Document:

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                                                                  Exhibit 10.57

                                                                  Execution Copy

                               SECURITY AGREEMENT

                  This security agreement (this "Agreement"), dated as of August
15, 2001, among Alamosa (Delaware), Inc., a Delaware corporation (the
"Company"), Wells Fargo Bank Minnesota, N.A., as security agent (in such
capacity the "Security Agent"), Wells Fargo Bank Minnesota, N.A., as collateral
agent (in such capacity, the "Collateral Agent")for Wells Fargo Bank Minnesota,
N.A., as trustee (in such capacity, the "August 2001 Trustee") under the August
2001 Indenture (as defined herein), for Wells Fargo Bank Minnesota, N.A., as
trustee (in such capacity, the "2001 Trustee") under the January 2001 Indenture
(as defined herein) and for Wells Fargo Bank Minnesota, N.A., as trustee (in
such capacity, the "2000 Trustee", and together with the August 2001 Trustee and
the January 2001 Trustee, the "Trustees") under the 2000 Indenture (as defined
herein), the August 2001 Trustee (as to paragraph 6(b)) the January 2001 Trustee
(as to paragraph 6(b)) and the 2000 Trustee (as to paragraph 6(b)).

                                    RECITALS

                  A. Pursuant to an Indenture dated as of January 31, 2001 (the
"January 2001 Indenture") among the Company, certain subsidiaries of the Company
(the "Subsidiary Guarantors") and the January 2001 Trustee, the Company issued
$250,000,000 aggregate principal amount of its 12 1/2% Senior Notes due 2011,
including any notes issued in exchange therefor in connection with one or more
registration statements (the "January 2001 Notes").

                  B. Pursuant to an Indenture dated as of August 15, 2001 (the
"August 2001 Indenture") among the Company, certain subsidiaries of the Company
(the "Subsidiary Guarantors") and the August 2001 Trustee, the Company is
issuing $150,000,000 aggregate principal amount of its 13 5/8% Senior Notes due
2011, including any notes issued in exchange therefor in connection with one or
more registration statements (the "August 2001 Notes").

                  C. Pursuant to an Indenture dated as of February 8, 2000 (the
"2000 Indenture", and together with the August 2001 Indenture and the January
2001 Indenture, the "Indentures") among the Company, certain subsidiaries of the
Company and the 2000 Trustee, the Company issued $350,000,000 aggregate
principal amount at maturity of its 12 7/8% Senior Discount Notes due 2010 (the
"2000 Notes", and together with the January 2001 Notes and the August 2001
Notes, the "Notes").

                  D. As security for its obligations under the Notes and the
Indentures, the Company hereby grants to the Collateral Agent, for the equal and
ratable benefit of the 2000 Trustee, the

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January 2001 Trustee and the August 2001 Trustee and the holders of the 2000
Notes, the January 2001 Notes and the August 2001 Notes, a security interest,
subject to and pending disbursement pursuant to this Agreement, in the Security
Account (as defined herein).

                  E. The parties have entered into this Agreement in order to
set forth the conditions upon which, and the manner in which, funds will be
disbursed from the Security Account and released from the security interest and
lien described above.

                  NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows;

         1. Defined Terms. Capitalized terms used and not defined herein shall
have the meanings assigned to such terms in either of the Indentures. In
addition to any other defined terms used herein, the following terms shall
constitute defined terms for purposes of this Agreement and shall have the
meanings set forth below:

                  "Applied" means that disbursed funds have been applied (i) to
the scheduled payment of interest on the Notes, (ii) to the release to the
Company in accordance with Section 3(c) hereof; or (iii) to any combination of
the foregoing.

                  "Available Funds" means (A) the sum of (i) the Initial Escrow
Amount and (ii) dividends and other earnings paid on the funds in the Security
Account (including holdings of U.S. Government Obligations), less (B) the
aggregate disbursements previously made pursuant to this Agreement.

                  "Business Day" shall have the meaning given such term in the
Indentures.

                  "Collateral" shall have the meaning given in Section 6(a)
hereof.

                  "Eligible Institution" means a commercial banking institution
that has combined capital and surplus of not less than $500 million or its
equivalent in foreign currency, whose debt is rated "A" (or higher) according to
Standard & Poor's Ratings Services ("S&P") or Moody's Investors Service, Inc.
("Moody's") at the time as of which any investment or rollover therein is made.

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                  "Interest Payment Date", with respect to any Notes, means the
Interest Payment Date for such Notes as set forth in the applicable Indenture.

                  "Initial Escrow Amount" shall mean $39,200,000 of the proceeds
from the offering of the August 2001 Notes.

                  "January Security Agreement" shall mean the security
agreement, dated as of January 31, 2001, among Alamosa (Delaware), Inc., a
Delaware corporation, Wells Fargo Bank Minnesota, N.A., as security agent, Wells
Fargo Bank Minnesota, N.A., as collateral agent for Wells Fargo Bank Minnesota,
as trustee under the Indenture dated as of January 31, 2001 between Alamosa
(Delaware), Inc. and Wells Fargo Bank Minnesota, N.A., as trustee, the 2001
Trustee (as to paragraph 6(b)) and the 2000 Trustee (as to paragraph 6(b)).

                  "Collateral Agent Payment Notice and Disbursement Request"
means a notice sent by the Collateral Agent on behalf of any of the August 2001
Trustee, the January 2001 Trustee or the 2000 Trustee to the Security Agent
notifying the Security Agent of an upcoming Interest Payment Date in respect of
the 2000 Notes, the January 2001 Notes or the August 2001 Notes and requesting a
disbursement, in substantially the form of Exhibit B hereto. Each Collateral
Agent Payment Notice and Disbursement Request shall be signed by an officer of
the Collateral Agent designated in a certificate of the Collateral Agent setting
forth specimen signatures of authorized officers delivered to the Security
Agent.

                  "Trustee Notice and Disbursement Request" means a notice sent
by the August 2001 Trustee, the January 2001 Trustee or the 2000 Trustee to the
Collateral Agent notifying the Collateral Agent of an upcoming Interest Payment
Date in respect of the 2000 Notes the January 2001 Notes or the August 2001
Notes and requesting a disbursement, in substantially the form of Exhibit A
hereto. Each Trustee Payment Notice and Disbursement Request shall be signed by
an officer of any of the August 2001 Trustee, the January 2001 Trustee or the
2000 Trustee designated in a certificate of the August 2001 Trustee, the January
2001 Trustee or the 2000 Trustee setting forth specimen signatures of authorized
officers delivered to the Collateral Agent.

                  "Security Account" shall mean the Security Account No.
11455501 established by the Security Agent at Wells Fargo Bank Minnesota, N.A.,
Sixth & Marquette, MAC N9303-110, Minneapolis, MN 55479, ABA# 091000019 in the
name "Alamosa (Delaware), Inc." and pursuant to Section 2(a) hereof.

                  "Security Account Statement" shall have the meaning given in
Section 2(f) hereof.

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                  "Withdrawal Certificate" means a certificate of the January
2001 Trustee to the Collateral Agent notifying the Collateral Agent that upon
the occurrence of a scheduled Interest Payment Date with respect to the January
2001 Notes, the January 2001 Trustee had applied to withdraw funds from the
January Security Account to make such payment and (ii) that there had been a
shortfall in the amount contained in such account. Any Withdrawal Certificate
shall be substantially in the form of Exhibit C to the Security Agreement and
shall be signed by an officer of the January 2001 Trustee designated in a
certificate of the January 2001 Trustee setting forth specimen signatures of
authorized officers delivered to the Collateral agent.

         2.       Security Account; Security Agent.

                  (a) Appointment of Security Agent; Establishment of Security
Account. The Company and the Collateral Agent on behalf of the August 2001
Trustee, the January 2001 Trustee and the 2000 Trustee hereby appoint the
Security Agent, and the Security Agent hereby accepts appointment, as Security
Agent, under the terms and conditions of this Agreement.

                  Concurrently with the execution and delivery hereof, the
Security Agent shall establish the Security Account at its office located at
Minneapolis, Minnesota. Subject to Section 3, Section 5 and the other terms and
conditions of this Agreement, all funds accepted by the Security Agent pursuant
to this Agreement shall be held in the Security Account, and all amounts from
time to time in the Security Account shall be held for the equal and ratable
benefit of the holders of the Notes. For all purposes under this Agreement, when
making ratability calculations concerning the distribution of funds between
holders of the August 2001, Notes, the January 2001 Notes and holders of the
2000 Notes, such calculations shall be made by taking the Accreted Value of the
2000 Notes outstanding at such time as the amount of the 2000 Notes outstanding
and by taking the principal amount of each of the January 2001 Notes and the
August 2001 Notes, respectively, outstanding at such time, plus all accrued but
unpaid interest thereon, as the amount of the January 2001 Notes and the August
2001 Notes outstanding, respectively. All such funds shall be held in the
Security Account until disbursed in accordance with the terms hereof. The
Security Account shall be under the sole dominion and control of the Security
Agent for the equal and ratable benefit of the holders of the Notes.
Concurrently with the execution and delivery hereof, the Company shall deliver
the Initial Escrow Amount to the Security Agent for credit to the Security
Account against the Security Agent's written acknowledgment and receipt of the
Initial Escrow Amount.

                  (b) Security Agent Compensation.  The Company shall
pay to the Security Agent such compensation for services to be

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performed by it under this Agreement as are set forth in Exhibit D to this
Agreement.

                  The Company shall reimburse the Security Agent upon request
for all reasonable expenses, disbursements, and advances incurred or made by the
Security Agent in implementing any of the provisions of this Agreement,
including reasonable compensation, expenses and disbursements of its counsel
(such compensation, expenses and disbursements of counsel not to exceed $15,000
in the aggregate), except any such expense, disbursement, or advance as may
arise from its gross negligence or wilful misconduct.

                  (c)      Investment of Funds in Security Account.  Funds
credited to the Security Account shall be invested and reinvested upon the
following terms and conditions:

                  (i) Acceptable Investments. All funds credited to the Security
         Account shall be initially invested by the Security Agent in U.S.
         Government Obligations in accordance with the Company's written
         instructions to the Security Agent. Thereafter, the Security Agent
         shall invest all funds (including proceeds of any such investments at
         maturity and dividends paid and other earnings on any such investments)
         in the Security Account in cash items or U.S. Government Obligations
         designated by the Company in writing from time to time. All U.S.
         Government Obligations in respect of the Security Account shall be
         assigned and credited to and held in the possession of or, in the case
         of U.S. Government Obligations in respect of the Security Account
         maintained in book entry form with the Federal Reserve Bank,
         transferred to a book entry account in the name of, the Security Agent
         in respect of the Security Account, for the equal and ratable benefit
         of the holders of the Notes (subject to Section 3 and Section 5), with
         such guarantees as are customary, except that U.S. Government
         Obligations in respect of the Security Account maintained in book entry
         form with the Federal Reserve Bank shall be transferred to a book entry
         account in the name of the Security Agent at the Federal Reserve Bank
         that includes only U.S. Government Obligations held by the Security
         Agent for its customers and segregated by separate recordation in
         respect of the Security Account in the books and records of the
         Security Agent, subject to the provisions of Section 5 hereof. The
         Security Agent shall credit all such investments to the Security
         Account.

                 (ii) Security Interest in Investments. No investment of funds
         in the Security Account shall be made unless the Company has certified
         to the Security Agent and the Collateral Agent acting for the equal and
         ratable benefit of the 2000 Trustee and the holders of the 2000 Notes,
         the

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         January 2001 Trustee and the holders of the January 2001 Notes and the
         August 2001 Trustee and the holders of the August 2001 Notes that, upon
         such investment, the Collateral Agent acting for the equal and ratable
         benefit of the 2000 Trustee and the holders of the 2000 Notes, the
         January 2001 Trustee and the holders of the January 2001 Notes and the
         August 2001 Trustee and the holders of the August 2001 Notes, will have
         a (to the Company's knowledge, with respect to priority only) first
         priority perfected security interest in the applicable investment. A
         certificate as to a class of investments need not be issued with
         respect to individual investments in securities in that class if the
         certificate applicable to the class remains accurate with respect to
         such individual investments. Counsel to the Company shall provide an
         Opinion of Counsel to the Security Agent or any Trustee, as applicable,
         in the event any such opinion is required for the applicable Indenture
         to remain in compliance with the Trust Indenture Act of 1939.

            (iii) Dividends and other Earnings. All dividends and other earnings
         paid on funds invested in U.S. Government Obligations shall be credited
         to the Security Account as additional Collateral for the benefit of the
         holders of the Notes (subject to Section 3 and Section 5) and shall be
         reinvested in accordance with the terms hereof at the Company's written
         instruction.

             (iv) Limitation on Security Agent's Responsibilities. The Security
         Agent's sole responsibilities under this Section 2 shall be (A) to
         retain possession of certificated U.S. Government Obligations (except,
         however, that the Security Agent may surrender possession to the issuer
         of any such U.S. Government Obligations for the purposes of effecting
         assignment, crediting interest, or reinvesting such security or
         reducing such security to cash) and to be the registered or designated
         owner of U.S. Government Obligations which are not certificated, (B) to
         follow the Company's written instructions given in accordance with
         Section 2(c)(i) hereof, (C) to invest and reinvest funds pursuant to
         this Section 2(c) and (D) to use its best efforts to reduce to cash
         such U.S. Government Obligations as may be required to fund any
         disbursement in accordance with Section 3 hereof. In connection with
         clause (A) above, the Security Agent will maintain continuous
         possession in the State of New York of certificated U.S. Government
         Obligations and cash included in the Collateral and will cause
         uncertificated U.S. Government Obligations to be registered in the
         book-entry system of, and transferred to an account of the Security
         Agent at, the Federal Reserve Bank of New York.

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                  (d) Substitution of Security Agent. The Security Agent may
resign by giving no less than 30 days' prior written notice to the Company and
the Collateral Agent acting on behalf of the August 2001 Trustee, the January
2001 Trustee and the 2000 Trustee. Such resignation shall take effect upon the
later to occur of (i) delivery of all funds and U.S. Government Obligations
maintained by the Security Agent hereunder and copies of all books, records,
plans and other documents in the Security Agent's possession relating to such
funds or U.S. Government Obligations or this Agreement to a successor Security
Agent ap pointed by the Company and (ii) the Company, the Collateral Agent
acting on behalf of the August 2001 Trustee, the January 2001 Trustee and the
2000 Trustee and such successor Security Agent entering into this Agreement or
any written successor agreement no less favorable to the interests of the
holders of the Notes and the Collateral Agent acting on behalf of the August
2001 Trustee, the January 2001 Trustee and the 2000 Trustee than this Agreement;
and the Security Agent shall thereupon be discharged of all obligations under
this Agreement and shall have no further duties, obligations or responsibilities
in connection herewith. If a successor Security Agent has not been appointed or
has not accepted such appointment within 30 days after notice of resignation is
given to the Company, the Security Agent may apply to a court of competent
jurisdiction for the appointment of a successor Security Agent and no such
resignation shall take effect until such appointment of a successor Security
Agent is made and the terms of the second sentence of this Section 2(d) have
been complied with.

                  (e) Security Account Statement. Each month, the Security Agent
shall deliver to the Company, the Collateral Agent, the August 2001 Trustee, the
January 2001 Trustee and the 2000 Trustee a statement of the Security Agent in a
form reasonably satisfactory to the Company and the Collateral Agent setting
forth with reasonable particularity the balance of funds then in the Security
Account and the manner in which such funds have been and are invested (the
"Security Account Statement"). The parties hereto irrevocably instruct the
Security Agent that on the first date upon which the balance in the Security
Account (including the holdings of all U.S. Government Obligations is reduced to
zero, the Security Agent shall, as soon as practicable, deliver to the Company,
to the August 2001 Trustee, the January 2001 Trustee, the 2000 Trustee and to
the Collateral Agent a written notice that the balance in the Security Account
has been reduced to zero.

                  (f)      Representations of Security Agent.  The Security
Agent represents and warrants that (i) the Security Account created by the
Security Agent for purposes of this Agreement is a "securities account" as
defined under Section 8-501 of the UCC

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and (ii) the Security Agent is a "securities intermediary" as defined under
Section 8-102(a) of the UCC.

         3.       Disbursements.

                  (a) Trustee Payment Notice and Disbursement Request;
Disbursements. The applicable Trustee shall, four Business Days prior to a
scheduled Interest Payment Date with respect to any of the Notes, submit to the
Collateral Agent a completed Trustee Payment Notice and Disbursement Request
substantially in the form of Exhibit A hereto. In the event that the applicable
Interest Payment Date relates to the January 2001 Notes, the applicable Trustee
shall also be required to submit to the Collateral Agent a completed Withdrawal
Certificate substantially in the form of Exhibit C hereto. In addition, the
applicable Trustee shall submit to the Collateral Agent a completed Trustee
Payment Notice and Disbursement Request substantially in the form of Exhibit A
hereto in the event that the condition set forth in the first sentence of
Section 3(d) is fulfilled.

                  (b) Collateral Agent Payment Notice and Disbursement Request;
Disbursements. The Collateral Agent, upon receipt of a Trustee Payment Notice,
shall, four Business Days prior to a scheduled Interest Payment Date with
respect to any of the Notes, submit to the Security Agent a completed Collateral
Agent Payment Notice and Disbursement Request substantially in the form of
Exhibit B hereto. In addition, the Collateral Agent shall submit to the Security
Agent a completed Collateral Agent Payment Notice and Disbursement Request
substantially in the form of Exhibit B hereto in the event that the condition
set forth in the first sentence of Section 3(d) is fulfilled.

                  The Security Agent's disbursement pursuant to any Collateral
Agent Payment Notice and Disbursement Request shall be subject to the
satisfaction of the applicable conditions set forth in Section 3(c) hereof.
Provided such Payment Notice and Disbursement Request is not rejected by it for
failure to comply with Section 3(c), the Security Agent, within two (2) Business
Days following receipt of such Collateral Agent Payment Notice and Disbursement
Request, shall disburse the funds requested in such Payment Notice and
Disbursement Request by wire or book- entry transfer of immediately available
funds to the account of the applicable Trustee.

                  (c) Conditions Precedent to Disbursement. The Security Agent's
payment of any disbursement shall be made only if: (A) the Collateral Agent
shall have submitted, in accordance with the provisions of Section 3(b) herein,
a completed Collateral Agent Payment Notice and Disbursement Request to the
Security Agent substantially in the form of Exhibit B hereto with blanks
appropriately filled in; provided, however, that the

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Security Agent shall notify the Collateral Agent as soon as reasonably possible
(but not later than two (2) Business Days from the date of receipt of the
Collateral Agent Payment Notice and Disbursement Request) if any Collateral
Agent Payment Notice and Disbursement Request is rejected for failure to comply
with Section 3(b) and the reasons therefor and upon such notification, the
Collateral Agent shall thereupon resubmit the Payment Notice and Disbursement
Request with appropriate changes; and (B) the Security Agent and the Collateral
Agent shall not have received any notice from the 2000 Trustee, the January 2001
Trustee or the August 2001 Trustee that there has occurred and is continuing an
Event of Default (as defined in the Indentures) (in which event the Security
Agent shall apply all Available Funds as required by Section 6(c)(iii) hereof).
Notwithstanding the previous sentence, in the event that an Event of Default
shall have previously occurred but shall at the time of the Collateral Agent's
submission of a completed Collateral Agent Payment Notice and Disbursement
Request to the Security Agent such Event of Default shall no longer be
continuing, then the Security Agent shall disburse the requested funds as set
forth in the Collateral Agent Payment Notice and Disbursement Request.

                  (d) Final Release. In the event there are any Available Funds
following the disbursement to be made in connection with the interest payment on
the August 2001 Notes due August 15, 2003, such Available Funds (including U.S.
Government Obligations Investments) shall be paid to the Company immediately
upon the submission to the Security Agent of a completed Payment Notice and
Disbursement Request substantially in the form of Exhibit A hereto; provided,
however, that no Event of Default shall have occurred and be continuing at the
time of the submission of such notice. Notwithstanding the previous sentence, in
the event that an Event of Default shall have previously occurred but shall at
the time of the Collateral Agent's submission of a completed Collateral Agent
Payment Notice and Disbursement Request to the Security Agent such Event of
Default shall no longer be continuing, then the Security Agent shall disburse
the requested funds as set forth in the Collateral Agent Payment Notice and
Disbursement Request. At such time as all amounts in the Security Account shall
have been disbursed or released in accordance with this Agreement, the security
interest in the Collateral evidenced by this Agreement shall terminate and be of
no further force and effect. In addition, upon release or disbursement of any
Collateral from the Security Account in accordance with the terms of this
Agreement, the security interest evidenced by this Escrow Agreement in the
Collateral so released shall terminate and be of no further force and effect.

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         4.       Security Agent.

                  Limitation of the Security Agent's Liability; Responsi
bilities of the Security Agent. The Security Agent's responsibility and
liability under this Agreement shall be limited as follows: (i) the Security
Agent does not represent, warrant or guaranty to the holders of the Notes from
time to time the performance of the Company; (ii) the Security Agent shall have
no responsibility to the Company or the holders of the Notes or the Collateral
Agent from time to time as a consequence of the performance by the Security
Agent hereunder, except for any gross negligence or wilful misconduct of the
Security Agent and except with respect to claims based upon such gross
negligence or wilful misconduct that are successfully asserted against the
Security Agent; (iii) the Company shall remain solely responsible for all
aspects of the Company's business and conduct; and (iv) the Security Agent is
not obligated to supervise, inspect, or inform the Company or any third party of
any matter referred to above.

                  No implied covenants or obligations shall be inferred from
this Agreement against the Security Agent, nor shall the Security Agent be bound
by the provisions of any agreement beyond the specific term hereof. Specifically
and without limiting the foregoing, the Security Agent shall in no event have
any liability in connection with its investment, reinvestment or liquidation, in
good faith and in accordance with the terms hereof, of any funds or U.S.
Government Obligations held by it hereunder, including without limitation any
liability for any delay not resulting from gross negligence or wilful misconduct
in such investment, reinvestment or liquidation, or for any loss of principal or
income incident to any such delay.

                  The Security Agent shall be entitled to rely upon any judicial
order or judgment, upon any written Opinion of Counsel or upon any
certification, instruction, notice, or other writing delivered to it by the
Company or the Collateral Agent in compliance with the provisions of this
Agreement without being required to determine the authenticity or the
correctness of any fact stated therein or the propriety or validity of service
thereof. The Security Agent may act in reliance upon any instrument comporting
with the provisions of this Agreement or signature believed by it to be genuine
and may assume that any person purporting to give notice or receipt or advice or
make any statement or execute any document in connection with the provisions
hereof has been duly authorized to do so.

                  At any time, the Security Agent may request in writing an
instruction in writing from the Company, and may at its own option include in
such request the course of action it proposes to take and the date on which it
proposes to act, regarding any matter arising in connection with its duties and
obligations

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hereunder; provided, however, that the Security Agent shall state in such
request that it believes in good faith that such proposed course of action is
consistent with another identified provision of this Agreement. The Security
Agent shall not be liable to the Company for acting without the Company's
consent in accordance with such a proposal on or after the date specified
therein if (i) the specified date is at least two Business Days after the
Company receives the Security Agent's request for instructions and its proposed
course of action, which instructions shall have been delivered to the Company at
least two Business Days prior to such action and (ii) prior to so acting, the
Security Agent has not received the written instructions requested from the
Company, which instructions shall have been delivered to the Company at least
two Business Days prior to such action.

                  The Security Agent may act pursuant to the written advice of
counsel chosen by it with respect to any matter relating to this Agreement and
(subject to this Section 4) shall not be liable for any action taken or omitted
in accordance with such advice.

                  The Security Agent shall not be called upon to advise any
party as to selling or retaining, or taking or refraining from taking any action
with respect to, any securities or other property credited hereunder.

                  In the event of any ambiguity in the provisions of this
Agreement with respect to any funds or property credited hereunder, the Security
Agent shall be entitled to refuse to comply with any and all claims, demands or
instructions with respect to such property or funds, and the Security Agent
shall not be or become liable for its failure or refusal to comply with
conflicting claims, demands or instructions. The Security Agent shall be
entitled to refuse to act until either any conflicting or adverse claims or
demands shall have been finally determined by a court of competent jurisdiction
or settled by agreement between the conflicting claimants as evidenced in a
writing, satisfactory to the Security Agent, in which event the Security Agent
shall act in accordance with such determination or agreement.

                  No provision of this Agreement shall require the Security
Agent to expend or risk its own funds or otherwise incur any financial liability
in the performance of any of its duties hereunder.

                  The Security Agent shall not be required to institute legal
proceedings of any kind and shall not be required to initiate or defend any
legal proceedings which may be instituted against it in respect of the subject
matter of this Agreement. If the Security Agent does elect to act it will do so
only to the

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                                      -12-

extent that it is indemnified to its satisfaction against the cost and expense
of such defense or initiation.

         5. Indemnity. (a) The Company shall indemnify, hold harmless and defend
the Security Agent and its directors, officers, agents, employees and
controlling persons, from and against any and all claims, actions, obligations,
liabilities and expenses, including defense costs, investigative fees and costs,
reasonable legal fees, and claims for damages arising from the Security Agent's
performance under this Agreement, except to the extent that such liability,
cost, legal fee, obligation, action, expense or claim is directly attributable
to the gross negligence or wilful misconduct of any of the foregoing persons.
The Security Agent shall not be entitled to recover any costs arising under this
Section 5 from funds available in the Security Account. The provisions of this
Section shall survive any termination, satisfaction or discharge of this
Agreement as well as the resignation or removal of the Security Agent.

                  (b) The Company shall indemnify, hold harmless and defend the
Collateral Agent and its directors, officers, agents, employees and controlling
persons, from and against any and all claims, actions, obligations, liabilities
and expenses, including defense costs, investigative fees and costs, reasonable
legal fees, and claims for damages arising from the Collateral Agent's
performance under this Agreement, except to the extent that such liability,
cost, legal fee, obligation, action, expense or claim is directly attributable
to the gross negligence or wilful misconduct of any of the foregoing persons.
The Collateral Agent shall not be entitled to recover any costs arising under
this Section 5 from funds available in the Collateral Account. The provisions of
this Section shall survive any termination, satisfaction or discharge of this
Agreement as well as the resignation or removal of the Collateral Agent.

         6.       Grant of Security Interest; Appointment of Collateral Agent;
Instructions to Security Agent.

                  (a) The Company hereby irrevocably grants a (to the Company's
knowledge, with respect to priority only) first priority security interest to
the Collateral Agent acting for the equal and ratable benefit of the August 2001
Trustee for the benefit of the holders of the August 2001 Notes, the January
2001 Trustee for the benefit of the holders of the 2001 Notes and the 2000
Trustee for the benefit of the holders of the 2000 Notes in all of the Company's
right, title and interest in the Security Account, all funds credited therein
and all U.S. Government Obligations held by (or otherwise maintained in the name
of) the Security Agent pursuant to Section 2 hereof and credited to the Security
Account, as well as all rights of the Company under this Agreement
(collectively, the "Collateral"), in order to secure

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                                      -13-

all obligations and indebtedness of the Company under the Notes and the
Indentures. The Company shall take all actions necessary on its part to insure
the continuance of a (to the Company's knowledge, with respect to priority only)
first priority security interest, for the term of this Agreement, in the
Collateral in favor of the Collateral Agent for the equal and ratable benefit of
the Trustees in order to secure such obligations and indebtedness.

                  (b) The Collateral Agent hereby declares and agrees, and each
of the August 2001 Trustee, the January 2001 Trustee and the 2000 Trustee
agrees, that the Collateral Agent holds the Collateral as contemplated by
Section (a) above as agent under the Agreement for the benefit of the August
2001 Trustee and the holders of the August 2001 Notes, the January 2001 Trustee
and the holders of the 2001 Notes and the 2000 Trustee and the holders of the
2000 Notes as provided herein. By acceptance of the benefits of this Agreement,
the August 2001 Trustee, the January 2001 Trustee and the 2000 Trustee (i)
consent to the appointment of the Collateral Agent as agent hereunder, (ii)
confirm that the Collateral Agent shall have the authority to act as the
exclusive agent of the August 2001 Trustee's, the January 2001 Trustee and the
2000 Trustee for enforcement of any remedies under or with respect to this
Agreement and the giving or withholding of any consent or approval relating to
any Collateral of any of the August 2001 Trustee, the January 2001 Trustee's or
the 2000 Trustee's obligations with respect thereto and (iii) agree that, except
as provided in this Agreement, it shall not take any action to enforce any of
such remedies or give any such consents or approvals.

                  (c) The Company and the Collateral Agent hereby irrevocably
instruct the Security Agent to, and the Security Agent will, (i) (A) maintain
sole dominion and control over funds credited to the Security Account for the
benefit of the Collateral Agent acting for the equal and ratable benefit of the
August 2001 Trustee for the benefit of the holders of the August 2001 Notes, the
January 2001 Trustee for the benefit of the holders of the January 2001 Notes
and the 2000 Trustee for the benefit of the 2000 Notes to the extent
specifically required herein, (B) maintain, or cause its agent within the State
of New York to maintain, possession of all certificated U.S. Government
Obligations purchased hereunder that are physically possessed by the Security
Agent in order for the Collateral Agent acting for the equal and ratable benefit
of the August 2001 Trustee for the benefit of the holders of the August 2001
Notes the January 2001 Trustee for the benefit of the holders of the January
2001 Notes and the 2000 Trustee for the benefit of the 2000 Notes to enjoy a
continuous perfected first priority security interest therein under the laws of
the State of New York (the Company hereby agreeing that in the event any
certificated U.S. Government

<PAGE>

                                      -14-

Obligations are in the possession of the Company or a third party, the Company
shall use its commercially reasonable efforts to deliver all such certificates
to the Security Agent for credit to the Security Account for the benefit of the
Collateral Agent acting for the equal and ratable benefit of the August 2001
Trustee for the benefit of the holders of the August 2001 Notes, the January
2001 Trustee for the benefit of the holders of the January 2001 Notes and the
2000 Trustee for the benefit of the 2000 Notes) and (C) maintain the Collateral
free and clear of all liens, security interests, safekeeping or other charges,
demands and claims against the Security Agent of any nature now or hereafter
existing in favor of anyone other than the Collateral Agent; (ii) promptly
notify the Collateral Agent if the Security Agent receives written notice that
any person other than the Collateral Agent has a lien or security interest upon
any portion of the Collateral and (iii) in addition to disbursing amounts held
in escrow pursuant to any Payment Notice and Disbursement Requests given to it
by the Collateral Agent pursuant to Section 3, upon receipt of both (A) written
notice from the Collateral Agent that either (x) as a result of an Event of
Default the indebtedness represented by the 2000 Notes, the January 2001 Notes
or the August 2001 Notes has been accelerated or (y) the maturity date of the
2000 Notes, the January 2001 Notes or the August 2001 Notes has occurred, under
any of the Indentures, and (B) direction from the Collateral Agent to disburse
all Available Funds to the applicable Trustee, as promptly as practicable, after
following the procedures set forth in the fourth paragraph of Section 4, the
Security Agent shall disburse all funds held in the Security Account to the
applicable Trustee and transfer title to all U.S. Government Obligations held by
the Security Agent hereunder to the Collateral Agent acting for the equal and
ratable benefit of the August 2001 Trustee for the benefit of the holders of the
August 2001 Notes, the January 2001 Trustee for the benefit of the January 2001
Notes and the 2000 Trustee for the benefit of the 2000 Notes. The lien and
security interest provided for by this Section 6 shall automatically terminate
and cease as to, and shall not extend or apply to, and the Collateral Agent
shall have no security interest in, any funds disbursed by the Security Agent to
the Company pursuant to this Agreement. The Security Agent shall act solely as
the Collateral Agent's agent in connection with the duties under this Section 6,
notwithstanding any other provision contained in this Agreement, without any
right to receive compensation from the Collateral Agent and without any
authority to obligate the Collateral Agent or to compromise or pledge its
security interest hereunder.

                  (d) Any money and U.S. Government Obligations collected by the
August 2001 Trustee, the January 2001 Trustee or the 2000 Trustee pursuant to
Section 6(c)(iii) shall be applied as provided in the Indentures.

<PAGE>

                                      -15-

                  (e) The Company will execute and deliver to the Collateral
Agent such instruments and documents as may be required or as the Collateral
Agent may reasonably deem necessary or advisable to confirm or perfect the
rights of the Collateral Agent under this Agreement and the Collateral Agent's
interest in the Collateral. The Company will take all necessary action to
preserve and protect the security interest created hereby as a lien and
encumbrance upon the Collateral.

                  (f) The Company hereby appoints the Collateral Agent as its
attorney-in-fact effective upon either (i) the acceleration of the indebtedness
represented by the 2000 Notes, the January 2001 Notes or the August 2001 Notes
due to the occurrence of an Event of Default under any of the Indentures or (ii)
the maturity of the 2000 Notes, the January 2001 Notes or the August 2001 Notes,
with full power of substitution to do any act which the Company is obligated
hereto to do, and the Collateral Agent may exercise such rights as the Company
might exercise with respect to the Collateral and to take any action in the
Company's name to protect the Collateral Agent's security interest hereunder.
Prior to the occurrence of an Event of Default known to the Collateral Agent,
the Collateral Agent shall have no duty or obligation to verify or maintain the
perfection of any security interest created hereby.

         7.       Collateral Agent.

                  Limitation of the Collateral Agent's Liability;
Responsibilities of the Collateral Agent. The Collateral Agent's responsibility
and liability under this Agreement shall be limited as follows: (i) the
Collateral Agent does not represent, warrant or guaranty to the holders of the
Notes from time to time the performance of either the August 2001 Trustee, the
January 2001 Trustee or the 2000 Trustee; (ii) the Collateral Agent shall have
no responsibility to the Company, the August 2001 Trustee, the January 2001
Trustee or the 2000 Trustee or the holders of the Notes from time to time as a
consequence of the performance by the Collateral Agent hereunder, except for any
gross negligence or wilful misconduct of the Collateral Agent and except with
respect to claims based upon such gross negligence or wilful misconduct that are
successfully asserted against the Collateral Agent; (iii) the August 2001
Trustee, the January 2001 Trustee and the 2000 Trustee shall remain solely
responsible for all aspects of their respective business and conduct; and (iv)
the Collateral Agent is not obligated to supervise, inspect, or inform the
Company or any third party of any matter referred to above.

                  No implied covenants or obligations shall be inferred from
this Agreement against the Collateral Agent, nor shall the Collateral Agent be
bound by the provisions of any agreement

<PAGE>

                                      -16-

beyond the specific term hereof. Specifically and without limiting the
foregoing, the Collateral Agent shall in no event have any liability in
connection with its capacity as Collateral Agent or the efforts of the August
2001 Trustee for the benefit of the holders of the August 2001 Notes, the
efforts of the January 2001 Trustee for the benefit of the holders of the
January 2001 Notes and the efforts of the 2000 Trustee for the benefit of the
2000 Notes, of any funds or U.S. Government Obligations held by it hereunder,
including without limitation any liability for any delay not resulting from
gross negligence or wilful misconduct in such capacity as Collateral Agent or
the efforts of the August 2001 Trustee for the benefit of the holders of the
August 2001 Notes, the efforts of the January 2001 Trustee for the benefit of
the holders of the January 2001 Notes and the efforts of the 2000 Trustee for
the benefit of the holders of the 2000 Notes, or for any loss of principal or
income incident to any such delay.

                  The Collateral Agent shall be entitled to rely upon any
judicial order or judgment, upon any written Opinion of Counsel or upon any
certification, instruction, notice, or other writing delivered to it by the
Company in compliance with the provisions of this Agreement without being
required to determine the authenticity or the correctness of any fact stated
therein or the propriety or validity of service thereof. The Collateral Agent
may act in reliance upon any instrument comporting with the provisions of this
Agreement or signature believed by it to be genuine and may assume that any
person purporting to give notice or receipt or advice or make any statement or
execute any document in connection with the provisions hereof has been duly
authorized to do so.

                  At any time, the Collateral Agent may request in writing an
instruction in writing from either the August 2001 Trustee, the January 2001
Trustee or the 2000 Trustee, and may at its own option include in such request
the course of action it proposes to take and the date on which it proposes to
act, regarding any matter arising in connection with its duties and obligations
hereunder; provided, however, that the Collateral Agent shall state in such
request that it believes in good faith that such proposed course of action is
consistent with another identified provision of this Agreement. The Collateral
Agent shall not be liable to any of the August 2001 Trustee, the January 2001
Trustee or the 2000 Trustee for acting without any of the August 2001 Trustee's
Consent, the January 2001 Trustee's Consent or the 2000 Trustee's Consent in
accordance with such a proposal on or after the date specified therein if (i)
the specified date is at least two Business Days after the Company receives the
Security Agent's request for instructions and its proposed course of action,
which instructions shall have been delivered to the Company at least two
Business Days prior to such

<PAGE>

                                      -17-

action and (ii) prior to so acting, the Security Agent has not received the
written instructions requested from the Company, which instructions shall have
been delivered to the Company at least two Business Days prior to such action.

                  The Collateral Agent may act pursuant to the written advice of
counsel chosen by it with respect to any matter relating to this Agreement and
(subject to this Section 7) shall not be liable for any action taken or omitted
in accordance with such advice.

                  The Collateral Agent shall not be called upon to advise any
party as to selling or retaining, or taking or refraining from taking any action
with respect to, any securities or other property credited hereunder.

                  In the event of any ambiguity in the provisions of this
Agreement with respect to any funds or property credited hereunder, the
Collateral Agent shall be entitled to refuse to comply with any and all claims,
demands or instructions with respect to such property or funds, and the
Collateral Agent shall not be or become liable for its failure or refusal to
comply with conflicting claims, demands or instructions. The Collateral Agent
shall be entitled to refuse to act until either any conflicting or adverse
claims or demands shall have been finally determined by a court of competent
jurisdiction or settled by agreement between the conflicting claimants as
evidenced in a writing, satisfactory to the Collateral Agent, in which event the
Collateral Agent shall act in accordance with such determination or agreement.

                  No provision of this Agreement shall require the Collateral
Agent to expend or risk its own funds or otherwise incur any financial liability
in the performance of any of its duties hereunder.

                  The Collateral Agent shall not be required to institute legal
proceedings of any kind and shall not be required to initiate or defend any
legal proceedings which may be instituted against it in respect of the subject
matter of this Agreement. If the Collateral Agent does elect to act it will do
so only to the extent that it is indemnified to its satisfaction against the
cost and expense of such defense or initiation.

         8.       Termination.  This Agreement shall terminate automatically
following disbursement of all funds remaining in the Security Account (including
U.S. Government Obligations), unless sooner terminated by agreement of the
parties hereto (in accordance with the terms hereof and not in violation of
either of the Indentures); provided, however, that the obligations of the
Company under Section 5 (and any existing claims thereunder)

<PAGE>

                                      -18-

shall survive termination of this Agreement or the resignation of the Security
Agent.

         9.       Miscellaneous.

                  (a) Waiver. Any party hereto may specifically waive any breach
of this Agreement by any other party, but no such waiver shall be deemed to have
been given unless such waiver is in writing, signed by the waiving party and
specifically designating the breach waived, nor shall any such waiver constitute
a continuing waiver of similar or other breaches.

                  (b) Invalidity. If for any reason whatsoever any one or more
of the provisions of this Agreement shall be held or deemed to be inoperative,
unenforceable or invalid in a particular case or in all cases, such
circumstances shall not have the effect of rendering any of the other provisions
of this Agreement inoperative, unenforceable or invalid, and the inoperative,
unenforceable or invalid provision shall be construed as if it were written so
as to effectuate, to the maximum extent possible, the parties' intent.

                  (c) Assignment; Successors. This Agreement is personal to the
parties hereto, and the rights and duties of any party hereunder shall not be
assignable except with the prior written consent of each of the other parties.
Notwithstanding the foregoing, this Agreement shall inure to and be binding upon
the parties and their successors and permitted assigns.

                  (d) Benefit. The parties hereto and their successors and
permitted assigns, but no others, shall be bound hereby and entitled to the
benefits hereof; provided, however, that the holders of the Notes and their
permitted assigns shall be entitled to the benefits hereof and to enforce this
Agreement in accordance with the terms of the applicable Indenture.

                  (e)  Time.  Time is of the essence of each provision of this
Agreement.

                  (f) Entire Agreement; Amendments. This Agreement, the
Indentures and the terms of the Notes thereunder contain the entire agreement
among the parties with respect to the subject matter hereof and supersede any
and all prior agreements, understandings and commitments, whether oral or
written. This Agreement may be amended only by a writing signed by a duly
authorized representative of each party hereto.

                  (g) Notices. Any notice or communication shall be in writing
and delivered in person or mailed by first-class mail or sent by facsimile (with
a hard copy delivered in person or by mail promptly thereafter) and addressed as
follows:

<PAGE>

                                      -19-

                  To Collateral Agent, Security Agent, August 2001 Trustee,
                  January 2001 Trustee or 2000 Trustee, in each case addressed
                  in its specific capacity:

                  Wells Fargo Bank Minnesota, N.A.
                  Sixth & Marquette
                  MAC N9303-110
                  Minneapolis, MN 55479
                  Attn: Corporate Trust Services-Alamosa (Delaware), Inc.
                  Facsimile: (612) 667-9825
                  Telephone: (612) 667-9764

                  To the Company:

                  Alamosa (Delaware), Inc.
                  5225 S. Loop 289
                  Lubbock, Texas 79424
                  Attn:  Kendall W. Cowan
                  Facsimile:  (806) 722-1423
                  Telephone:  (806) 722-1100

                  with a copy to:

                  Skadden, Arps, Slate, Meagher & Flom LLP
                  Four Times Square
                  New York, NY 10036
                  Attn: Fred B. White, III
                  Facsimile: 212-735-2000
                  Telephone: 212-735-3000

or at such other address as the specified entity most recently may have
designated in writing in accordance with this Section.

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

                  (i)      Captions.  Captions in this Agreement are for
                           --------
convenience only and shall not be considered or referred to in
resolving questions of interpretation of this Agreement.

                  (j) Choice of Law. The existence, validity, construc tion,
operation and effect of any and all terms and provisions of this Agreement shall
be determined in accordance with and governed by the laws of the State of New
York. The parties to this Agreement hereby agree that jurisdiction over such
parties and over the subject matter of any action or proceeding arising under
this Agreement may be exercised by a competent Court of the State of New York,
or by a United States Court sitting in New

<PAGE>

                                      -20-

York City. The Company hereby submits to the personal jurisdiction of such
courts, hereby waives personal service of process upon it and consents that any
such service of process may be made by certified or registered mail,
return-receipt requested, directed to the Company at its address last specified
for notices hereunder, and service so made shall be deemed completed five (5)
days after the same shall have been so mailed. All actions and proceedings
brought by the Company, or the Trustee against the Security Agent relating to or
arising from, directly or indirectly, this Agreement shall be litigated only in
Federal or New York State courts within the State of New York.

                  (k) The Company hereby represents and warrants that this
Agreement has been duly authorized, executed and delivered on its behalf and
constitutes the legal, valid and binding obligation of the Company. The
execution, delivery and performance of this Agreement by the Company does not
violate any applicable law or regulation to which the Company is subject and
does not require the consent of any governmental or other regulatory body to
which the Company is subject, except for such consents and approvals as have
been obtained and are in full force and effect. The Company hereby covenants
that it will not change its jurisdiction of incorporation without providing the
Security Agent and the Collateral Agent with 30 days prior written notice of
such change.

                  (l) Each of the Security Agent and the Collateral Agent hereby
represents and warrants that this Agreement has been duly authorized, executed
and delivered on its behalf and constitutes its legal, valid and binding
obligation.

<PAGE>

                                      -S1-

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

SECURITY AGENT:
                                              WELLS FARGO BANK MINNESOTA,
                                              N.A., as Security Agent

                                              By:/s/ Michael T. Lechner
                                                 -------------------------------
                                                 Name: Michael T. Lechner
                                                 Title:  Corporate Trust
                                                         Officer

August 2001 TRUSTEE:(as to
Paragraph 6(b) only):                         WELLS FARGO BANK MINNESOTA,
                                              N.A., as Trustee

                                              By:/s/ Michael T. Lechner
                                                 -------------------------------
                                                 Name: Michael T. Lechner
                                                 Title:  Corporate Trust
                                                         Officer

January 2001 TRUSTEE:(as to
Paragraph 6(b) only):                         WELLS FARGO BANK MINNESOTA,
                                              N.A., as Trustee

                                              By:/s/ Michael T. Lechner
                                                 -------------------------------
                                                 Name: Michael T. Lechner
                                                 Title:  Corporate Trust
                                                         Officer

2000 TRUSTEE (as to
Paragraph 6(b) only):                         WELLS FARGO BANK MINNESOTA,
                                              N.A., as Trustee

                                              By:/s/ Michael T. Lechner
                                                 -------------------------------
                                                 Name: Michael T. Lechner
                                                 Title:  Corporate Trust
                                                         Officer

<PAGE>

                                      -S2-

COLLATERAL AGENT:                             WELLS FARGO BANK MINNESOTA,
                                              N.A., as Collateral Agent

                                              By:/s/ Michael T. Lechner
                                                 -------------------------------
                                                 Name: Michael T. Lechner
                                                 Title:  Corporate Trust
                                                         Officer

<PAGE>

                                      -S3-

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

COMPANY:                                      ALAMOSA (DELAWARE), INC.

                                              By:/s/ David E. Sharbutt
                                                 -------------------------------
                                                 Name: David E. Sharbutt
                                                 Title:  Chairman of the
                                                         Board and CEO

<PAGE>

                         EXHIBIT A TO SECURITY AGREEMENT

             Form of Trustee Payment Notice and Disbursement Request

                     (Letterhead of the Applicable Trustee)

                                     [Date]

Attn:     Collateral Agent
          Wells Fargo Bank Minnesota, N.A.
          Corporate Trust Services
          Escrow Accounts

          Re:  Disbursement Request No. ________________
               (indicate whether revised)

Ladies and Gentlemen:

                  We refer to the Security Agreement, dated as of August 15,
2001 (the "Security Agreement") among Alamosa (Delaware), Inc., a Delaware
corporation (the "Company"), Wells Fargo Bank Minnesota, N.A., as security agent
(in such capacity the "Security Agent"), Wells Fargo Bank Minnesota, N.A., as
collateral agent (in such capacity, the "Collateral Agent") for Wells Fargo Bank
Minnesota, N.A., as trustee (in such capacity, the "August 2001 Trustee"), Wells
Fargo Bank Minnesota, N.A., as trustee under the August 2001 Indenture (as
defined herein) (in such capacity, the "January 2001 Trustee") under the January
2001 Indenture (as defined herein) and for Wells Fargo Bank Minnesota, N.A., as
trustee (in such capacity, the "2000 Trustee", and together with the August 2001
Trustee and the January 2001 Trustee, the "Trustees") under the 2000 Indenture,
the August 2001 Trustee (as to paragraph 6(b)), the January 2001 Trustee (as to
paragraph 6(b)) and the 2000 Trustee (as to paragraph 6(b)). Capitalized terms
used and not otherwise defined herein shall have the meaning given in the
Security Agreement.

                  This letter constitutes a Trustee Payment Notice and
Disbursement Request under the Security Agreement.

                  [choose one of the following, as applicable]

                  [The undersigned hereby notifies you that a scheduled interest
payment on the August 2001 Notes in the amount of $_________ is due and payable
on ___________, ____ and requests that you for the benefit of us send to the
Security Agent a Collateral Agent Payment and Disbursement Request requesting

<PAGE>

                                      -S2-

disbursement of funds contained in the Security Account in such amount.](1)

                  [The undersigned hereby notifies you that a scheduled interest
payment on the 2000 Notes in the amount of $_________ is due and payable on
___________, ____ and requests that you for the benefit of us send to the
Security Agent a Collateral Agent Payment and Disbursement Request requesting
disbursement of funds contained in the Security Account in such amount.](2)

                  [The undersigned hereby (i) notifies you that a scheduled
interest payment on the January 2001 Notes in the amount of $_________ is due
and payable on ________, ____, (ii) that the undersigned, in its capacity as
January 2001 Trustee, has delivered to the Collateral Agent a completed
Withdrawal Certificate substantially in the form of Exhibit C, and (iii) hereby
requests a disbursement of funds contained in the Security Account in the amount
of the Shortfall Amount (as defined in the Withdrawal Certificate).](3)

                  [The undersigned hereby authorizes you, pursuant to Section
3(d) of the Security Agreement, to send to the Security Agent a Collateral Agent
Payment and Disbursement Notice to release all Available Funds in the Security
Account to the Company (to an account designated by the Company in writing) and
to release all U.S. Government Obligations in the Security Account to the
Company (to an account designated by the Company in writing).]

                  In connection with the requested disbursement, the undersigned
hereby notifies you that:

                  1.       We have no actual knowledge that any Event of
         Default has occurred and is continuing with respect to any
         of the Notes.

                  2.       All prior disbursements from the Security Account
         have been Applied.

------------------
        (1) Language applicable only when an interest payment on the August 2001
Notes is due.

        (2) Language applicable only when an interest payment on the August 2001
Notes is due.

        (3) Language applicable only in the event of a scheduled interest
payment on the January 2001 Notes after an attempted draw by the January 2000
Trustee on the January Security Account that results in a shortfall.

<PAGE>

                                      -S3-

                  3.       Wells Fargo Bank Minnesota, N.A.
                           ABA # 09100019
                           F/F/C: 0001038377
                           Credit to: 11455500
                           Ref: Alamosa

                  The Collateral Agent is entitled to rely on the foregoing in
giving the Security Agent a Collateral Agent Payment Notice and Disbursement
Request requesting disbursement of funds relating to this Trustee Payment Notice
and Disbursement Request.

                                           [WELLS FARGO BANK MINNESOTA,
                                           N.A., as August 2001 Trustee

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

                                           [WELLS FARGO BANK MINNESOTA,
                                           N.A., as January 2001 Trustee

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

                                           [WELLS FARGO BANK MINNESOTA,
                                           N.A., as 2000 Trustee

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

<PAGE>

                         EXHIBIT B TO SECURITY AGREEMENT

        Form of Collateral Agent Payment Notice and Disbursement Request

                      (Letterhead of the Collateral Agent)

                                     [Date]

Attn:    Wells Fargo Bank Minnesota, N.A.
         Corporate Trust Services
         Escrow Accounts

         Re:  Disbursement Request No.
              (indicate whether revised)

Ladies and Gentlemen:

                  We refer to the Security Agreement, dated as of August 15,
2001 (the "Security Agreement") among Alamosa (Delaware), Inc., a Delaware
corporation (the "Company"), Wells Fargo Bank Minnesota, N.A., as security agent
(in such capacity the "Security Agent"), Wells Fargo Bank Minnesota, N.A., as
collateral agent (in such capacity, the "Collateral Agent") for Wells Fargo Bank
Minnesota, N.A., as trustee (in such capacity, the "August 2001 Trustee"), Wells
Fargo Bank Minnesota, N.A., as trustee under the August 2001 Indenture (as
defined herein) (in such capacity, the "January 2001 Trustee") under the January
2001 Indenture (as defined herein) and for Wells Fargo Bank Minnesota, N.A., as
trustee (in such capacity, the "2000 Trustee", and together with the August 2001
Trustee and the January 2001 Trustee, the "Trustees") under the 2000 Indenture,
the August 2001 Trustee (as to paragraph 6(b)), the January 2001 Trustee (as to
paragraph 6(b)) and the 2000 Trustee (as to paragraph 6(b)). Capitalized terms
used and not otherwise defined herein shall have the meaning given in the
Security Agreement.

                  This letter constitutes a Collateral Agent Payment Notice and
Disbursement Request under the Security Agreement.

                  [choose one of the following, as applicable]

                  [The undersigned hereby notifies you that a scheduled interest
payment on the August 2001 Notes in the amount of $_________ is due and payable
on ___________, ____ and requests a

<PAGE>

                                      -S2-

disbursement of funds contained in the Security Account in such amount.](4)

                  [The undersigned hereby notifies you that a scheduled interest
payment on the 2000 Notes in the amount of $_________ is due and payable on
___________, ____ and requests a disbursement of funds contained in the Security
Account in such amount.](5)

                  [The undersigned hereby (i) notifies you that a scheduled
interest payment on the January 2001 Notes in the amount of $_________ is due
and payable on ________, ____, (ii) that the January 2001 Trustee has delivered
to the undersigned in its capacity as Collateral Agent a completed Withdrawal
Certificate substantially in the form of Exhibit C and (iii) hereby requests a
disbursement of funds contained in the Security Agreement in the amount of the
Shortfall Amount (as defined in the Withdrawal Certificate).](6)

                  [The undersigned hereby authorizes you, pursuant to Section
3(d) of the Security Agreement, to release all Available Funds in the Security
Account to the Company (to an account designated by the Company in writing) and
to release all U.S. Government Obligations in the Security Account to the
Company (to an account designated by the Company in writing).]

                  In connection with the requested disbursement, the undersigned
hereby notifies you that:

                  1.       We have no actual knowledge that any Event of
         Default has occurred and is continuing with respect to any
         of the Notes.

                  2.       All prior disbursements from the Security Account
         have been Applied.

                  3.       Wells Fargo Bank Minnesota, N.A.
                           ABA # 09100019
                           F/F/C: 0001038377
                           Credit to: 11455500
---------------
        (4) Language applicable only when an interest payment on the August 2001
Notes is due.

        (5) Language applicable only when an interest payment on the 2000 Notes
is due.

        (6) Language applicable only in the event of a scheduled interest
payment on the January 2001 Notes after an attempted draw by the January 2001
Trustee on the January Security Account that results in a shortfall.

<PAGE>

                                      -S3-

                       Ref: Alamosa

                  The Security Agent is entitled to rely on the foregoing in
disbursing funds relating to this Collateral Agent Payment Notice and
Disbursement Request.

                                             WELLS FARGO BANK MINNESOTA,
                                             N.A., as Collateral Agent

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

<PAGE>

                         EXHIBIT C TO SECURITY AGREEMENT

                         Form of Withdrawal Certificate

                    (Letterhead of the January 2001 Trustee)

                                     [Date]

Attn:    Collateral Agent
         Wells Fargo Bank Minnesota, N.A.
         Corporate Trust Services
         Escrow Accounts

         Re:   Shortfall In Disbursement Request No.
               (indicate whether revised)

Ladies and Gentlemen:

                  We refer to the Security Agreement, dated as of August 15,
2001 (the "Security Agreement") among Alamosa (Delaware), Inc., a Delaware
corporation (the "Company"), Wells Fargo Bank Minnesota, N.A., as security agent
(in such capacity the "Security Agent"), Wells Fargo Bank Minnesota, N.A., as
collateral agent (in such capacity, the "Collateral Agent") for Wells Fargo Bank
Minnesota, N.A., as trustee (in such capacity, the "August 2001 Trustee"), Wells
Fargo Bank Minnesota, N.A., as trustee under the August 2001 Indenture (as
defined herein) (in such capacity, the "January 2001 Trustee") under the January
2001 Indenture (as defined herein) and for Wells Fargo Bank Minnesota, N.A., as
trustee (in such capacity, the "2000 Trustee", and together with the August 2001
Trustee and the January 2001 Trustee, the "Trustees") under the 2000 Indenture,
the August 2001 Trustee (as to paragraph 6(b)), the January 2001 Trustee (as to
paragraph 6(b)) and the 2000 Trustee (as to paragraph 6(b)). Capitalized terms
used and not otherwise defined herein shall have the meaning given in the
Security Agreement.

                  "January Security Agreement" shall mean the security
agreement, dated as of January 31, 2001, among Alamosa (Delaware), Inc., a
Delaware corporation, Wells Fargo Bank Minnesota, N.A., as security agent, Wells
Fargo Bank Minnesota, N.A., as collateral agent for Wells Fargo Bank Minnesota,
as trustee under the Indenture dated as of January 31, 2001 between Alamosa
(Delaware), Inc. and Wells Fargo Bank Minnesota, N.A., as trustee, the 2001
Trustee (as to paragraph 6(b)) and the 2000 Trustee (as to paragraph 6(b)).

                  This letter constitutes a Withdrawal Certificate under the
Security Agreement.

<PAGE>

                                      -S2-

                  [The undersigned hereby (i) notifies you that a scheduled
interest payment on the January 2001 Notes in the amount of $_________ was due
and payable on ________, ____, (ii) that the undersigned, in its capacity as
January 2001 Trustee, has delivered to the Collateral Agent under the January
Security Agreement a completed Trustee Notice and Disbursement Request in
accordance with the terms of the January Security Agreement and (iii) was
informed by the Collateral Agent under the January Security Agreement that there
was a shortfall in the funds available for disbursement pursuant to such Trustee
Notice and Disbursement Request in the amount of $___________(the "Shortfall
Amount").

                  The Collateral Agent is entitled to rely on the foregoing in
giving the Security Agent a Collateral Agent Payment Notice and Disbursement
Request requesting disbursement of funds relating to the Trustee Payment Notice
and Disbursement Request following receipt by the Collateral Agent of this
Withdrawal Certificate.

                                     [WELLS FARGO BANK MINNESOTA,
                                     N.A., as August 2001 Trustee

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

                                     [WELLS FARGO BANK MINNESOTA,
                                     N.A., as January 2001 Trustee

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

                                     [WELLS FARGO BANK MINNESOTA,
                                     N.A., as 2000 Trustee

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

<PAGE>

                                      -S1-

                         EXHIBIT D TO SECURITY AGREEMENT

                           Security Agent Compensation

Acceptance:                        $3,000

Annual Administration:             $3,000<PAGE>   1
                                                                     EXHIBIT 4.1

                                  DISCOVER BANK

                      Master Servicer, Servicer and Seller

                                       and

                         U.S. BANK NATIONAL ASSOCIATION

                                     Trustee

                       on behalf of the Certificateholders

                             FIRST AMENDMENT TO THE
                       SERIES SUPPLEMENT FOR SERIES 2001-1
                           dated as of January 4, 2001

                                       to

                         POOLING AND SERVICING AGREEMENT
                           Dated as of October 1, 1993

                                   Dated as of
                                 August 24, 2001

<PAGE>   2

          THIS FIRST AMENDMENT TO THE SERIES SUPPLEMENT FOR SERIES 2001-1 (the
"Amendment"), dated as of August 24, 2001, is entered into by and between
DISCOVER BANK (formerly Greenwood Trust Company), a Delaware banking
corporation, as Master Servicer, Servicer and Seller ("Discover Bank") and U.S.
BANK NATIONAL ASSOCIATION (formerly First Bank National Association, successor
trustee to Bank of America Illinois, formerly Continental Bank, National
Association), as Trustee (the "Trustee").

          WHEREAS, Discover Bank and the Trustee have entered into the SERIES
SUPPLEMENT FOR SERIES 2001-1 (the "Series Supplement"), dated as of January 4,
2001 with respect to the Series 2001-1 Certificates, pursuant to Section 6.06 of
that certain Pooling and Servicing Agreement (the "Pooling and Servicing
Agreement"), dated as of October 1, 1993, as amended, relating to Discover Card
Master Trust I; and

          WHEREAS, pursuant to subsection 13.01(a)(4) of the Pooling and
Servicing Agreement, Discover Bank and the Trustee desire to amend the
definition of "Maximum Class B Credit Enhancement Amount" in the Series Term
Sheet.

          NOW, THEREFORE, in consideration of the foregoing and the mutual
agreements herein contained, each party agrees as follows for the benefit of the
other parties and for the benefit of the Certificateholders:

          1. Definitions. Unless otherwise specified, capitalized terms used in
this Amendment shall have the same meanings ascribed to them in the Series
Supplement.

          2. Amendment to the definition of "Maximum Class B Credit Enhancement
             Amount".

             (a)  The definition for "Maximum Class B Credit Enhancement Amount"
                  is hereby amended and restated in its entirety to read as
                  follows:

             On any Distribution Date (a) prior to the making of an Effective
             Alternative Credit Support Election, the greater of (i) $12,631,580
             and (ii) (x) if a Supplemental Credit Enhancement Event has not
             occurred, an amount equal to 7.5% of the Series Investor Interest
             as of the last day of the related Due Period, or (y) if a
             Supplemental Credit Enhancement Event has occurred, an amount equal
             to 8.0% of the Series Investor Interest as of the last day of the
             related Due Period, (b) subsequent to the making of an Effective
             Alternative Credit Support Election, the greater of (i) $12,631,580
             and (ii) an amount equal to 12.5% of the Series Investor Interest
             as of the last day of the related Due Period, provided, however,
             that if an Amortization Event with respect to the Series
             established hereby occurs, the Maximum Class B Credit Enhancement
             Amount for each Distribution Date thereafter shall equal the
             Maximum Class B Credit

<PAGE>   3

             Enhancement Amount for the Distribution Date immediately
             preceding the occurrence of the Amortization Event; and provided,
             further, that if a Credit Enhancement Drawing has been made,
             until such time as the Available Class B Credit Enhancement
             Amount has been reinstated in an amount at least equal to the
             amount of such Credit Enhancement Drawing, the Maximum Class B
             Credit Enhancement Amount shall be the Maximum Class B Credit
             Enhancement Amount as of the date of such Credit Enhancement
             Drawing.

          3. Effect Upon the Series Supplement. Except as specifically set forth
herein, the Series Supplement shall remain in full force and effect and is
hereby ratified and confirmed.

          4. Counterparts. This Amendment may be executed in two or more
counterparts (and by different parties on separate counterparts), each of which
shall be an original, but all of which together shall constitute one and the
same instrument.

                                       2
<PAGE>   4

          IN WITNESS WHEREOF, Discover Bank and the Trustee have caused this
Amendment to be duly executed by their respective officers as of the day and
year first above written.

                                   DISCOVER BANK,
                                    as Master Servicer, Servicer and Seller

                                   By:     /s/ MICHAEL F. RICKERT
                                          --------------------------------------
                                   Name:   Michael F. Rickert
                                   Title:  Vice President, Chief Accounting
                                            Officer and Treasurer

                                   U.S. BANK NATIONAL ASSOCIATION, as Trustee

                                   By:     /s/ PATRICIA M. CHILD
                                          --------------------------------------
                                   Name:   Patricia M. Child
                                   Title:  Vice President

                                       3

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