     aggregate principal amount of the CS Senior Notes, which consent shall be
     in substantially the form of Exhibit F attached hereto.

          (viii) Bankruptcy Proceedings. In the event that Heartland or CS
     Wireless shall have commenced a case under title 11 of the United States
     Code (the "Bankruptcy Code"), the court(s) having jurisdiction over such
     case(s) shall have entered an order (or orders, if both Heartland and CS
     Wireless are debtors under the Bankruptcy Code) (a) authorizing the
     assumption of this Agreement and the BTA Lease Agreement and (b) approving
     the transactions contemplated herein, and such order(s) shall become final
     and non-appealable; provided, however, nothing herein shall preclude the
     parties from consummating the transactions contemplated herein if the
     parties, in their discretion, waive the requirement that such order(s) be
     final and non-appealable. No notice of such waiver of this or any other
     condition to CAI's obligations to consummate the transactions contemplated
     hereby need be given except to Heartland, as explicitly required in this
     Agreement, it being the intention of the parties hereto that CAI shall be
     entitled to, and is not waiving, the protections of Section 363(m) of the
     Bankruptcy Code, the mootness doctrine, and any similar statute or body of
     law if either or both of the Stage I and Stage II Closings occurs in the
     absence of a final and non-appealable order.

          (ix) Proceedings and Documents. All corporate and other proceedings in
     connection with the Stage I Transactions contemplated by this Agreement and
     all documents and instruments incident to such transactions shall be
     reasonably satisfactory to Heartland, CAI and CS Wireless, as the case may
     be, and each party hereto shall have received all such counterpart
     originals or certified or other copies of such documents as it may
     reasonably request.

     (b) The obligations of Heartland and CS Wireless to consummate the Stage II
Transactions are subject to the fulfillment prior to or on the Stage II Closing
Date of the following conditions (each of which may be waived in whole or in
part by the party being benefitted thereby in its sole discretion):

          (i) Consummation of Stage I Transactions. The Stage I Transactions
     shall have been consummated.

          (ii) Representations and Warranties. The representations and
     warranties of Heartland and CS Wireless contained in this Agreement shall
     be complete and correct in all material respects when made and at the Stage
     II Closing Date (except to the extent that such representations and
     warranties relate specifically to an earlier date).

          (iii) Compliance. Each of Heartland and CS Wireless shall have
     performed and complied in all material respects with all agreements and
     conditions contained in this

                                       10

<PAGE>   14

     Agreement required to be performed or complied with by each of them prior
     to or on the Stage II Closing Date.

          (iv) Compliance Certificates. Each of Heartland and CS Wireless shall
     have delivered to the other an Officer's Certificate dated the Stage II
     Closing Date, certifying that (A) the conditions specified in subsections
     (i) through (iii) of this Section 7(b), solely as such conditions relate to
     the certifying party, have been fulfilled, (B)(1) resolutions adopted by
     the Board of Directors of Heartland and CS Wireless delivered at the Stage
     I Closing, and (2) such other corporate proceedings relating to the
     authorization, execution and performance of the transactions contemplated
     hereby are still in full force and effect and have not been rescinded,
     modified or amended.

          (v) Transactions Permitted under Applicable Law. On the Stage II
     Closing Date, the Stage II Transactions shall (A) be permitted by the laws
     and regulations of each jurisdiction or Governmental Authority, including,
     without limitation, the FCC, to which Heartland or CS Wireless or any of
     their respective affiliates, as the case may be, is subject, and (B) not
     violate any applicable law or regulation.

          (vi) Certain Proceedings and Regulatory Matters. At the Stage II
     Closing, none of the parties hereto shall be subject to any judgment, writ,
     order, decree or injunction of any court of competent jurisdiction which
     restrains, enjoins or prohibits the consummation of the Stage II
     Transactions contemplated by this Agreement, nor shall there be pending any
     suit, action, investigation, inquiry or other proceeding by any person
     (including, without limitation, any Governmental Authority) that (A) seeks
     injunctive or other relief or remedies in connection with such transactions
     or that makes consummation of the Stage II Transactions subject to
     significant uncertainty, (B) could prevent or make illegal the consummation
     of the Stage II Transactions contemplated hereby, of (C) imposes or would
     be reasonably expected to impose any remedy, condition or restriction on a
     party hereto which, in its reasonable judgment, is material and adverse to
     such party.

          (vii) Third Party Authorization, Consent, etc. All required
     authorizations, consents, approvals or waivers of any third party,
     including, without limitation, consents of Governmental Authorities, if
     any, and any lender to any of the parties hereto, in connection with the
     Stage II Transactions contemplated hereby shall have been obtained.

          (viii) Proceedings and Documents. All corporate and other proceedings
     in connection with the Stage II Transactions contemplated by this Agreement
     and all documents and instruments incident to such transactions shall be
     reasonably satisfactory to Heartland, CAI and CS Wireless, as the case may
     be, and each party hereto shall have received all such counterpart
     originals or certified or other copies of such documents as it may
     reasonably request.

          (ix) Due Diligence Complete. Each of Heartland and CS Wireless shall
     have completed their business and legal due diligence investigation of the
     assets to be transferred under Section 4, the results of which shall be
     reasonably acceptable to the party performing such investigation.

                                       11

<PAGE>   15

     (c) The obligations of CAI and CS Wireless to consummate the Stage I
Transactions are subject to the fulfillment prior to or on the Stage I Closing
Date, of the following condition (which may be waived in whole or in part by the
party being benefitted thereby in its sole discretion):

          (i) Resignation of Heartland Directors. The Heartland Directors and
     the Heartland Independent Director shall have resigned from the Board of
     Directors of CS Wireless, and all committees thereof effective as of the
     Stage I Closing Date.

     Section 8. Representations and Warranties of the Parties.

     (a) Heartland Representations and Warranties. As a material inducement to
CAI and CS Wireless to enter into this Agreement and effect the transactions
contemplated hereby, Heartland hereby represents and warrants that:

          (i) Title to CS Wireless Common Stock Held by Heartland. Heartland has
     and, subject to the terms and conditions of this Agreement, will sell,
     assign, transfer, convey and deliver, good and indefeasible title to
     3,836,035 shares of CS Wireless Common Stock, which shares comprise
     Heartland's entire equity interest in CS Wireless, free and clear of any
     security interest, claim, lien, pledge, option, encumbrance, charge,
     agreement, voting trust, proxy or other restriction (each, an
     "Encumbrance"), other than those Encumbrances created or existing by virtue
     of the Stockholders' Agreement.

          (ii) Title To Heartland Assets Transferred Hereunder. Except as set
     forth on Schedule 8(a)(ii) attached hereto, Heartland has and, subject to
     the terms and conditions of this Agreement, will sell, assign, transfer,
     convey and deliver, good and indefeasible title to (or a valid leasehold
     interest in) all of the Heartland FCC Assets, the Heartland Leases and the
     Portsmouth Non-FCC Assets transferred hereunder, free and clear of any and
     all Encumbrances.

          (iii) Organization and Qualification. Heartland is a corporation duly
     organized, validly existing and in good standing under the laws of its
     jurisdiction of incorporation and is duly qualified as a foreign
     corporation and in good standing in each other jurisdiction in which the
     ownership, lease or operation of its property and assets or the conduct of
     its business requires such qualification. Heartland has all corporate and
     other necessary power and authority, and the legal right, to own or to hold
     under lease the properties it purports to own or hold under lease and to
     transact the business it transacts and proposes to transact. Heartland has
     all corporate and other necessary power and authority, and the legal right,
     to execute and deliver this Agreement, and each of the other documents
     contemplated hereby to which it is or is to be a party, and to perform its
     obligations hereunder and thereunder and to consummate the transactions
     contemplated hereby and thereby.

          (iv) Authorization. The execution, delivery and performance of this
     Agreement by Heartland does not and will not (A) conflict with or result in
     a breach of the terms, conditions or provisions of, (B) constitute a
     default under, (C) result in the creation of any Encumbrance upon any of
     the Heartland FCC Assets or Heartland Leases pursuant to, (D)

                                       12

<PAGE>   16

     give any third party the right to modify, terminate or accelerate any
     obligation under, (E) result in a violation of, or (F) require any
     authorization, consent, approval, exemption or other action by or notice or
     declaration or filing with any Governmental Authority or any other Person
     (other than as has been duly made or obtained) pursuant to, the charter or
     bylaws of Heartland, or any law, statute, rule or regulation to which
     Heartland or any of its assets is subject, or any agreement, instrument,
     order, judgment or decree to which Heartland or any of its assets is
     subject.

          (v) Compliance with Laws. Except as set forth on Schedule 8(a)(v),
     Heartland is in compliance in all material respects with all laws, rules
     and regulations applicable to the Portsmouth Non-FCC Assets, the Heartland
     FCC Assets and Heartland Leases (including obtaining all authorizations,
     consents, approvals, orders, licenses, exemptions from, and making all
     filings or registrations or qualifications with, any Governmental
     Authority), the noncompliance with which reasonably could have a material
     adverse effect on such assets or the use thereof, and Heartland is in
     compliance in all material respects with all provisions of applicable FCC
     licenses including, without limitation, any build-out requirements and
     other obligations, and with all leases, subleases and sublicenses to it of
     MMDS or MDS channels comprising the Heartland FCC Assets or the Heartland
     Leases, as the case may be. The FCC licenses and channel leases comprising
     the Heartland FCC Assets and Heartland Leases conform in all material
     respects to all applicable laws, ordinances, codes, licensing requirements,
     rules and regulations, and Heartland has not received any notice to the
     contrary. Except as set forth on Schedule 8(a)(v), there are no proceedings
     or complaints or, to the best of Heartland's knowledge, investigations
     pending before or by any Governmental Authority which could reasonably be
     expected to have a material adverse effect on any FCC license or channel
     lease comprising the Heartland FCC Assets or Heartland Leases. All
     applications, reports, fees, filings and other submissions required under
     the Communications Act relating to the Heartland FCC Assets and Heartland
     Leases have been made or paid in a timely fashion.

          (vi) FCC Licenses. Schedule 3(b) attached hereto correctly sets forth
     all of the FCC licenses comprising the Heartland FCC Assets and correctly
     sets forth the termination date of each such FCC license, and Schedule
     4(b)(i) attached hereto identifies all FCC licenses and the owner thereof
     with respect to each of the leased channels comprising the Heartland
     Leases. Each FCC license comprising the Heartland FCC Assets or the
     Heartland Leases allowing the construction or the operation of radio
     station facilities by a lessor of channel capacity who is obligated to
     lease the capacity of the radio station (in whole or in part) under a lease
     agreement or management/option agreement listed on Schedules 3(b) or
     4(b)(i) attached hereto is in full force and effect, and, to the best of
     Heartland's knowledge, neither the licensee of such FCC license nor the FCC
     license is subject to any complaint, investigation or proceeding by or
     before the FCC, or on appeal from the FCC, which looks toward or would
     result in the revocation, modification or non-renewal of the FCC license.
     Except as set forth on Schedule 8(a)(vi), each of such FCC licenses for an
     MMDS or MDS station has a construction completion date which has not
     elapsed or, if such date has elapsed, a request to the FCC to extend that
     date for at least six (6) months has been properly filed and is pending, or
     an application for certification or completion of construction has been
     properly filed. Except as set forth on Schedule 8(a)(vi), the FCC has
     granted one or more

                                       13

<PAGE>   17

     FCC licenses to each lessor of the channel capacity subject to the lease
     and lease/option agreements comprising the Heartland FCC Assets or the
     Heartland Leases allowing that lessor to construct and/or operate each
     radio station required for the lessor to provide to lessee under each such
     agreement executed by such lessor the channel capacity subject to that
     agreement.

          (vii) Litigation. Except as set forth on Schedule 8(a)(vii), there is
     no action, suit, proceeding, arbitration, litigation or government
     proceeding (including, without limitation, those related to FCC,
     environmental or similar matters), or inquiry or investigation by any
     Governmental Authority known to Heartland, in each case domestic or
     foreign, pending against, or involving the Heartland FCC Assets, the
     Heartland Leases or the Portsmouth Non-FCC Assets or the use thereof which
     (A) questions the validity of this Agreement or any action taken or to be
     taken by Heartland pursuant to or in connection with this Agreement, (B) is
     required to be, and has not been, so disclosed in the filings with the SEC
     by Heartland (and such proceedings as are summarized in such SEC filings
     are accurately described in all material respects), or (C) could reasonably
     be expected to materially adversely affect the FCC licenses or channel
     leases comprising the Heartland FCC Assets and the Heartland Leases or the
     operation of the channels and transmission facilities relating thereto.

          (viii) No Violation, etc. Heartland has not violated any law or any
     governmental regulation or requirement which violation has had or would
     reasonably be expected to have a material adverse effect upon the financial
     condition, operating results, assets, operations or business prospects of
     Heartland relating to the Heartland FCC Assets, the Heartland Leases or the
     Portsmouth Non-FCC Assets, and Heartland has not received notice of any
     such violation. Heartland is not subject to, or has reason to believe it
     may become subject to, any material liability (contingent or otherwise) or
     corrective or remedial obligation arising under any environmental law, rule
     or regulation relating to the Heartland FCC Assets, the Heartland Leases or
     the Portsmouth Non-FCC Assets.

          (ix) Copyright Matters. Heartland has submitted all requisite notices
     (if any are required) under the Copyright Act for the carriage of all
     Broadcast Stations as currently carried over any of the Heartland FCC
     Assets. Heartland has filed in a timely manner with the Copyright Office
     all required documents, instruments and statements of account and have
     remitted payments of all required royalty fees with respect to compulsory
     licenses provided for in Section III of the Copyright Act for the carriage
     of broadcast signals in connection with the Heartland FCC Assets. Heartland
     is not liable to any Person for copyright infringement under the Copyright
     Act as a result of its business operations relating to the Heartland FCC
     Assets and the Heartland Leases. There have been no inquiries received from
     the Copyright Office or any other party, which questioned such statements
     of account or any copyright royalty payments made by Heartland with respect
     to the Heartland FCC Assets or Heartland Leases, and no claim, action or
     demand for copyright infringement or for non-payment of royalties is
     pending or, to the knowledge of Heartland, threatened against Heartland
     with respect to the Heartland FCC Assets or Heartland Leases.

          (x) Condition of Portsmouth Non-FCC Assets. Except as set forth on
     Schedule

                                       14

<PAGE>   18

     8(a)(x) and except for ordinary wear and tear, the Portsmouth Non-FCC
     Assets are in good working order for the purpose for which they were
     intended. All transmitters included in the Portsmouth Non-FCC Assets used
     in the Portsmouth market meet all material applicable FCC acceptance and
     frequency stability requirements.

          (xi) No Interference Caused by Portsmouth Market. With respect to its
     Portsmouth market, Heartland has not received any written complaint that
     it, or any channels used in its Portsmouth market, is causing interference
     to any reception, transmission or detection system.

     (b) CS Wireless Representations and Warranties. As a material inducement to
Heartland and CAI to enter into this Agreement and effect the transactions
contemplated hereby, CS Wireless hereby represents and warrants that:

          (i) Title to CPE and Radcliffe Non-FCC Assets. CS Wireless has and,
     subject to the terms and conditions of this Agreement, will sell, assign,
     transfer, convey and deliver, good and indefeasible title to the CPE and
     Radcliffe Non-FCC Assets, free and clear of any and all Encumbrances.

          (ii) Title to CS Wireless FCC Assets and CS Leases Transferred
     Hereunder. Except as set forth on Schedule 8(b)(ii) attached hereto, CS
     Wireless has and, subject to the terms and conditions of this Agreement,
     will sell, assign, transfer, convey and deliver, good and indefeasible
     title to (or a valid leasehold interest in) all of the CS Wireless FCC
     Assets and CS Leases transferred hereunder, free and clear of any and all
     Encumbrances.

          (iii) Organization and Qualification. CS Wireless is a corporation
     duly organized, validly existing and in good standing under the laws of its
     jurisdiction of incorporation and is duly qualified as a foreign
     corporation and in good standing in each other jurisdiction in which the
     ownership, lease or operation of its property and assets or the conduct of
     its business requires such qualification. CS Wireless has all corporate and
     other necessary power and authority, and the legal right, to own or to hold
     under lease the properties it purports to own or hold under lease and to
     transact the business it transacts and proposes to transact. CS Wireless
     has all corporate and other necessary power and authority, and the legal
     right, to execute and deliver this Agreement, and each of the other
     documents contemplated hereby to which it is or is to be a party, and to
     perform its obligations hereunder and thereunder and to consummate the
     transactions contemplated hereby and thereby.

          (iv) Authorization. The execution, delivery and performance of this
     Agreement by CS Wireless does not and will not (A) conflict with or result
     in a breach of the terms, conditions or provisions of, (B) constitute a
     default under, (C) result in the creation of any Encumbrance upon any of
     the CPE, the Radcliffe Non-FCC Assets, the CS Leases or the CS Wireless FCC
     Assets pursuant to, (D) give any third party the right to modify, terminate
     or accelerate any obligation under, (E) result in a violation of, or (F)
     require any authorization, consent, approval, exemption or other action by
     or notice or declaration or filing with any Governmental Authority or any
     other Person (other than as has been duly made or obtained)

                                       15

<PAGE>   19

     pursuant to, the charter or bylaws of CS Wireless, or any law, statute,
     rule or regulation to which CS Wireless or any of its assets is subject, or
     any agreement, instrument, order, judgment or decree to which CS Wireless
     or any of its assets is subject.

          (v) Compliance with Law. Except as set forth on Schedule 8(b)(v), CS
     Wireless is in compliance in all material respects with all laws, rules and
     regulations applicable to the CPE, the Radcliffe Non-FCC Assets, the CS
     Leases and the CS Wireless FCC Assets (including obtaining all
     authorizations, consents, approvals, orders, licenses, exemptions from, and
     making all filings or registrations or qualifications with, any
     Governmental Authority), the noncompliance with which reasonably could have
     a material adverse effect on such assets or the use thereof, and CS
     Wireless is in compliance in all material respects with all provisions of
     applicable FCC licenses including, without limitation, any build-out
     requirements and other obligations, and with all leases, subleases and
     sublicenses to it of MMDS, MDS, or ITFS channels comprising the CS Wireless
     FCC Assets and CS Leases, as the case may be. The FCC licenses and channel
     leases comprising the CS Wireless FCC Assets and CS Leases conform in all
     material respects to all applicable laws, ordinances, codes, licensing
     requirements, rules and regulations, and CS Wireless has not received any
     notice to the contrary. Except as set forth on Schedule 8(b)(v), there are
     no proceedings or complaints or, to the best of CS Wireless' knowledge,
     investigations pending before or by any Governmental Authority which could
     reasonably be expected to have a material adverse effect on any FCC license
     or channel lease comprising the CS Wireless FCC Assets or CS Leases. All
     applications, reports, fees, filings and other submissions required under
     the Communications Act relating to the CS Wireless FCC Assets and CS Leases
     have been made or paid in a timely fashion.

          (vi) FCC Licenses. Schedule 3(a)(ii) attached hereto correctly sets
     forth all of the FCC licenses comprising any portion of the CS Wireless FCC
     Assets and correctly sets forth the termination date of each such FCC
     license, and Schedule 4(a)(i) identifies all FCC licenses and the owner
     thereof with respect to each of the leased channels comprising the CS
     Leases. Each FCC license comprising the CS Wireless FCC Assets or CS Leases
     allowing the construction or the operation of radio station facilities by a
     lessor of channel capacity who is obligated to lease the capacity of the
     radio station (in whole or in part) under a lease agreement or
     management/option agreement listed on Schedules 3(a)(ii) or 4(a)(i)
     attached hereto is in full force and effect, and, to the best of CS
     Wireless' knowledge, neither the licensee of such FCC license nor the FCC
     license is subject to any complaint, investigation or proceeding by or
     before the FCC, or on appeal from the FCC, which looks toward or would
     result in the revocation, modification or non-renewal of the FCC license.
     Except as set forth on Schedule 8(b)(vi), each of such FCC licenses for an
     ITFS, MMDS or MDS station has a construction completion date which has not
     elapsed or, if such date has elapsed, a request to the FCC to extend that
     date for at least six (6) months has been properly filed and is pending, or
     an application for certification of completion of construction has been
     properly filed. Except as set forth on Schedule 8(b)(vi), the FCC has
     granted one or more FCC licenses to each lessor of the channel capacity
     subject to the lease and lease/option agreements comprising the CS Wireless
     FCC Assets or the CS Leases allowing that lessor to construct and/or
     operate each radio station required for the lessor to provide to lessee
     under each such agreement executed by such lessor the channel capacity
     subject to that agreement.

                                       16

<PAGE>   20

          (vii) Litigation. Except as set forth on Schedule 8(b)(vii), there is
     no action, suit, proceeding, arbitration, litigation or government
     proceeding (including, without limitation, those related to FCC,
     environmental or similar matters), or inquiry or investigation by any
     Governmental Authority known to CS Wireless, in each case domestic or
     foreign, pending against (or circumstances that may give rise to the same),
     or involving the CPE, the CS Wireless FCC Assets, the CS Leases or the
     Radcliffe Non-FCC Assets or the use thereof which (A) questions the
     validity of this Agreement or any action taken or to be taken by CS
     Wireless pursuant to or in connection with this Agreement, (B) is required
     to be, and has not been, so disclosed in the filings with the SEC by CS
     Wireless (and such proceedings as are summarized in such SEC filings are
     accurately described in all material respects), or (C) could reasonably be
     expected to materially adversely affect the FCC licenses or channel leases
     comprising the CS Wireless FCC Assets or CS Leases or the operation of the
     channels and transmission facilities relating thereto.

          (viii) No Violation, etc. CS Wireless has not violated any law or any
     governmental regulation or requirement which violation has had or would
     reasonably be expected to have a material adverse effect upon the financial
     condition, operating results, assets, operations or business prospects of
     CS Wireless relating to the CPE, the CS Wireless FCC Assets, the CS Leases
     or the Radcliffe Non-FCC Assets, and CS Wireless has not received notice of
     any such violation. CS Wireless is not subject to, or has reason to believe
     it may become subject to, any material liability (contingent or otherwise)
     or corrective or remedial obligation arising under any environmental law,
     rule or regulation relating to the CPE, the CS Wireless FCC Assets, the CS
     Leases or the Radcliffe Non-FCC Assets.

          (ix) Copyright Matters. CS Wireless has submitted all requisite
     notices (if any are required) under the Copyright Act for the carriage of
     all Broadcast Stations as currently carried over any of the CS Wireless FCC
     Assets. CS Wireless has filed in a timely manner with the Copyright Office
     all required documents, instruments and statements of account and have
     remitted payments of all required royalty fees with respect to compulsory
     licenses provided for in Section III of the Copyright Act for the carriage
     of broadcast signals in connection with the CS Wireless FCC Assets. CS
     Wireless is not liable to any Person for copyright infringement under the
     Copyright Act as a result of its business operations relating to the CS
     Wireless FCC Assets and CS Leases. There have been no inquiries received
     from the Copyright Office or any other party, which questioned such
     statements of account or any copyright royalty payments made by CS Wireless
     with respect to the CS Wireless FCC Assets or CS Leases, and no claim,
     action or demand for copyright infringement or for non-payment of royalties
     is pending or, to the knowledge of CS Wireless, threatened against CS
     Wireless with respect to the CS Wireless FCC Assets or CS Leases.

          (x) Condition of CPE and Radcliffe Non-FCC Assets. Except as set forth
     on Schedule 8(b)(x) and except for ordinary wear and tear, the CPE and the
     Radcliffe Non-FCC Assets are in good working order for the purpose for
     which they were intended. All transmitters included in the Radcliffe
     Non-FCC Assets used in the Radcliffe market meet all material applicable
     FCC acceptance and frequency stability requirements.

                                       17

<PAGE>   21

          (xi) No Interference Caused by Radcliffe Market, CS Wireless FCC
     Assets or CS Leases. With respect to its Radcliffe market, CS Wireless has
     not received any written complaint that it, or any channels used in its
     Radcliffe market or otherwise comprising CS Wireless FCC Assets and CS
     Leases, is causing interference to any reception, transmission or detection
     system.

     (c) As a material inducement to Heartland and CS Wireless to enter into
this Agreement and effect the transactions contemplated hereby, CAI hereby
represents and warrants that as of the date hereof:

          (i) Organization and Qualification. CAI is a corporation duly
     organized, validly existing and in good standing under the laws of its
     jurisdiction of incorporation and is duly qualified as a foreign
     corporation and in good standing in each other jurisdiction in which the
     ownership, lease or operation of its property and assets or the conduct of
     its business requires such qualification. CAI has all corporate and other
     necessary power and authority, and the legal right, to own or to hold under
     lease the properties it purports to own or hold under lease and to transact
     the business it transacts and proposes to transact. CAI has all corporate
     and other necessary power and authority, and the legal right, to execute
     and deliver this Agreement, and each of the other documents contemplated
     hereby to which it is or is to be a party, and to perform its obligations
     hereunder and thereunder and to consummate the transactions contemplated
     hereby and thereby.

          (ii) Authorization. The execution, delivery and performance of this
     Agreement by CAI does not and will not (A) conflict with or result in a
     breach of the terms, conditions or provisions of, (B) constitute a default
     under, (C) give any third party the right to modify, terminate or
     accelerate any obligation under, (D) result in a violation of, of (E)
     require any authorization, consent, approval, exemption or other action by
     or notice or declaration or filing with any Governmental Authority or any
     other Person (other than as has been duly made or obtained) pursuant to,
     the charter or bylaws of CAI, or any law, statute, rule or regulation to
     which CAI or any of its assets in subject, or any agreement, instrument,
     order, judgment or decree to which CAI or any of its assets is subject.

          (iii) Litigation. Except as set forth on Schedule 8(c)(iii), there is
     no action, suit, proceeding, arbitration, litigation or government
     proceeding (including, without limitation, those related to FCC,
     environmental or similar matters), or inquiry or investigation by any
     Governmental Authority known to CAI, in each case domestic or foreign,
     pending against or involving CAI which (A) questions the validity of this
     Agreement or any action taken or to be taken by CAI pursuant to or in
     connection with this Agreement or (B) is required to be, and has not been,
     so disclosed in the filings with the SEC by CAI (and such proceedings as
     are summarized in such SEC filings are accurately described in all material
     respects).

          (iv) No Violation, etc. CAI has not violated any law or any
     governmental regulation or requirement which violation has had or would
     reasonably be expected to have a material adverse effect upon the financial
     condition, operating results, assets, operations or business prospects of
     CAI, and CAI has not received notice of any such violation. CAI

                                       18

<PAGE>   22

     is not subject to, or has reason to believe it may become subject to, any
     material liability (contingent or otherwise) or corrective or remedial
     obligation arising under any environmental law, rule or regulation.

          (v) Investment Representation. CAI is purchasing the CS Wireless
     Common Stock for its own account and not with a view to the public
     distribution thereof. CAI acknowledges that the CS Wireless Common Stock
     has not been registered under the Securities Act , and that such shares may
     be resold only if registered pursuant to the provisions of the Securities
     Act, or if an exemption from registration is available.

     Section 9. Covenants of All of the Parties.

     (a) Unless otherwise indicated:

          (i) Each of the parties hereto agrees to use commercially reasonable
     efforts to bring about the fulfillment of the conditions precedent to the
     Stage I Closing.

          (ii) Subject to the terms and conditions provided herein, each of the
     parties hereto agrees to (A) use commercially reasonable efforts to take,
     or cause to be taken, all action and to do, or cause to be done, all things
     necessary, proper or advisable under applicable law and regulation to
     consummate and make effective the Stage I Transactions in accordance with
     the terms of this Agreement, perform each of its obligations hereunder,
     including without limitation, the obligations of the parties set forth in
     Section 6 hereof, and (B) cooperate following the Stage I Closing in the
     taking of any actions necessary or desirable in order to effect the
     purposes of this Agreement with respect to the Stage I Transactions.

          (iii) Each party hereto shall promptly inform each of the other
     parties hereto of any circumstance or set of circumstances which could
     reasonably be expected to impair such party's ability to perform any of its
     obligations under this Agreement.

     (b) Unless otherwise indicated:

          (i) Each of the parties hereto agrees to use commercially reasonable
     efforts to bring about the fulfillment of the conditions precedent to the
     Stage II Closing.

          (ii) Subject to the terms and conditions provided herein, each of the
     parties hereto agrees to (A) use commercially reasonable efforts to take,
     or cause to be taken, all action and to do, or cause to be done, all things
     necessary, proper or advisable under applicable law and regulation to
     consummate and make effective the Stage II Transactions in accordance with
     the terms of this Agreement and (B) cooperate following the Stage II
     Closing in the taking of any actions necessary or desirable in order to
     effect the purposes of this Agreement with respect to the Stage II
     Transactions.

          (iii) Each party hereto shall promptly inform each of the other
     parties hereto of any circumstance or set of circumstances which could
     reasonably be expected to impair such party's ability to perform any of its
     obligations under this Agreement.

                                       19

<PAGE>   23

     Section 10. Covenants of Heartland. In addition to the covenants set forth
in Section 9 above:

     (a) Between the date hereof and the Stage I Closing, Heartland shall:

          (i) Retain and safeguard the CS Wireless Common Stock held by it, and
     maintain such CS Wireless Common Stock free and clear of any and all
     Encumbrances and shall not allow, permit or suffer to exist any
     Encumbrance, sale, assignment, lease, waiver of rights or granting of a
     proxy with respect to, voting agreement or trust affecting other than the
     Stockholders' Agreement, or otherwise transfer or dispose of the CS
     Wireless Common Stock held by Heartland.

          (ii) Within three business days of its commencement of a case under
     the Bankruptcy Code, if prior thereto the Stage I Closing has not occurred,
     (a) file with the bankruptcy court a motion (together with appropriate
     supporting papers) requesting the bankruptcy court to enter, an order in
     form and substance reasonably acceptable to CAI and CS Wireless (1)
     authorizing Heartland to assume this Agreement, (2) approving the
     transactions contemplated herein, and (3) authorizing Heartland to assume
     the BTA Lease Agreement, and (b) seek a hearing on such motion to be held
     within 20 days of the date of the filing thereof.

     (b) Between the date hereof and the Stage II Closing, Heartland shall:

          (i) Use its reasonable efforts (A) to cause to be maintained in full
     force and effect, and (B) to cause the holders to renew when required to
     prevent the lapse of, all FCC-issued licenses, conditional licenses and
     authorizations comprising any portion of the Heartland FCC Assets or
     Heartland Leases.

          (ii) Use reasonable efforts to perform each and every obligation of
     the lessee under any and all excess channel capacity lease agreements or
     MDS transmission capacity lease agreements comprising any portion of the
     Heartland FCC Assets or Heartland Leases.

          (iii) Use reasonable efforts to cause each of its lessors to prosecute
     in good faith and diligently pursue each MDS application and ITFS
     application for facilities subject to a lease agreement with Heartland that
     comprise any portion of the Heartland FCC Assets or Heartland Leases.

          (iv) Operate the Heartland FCC Assets in the ordinary course of
     business in accordance with past practices for such operation (except where
     such conduct would conflict with any covenant or other obligation of
     Heartland under this Agreement).

          (v) Promptly notify CAI and CS Wireless in writing of any unusual or
     material developments with respect to the business or operations of any of
     the Heartland FCC Assets or Heartland Leases and of any material changes in
     any of the information contained in Heartland's representation and
     warranties contained in this Agreement.

                                       20

<PAGE>   24

          (vi) Subsequent to its commencement of a case under the Bankruptcy
     Code, seek bankruptcy court approval of, and use its best efforts to
     obtain, an order in form and substance reasonably acceptable to CAI and CS
     Wireless (1) authorizing the assumption of this Agreement, (2) approving
     the transactions contemplated herein, and (3) authorizing Heartland to
     assume the BTA Lease and Option Agreement.

     (c) Between the date hereof and the Stage II Closing, Heartland shall not
allow, permit or suffer to exist:

          (i)The creation, assumption or permitting to exist of any Encumbrance,
     other than the lien for taxes not yet due and payable, on any of the
     Heartland FCC Assets or Heartland Leases.

          (ii) The sale, assignment, lease, waiver of rights with respect to,
     sublease or other transfer or disposal of any and all FCC-issued licenses,
     conditional licenses and authorizations, or the lessee's leasehold interest
     in any excess channel capacity lease agreements or MDS transmission
     capacity lease agreements comprising any portion of the Heartland FCC
     Assets or Heartland Leases.

          (iii) Any material action, or material failure to act under excess
     channel capacity lease agreements or MDS transmission capacity lease
     agreements comprising any portion of the Heartland FCC Assets or Heartland
     Leases, which would constitute a default or a potential default thereunder
     (assuming that any requirements of notice or lapse of time have occurred).

     Section 11. Covenants of CS Wireless. In addition to the covenants set
forth in Section 9 above:

     (a) Between the date hereof and the Stage I Closing,

          (i) CS Wireless shall retain and safeguard the CS Wireless Non-FCC
     Assets and the CS Wireless FCC Assets held by it, and maintain such CS
     Wireless Non-FCC Assets free and clear of all Encumbrances and shall not
     allow, permit or suffer to exist any Encumbrance, sale, assignment, lease,
     waiver of rights with respect to, or otherwise transfer or dispose of the
     CS Wireless Non-FCC Assets and the CS Wireless FCC Assets held by CS
     Wireless; and

          (ii) Within three business days of its commencement of a case under
     the Bankruptcy Code, if prior thereto the Stage I Closing has not occurred,
     (a) file with the bankruptcy court a motion (together with appropriate
     supporting papers) requesting the bankruptcy court to enter, an order in
     form and substance reasonably acceptable to Heartland and CAI (1)
     authorizing CS Wireless to assume this Agreement, (2) approving the
     transactions contemplated herein, and (3) authorizing CS Wireless to assume
     the BTA Lease Agreement, and (b) seek a hearing on such motion to be held
     within 20 days of the date of the filing thereof.

                                       21

<PAGE>   25

     (b) Between the date hereof and the Stage II Closing, CS Wireless shall:

          (i) Use its reasonable efforts (A) to cause to be maintained in full
     force and effect, and (B) to cause the holders to renew when required to
     prevent the lapse of, all FCC-issued licenses, conditional licenses and
     authorizations comprising any portion of the CS Wireless FCC Assets or CS
     Leases.

          (ii) Use reasonable efforts to perform each and every obligation of
     the lessee under any and all excess channel capacity lease agreements or
     MDS transmission capacity lease agreements comprising any portion of the CS
     Wireless FCC Assets or CS Leases.

          (iii) Use reasonable efforts to cause each of its lessors to prosecute
     in good faith and diligently pursue each MDS application and ITFS
     application for facilities subject to a lease agreement with CS Wireless
     that comprise any portion of the CS Wireless FCC Assets or CS Leases.

          (iv) Operate the CS Wireless FCC Assets in the ordinary course of
     business in accordance with past practices for such operation (except where
     such conduct would conflict with any covenant or other obligation of CS
     Wireless under this Agreement).

          (v) Promptly notify Heartland and CAI in writing of any unusual or
     material developments with respect to the business or operations of any of
     the CS Wireless FCC Assets or CS Leases and of any material changes in any
     of the information contained in CS Wireless' representation and warranties
     contained in this Agreement.

          (vi) Subsequent to its commencement of a case under the Bankruptcy
     Code, seek bankruptcy court approval of, and use its best efforts to
     obtain, an order in form and substance reasonably acceptable to Heartland
     (1) authorizing the assumption of this Agreement, (2) approving the
     transactions contemplated herein, and (3) authorizing CS Wireless to assume
     the BTA Lease and Option Agreement.

     (c) Between the date hereof and the Stage II Closing, CS Wireless shall not
allow, permit or suffer to exist:

          (i) The creation, assumption or permitting to exist of any
     Encumbrance, other than the lien for taxes not yet due and payable, on any
     of the CS Wireless FCC Assets or CS Leases. (ii) The sale, assignment,
     lease, waiver of rights with respect to, sublease or other transfer or
     disposal of any and all FCC-issued licenses, conditional licenses and
     authorizations, or the lessee's leasehold interest in any excess channel
     capacity lease agreements or MDS transmission capacity lease agreements
     comprising any portion of the CS Wireless FCC Assets or CS Leases.

          (iii) Any material action, or material failure to act under excess
     channel capacity lease agreements or MDS transmission capacity lease
     agreements comprising any portion

                                       22

<PAGE>   26

     of the CS Wireless FCC Assets or CS Leases, which would constitute a
     default or a potential default of the lessee thereunder (assuming that any
     requirements of notice or lapse of time have occurred).

     Section 12. Releases and Indemnification. As further consideration for the
transactions contemplated hereby, the parties agree as follows:

     (a) At the Stage I Closing, without further action by the parties, CS
Wireless shall release and forever discharge Heartland, its subsidiaries,
affiliates, stockholders, officers, directors, agents, employees, successors and
assigns from any and all actions claims, liabilities, damages, demands,
responsibility and accountability of every nature whatsoever ("Claims"), whether
known or unknown, which CS Wireless ever had, then has or may have for, upon or
by reason of any matter, cause or thing whatsoever against Heartland arising out
of that certain Administrative Services Agreement dated as of February 23, 1996
(the "Services Agreement") by and between Heartland and CS Wireless, including,
without limitation, CS Wireless Systems, Inc. v. Heartland Wireless
Communications, Inc.; Cause No. 98-CI-15104; 225th District Court, Bexar County,
Texas, from the beginning of the world to the Stage I Closing Date, or which CS
Wireless may from and after the Stage I Closing Date have against Heartland by
reason of any matter, act, omission, cause or event arising solely out of the
Services Agreement, which has occurred or which has been done or suffered to be
done before the Stage I Closing Date. CS Wireless hereby agrees to withdraw,
with prejudice, CS Wireless Systems, Inc. v. Heartland Wireless Communications,
Inc.; Cause No. 98-CI-15104; 225th District Court, Bexar County, Texas on or
before the Stage I Closing.

     (b) At the Stage I Closing, without further action by the parties,
Heartland shall release and forever discharge CS Wireless, its subsidiaries,
affiliates, stockholders, officers, directors, agents, employees, successors and
assigns from any and all Claims, whether known or unknown, which Heartland ever
had, then has or may have for, upon or by reason of any matter, cause or thing
whatsoever against CS Wireless arising out of the Services Agreement and any
Claim capable of being asserted in connection therewith from the beginning of
the world to the Stage I Closing Date, or which Heartland may hereafter have
against CS Wireless by reason of any matter, act, omission, cause or event
arising solely out of the Services Agreement, which has occurred or which has
been done or suffered to be done before the Stage I Closing Date.

     (c) At the Stage I Closing, without further action by the parties, each of
the parties hereto shall release and forever discharges the other parties
hereto, their respective subsidiaries, affiliates, stockholders, officers,
directors, agents, employees, successors and assigns from any and all Claims,
whether known or unknown, which each such party ever had, then has or may have
for, upon or by reason of any matter, cause or thing whatsoever against the
other parties hereto arising solely out of the Participation Agreement or the
Stockholders' Agreement from the beginning of the world to the Stage I Closing
Date, or which each such party may hereafter have against the other parties
hereto by reason of any matter, act, omission, cause or event arising solely out
of the Participation Agreement or the Stockholders' Agreement, which has
occurred or which has been done or suffered to be done before the date hereof.

     (d) CS Wireless acknowledges and ratifies the terms and conditions of that
certain Separation Agreement dated as of October 19, 1998 (the "Separation
Agreement") by and between

                                       23

<PAGE>   27

Frank H. Hosea ("Hosea") and CS Wireless. CS Wireless acknowledges that (i)
Hosea has been employed by Heartland as Senior Vice President - Video Operations
and (ii) Hosea's employment by Heartland does not violate or breach the
Non-Compete Restrictions as defined and set forth in Section 5 of the Separation
Agreement or any non-disclosure covenants contained in Paragraph 9(a) of the
Employment Agreement dated as of April 2, 1997 or the Non-Disclosure Agreement
dated as of April 2, 1997 between Hosea and CS Wireless. Notwithstanding
anything to the contrary set forth in this Section 12(d), CS Wireless'
acknowledgment set forth herein shall not modify or constitute a waiver of CS
Wireless' rights to enforce Hosea's non-disclosure covenants relating to any
person or entity other than Heartland or its existing wholly-owned subsidiaries
set forth in Section 2 of the Separation Agreement or Hosea's obligations
relating to any person or entity other than Heartland or its existing
wholly-owned subsidiaries under the Employment Agreement and Non-Disclosure
Agreement referred to above CS Wireless expressly agrees to assume the
Separation Agreement described above in any bankruptcy proceeding filed by or
against CS Wireless.

     (e) Notwithstanding anything to the contrary, CAI shall indemnify and hold
Heartland harmless from any and all Claims arising from or in connection with
CAI's purchase from Heartland of the CS Wireless Common Stock at the Stage I
Closing pursuant to Section 2 of this Agreement, including any such Claims
arising from, in connection with, or related to any subsequent disposition or
transfer of the CS Wireless Common Stock by CAI; provided, however, any
liability of CAI to Heartland arising by operation of this Section 12(e) arising
from, in connection with, or related to a subsequent disposition or transfer of
the CS Wireless Common Stock by CAI to CS Wireless shall be deemed fully
satisfied by CAI with the return to CS Wireless of any and all consideration
received by CAI from CS Wireless for such disposition or transfer, and
thereafter, Heartland shall no longer have any claim for indemnification against
CAI under this Section 12(e).

     (f) In the event CS Wireless commences a bankruptcy proceeding, CAI shall
use its best efforts in its capacity as a stockholder of CS Wireless, and shall
cause the CAI Directors and CAI Independent Directors (each as defined in the
Stockholders' Agreement) to use their best efforts, recognizing and taking into
consideration the various fiduciary duties owed by such directors to various CS
Wireless constituencies, to cause (i) CS Wireless to fulfill its obligations to
the Heartland Directors, the Heartland Independent Directors and Hosea, and (ii)
CS Wireless to treat its indemnity obligations to the Heartland Directors, the
Heartland Independent Directors and Hosea no less favorably than CS Wireless
treats its indemnity obligations to any other person who has served, is serving
or may hereafter serve as a member of the board of directors of CS Wireless.

     Section 13. Termination.

     (a) This Agreement may be terminated at any time prior to the Stage I
Closing by mutual written consent of the parties hereto.

     (b) This Agreement shall terminate (without further action or notice (in
writing or otherwise) by any of the parties hereto), unless CAI and Heartland
shall have extended in writing date or the period set forth in this Section 13
(or any of the extended dates or periods), if the Stage I Closing shall not have
occurred by December 4, 1998.

     (c) In the event of a termination of this Agreement in accordance with this
Section 13,

                                       24

<PAGE>   28

this Agreement shall forthwith become void and of no further force and effect,
and there shall be no liability hereunder on the part of any party or its
affiliates, directors, officers, shareholders, agents or other representatives;
provided, however, that Sections 2(b), 13, 15 and 16, inclusive, shall survive
any termination of this Agreement, and (ii) nothing herein shall relieve any
party from liability for any breach of this Agreement; provided further,
however, that if the Stage I Closing shall have occurred prior to the
termination of this Agreement, Section 12 shall survive and nothing contained
herein shall limit, abridge or otherwise affect, or relieve any party from, the
continuing rights and obligations arising out of such Stage I Closing.

     Section 14. Further Assurances. The parties hereto agree to take all
actions necessary or advisable, in the opinion of the party taking such action,
to effect the terms of the provisions hereof.

     Section 15. No Waiver. Failure by any party hereto to insist on strict
performance or observance of any provision of this Agreement or to exercise any
right or remedy shall not be construed as a waiver of any right or remedy with
respect to any existing or subsequent breach or default.

     Section 16. Miscellaneous.

     (a) Entire Agreement. This Agreement and the exhibits and schedules
attached hereto and the BTA Lease and Option Agreement, as amended, constitute
the entire agreement among the parties with respect to the subject matter hereof
and supersedes any and all previous agreements, representations and
understandings among the parties hereto with respect to such matters whether
oral or in writing.

     (b) Governing Law. This Agreement shall be governed by and construed in
accordance with the law of the State of Delaware, without regard to the
principles of conflicts of laws thereof.

     (c) Severability. The invalidity or unenforceability of any provision of
this Agreement shall not affect the validly or enforceability of any other
provision of this Agreement, each of which shall remain in full force and
effect.

     (d) No Third Party Beneficiaries. This Agreement shall be binding upon and
inure to the benefit of the parties hereto and their respective successors and
permitted assigns. Except for the persons not parties to this Agreement who are
being released or indemnified pursuant to Section 12, nothing in this Agreement
shall create or be deemed to create any third party beneficiary rights in any
person not party to this Agreement, including, without limitation, (i) any
receiver appointed for any party hereto, or (ii) any trustee, responsible
officer or other person or entity appointed to manage business or property of
any party hereto in such party's case under any chapter of the Bankruptcy Code.

     (e) Amendments. This Agreement may be amended, supplemented or modified,
and any provision hereof may be waived, only pursuant to a written instrument
making specific reference to this Agreement signed by each of the parties
hereto.

     (f) Expenses. Each of the parties hereto shall be solely responsible for
its fees and

                                       25

<PAGE>   29

expenses incurred in connection with the negotiation, execution, delivery and
performance of this Agreement and the transactions contemplated hereby.

     (g) Counterparts. This Agreement may be executed by facsimile and in any
number of counterparts, each of which shall be deemed an original, but all of
which together shall constitute one and the same instrument.

     (h) Public Announcements. The parties hereto will agree upon the timing and
content of an initial press release to be issued describing the transactions
contemplated by this Agreement, and will not make any public announcement
thereof prior to reaching such agreement unless required to do so by applicable
law or regulation.

     (i) Names, Captions, etc. The name assigned this Agreement and the section
captions used herein are for convenience or reference only and shall not affect
the interpretation or construction thereof.

     (j) No Strict Construction. The parties hereto have participated jointly in
the negotiation and drafting of this Agreement. In the event an ambiguity or
question of intent or interpretation arises, this Agreement shall be construed
as if drafted jointly by the parties hereto, and no presumption or burden of
proof shall arise favoring or disfavoring any party by virtue of authorship of
any of the provisions of this Agreement.

     (k) Enforcement of Agreement. The parties hereto agree that irreparable
damage would occur in the event that any provision of this Agreement was not
performed in accordance with its specific terms or was otherwise breached. It is
accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce the terms and
provisions hereof in any state or federal court in the State of Delaware, this
being in addition to any other remedy to which they are entitled at law or in
equity.

              [The balance of this page intentionally left blank.]

                                       26

<PAGE>   30

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement through
their duly authorized representatives on the day and year first above written.

                                       HEARTLAND WIRELESS
                                       COMMUNICATIONS, INC.

                                       By: /s/ MARJEAN HENDERSON
                                           -------------------------------------
                                       Name:  Marjean Henderson
                                       Title: Sr. VP & CFO

                                       CS WIRELESS SYSTEMS, INC.

                                       By: /s/ DAVID E. WEBB
                                           -------------------------------------
                                       Name:  David E. Webb
                                       Title: Chief Executive Officer

                                       CAI WIRELESS SYSTEMS, INC.

                                       By: /s/ ILLEGIBLE
                                           -------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       27

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