<PAGE>

                                                                     Exhibit 4.3

                              TELECORP PCS, INC.

                  Senior Subordinated Discount Notes Due 2010



                     Form of SECURITIES PURCHASE AGREEMENT


                         Dated as of __________, 2000
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
<S>                                                                         <C>
1.   Sale; Closing.........................................................    2
      1.1  Closing.........................................................    2
      1.2  Payment.........................................................    2
      1.3  Legal Fees......................................................    3

2.   Representations, Warranties and Agreements of the Company.............    3

      2.1  Private Placement...............................................    3
      2.2  Organization....................................................    3
      2.3  Capitalization..................................................    3
      2.4  Authority.......................................................    4
      2.5  Legality of Securities Purchase Agreement.......................    4
      2.6  Legality of Indenture...........................................    4
      2.7  Legality of Notes...............................................    4
      2.8  No Conflict.....................................................    4
      2.9  SEC Documents; Undisclosed Liabilities..........................    5
     2.10  Litigation......................................................    6
     2.11  Restraints on Issuance..........................................    6
     2.12  Compliance with Laws and Agreements.............................    6
     2.13  Licenses........................................................    6
     2.14  Taxes...........................................................    7
     2.15  Investment Company; Public Utility Holding Company..............    7
     2.16  Management Controls.............................................    7
     2.17  Insurance.......................................................    7
     2.18  Intellectual Property...........................................    7
     2.19  Properties......................................................    8
     2.20  Labor Matters...................................................    8
     2.21  ERISA...........................................................    8
     2.22  Environmental...................................................    8
     2.23  Business Practices..............................................    9
     2.24  Warrants; Options...............................................    9
     2.25  Margin Securities...............................................    9
     2.26  Integration.....................................................    9
     2.27  No General Solicitation.........................................    9
     2.28  No Business with Cuba...........................................    9
     2.29  No Material Adverse Change......................................   10
     2.30  Fee Licenses....................................................   10
     2.31  Communications Act..............................................   10
     2.32  Build-Out Plan..................................................   11
     2.33  Certain Fees....................................................   11
</TABLE>

                                      -i-
<PAGE>

<TABLE>
<S>                                                                           <C>
3.   Representations of Purchaser..........................................   11

4.   Agreements of the Company.............................................   11

      4.1  Reports.........................................................   11
      4.2  Blue Sky Qualification..........................................   11
      4.3  Integration.....................................................   11
      4.4  No General Solicitation.........................................   12
      4.5  No Offers.......................................................   12
      4.6  Rule 144........................................................   12
      4.7  Investment Company Act..........................................   12
      4.8  Availability of Company Personnel...............................   13
      4.9  Satisfactory Objections.........................................   13
     4.10  Net Proceeds....................................................   13

5.   Conditions............................................................   13

      5.1  Disclosure......................................................   13
      5.2  Corporate Proceedings...........................................   13
      5.3  Opinions........................................................   13
      5.4  Registration Rights Agreement...................................   13
      5.5  Indenture; Notes................................................   14
      5.6  Material Adverse Change.........................................   14
      5.7  Downgrade of Debt Securities....................................   14
      5.8  Merger..........................................................   14
      5.9  Repayment of Bridge Debt........................................   14
     5.10  Procurement Contract............................................   14
     5.11  Consents, Agreements............................................   14
     5.12  No Actions Pending..............................................   15
     5.13  Purchase Permitted By Applicable Law............................   15
     5.14  Fees............................................................   15
     5.15  Documentation...................................................   15
</TABLE>

                                     -ii-
<PAGE>

<TABLE>
<S>                                                                           <C>

       6.  Termination.....................................................   15

       7.  Special Event of Default........................................   15

       8.  Definitions.....................................................   15

       9.  Fees and Expenses...............................................   17

      10.  Survival of Representations and Warranties......................   18

      11.  Amendments and Waivers..........................................   18

      12.  Notices, etc....................................................   18

      13.  Indemnification.................................................   19

      14.  Successors and Assigns; Replacement of Notes....................   19

      15.  Miscellaneous...................................................   20

      16.  Submission To Jurisdiction; Waivers.............................   20

      17.  Waivers of Jury Trial...........................................   20
</TABLE>

                                     -iii-
<PAGE>

                              TeleCorp PCS, Inc.
                             1010 North Glebe Road
                           Arlington, Virginia 22201

                  Senior Subordinated Discount Notes due 2010

                                                                __________, 2000

Lucent Technologies Inc.
600 Mountain Avenue
Murray Hill, New Jersey  07974

Ladies and Gentlemen:

          TeleCorp PCS, Inc., a Delaware corporation (the "Company"), has
                                                           -------
authorized and proposes to issue and sell $[  ],000,000 aggregate principal
amount of its __%/1/ Senior Subordinated Discount Notes due 2010 (the "Notes").
                                                                       -----
The Notes will be issued pursuant to an Indenture to be dated as of ___, 2000
(the "Indenture") between the Company and [    ] as trustee (the "Trustee") and
      ---------                                                   -------
will be guaranteed on an unsecured senior subordinated basis by each of the
Subsidiary Guarantors (as defined in the Indenture).

          On or prior to the Commitment Termination Date, the Company will issue
and sell to you pursuant to the terms of the Indenture and, subject to the terms
of this Agreement, you will purchase from the Company, Notes in an aggregate
principal amount not to exceed $__,000,000.

          You and your direct and indirect transferees will be entitled to the
benefits of an Exchange and Registration Rights Agreement substantially in the
form attached hereto as Annex A (the "Registration Rights Agreement") pursuant
                                      -----------------------------
to which the Company will agree to file with the Securities and Exchange
Commission (the "Commission") (i) a registration statement (the "Exchange Offer
                 ----------                                      --------------
Registration Statement") under the Securities Act of 1933 (the "Securities Act")
----------------------                                          --------------
registering an issue of senior subordinated notes of the Company (the "Exchange
                                                                       --------
Notes") which are identical in all material respects to the Notes (except that
-----
the Exchange Notes will not contain terms with respect to transfer restrictions
or registration rights) and (ii) under certain circumstances, a shelf
registration statement under the Securities Act (the "Shelf Registration
                                                      ------------------
Statement").
---------

__________________________
/1/ Rate will be 25 basis points below the market rate (computed on a bond
basis) for the TeleCorp Wireless Notes due 2009; parties to determine whether
market rate will be the date of issuance or a trailing average price for a
specified period of time.
<PAGE>

          Certain capitalized terms used in this Agreement are defined in
Section 8; all references to a "Schedule" or an "Exhibit" are, unless otherwise
---------
specified, to a Schedule or an Exhibit attached to this Agreement.

          The Company hereby agrees with you as follows:

          1.   Sale; Closing.
               -------------

          1.1  Closing.  (a)  The sale of the Notes to be purchased by you shall
               -------
take place at a closing (the "Closing") on a date (the "Closing Date") not less
                              -------                   ------------
than five Business Days after each of the conditions set forth in Section 5 has
                                                                  ---------
been satisfied or such other time as the Company and you may agree and at such
location as the Company and you may agree. At the Closing, the Company will
deliver to you the Notes to be purchased by you (which amount shall be specified
by the Company to you in a notice delivered not less than five Business Days
prior to the Closing Date) in the form of a single Note (or such greater number
of Notes in denominations of at least $1,000 as you may request in a notice to
the Company not less than two Business Days prior to the Closing Date) dated the
Closing Date and registered in your name (or in the name of your nominee).

          (b)  Not less than 10 Business Days prior to the Closing the Company,
by written notice, may advise you that it will elect to sell Notes to you on two
occasions; provided that (i) each such sale of Notes shall be for a principal
           --------
amount of not less than $[   ],000,000;/2/ (ii) each such issuance shall be
pursuant to an indenture which is substantially identical to the Indenture;
(iii) the parties shall have entered into a securities purchase agreement
substantially identical to this Agreement; and (iv) the parties shall have
entered into a registration rights agreement which is substantially identical to
the Registration Rights Agreement. If the Company makes such election, any
subsequent sale of Notes to be purchased by you will take place at a closing
(the "Second Closing") on a date specified by the Company (the "Second Closing
      --------------                                            --------------
Date") which is not less than five Business Days after a notice from the Company
----
stating that each of the conditions set forth in the securities purchase
agreement relating to such subsequent sale has been satisfied and at such
location as the Company and you may agree. At the Second Closing, the Company
will deliver to you the Notes to be purchased by you in the form of a single
Note (or such greater number of Notes in denominations of at least $1,000 as you
may request not less than two Business Days prior to the Second Closing Date)
dated the Second Closing Date and registered in your name (or in the name of
your nominee).

          1.2  Payment.  Payment for each of the Notes shall be in immediately
               -------
available funds [or, if you elect, by notice to the Company not less than three
Business Days prior to the closing in respect of such Notes, by means of a
credit against amounts due to the Vendor (as defined below) under the General
Agreement for Purchase of Personal Communication Systems and Services effective
as of May 12, 1998 between TeleCorp Wireless, Inc. (formerly known as TeleCorp
PCS, Inc.) and you as Vendor (the "Vendor"), as amended at the Closing Date (the
                                   ------
"Procurement Contract"); provided that, if you elect to credit amounts under the
 --------------------    --------
Procurement Contract, (i) you shall specify by notice to the Company one
Business Day prior to such Closing


________________________
/2/ 50% of principal amount to be issued.

                                      -2-
<PAGE>

which invoices will be so credited and (ii) on the Closing Date, you shall
deliver copies of such invoices marked "paid" against presentation of the Notes
to be delivered by the Company./3/]

          1.3  Legal Fees.  On the Closing Date, the Company will pay the
               ----------
reasonable fees and disbursements of your special counsel in connection with the
transactions contemplated by this Agreement and thereafter the Company will
promptly pay additional reasonable fees and disbursements of such special
counsel incurred in connection with such transactions.

          2.   Representations, Warranties and Agreements of the Company./4/
               ---------------------------------------------------------
The Company represents and warrants to, and agrees with you as follows:

          2.1  Private Placement. Assuming the accuracy of your representations
               -----------------
and warranties contained in Section 3. and your compliance with the agreements
                            ----------
set forth therein, it is not necessary, in connection with the issuance and sale
of the Notes to you and the offer, resale and delivery of the Notes by you in
the manner contemplated by this Agreement to register the Securities under the
Securities Act or to qualify the Indenture under the Trust Indenture Act of 1939
(the "Trust Indenture Act").
      -------------------

          2.2  Organization.  Except as set forth in Schedule 2.2 hereto, the
               ------------                          ------------
Company has no subsidiaries and holds no minority interest in any entity. The
Company and each of its subsidiaries have been duly incorporated or formed and
are validly existing as corporations, limited liability companies or limited
partnerships in good standing under the laws of their respective jurisdictions
of incorporation or formation, are duly qualified to do business and are in good
standing as foreign corporations, limited liability companies or limited
partnerships in each jurisdiction in which their respective ownership or lease
of property or the conduct of their respective businesses requires such
qualification, and have all power and authority necessary to own or hold their
respective properties and to conduct the businesses in which they are engaged,
except where the failure to so qualify or have such power or authority could
not, singularly or in the aggregate, be reasonably expected to have a material
adverse effect on (i) the condition (financial or otherwise), results of
operations, business or business prospects of the Company and its subsidiaries
taken as a whole, (ii) the ability of the Company or any of its subsidiaries to
perform its obligations under the Transaction Documents or (iii) the validity or
enforceability of any Transaction Document or the rights and remedies of the
Holders of the Notes (a "Material Adverse Effect").
                         -----------------------

          2.3  Capitalization.  As of the Closing Date, the Company will have an
               --------------
authorized capitalization as set forth in Schedule 2.3; all the outstanding
                                          ------------
shares of capital stock of the Company have been duly and validly authorized and
issued and are fully paid and non-assessable; and the capital stock of the
Company conforms in all material respects to the description thereof contained
in the [Form S-4 prepared in connection with the Merger]/5/. All the

------------
/3/ Remains only if Procurement Contract is at post-merger TeleCorp PCS, Inc.
level.

/4/ Subject to scheduled exceptions as may be determined at the time this
Agreement is executed.

/5/ To be updated to include the most recent description of capital stock that
is on file with the SEC at the time this Agreement is executed.

                                      -3-
<PAGE>

outstanding shares of capital stock of each subsidiary of the Company have been
duly and validly authorized and issued, are fully paid and non-assessable and,
except as set forth on Schedule 2.3, are owned directly or indirectly by the
                       ------------
Company, free and clear of any Lien.

          2.4  Authority.  The Company has full right, power and authority to
               ---------
execute and deliver this Agreement, the Indenture, the Registration Rights
Agreement and the Notes (collectively, the "Transaction Documents") and to
                                            ---------------------
perform its obligations hereunder and thereunder; and all corporate action
required to be taken for the due and proper authorization, execution and
delivery of each of the Transaction Documents and the consummation of the
transactions contemplated thereby have been duly and validly taken.

          2.5  Legality of Securities Purchase Agreement.  This Agreement has
               -----------------------------------------
been duly authorized, executed and delivered by the Company and constitutes a
valid and legally binding agreement of the Company.

          2.6  Legality of Registration Rights Agreement.  The Registration
               -----------------------------------------
Rights Agreement has been duly authorized by the Company and, when duly executed
and delivered in accordance with its terms by each of the parties thereto, will
constitute a valid and legally binding agreement of the Company enforceable
against the Company in accordance with its terms, except to the extent that such
enforceability may be limited by applicable bankruptcy, insolvency, fraudulent
conveyance, reorganization, moratorium and other similar laws affecting
creditors rights generally and by general equitable principles (whether
considered in a proceeding in equity or at law).

          2.7  Legality of Indenture.  The Indenture has been duly authorized by
               ---------------------
the Company and, when duly executed and delivered in accordance with its terms
by each of the parties thereto, will constitute a valid and legally binding
agreement of the Company enforceable against the Company in accordance with its
terms, except to the extent that such enforceability may be limited by
applicable bankruptcy, insolvency, fraudulent conveyance, reorganization,
moratorium and other similar laws affecting creditors rights generally and by
general equitable principles (whether considered in a proceeding in equity or at
law). On the Closing Date, the Indenture will conform in all material respects
to the requirements of the Trust Indenture Act and the rules and regulations of
the Commission applicable to an indenture which is qualified thereunder.

          2.8  Legality of Notes.  The Notes have been duly authorized by the
               -----------------
Company and, when duly executed, authenticated, issued and delivered as provided
in the Indenture and paid for as provided herein, will be duly and validly
issued and outstanding and will constitute valid and legally binding obligations
of the Company, as issuer, entitled to the benefits of the Indenture and
enforceable against the Company as issuer, in accordance with their terms,
except to the extent that such enforceability may be limited by applicable
bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and
other similar laws affecting creditors rights generally and by general equitable
principles (whether considered in a proceeding in equity or at law).

          2.9  No Conflict.  The execution, delivery and performance by the
               -----------
Company of each of the Transaction Documents to which it is a party, the
issuance, authentication, sale and

                                      -4-
<PAGE>

delivery of the Notes and compliance by the Company with the terms thereof and
the consummation of the transactions contemplated by the Transaction Documents
(i) will not conflict with or result in a breach or violation of any of the
terms or provisions of, or constitute a default under, or result in the creation
or imposition of any lien, charge or encumbrance upon any property or assets of
the Company or any of its subsidiaries (other than as provided by the Indenture)
pursuant to, any material indenture, mortgage, deed of trust, loan agreement or
other material agreement or instrument to which the Company or any of its
subsidiaries is a party or by which the Company or any of its subsidiaries is
bound or to which any of the property or assets of the Company or any of its
subsidiaries is subject, nor will such actions result in any violation of the
provisions of the charter or by-laws of the Company or any of its subsidiaries
or any statute or any judgment, order, decree, rule or regulation of any court
or arbitrator or governmental agency or body having jurisdiction over the
Company or any of its subsidiaries or any of their properties or assets; except
where such conflict, breach, violation, default or lien, charge or encumbrance
would not, singularly or in the aggregate, have a Material Adverse Effect and
(ii) no consent, approval, authorization or order of, or filing or registration
with, any such court or arbitrator or governmental agency or body under any such
statute, judgment, order, decree, rule or regulation is required for the
execution, delivery and performance by the Company of each of the Transaction
Documents, the issuance, authentication, sale and delivery of the Notes and
compliance by the Company with the terms thereof and the consummation of the
transactions contemplated by the Transaction Documents, except for such
consents, approvals, authorizations, filings, registrations or qualifications
(i) which shall have been obtained or made prior to the Closing Date, (ii) as
may be required to be obtained or made under the Securities Act and the rules
and regulations promulgated thereunder and applicable state securities laws as
provided in the Registration Rights Agreement, (iii) the failure to obtain could
not reasonably be expected to have a Material Adverse Effect or (iv) which are
otherwise not material in the context of the sale of the Notes.

          2.10  SEC Documents; Undisclosed Liabilities.  Since ________________,
                --------------------------------------
the Company and its subsidiaries have filed with the Commission all reports,
schedules, forms, statements and other documents (including exhibits and all
other information incorporated therein) the ("SEC Documents") required to be
                                              -------------
filed under the Securities Act and the Securities Exchange Act of 1934 (the
"Exchange Act"). As of their respective dates, the SEC Documents complied in all
 ------------
material respects with the requirements of the Securities Act or the Exchange
Act, as the case may be, and the rules and regulations of the SEC promulgated
thereunder applicable to such SEC Documents. Except to the extent that
information contained in any SEC Document has been revised or superseded by a
later filed SEC Document, none of the SEC Documents when filed contained any
untrue statement of a material fact or omitted to state a material fact required
to be stated therein or necessary in order to make the statements therein, in
light of the circumstances under which they were made, not misleading. The
financial statements of the Company and its subsidiaries included in the SEC
Documents comply as to form, as of their respective dates of filing with the
SEC, in all material respects with applicable accounting requirements and the
published rules and regulations of the Commission with respect thereto, have
been prepared in accordance with generally accepted accounting principles
(except, in the case of unaudited statements, as permitted by Form 10-Q of the
Commission) applied on a consistent basis during the periods involved (except as
may be indicated in the notes thereto) and fairly present in all material
respects the consolidated financial position of the Company and its subsidiaries
as of the dates thereof and the results of their operations and cash flows
for the

                                      -5-
<PAGE>

periods then ended (subject, in the case of unaudited statements, to normal
recurring year-end audit adjustments). Except for liabilities (i) reflected in
such financial statements or in the notes thereto, (ii) incurred in the ordinary
course of business consistent with past practice since the date of the most
recent audited financial statements included in the SEC Documents, or (iii)
incurred in connection with this Agreement or the transactions contemplated
hereby, neither the Company nor any of its subsidiaries has any liabilities or
obligations (whether absolute, accrued, contingent or otherwise) of any nature
which, individually or in the aggregate, could reasonably be expected to have a
Material Adverse Effect on the Company or its subsidiaries taken as a whole.

          2.11  Litigation.  There are no legal or governmental proceedings
                ----------
pending to which the Company or any of its subsidiaries is a party or of which
any property or assets of the Company or any of its subsidiaries is the subject,
other than proceedings described in the SEC Documents affecting the wireless
communications industry generally which (i) singularly or in the aggregate, if
determined adversely to the Company or any of its subsidiaries, could reasonably
be expected to have a Material Adverse Effect or (ii) question the validity or
enforceability of any of the Transaction Documents or any action taken or to be
taken pursuant thereto; and to the best knowledge of the Company, no such
proceedings are threatened or contemplated by governmental authorities or
threatened by others.

          2.12  Restraints on Issuance.  To the best knowledge of the Company,
                ----------------------
no action has been taken and no statute, rule, regulation or order has been
enacted, adopted or issued by any governmental agency or body which prevents the
issuance of the Notes or suspends the sale of the Notes in any jurisdiction; no
injunction, restraining order or order of any nature by any federal or state
court of competent jurisdiction has been issued with respect to the Company or
any of its subsidiaries which would prevent or suspend the issuance or sale of
the Notes in any jurisdiction; no action, suit or proceeding is pending against
or, to the best knowledge of the Company, threatened against or affecting the
Company or any of its subsidiaries before any court or arbitrator or any
governmental agency, body or official, domestic or foreign, which could
reasonably be expected to interfere with or adversely affect the issuance of the
Notes or in any manner draw into question the validity or enforceability of any
of the Transaction Documents or any action taken or to be taken pursuant
thereto.

          2.13  Compliance with Laws and Agreements.  Neither the Company nor
                -----------------------------------
any of its subsidiaries is (i) in violation of its charter, by-laws, operating
agreement or limited partnership agreement, as appropriate, (ii) in default, and
no event has occurred which, with notice or lapse of time or both, would
constitute a default, in the due performance or observance of any term, covenant
or condition contained in any material indenture, mortgage, deed of trust, loan
agreement or other material agreement or instrument to which it is a party or by
which it is bound or to which any of its property or assets is subject or (iii)
in violation of any law, ordinance, governmental rule, regulation or court
decree to which it or its property or assets may be subject, except, in the case
of clause (ii) or clause (iii), for any default or violation that could not
reasonably be expected to have a Material Adverse Effect.

          2.14  Licenses.  Except as disclosed in the SEC Documents, the Company
                --------
and each of its subsidiaries possess all material licenses, certificates,
authorizations and permits issued by, and have made all declarations and filings
with, the appropriate federal, state or

                                      -6-
<PAGE>

foreign regulatory agencies or bodies which are necessary or desirable for the
ownership of their respective properties or the conduct of their respective
businesses, except where the failure to possess or make the same would not,
singularly or in the aggregate, have a Material Adverse Effect, and neither the
Company nor any of its subsidiaries has received notification of any revocation
or modification of any such license, certificate, authorization or permit or has
any reason to believe that any such license, certificate, authorization or
permit will not be renewed in the ordinary course.

          2.15  Taxes.  The Company and each of its subsidiaries have filed all
                -----
federal, state, local and foreign income and franchise tax returns required to
be filed through the date hereof and have paid all taxes due thereon, and no tax
deficiency has been determined adversely to the Company or any of its
subsidiaries which has had (nor does the Company or any of its subsidiaries have
any knowledge of any tax deficiency which, if determined adversely to the
Company or any of its subsidiaries, could reasonably be expected to have) a
Material Adverse Effect.

          2.16  Investment Company; Public Utility Holding Company.  Neither the
                --------------------------------------------------
Company nor any of its subsidiaries is (i) an investment company or a company
controlled by an investment company within the meaning of the Investment Company
Act of 1940, as amended (the Investment Company Act), and the rules and
regulations of the Commission thereunder or (ii) a holding company or a
subsidiary company of a holding company or an affiliate thereof within the
meaning of the Public Utility Holding Company Act of 1935, as amended.

          2.17  Management Controls.  The Company and each of its subsidiaries
                -------------------
maintain a system of internal accounting controls sufficient to provide
reasonable assurance that (i) transactions are executed in accordance with
management's general or specific authorizations; (ii) transactions are recorded
as necessary to permit preparation of financial statements in conformity with
generally accepted accounting principles and to maintain asset accountability;
(iii) access to financial assets is permitted only in accordance with
management's general or specific authorization; and (iv) the recorded
accountability for assets is compared with the existing assets at reasonable
intervals and appropriate action is taken with respect to any differences to the
extent necessary.

          2.18  Insurance.  The Company and each of its subsidiaries have
                ---------
insurance covering their respective properties, operations, personnel and
businesses, which insurance is in amounts and insures against such losses and
risks as are adequate to protect the Company and its subsidiaries and their
respective businesses, determined by reference to the insurance maintained by
other companies in the wireless communications industry. Neither the Company nor
any of its subsidiaries has received notice from any insurer or agent of such
insurer that capital improvements or other expenditures are required or
necessary to be made in order to continue such insurance.

          2.19  Intellectual Property.  Except as disclosed in Schedule 2.19,
                ---------------------                          -------------
the Company and each of its subsidiaries own or possess adequate rights to use
all patents, patent applications, trademarks, service marks, trade names,
trademark registrations, service mark registrations, copyrights, licenses and
know-how (including trade secrets and other unpatented and/or unpatentable
proprietary or confidential information, systems or procedures) necessary for
the

                                      -7-
<PAGE>

conduct of their respective businesses, except where the failure to possess such
rights could not reasonably be expected to have a Material Adverse Effect; and
the conduct of their respective businesses will not conflict in any respect
with, and the Company and its subsidiaries have not received any notice of any
claim of conflict with, any such rights of others that, if determined adversely
to the Company or any of its subsidiaries would, individually or in the
aggregate, have a Material Adverse Effect.

          2.20  Properties.  The Company and each of its subsidiaries have good
                ----------
and marketable title in fee simple to, or have valid rights to lease or
otherwise use, all items of real and personal property which are material to the
business of the Company and its subsidiaries, in each case free and clear of all
liens, encumbrances, claims and defects and imperfections of title except such
as (i) do not materially interfere with the use made and proposed to be made of
such property by the Company and its subsidiaries or (ii) could not reasonably
be expected to have a Material Adverse Effect.

          2.21  Labor Matters.  No labor disturbance by or dispute with the
                -------------
employees of the Company or any of its subsidiaries exists or, to the best
knowledge of the Company, is contemplated or threatened.

          2.22  ERISA.  No prohibited transaction (as defined in Section 406 of
                -----
the Employee Retirement Income Security Act of 1974, as amended, including the
regulations and published interpretations thereunder ("ERISA"), or Section 4975
                                                       -----
of the Internal Revenue Code of 1986, as amended from time to time (the "Code"))
                                                                         ----
or accumulated funding deficiency (as defined in Section 302 of ERISA) or any of
the events set forth in Section 4043(b) of ERISA (other than events with respect
to which the 30-day notice requirement under Section 4043 of ERISA has been
waived) has occurred with respect to any employee benefit plan of the Company or
any of its subsidiaries which could reasonably be expected to have a Material
Adverse Effect; each such employee benefit plan is in compliance in all material
respects with applicable law, including ERISA and the Code, except where such
noncompliance, individually or in the aggregate, could not reasonably be
expected to have a Material Adverse Effect; the Company and each of its
subsidiaries have not incurred and do not expect to incur liability under Title
IV of ERISA with respect to the termination of, or withdrawal from, any pension
plan for which the Company or any of its subsidiaries would have any liability;
and each such pension plan that is intended to be qualified under Section 401(a)
of the Code has filed for or received a favorable determination letter from the
Internal Revenue Service and the Company has not amended any such pension plan
in any way that could reasonably be expected to cause the loss of such
qualification.

          2.23  Environmental.  There has been no storage, generation,
                -------------
transportation, handling, treatment, disposal, discharge, emission or other
release of any kind of toxic or other wastes or other hazardous substances by,
due to or caused by the Company or any of its subsidiaries (or, to the best
knowledge of the Company, any other entity (including any predecessor) for whose
acts or omissions the Company or any of its subsidiaries is or could reasonably
be expected to be liable) upon any of the property now or previously owned or
leased by the Company or any of its subsidiaries, or upon any other property, in
violation of any statute or any ordinance, rule, regulation, order, judgment,
decree or permit or which would, under any statute or any ordinance, rule
(including rule of common law), regulation, order, judgment,

                                      -8-
<PAGE>

decree or permit, give rise to any liability, except for any violation or
liability that could not reasonably be expected to have, singularly or in the
aggregate with all such violations and liabilities, a Material Adverse Effect;
and there has been no disposal, discharge, emission or other release of any kind
onto such property or into the environment surrounding such property of any
toxic or other wastes or other hazardous substances with respect to which the
Company has knowledge, except for any such disposal, discharge, emission or
other release of any kind which could not reasonably be expected to have,
singularly or in the aggregate with all such discharges and other releases, a
Material Adverse Effect.

          2.24  Business Practices.  Neither the Company nor, to the best
                ------------------
knowledge of the Company, any director, officer, agent, employee or other person
associated with or acting on behalf of the Company or any of its subsidiaries
has (i) used any corporate funds for any unlawful contribution, gift,
entertainment or other unlawful expense relating to political activity; (ii)
made any direct or indirect unlawful payment to any foreign or domestic
government official or employee from corporate funds; (iii) violated or is in
violation of any provision of the Foreign Corrupt Practices Act of 1977, as
amended; or (iv) made any unlawful bribe, rebate, payoff, influence payment,
kickback or other unlawful payment.

          2.25  Warrants; Options.  Except as described in Schedule 2.25, there
                -----------------                          -------------
are no outstanding subscriptions, rights, warrants, calls or options to acquire,
or instruments convertible into or exchangeable for, or agreements or
understandings with respect to the sale or issuance of, any shares of capital
stock of or other equity or other ownership interest in the Company or any of
its subsidiaries.

          2.26  Margin Securities. Neither the Company nor any of its
                -----------------
subsidiaries owns any margin securities as that term is defined in Regulation U
of the Board of Governors of the Federal Reserve System (the Federal Reserve
Board), and none of the proceeds of the sale of the Securities will be used,
directly or indirectly, for the purpose of purchasing or carrying any margin
security, for the purpose of reducing or retiring any indebtedness which was
originally incurred to purchase or carry any margin security or for any other
purpose which might cause any of the Notes to be considered a purpose credit
within the meanings of Regulation T, U or X of the Federal Reserve Board.

          2.27  Integration.  Neither the Company nor any of its affiliates has,
                -----------
directly or through any agent, sold, offered for sale, solicited offers to buy
or otherwise negotiated in respect of, any security (as such term is defined in
the Securities Act), which is or will be integrated with the sale of the Notes
in a manner that would require registration of the Securities under the
Securities Act.

          2.28  No General Solicitation.  None of the Company or any of its
                -----------------------
affiliates or any other person acting on its or their behalf has engaged, in
connection with the offering of the Notes, in any form of general solicitation
or general advertising within the meaning of Rule 502(c) under the Securities
Act.

          2.29  No Business with Cuba.  None of the Company or any of its
                ---------------------
subsidiaries does business with the government of Cuba or with any person or
affiliate located in Cuba within the meaning of Florida Statutes Section
517.075.

                                      -9-
<PAGE>

          2.30  No Material Adverse Change.  Since July 10, 2000, (i) there has
                --------------------------
been no material adverse change or any development involving a prospective
material adverse change in the condition, financial or otherwise, or in the
earnings, business affairs, management or business prospects of the Company and
its subsidiaries, taken as a whole, whether or not arising in the ordinary
course of business, (ii) neither the Company has incurred any material liability
or obligation, direct or contingent, other than in the ordinary course of
business, (iii) the Company has not entered into any material transaction other
than in the ordinary course of business and (iv) there has not been any change
in the capital stock or long-term debt of the Company, or any dividend or
distribution of any kind declared, paid or made by the Company on any class of
its capital stock.

          2.31  Fee Licenses.  (i) The Company and its subsidiaries have the
                ------------
full use and benefit of all broadband personal communications services ("PCS")
                                                                         ---
licenses issued by the Federal Communications Commission (the "FCC") to the
                                                               ---
Company and its subsidiaries (the "Licenses") necessary to operate assets
                                   --------
constituting a radio communications system authorized under the rules for
wireless communications services (including any license and the network,
marketing, distribution, sales, customer interface and operations functions
relating thereto) owned and operated by the Company or any of its subsidiaries
in the Major Trading Areas (as defined in 47 C.F.R. 24.202) and the Basic
Trading Areas (as defined in 47 C.F.R. 24.202) listed on Parts A, B, C and D of
Schedule 2.31 and each other area in which the Company or any of its
-------------
subsidiaries conducts a broadband PCS business; (ii) such Licenses have been
duly issued by the FCC, are (in the case of Licenses listed on Parts A, B, C and
D of Schedule 2.31) or will be (upon consummation of the relevant transaction in
     -------------
the case of Licenses listed on Parts E and F of Schedule 2.31) held by a wholly
                                                -------------
owned subsidiary of the Company and are in full force and effect and (iii) the
Company and its subsidiaries are in compliance in all material respects with all
the provisions of each such License held by any of them.

          2.32  Communications Act. (i) The Company and each of its subsidiaries
                ------------------
are in compliance in all material respects with the Communications Act of 1934,
and any similar or successor federal statute, and the rules and regulations and
published policies of the FCC thereunder, as amended and as in effect from time
to time (collectively, the "Communications Act"), and all requirements of the
                            ------------------
FCC, including the very small business requirements (as defined in 47 C.F.R.
101, 112(b)); (ii) the Company has no knowledge of any investigation, notice of
apparent liability, violation, forfeiture or other order or complaint issued by
or before the FCC, or of any other proceedings (other than proceedings relating
to the wireless communications industries generally) of or before the FCC, which
could reasonably be expected to have a Material Adverse Effect; (iii) no event
has occurred which (A) has resulted in, or after notice or lapse of time or both
would result in, revocation, suspension, adverse modifications, non-renewal,
impairment, restriction or termination of, or order of forfeiture with respect
to, any License in any respect which could reasonably be expected to have a
Material Adverse Effect or (B) affects or could reasonably be expected in the
future to affect any of the rights of the Company or any of its subsidiaries
under any License held by the Company or any of its subsidiaries in any respect
which could reasonably be expected to have a Material Adverse Effect; (iv) the
Company and each of its subsidiaries have duly filed in a timely manner all
material filings, reports, applications, documents, instruments and information
required to be filed under the Communications Act, and all such filings were
when made true, correct and

                                      -10-
<PAGE>

complete in all material respects; and (v) the Company has no reason to believe
that each License of the Company or any of its subsidiaries will not be renewed
in the ordinary course.

          2.33  Build-Out Plan.  TeleCorp Wireless is in compliance in all
                --------------
material respects with its Minimum Build-Out Plan, as defined in the Securities
Purchase Agreement dated January 23, 1998, among AT&T Wireless PCS Inc., TWR
Cellular, Inc., the Cash Equity Investors (as identified therein), the TeleCorp
Investors (as identified therein), Gerald Vento, Thomas Sullivan and TeleCorp
Wireless (the "Equity Securities Purchase Agreement").
               ------------------------------------

          2.34  Certain Fees. Except for the fees referred to in Section 1.3, no
                ------------                                     -----------
broker's or finder's fee or commission has been paid or will be payable by the
Company with respect to the offer, issue and sale of the Notes or with respect
to the transactions contemplated hereunder and the Company hereby indemnifies
you against, and will hold you harmless from, any claim, demand or liability
asserted against you for broker's or finder's fees alleged to have been incurred
by the Company or any other Person (other than you or your affiliates) in
connection with any such offer, issue and sale or the transactions contemplated
hereunder or any of the other transactions contemplated by this Agreement.

          3. Representations of Purchaser. You represent, warrant and agree that
             ----------------------------
(i) you are purchasing the Notes pursuant to a private sale exempt from
registration under the Securities Act and (ii) you have not solicited offers
for, or offered or sold, and will not solicit offers for, or offer or sell, the
Securities by means of any form of general solicitation or general advertising
within the meaning of Rule 502(c) of Regulation D under the Securities Act
("Regulation D") or in any manner involving a public offering within the meaning
  ------------
of Section 4(2) of the Securities Act.

          4. Agreements of the Company.  The Company agrees:
             -------------------------

          4.1  Reports.  For so long as the Notes are outstanding, to furnish to
               -------
you copies of any annual reports, quarterly reports and current reports filed by
the Company with the Commission on Forms 10-K, 10-Q and 8-K, or such other
similar forms as may be designated by the Commission, and such other documents,
reports and information as shall be furnished by the Company to the Trustee or
to the Holders of the Notes pursuant to the Indenture or the Exchange Act or any
rule or regulation of the Commission thereunder.

          4.2  Blue Sky Qualification. The Company shall promptly take from time
               ----------------------
to time such actions as you may reasonably request to qualify the Notes for
offering and sale under the securities or blue sky laws of such jurisdictions as
you may designate and to continue such qualifications in effect for so long as
required for the resale of the Notes; and to arrange for the determination of
the eligibility for investment of the Notes under the laws of such jurisdictions
as you may reasonably request; provided that the Company and its subsidiaries
shall not be obligated to qualify as foreign corporations in any jurisdiction in
which they are not so qualified or to file a general consent to service of
process in any jurisdiction.

          4.3  Integration.  The Company shall not, and the Company shall cause
               -----------
its affiliates not to, sell, offer for sale or solicit offers to buy or
otherwise negotiate in respect of any security (as such term is defined in the
Securities Act) which could be integrated with the sale of

                                      -11-
<PAGE>

the Securities in a manner which would require registration of the Securities
under the Securities Act.

          4.4  No General Solicitation.  Except following the effectiveness of
               -----------------------
the Exchange Offer Registration Statement or the Shelf Registration Statement,
as the case may be, the Company shall not, shall cause its affiliates not to,
and shall not authorize or knowingly permit any person acting on its behalf to,
solicit any offer to buy or offer to sell the Securities by means of any form of
general solicitation or general advertising within the meaning of Regulation D
or in any manner involving a public offering within the meaning of Section 4(2)
of the Securities Act; and not to offer, sell, contract to sell or otherwise
dispose of, directly or indirectly, any securities under circumstances where
such offer, sale, contract or disposition would cause the exemption afforded by
Section 4(2) of the Securities Act to cease to be applicable to the offering and
sale of the Notes.

          4.5  No Offers. For a period of 180 days from the date of the Closing,
               ---------
the Company shall not offer for sale, sell, contract to sell, pledge or
otherwise dispose of, directly or indirectly, or file a registration statement
for, or announce any offer, sale, contract for sale of or other disposition of
any debt securities issued or guaranteed by the Company or any of its
subsidiaries (other than (i) the Notes or the Exchange Securities, (ii) notes
issued by the Company pursuant to the Note Purchase Agreement dated as of May
11, 1998, as amended in October 1999, between TeleCorp Wireless and Lucent
Technologies Inc., (iii) debt securities issued or guaranteed by the Company or
any of its subsidiaries pursuant to credit arrangements with a vendor or
supplier or any financial institution acting on behalf of such vendor or
supplier; provided that any such vendor credit arrangement contains terms
prohibiting the remarketing of all debt securities issued or guaranteed
thereunder for a period of not less than 180 days from the Closing Date and (iv)
the 11 5/8% Senior Subordinated Discount Notes issued by TeleCorp Wireless
pursuant to an Indenture dated April 23, 1999 and the 10 5/8% Senior
Subordinated Notes issued by TeleCorp Wireless pursuant to an Indenture dated
July 14, 2000 and (v) any debt securities issued by the Company or any of its
subsidiaries to the U.S. Government in connection with the acquisition of any
License from the FCC or any debt securities assumed by the Company or any of its
subsidiaries in connection with the acquisition of any License or any entity
engaged in a Permitted Business (as defined in the Indenture).

          4.6  Rule 144. During the period from the Closing Date until two years
               --------
after the Closing Date, without your prior written consent, the Company will
not, and will not permit any of its affiliates (as defined in Rule 144 under the
Securities Act) to, resell any of the Notes that have been reacquired by them,
except for Notes purchased by the Company or any of its affiliates and resold in
a transaction registered under the Securities Act.

          4.7  Investment Company Act. For two years following the date on which
               ----------------------
the Notes are issued, the Company will not be or become, or be or become owned
by, an open-end investment company, unit investment trust or face-amount
certificate company that is or is required to be registered under Section 8 of
the Investment Company Act, and to not be or become, or be or become owned by, a
closed-end investment company required to be registered, but not registered
thereunder.

                                      -12-
<PAGE>

          4.8   Availability of Company Personnel. In connection with the
                ---------------------------------
offering of the Notes, the Company will make its officers, employees,
independent accountants and legal counsel reasonably available upon request by
you.

          4.9   Satisfactory Objections.  The Company shall do and perform all
                -----------------------
things required to be done and performed by it under this Agreement that are
within its control prior to or after the Closing Date, and shall use
commercially reasonable efforts to satisfy all conditions precedent on its part
to the delivery of the Notes.

          4.10  Net Proceeds.  The Company shall apply the net proceeds from the
                ------------
sale of the Notes for general corporate purposes.

          4.11  TeleCorp/Tritel Consent.  To the extent not previously obtained,
                -----------------------
the Company shall use its reasonable best efforts to obtain under the Tritel
Credit Agreement or the TeleCorp Wireless Credit Agreement, as applicable, the
consent contemplated under the definition of the "TeleCorp/Tritel Consent".

          5.    Conditions.  Your obligation to purchase the Notes hereunder is
                ----------
subject to the accuracy, on and as of the date hereof and the Closing Date, of
the representations and warranties of the Company contained herein, to the
accuracy of the statements of the Company and their respective officers made in
any certificates delivered pursuant hereto, to the performance by the Company of
its respective obligations hereunder, and to each of the following additional
terms and conditions:

          5.1   Disclosure.  You shall not have discovered and disclosed to the
                ----------
Company on or prior to the Closing Date that any written material delivered by
the Company to you taken as a whole contains any untrue statement of a fact
which is material or omits to state any fact which is material and is required
to be stated therein or is necessary to make the statements therein not
misleading.

          5.2   Corporate Proceedings.  All corporate proceedings and other
                ---------------------
legal matters incident to the authorization, form and validity of each of the
Transaction Documents, and all other legal matters relating to the Transaction
Documents and the transactions contemplated thereby, shall be satisfactory in
all material respects to you, and the Company shall have furnished to you all
documents and information that you or your counsel may reasonably request to
enable them to pass upon such matters.

          5.3   Opinions.  [    ] shall have furnished to you its written
                --------
opinion, as counsel to the Company, addressed to you and dated the Closing Date,
in form and substance reasonably satisfactory to you, and [Wiley, Rein &
Fielding ] shall have furnished to you its written opinion, as special
communications counsel to the Company, addressed to you and dated as of the
Closing Date, in form and substance reasonably satisfactory you.

          5.4   Registration Rights Agreement.  You shall have received a
                -----------------------------
counterpart of the Registration Rights Agreement which shall have been executed
and delivered by a duly authorized officer of the Company.

                                      -13-
<PAGE>

          5.5  Indenture; Notes. The Indenture shall have been duly executed and
               ----------------
delivered by the Company, and the Trustee, and the Notes shall have been duly
executed and delivered by the Company and duly authenticated by the Trustee.

          5.6  Material Adverse Change. Subsequent to July 10, 2000, there shall
               -----------------------
not have been any change in the capital stock or long-term debt or any change,
or any development involving a prospective change in or affecting the condition
(financial or otherwise), results of operations, business or prospects of the
Company and its subsidiaries taken as a whole, the effect of which, in any such
case described above, is, in your reasonable judgment, so material and adverse
as to make it impracticable or inadvisable to proceed with the sale or delivery
of the Notes on the terms and in the manner contemplated by this Agreement.

          5.7  Downgrade of Debt Securities. Subsequent to July 10, 2000, (i) no
               ----------------------------
downgrading shall have occurred in the rating accorded any of the Company's or
its subsidiaries' debt securities or preferred stock by any "nationally
recognized statistical rating organization", as such term is defined by the
Commission for purposes of Rule 436(g)(2) of the rules and regulations under the
Securities Act, and (ii) no such organization shall have publicly announced that
is has under surveillance or review (other than an announcement with positive
implications of a possible upgrading), its rating of any of the Company's or any
of its subsidiaries' debt securities or preferred stock.

          5.8  Merger. The Merger shall have been consummated and you shall have
               ------
received evidence satisfactory to you that the transaction contemplated under
the Merger Agreement has been consummated in accordance with the terms and
provisions thereof.

          5.9  Repayment of Bridge Debt.  You shall have received satisfactory
               ------------------------
evidence that all obligations under the Credit Agreement dated as of July 13,
2000 among Black Label Wireless, Inc., the lenders party thereto and you as
agent has been satisfied and the commitments thereunder have been terminated.

          5.10 Procurement Contract. The Procurement Contract (including
               --------------------
Amendment No. 8 thereto dated as of July 14, 2000) shall be a legal, valid and
binding obligation of the Company enforceable in accordance with its terms,
shall be in full force and effect and no default or breach by the Company shall
have occurred thereunder which is continuing.

          5.11 Consents, Agreements. The Company shall have obtained all
               --------------------
consents and waivers under any term of any agreement or instrument to which it
is a party or by which it or any of its properties or assets are bound
including, without limitation, any consents or waivers required under the
TeleCorp Wireless Credit Agreement including the TeleCorp/Tritel Consent, or any
term of any applicable law, ordinance, rule or regulation of any Governmental
Authority or any term of any applicable order, judgment or decree of any court,
arbitrator or Governmental Authority, necessary or appropriate in connection
with this Agreement, the Equity Securities Purchase Agreement and the
Procurement Contract, and such consents and waivers shall be in full force and
effect on the Closing Date. A complete and correct copy of each such consent and
waiver shall have been delivered to you.

                                      -14-
<PAGE>

          5.12  No Actions Pending. There shall be no suit, action,
                ------------------
investigation, inquiry or other proceeding by or before any Governmental
Authority or any other Person or any other legal or administrative proceeding,
pending or, to the Company's knowledge, threatened, which questions the validity
or legality of the transactions contemplated hereunder or the payment,
prepayment, administration, sale or other disposition of the Notes or
performance by the Company of its obligations under this Agreement, the
Indenture the Registration Rights Agreement or the Notes and seeks damages or
injunctive or other equitable relief in connection therewith.

          5.13  Purchase Permitted By Applicable Law.  On the Closing Date, your
                ------------------------------------
purchase of Notes (i) shall be permitted by the laws and regulations of each
jurisdiction to which you are subject and (ii) shall not subject you to any tax
(other than taxes based on net income) or penalty.

          5.14  Fees.  The fees required to be paid on the Initial Closing Date
                ----
under Section 1.3 shall have been paid.
      -----------

          5.15  Documentation.  All opinions, letters, evidence and certificates
                -------------
mentioned above or elsewhere in this Agreement shall be deemed to be in
compliance with the provisions hereof only if they are in form and substance
reasonably satisfactory to you.

          6.  Termination.  You may terminate the obligations hereunder, in your
              -----------
absolute discretion, by notice given to and received by the Company prior to
delivery of and payment for the Notes if, prior to that time, any of the events
described in Sections 5.6, 5.7, 5.9 and 5.10 shall have occurred and be
             ------------  ---  ---     ----
continuing.

          7.  Special Event of Default.  Until the occurrence of any of the
              ------------------------
Special Default Release Conditions, the parties hereto agree and the Trustee
acknowledges that it shall be an Event of Default under the Indenture and that
the Trustee or the Holders of at least 25% in aggregate principal amount at
maturity of the outstanding Notes may exercise any of the remedies contemplated
thereunder if the Company shall be in default of or shall breach any of its
obligations under the Procurement Contract and as a result thereof such
Procurement Contract shall have terminated.

          8.  Definitions. As used herein the following terms have the following
              -----------
respective meanings:

          affiliate:  any Person directly or indirectly controlling or
          ---------
controlled by or under common control with another Person or any subsidiary of
such other Person; provided that, for purposes of this definition, "control"
                   --------
(including, with correlative meanings, the terms "controlled by" and "under
common control with"), as used with respect to any Person, shall mean the
possession, directly or indirectly, of the power to direct or cause the
direction of the management and policies of such Person, whether through the
ownership of voting securities or by contract or otherwise.

          Business Day: the meaning specified in the Indenture.
          ------------

                                      -15-
<PAGE>

          Commitment Termination Date:  the earlier of (a) June 30, 2002 and (b)
          ---------------------------
the first anniversary of the consummation of the Merger.

          Default:  the meaning specified in the Indenture.
          -------

          Event of Default:  the meaning specified in the Indenture.
          ----------------

          Governing Documents:  as to any Person, its articles or certificate of
          -------------------
incorporation and by-laws, its partnership agreement, its certificate of
formation and operating agreement, or the other organizational or governing
documents of such Person.

          Governmental Authority:  any nation or government, any state or other
          ----------------------
political subdivision thereof and any entity exercising executive, legislative,
judicial, regulatory or administrative functions of or pertaining to government.

          Holders:  the meaning specified in the Indenture.
          -------

          Indebtedness:  the meaning specified in the Indenture.
          ------------

          Iowa Market:  the meaning given to such term in the Procurement
          -----------
Contract.

          Lien:  the meaning specified in the Indenture.
          ----

          Merger:  the meaning given to such term in the Merger Agreement.
          ------

          Merger Agreement:  the Agreement and Plan of Reorganization and
          ----------------
Contribution dated as of February 28, 2000 by and among TeleCorp Wireless,
Tritel and AT&T Wireless.

          Person:  an individual, a partnership, an association, a joint
          ------
venture, a corporation, a limited liability Company, a business, a trust, an
unincorporated organization or a government or any department, agency or
subdivision thereof.

          reasonable best efforts: shall mean prompt, substantial and persistent
          -----------------------
efforts as a prudent Person desirous of achieving a result would use in a
similar circumstances; provided that the Company, shall be required to expend
                       --------
expend only such resources as are commercially reasonable in the applicable
circumstances.

          Required Holders:  at any time prior to the [Exchange], Holders of the
          ----------------
Notes in an aggregate amount equal to at least a majority of the aggregate
amount of the Notes then outstanding.

          Special Default Release Conditions: the first to occur of the
          ----------------------------------
following events: (i) none of the Securities are then held by you or your
affiliates, (ii) the Company shall have acquired from the Vendor, shall have
deployed and shall have paid all amounts to the Vendor with respect to one
mobile switching center and fifty base stations for Iowa Markets and one mobile
switching center and one hundred base stations for Wisconsin Markets and (iii)
the Exchange Notes shall have been issued.

                                      -16-
<PAGE>

          subsidiary:  with respect to any Person, any corporation or other
          ----------
entity at least 50% (by number of votes) of the Voting Stock or voting power of
which is at the time owned by such Person or by one or more subsidiaries or by
such Person and one or more subsidiaries.  Unless otherwise indicated, all
references to subsidiaries shall be deemed reference to the Company's
subsidiaries.

          TeleCorp Wireless: TeleCorp Wireless, Inc. (formerly known as TeleCorp
          -----------------
PCS, Inc.), a Delaware corporation.

          TeleCorp/Tritel Wireless Consent:  the written consent of the Lenders
          --------------------------------
under the TeleCorp Wireless Credit Agreement or the Tritel Credit Agreement
permitting TeleCorp Wireless or Tritel, as the case may be, to make Restricted
Payments (as defined under the TeleCorp Wireless Credit Agreement or the Tritel
Credit Agreement, as the case may be ) to the Company or any of its subsidiaries
(as directed by the Company), in cash, and without restriction, in an amount
equal to the proceeds of any equity investment contributed by the Company
directly or indirectly to Tritel or TeleCorp Wireless or any of their respective
subsidiaries from the proceeds of the Notes (the amount of such equity
investment to be determined in good faith by the board of directors of the
Company), which dividends shall be payable not later than the first date on
which a cash interest payment is required to be made in respect of the Notes,
such amount not to exceed the amount of excess cash flow generated after the
date such equity investment first occurs or the amount of scheduled payments of
principal and interest).

          TeleCorp Wireless Credit Agreement:  means the Credit Agreement dated
          ----------------------------------
as of July 17, 1998, as amended, waived or otherwise modified from time to time,
among TeleCorp Wireless, the financial institutions named therein as lenders,
The Chase Manhattan Bank, as Administrative Agent and Issuing Bank, TD
Securities (USA) Inc., as Syndication Agent, and Bankers Trust Company, as
Documentation Agent.

          Tritel: Tritel, Inc., a Delaware corporation.
          ------

          Tritel Credit Agreement:  the meaning specified in the Indenture.
          -----------------------

          Wisconsin Market:  the meaning specified in the Procurement  Contract.
          ----------------

          Voting Stock: with reference to any corporation, stock of any class or
          ------------
classes (or equivalent interests), if the holders of the stock of such class or
classes (or equivalent interests) are ordinarily, in the absence of
contingencies, entitled to vote for the election of the directors (or Persons
performing similar functions) of such corporation, even though the right so to
vote has been suspended by the happening of such a contingency.

          9.  Fees and Expenses. Whether or not the transactions contemplated by
              -----------------
this Agreement shall be consummated, the Company will pay all reasonable
expenses in connection with such transactions and in connection with any
amendments or waivers (whether or not the same become effective) under or in
respect of this Agreement, the Indenture, the Notes and the Registration Rights
Agreement, including, without limitation:  (a) the cost and expenses of
preparing and reproducing this Agreement, the Indenture and the Registration
Rights Agreement and the Notes, of furnishing all opinions by counsel for the
Company (including any opinions

                                      -17-
<PAGE>

requested by your special counsel as to any legal matter arising hereunder) and
all certificates on behalf of the Company, and of the Company's performance of
and compliance with all agreements and conditions contained herein on its part
to be performed or complied with; (b) the cost of delivering to your principal
office, insured to your satisfaction, the Notes sold to you hereunder and any
Notes delivered to you upon any substitution of Notes pursuant to the terms of
the Indenture, and of your delivering any Notes, insured to your satisfaction,
upon any such substitution; (c) the costs of preparing the Exchange Offer
Registration Statement, the Shelf Registration Statement, if any, and the
Exchange Notes; (d) the reasonable expenses and disbursements of special counsel
for the Holders of the Notes in connection with such transactions and any such
amendments or waivers; (e) the fees and expenses of the Trustee and any paying
agent (including related fees and expenses of counsel to such parties) and (f)
the reasonable out-of-pocket expenses incurred by you in connection with such
transactions and any such amendments or waivers. The Company also will pay, and
will save you and each Holder of any Notes harmless from, all claims in respect
of the fees, if any, of brokers and finders and any and all liabilities with
respect to any taxes (including interest and penalties but excluding taxes
measured by or payable with respect to gross or net income) which may be payable
in respect of the execution and delivery of this Agreement, the Indenture, the
Registration Rights Agreement, the issue of the Notes and any amendment or
waiver under or in respect of this Agreement, the Indenture, the Registration
Rights Agreement and the Notes. The obligation of the Company under this Section
                                                                         -------
9 shall survive any disposition or payment of the Notes and the termination of
-
this Agreement.

          10.  Survival of Representations and Warranties.  All representations
               ------------------------------------------
and warranties contained in this Agreement or made in writing by or on behalf of
the Company in connection with the transactions contemplated by this Agreement
shall survive the execution and delivery of this Agreement, any investigation at
any time made by you or on your behalf, the purchase of the Notes by you under
this Agreement and any disposition or payment of the Notes. All statements
contained in any certificate or other instrument delivered by or on behalf of
the Company pursuant to this Agreement shall be deemed representations and
warranties of the Company under this Agreement.

          11.  Amendments and Waivers. Any term of this Agreement may be amended
               ----------------------
and the observance of any term of this Agreement may be waived (either generally
or in a particular instance and either retroactively or prospectively) only with
the written consent of the Company and the Required Holders.

          12.  Notices, etc.  Except as otherwise provided in this Agreement,
               -------------
notices and other communications under this Agreement shall be in writing and
shall be delivered by hand or courier service, or mailed by registered or
certified mail, return receipt requested, addressed, (a) if to you, at the
address set forth in Schedule A or at such other address as you shall have
                     ----------
furnished to the Company in writing, with respect to payments on Notes held by
you or your nominee, or (b) if to any other Holder of any Note, at such address
as such other Holder shall have furnished to the Company in writing, or, until
any such other Holder so furnishes to the Company an address, then to and at the
address of the last Holder of such Notes who has furnished an address to the
Company, or (c) if to the Company, at its address set forth at the beginning of
this Agreement, to the attention of General Counsel and Chief Financial Officer,
with copies to ____________________________________ or at such other address, or
to the

                                      -18-
<PAGE>

attention of such other officer, as the Company shall have furnished to you and
each such other Holder in writing. Any notice so addressed and delivered by hand
or courier shall be deemed to be given when received, and any notice so
addressed and mailed by registered or certified mail shall be deemed to be given
three Business Days after being so mailed.

          13.  Indemnification. The Company will indemnify and hold harmless
               ---------------
each Holder of Notes and each person who controls a Holder within the meaning of
the Securities Act or the Exchange Act and each of the Holder's subsidiaries and
each Holder's respective directors, officers, employees, agents and advisors
(any and all of whom are referred to as the "Indemnified Party") from and
                                             -----------------
against any and all losses, claims, damages and liabilities, whether joint or
several (including all legal fees or other expenses reasonably incurred by
counsel for any Indemnified Party in connection with the preparation for or
defense of any pending or threatened third party claim, action or proceeding,
whether or not resulting in any liability), to which such Indemnified Party may
become subject (whether or not such Indemnified Party is a party thereto) under
any applicable federal or state law or otherwise, caused by or arising out of,
this Agreement or any transaction contemplated hereby or thereby (including,
without limitation, any of the foregoing relating to the violation of, non-
compliance with or liability under any environmental law applicable to the
operations of the Company or its subsidiaries), other than, with respect to any
Indemnified Party, losses, claims, damages or liabilities that are the result of
the gross negligence or willful misconduct of such Indemnified Party.

          Promptly after receipt by an Indemnified Party of notice of any claim,
action or proceeding with respect to which an Indemnified Party is entitled to
indemnity hereunder, such Indemnified Party will notify the Company of such
claim or the commencement of such action or proceeding; provided that the
                                                        --------
failure of an Indemnified Party to give notice as provided herein shall not
relieve the Company of its obligations under this Section 13 with respect to
                                                  ----------
such Indemnified Party, except to the extent that the Company is actually
prejudiced by such failure. The Company will assume the defense of such claim,
action or proceeding and will employ counsel reasonably satisfactory to the
Indemnified Party and will pay the fees and expenses of such counsel.
Notwithstanding the preceding sentence, the Indemnified Party will be entitled,
at the expense of the Company, to employ counsel separate from counsel for the
Company and for any other party in such action if the Indemnified Party
reasonably determines that a conflict of interest or other reasonable basis
exists which makes representation by counsel chosen by the Company not
advisable, but the Company will not be obligated to pay the fees and expenses of
more than one counsel for all Indemnified Parties.

          The agreements in this Section 13 shall survive repayment of the Notes
                                 ----------
and all other amounts payable hereunder.

          14.  Successors and Assigns.  This Agreement shall be binding upon and
               ----------------------
inure to the benefit of the Company, the Holders and their respective successors
and assigns, except that the Company may not assign or transfer any of its
rights or obligations under this Agreement, the Indenture, the Registration
Rights Agreement or the Notes without the prior written consent of each Holder.

                                      -19-
<PAGE>

          15.  Miscellaneous.  This Agreement shall be binding upon and inure to
               -------------
the benefit of and be enforceable by the respective successors and assigns of
the parties hereto, whether so expressed or not, and, in particular, shall inure
to the benefit of and be enforceable by any Holder or Holders at the time of the
Notes or any part thereof. This Agreement embodies the entire agreement and
understanding between you and the Company and supersedes all prior agreements
and understandings relating to the subject matter hereof. This Agreement shall
be construed and enforced in accordance with and governed by the law of the
State of New York. The headings in this Agreement are for purposes of reference
only and shall not limit or otherwise affect the meaning hereof. This Agreement
may be executed in any number of counterparts, each of which shall be an
original, but all of which together shall constitute one instrument.

          16.  Submission To Jurisdiction; Waivers.  The Company hereby
               --------------------------------
irrevocably and unconditionally:

          (a)  submits for itself and its property in any legal action or
proceeding relating to this Agreement, or for recognition and enforcement of any
judgment in respect thereof, to the non-exclusive general jurisdiction of the
courts of the State of New York, the courts of the United States of America for
the Southern District of New York, and appellate courts from any thereof;

          (b)  consents that any such action or proceeding may be brought in
such courts and waives any objection that it may now or hereafter have to the
venue of any such action or proceeding in any such court or that such action or
proceeding was brought in an inconvenient court and agrees not to plead or claim
the same;

          (c)  agrees that service of process in any such action or proceeding
may be effected by mailing a copy thereof by registered or certified mail (or
any substantially similar form of mail), postage prepaid, to the Company at its
address set forth in Section 12 or at such other address of which you shall have
                     ----------
been notified pursuant thereto;

          (d)  agrees that nothing contained herein shall affect the right to
effect service of process in any other manner permitted by law or shall limit
the right to sue in any other jurisdiction; and

          (e)  waives, to the maximum extent not prohibited by law, any right it
may have to claim or recover in any legal action or proceeding referred to in
this Section 16 any special, exemplary, punitive or consequential damages.
     ----------

          17.  Waivers of Jury Trial. The Company and you hereby irrevocably and
               ---------------------
unconditionally waive trial by jury in any legal action or proceeding relating
to this agreement and for any counterclaim therein.

                                      -20-
<PAGE>

          If you are in agreement with the foregoing, please sign the form of
agreement on the accompanying counterparts of this letter and return one of the
same to the Company, whereupon this letter shall become a binding agreement
between you and the Company.

                                             Very truly yours,

                                             TELECORP PCS, INC.

                                             By:____________________________
                                                Title:

The foregoing Agreement is
hereby agreed to as of the
date thereof.

LUCENT TECHNOLOGIES INC.


By:______________________
   Title:

Solely for purpose of Section 7
Acknowledged and Agreed
[Trustee].


By:______________________
   Title:

                                      -21-
<PAGE>

                                  SCHEDULE A

                             PURCHASER INFORMATION

Lucent Technologies Inc.
600 Mountain Avenue
Murray Hill, New Jersey 07974

                                      -22-