<PAGE>   1
                                                                   EXHIBIT 10.87

                       FIRST AMENDMENT TO CREDIT AGREEMENT
                       -----------------------------------

         THIS FIRST AMENDMENT TO CREDIT AGREEMENT (the "AMENDMENT"), dated as of
February 24, 1998, among PHONETEL TECHNOLOGIES, INC., an Ohio corporation (the
"BORROWER"), ING (U.S.) CAPITAL CORPORATION, a Delaware corporation ("ING"),
TRANSAMERICA BUSINESS CREDIT CORPORATION, a Delaware corporation
("TRANSAMERICA"), FINOVA CAPITAL CORPORATION, a Delaware corporation ("FINOVA"),
and AMERICAN NATIONAL BANK, a national banking association, constituting all of
the Lenders under the Credit Agreement referenced below, ING in its capacity as
Agent for the Lenders and Transamerica and Finova in their capacity as Co-Agents
for the Lenders.

         RECITALS:

         A. The Borrower, the Lenders, the Agent and the Co-Agents have entered
into a certain Credit Agreement, dated as of May 30, 1997 (the "CREDIT
AGREEMENT"). Capitalized terms used herein and not otherwise defined shall have
the meanings ascribed to such terms in the Credit Agreement.

         B. The Borrower has requested that the Expansion Loan Commitment be
reduced to $55,000,000, that the Revolving Credit Commitment be increased to
$20,000,000 and that certain other covenants and provisions in the Credit
Agreement be amended as set forth herein.

         C. The Lenders are agreeable to amending the Credit Agreement on the
terms and conditions set forth herein.

         NOW, THEREFORE, the parties hereto agree as follows:

1.       AMENDMENT TO ARTICLE I. Article I of the Credit Agreement is hereby
         amended as follows:

         (a) The definitions of "EBITDA", "Expansion Loan Commitment Amount",
"Percentage" and "Revolving Credit Commitment Amount" are replaced with the
following:

                  "EBITDA" means, for any Person or business for any period, an
         amount equal to Net Income PLUS (to the extent deducted in determining
         Net Income) interest expense, provisions for income taxes,
         depreciation, amortization of intangible assets and other non-cash
         charges (other than restructuring charges, as determined in accordance
         with GAAP), expenses related to the termination of the merger agreement
         with Communications Central Inc. of $7,861,743 and $35,478,
         respectively, recorded during the periods ended September 30, 1997 and
         December 31, 1997, adjustment for the period ending September 30, 1997
         of dial-around compensation revenue previously recognized in the amount
         of $2,408,059, expenses related to obtaining bondholder consents
         recorded during the period ended December 31, 1997 in the amount of
         $735,876 and nonrecurring general and administrative expenses at
         $52,545 and $36,660, respectively, recorded


<PAGE>   2

         during the periods ended September 30, 1997 and December 31, 1997,
         MINUS (to the extent included in determining Net Income) non-cash
         credits and revenues.

                  "EXPANSION LOAN COMMITMENT AMOUNT" means $55,000,000 as such
         amount may be reduced from time to time pursuant to SECTION 3.3.4.

                  "PERCENTAGE" of any Lender means, at any time, in respect of
         the Commitment and the Loans, the percentage set forth opposite such
         Lender's signature to the First Amendment to Credit Agreement, adjacent
         to the caption "Percentage", as the same may be adjusted pursuant to
         SECTION 9.11
 .
                  "REVOLVING CREDIT COMMITMENT AMOUNT" means $20,000,000, as
         such amount may be reduced from time to time pursuant to SECTION 3.3.4.

         (b) The following new definitions are added to Article I in proper
alphabetical order:

                  "ADDITIONAL LETTERS OF CREDIT" means letters of credit issued
         for the account of the Borrower or any of its Subsidiaries after the
         date of the First Amendment, excluding Letters of Credit.

                  "FIRST AMENDMENT TO CREDIT AGREEMENT" means the First
         Amendment to Credit Agreement, dated as of February 24, 1998, among
         Borrower, the Lenders, the Agent and the Co-Agents.

                  "MONTHLY PAYMENT DATE" means the last day of each calendar
         month, or, if such day is not a Business Day, the immediately preceding
         Business Day.

         (c) The definition of "Quarterly Payment Date" is deleted and all
references in the Credit Agreement to "Quarterly Payment Date" are replaced with
references to "Monthly Payment Date".

 2.      AMENDMENT TO SECTION 2.1.3. Section 2.1.3 of the Credit Agreement is
         hereby amended by replacing subsections (1), (7), (8) and (9) thereof
         with the following:


                  (1) the then aggregate outstanding principal amount of all
         Expansion Loans, PLUS the then aggregate outstanding principal amount
         of all Revolving Credit Loans PLUS the then aggregate amount of
         outstanding Letter of Credit Obligations PLUS the aggregate undrawn
         face amount of the Existing Letters of Credit, PLUS the aggregate
         undrawn face amount of Additional Letters of Credit, would exceed the
         Borrowing Base;

                  (7) the then aggregate outstanding principal amount of all
         Expansion Loans would not exceed $20,000,000 and the then aggregate
         outstanding principal



                                      -2-
<PAGE>   3

         amount of all Revolving Credit Loans, PLUS the then aggregate amount of
         outstanding Letter of Credit Obligations, would not exceed $20,000,000,
         and the making of such Loan or the issuance of such Letter of Credit,
         as the case may be, would not be permitted under Section 4.07(b)(i) of
         the Senior Notes Indenture; or

                  (8) the then aggregate outstanding principal amount of all
         Expansion Loans would exceed $20,000,000, but the then aggregate
         outstanding principal amount of all Loans, PLUS the then aggregate
         amount of outstanding Letter of Credit Obligations, would not exceed
         $65,000,000 and the "Consolidated Fixed Charge Coverage Ratio", as such
         term is defined in the Senior Notes Indenture, of the Borrower and its
         Subsidiaries would be less than (x) 2.50 to 1.0 if such Loan is made
         prior to December 31, 1998 or (y) 2.75 to 1.0 if such Loan is made on
         or after December 31, 1998; or

                  (9) the then aggregate outstanding principal amount of all
         Loans, PLUS the then aggregate amount of all outstanding Letter of
         Credit Obligations, would exceed $65,000,000 and the "Consolidated
         Fixed Charge Coverage Ratio", as such term is defined in the Senior
         Notes Indenture, of the Borrower and its Subsidiaries would be less
         than 3.3 to 1.0;

3.       AMENDMENT TO SECTION 3.3. Section 3.3 of the Credit Agreement is
         hereby amended as follows:

                  (a) Section 3.3.1 is amended by replacing subsection (b)(i) of
         such Section with the following:

                           (b) (i) shall, on any Business Day on which the
                  aggregate outstanding principal amount of all Expansion Loans
                  PLUS the aggregate outstanding principal amount of all
                  Revolving Credit Loans PLUS the then aggregate amount of
                  Letter of Credit Obligations PLUS the aggregate undrawn face
                  amount of Existing Letters of Credit PLUS the aggregate
                  undrawn face amount of Additional Letters of Credit exceeds
                  the Borrowing Base, make a mandatory prepayment of the
                  outstanding principal amount of Expansion Loans and Revolving
                  Credit Loans in an amount equal to such excess amount (such
                  prepayment to be applied first to all of the Revolving Credit
                  Loans until paid in full and then to Expansion Loans);

                  (b) Section 3.3.1 is hereby further amended by deleting the
         word "and" at the end of subsection (e), replacing the "." at the end
         of subsection (f) with "; and" and adding the following as a new
         subsection (g):




                                      -3-
<PAGE>   4


                           (g) shall, on any Business Day on which the aggregate
                  cash and Cash Equivalent Investments of Borrower, PLUS all
                  cash collateral pledged to secure the Existing Letters of
                  Credit, exceeds $5,000,000, make a mandatory prepayment of the
                  Loans in an amount equal to such excess.

 4.      AMENDMENT TO SECTION 4.2.5. Section 4.2.5 of the Credit Agreement is
         hereby amended by replacing such Section in its entirety with the
         following:

                  SECTION 4.2.5 REQUIRED LENDER APPROVAL OF ACQUISITION. The
         Agent shall have received the written approval of the Required Lenders
         to the Acquisition to be financed with the proceeds of such Borrowing,
         which approval may be granted or withheld by any Lender in its sole and
         absolute discretion.

 5.      AMENDMENT TO SECTION 4.3.7. Section 4.3.7 of the Credit Agreement is
         hereby amended by replacing subsections (a), (b) and (c) of such
         Section in their entirety with the following:

                  (a) if the then aggregate outstanding principal amount of all
         Expansion Loans would not exceed $20,000,000 and the then aggregate
         outstanding principal amount of all Revolving Credit Loans, PLUS the
         then aggregate amount of outstanding Letter of Credit Obligations,
         would not exceed $20,000,000, such Borrowing or issuance of a Letter of
         Credit is permitted under Section 4.07(b)(i) and all other applicable
         provisions of the Senior Notes Indenture;

                  (b) if the then aggregate outstanding principal amount of all
         Expansion Loans would exceed $20,000,000, but the then aggregate
         outstanding principal amount of all Loans, plus the then aggregate
         amount of outstanding Letter of Credit Obligations, would not exceed
         $65,000,000, the "Consolidated Fixed Charge Coverage Ratio", as such
         term is defined in the Senior Notes Indenture, of the Borrower and its
         Subsidiaries would be greater than or equal to (x) 2.50 to 1.0 if such
         Loan is made on or after December 31, 1997 and prior to December 31,
         1998 or (y) 2.75 to 1.0 if such Loan is made on or after December 31,
         1998, and such Borrowing is permitted by all applicable provisions of
         the Senior Notes Indenture; and

                  (c) if the then aggregate outstanding principal amount of
         Loans, PLUS the then aggregate amount of outstanding Letter of Credit
         Obligations, would exceed $65,000,000, the "Consolidated Fixed Charge
         Coverage Ratio", as such term is defined in the Senior Notes Indenture,
         of the Borrower and its Subsidiaries would be greater than or equal to
         3.3 to 1.0, and such Borrowing or issuance of a Letter of Credit is
         otherwise permitted by all applicable provisions of the Senior Notes
         Indenture;




                                      -4-
<PAGE>   5


 6.      AMENDMENTS TO SECTION 6.1.1. Section 6.1.1 of the Credit Agreement is
         hereby amended as follows:

                  (a) The following is added as a new subsection (a)(iv) to such
         Section:

                  (iv) promptly when available and in any event within
         forty-five (45) days after the close of each Fiscal Year, an unaudited
         consolidated balance sheet for the Borrower and its Subsidiaries at the
         close of such Fiscal Year, and related unaudited consolidated
         statements of operations, retained earnings, and cash flows for such
         Fiscal Year, of the Borrower and its Subsidiaries (with comparable
         information at the close of and for the prior Fiscal Year);

                  (b) The lead-in phrase of subsection (b) of such Section,
         which states "promptly when available and in any event within thirty
         (30) days after the close of each calendar month of each Fiscal Year",
         is replaced with "promptly when available and in any event (x) within
         thirty (30) days after the close of the first two calendar months of
         each Fiscal Quarter and (y) within forty-five days (45) after the close
         of the third calendar month of each Fiscal Quarter".

                  (c) The reference to "thirty (30) days" in subsection (c) of
         such Section is replaced with "forty-five (45) days".

 7.      AMENDMENT TO SECTION 6.1. Section 6.1 of the Credit Agreement is hereby
         further amended by replacing Section 6.1.12 (Interest Rate Protection)
         in its entirety with "Section 6.1.12. Intentionally Deleted." and by
         deleting Section 6.1.16 (Substitution of Existing Letters of Credit) in
         its entirety.

 8.      AMENDMENT TO SECTION 6.2.2. Section 6.2.2 of the Credit Agreement is
         hereby amended by replacing subsection (f) thereof with the following:

                  (f) Indebtedness existing on the Closing Date and set forth in
         ITEM 10 ("Existing Indebtedness") of the Disclosure Schedule, and
         Additional Letters of Credit to the extent that the aggregate stated
         face amount of the Additional Letters of Credit and the Existing
         Letters of Credit does not exceed $3,000,000;

 9.      AMENDMENT TO SECTION 6.2.4. Section 6.2.4 of the Credit Agreement is
         hereby amended by replacing subsections (a), (b) and (d) of such
         Section with the following:

                  (a) FIXED CHARGE COVERAGE RATIO. The Borrower will not permit
         its Fixed Charge Coverage Ratio for the twelve-month period ending on
         the last day of any Fiscal Quarter to be less than the ratio set forth
         opposite such Fiscal Quarter (for the Fiscal Quarter ending on March
         31, 1998, such ratio to be calculated as provided in clause (e) of this
         SECTION 6.2.4):



                                      -5-
<PAGE>   6

<TABLE>
<CAPTION>

                  FISCAL QUARTER ENDING:             RATIO
                  ----------------------             -----

<S>                                                  <C>
                  March 31, 1998                     0.8
                  June 30, 1998                      0.9
                  September 30, 1998                 1.0
                  December 31, 1998                  1.2
                  March 31, 1999                     1.3
                  June 30, 1999                      1.3
                  September 30, 1999                 1.4
                  December 31, 1999                  1.4
                  March 31, 2000                     1.4
                  June 30, 2000                      1.4
</TABLE>

                  (b) DEBT TO EBITDA RATIO. The Borrower will not permit the
         Debt to EBITDA Ratio of the Borrower and its Subsidiaries for the
         twelve-month period ending on the last day of any Fiscal Quarter to be
         more than the ratio set forth opposite such Fiscal Quarter (for the
         Fiscal Quarter ending on March 31, 1998, such ratio shall be calculated
         as provided in clause (e) of this SECTION 6.2.4):

<TABLE>
<CAPTION>

                  FISCAL QUARTER ENDING:             RATIO
                  ----------------------             -----

<S>                                                  <C>
                  March 31, 1998                     10.5
                  June 30, 1998                      7.5
                  September 30, 1998                 6.5
                  December 31, 1998                  5.5
                  March 31, 1999                     5.0
                  June 30, 1999                      5.0
                  September 30, 1999                 5.0
                  December 31, 1999                  4.5
                  March 31, 2000                     4.5
                  June 30, 2000                      4.0
</TABLE>

                  (d) INTEREST COVERAGE RATIO. The Borrower will not permit the
         Interest Coverage Ratio of the Borrower and its Subsidiaries for the
         twelve-month period ending on the last day of any Fiscal Quarter to be
         less than the ratio set forth opposite such Fiscal Quarter (for the
         Fiscal Quarter ending on March 31, 1998, such ratio to be calculated as
         provided in clause (e) of this SECTION 6.2.4.):

<TABLE>
<CAPTION>

                  FISCAL QUARTER ENDING:             RATIO
                  ----------------------             -----

<S>                                                  <C>
                  March 31, 1998                     1.1
                  June 30, 1998                      1.2
                  September 30, 1998                 1.3
</TABLE>



                                      -6-
<PAGE>   7

<TABLE>

<S>                                                  <C>
                  December 31, 1998                  1.6
                  March 31, 1999                     1.7
                  June 30, 1999                      1.8
                  September 30, 1999                 1.8
                  December 31, 1999                  1.9
                  March 31, 2000                     1.9
                  June 30, 2000                      1.9.
</TABLE>

 10.     AMENDMENT TO SECTION 6.2.5. Section 6.2.5 of the Credit Agreement is
         hereby amended by replacing the proviso at the end of such Section with
         the following:

                  PROVIDED, HOWEVER, that expenditures consisting of
                  Acquisitions approved by the Required Lenders in writing and
                  expenditures paid with insurance proceeds received upon the
                  occurrence of a Loss which are made to replace or repair
                  damage to destroyed assets will not be included in the
                  foregoing calculation for the Fiscal Year such Acquisition,
                  replacement or repair was made.

 11.     AMENDMENT TO SECTION 6.2.6. Section 6.2.6 of the Credit Agreement is
         hereby amended by replacing clause (b) of such Section with the
         following:

         (b) any lease of real property or any vehicle lease entered into by the
         Borrower or any Subsidiary after the Closing Date in the ordinary
         course of business (including, without limitation, leasing corporate
         office space),

 12.     AMENDMENT TO SECTION 6.2.7. Section 6.2.7 of the Credit Agreement is
         hereby amended by replacing subsection (a) of such Section with the
         following:

                  (a) Cash and Cash Equivalent Investments of Borrower,
         including all cash collateral pledged to secure the Existing Letters of
         Credit, PROVIDED that if any Loans are outstanding; such Cash and Cash
         Equivalent Investments shall not exceed $5,000,000 in the aggregate;

 13.     AMENDMENT TO SECTION 6.2.10. Section 6.2.10 of the Credit Agreement is
         hereby amended by replacing subsection (a) of such Section with the
         following:




                                      -7-
<PAGE>   8


         (a) The Borrower will not, and will not permit any Subsidiary to,
         liquidate or dissolve, consolidate with, or merge into or with, any
         other corporation, or purchase or otherwise acquire all, substantially
         all or a substantial portion of the assets of any Person (or of any
         division or business unit thereof) or purchase or otherwise acquire
         installed Telephones from any Person, except that any such Subsidiary
         may liquidate or dissolve voluntarily into, and may merge with and
         into, the Borrower or any other wholly-owned Subsidiary (so long as the
         Borrower or such wholly-owned Subsidiary is the surviving corporation),
         PROVIDED, HOWEVER, that

                           (i) the Borrower shall be permitted to merge with and
                  into a Delaware corporation for the sole purpose of changing
                  its state of incorporation to the State of Delaware provided
                  that (A) the shareholders of the surviving corporation
                  immediately after such merger are the shareholders of the
                  Borrower immediately prior to such merger, (B) the number of
                  authorized and issued and authorized and unissued shares, and
                  the respective classes and series, of capital stock of the
                  surviving corporation shall be the same as the number of
                  authorized and issued and authorized and unissued shares, and
                  the respective classes and series of capital stock of the
                  Borrower immediately prior to such merger, (C) the voting
                  powers, designations, preferences and relative, participating,
                  optional or other special rights, and qualifications,
                  limitations and restrictions of all classes and series of
                  capital stock of the surviving corporation shall be identical
                  to the voting powers, designations, preferences (including,
                  without limitation, stated values and liquidation preferences)
                  and relative, participating, optional or other special rights,
                  and qualifications, limitations and restrictions of the
                  respective classes and series of the capital stock of the
                  Borrower as in effect immediately prior to such merger, and
                  (D) the Lenders shall have received (1) an assumption
                  agreement in form and substance satisfactory to the Required
                  Lenders, duly executed by the surviving corporation and
                  pursuant to which the surviving corporation shall expressly
                  assume all of the obligations of the Borrower under this
                  Agreement and the other Loan Documents, and (2) such
                  acknowledgments, certificates, instruments and legal opinions
                  relating to such merger and assumption agreement as the
                  Required Lenders shall reasonably request;

                           (ii) the Borrower and its Subsidiaries may consummate
                  the Closing Date Acquisitions; and

                           (iii) the Borrower and its Subsidiaries may
                  consummate other Acquisitions with the prior written consent
                  of the Required Lenders.

 14.     REPRESENTATIONS, WARRANTIES AND COVENANTS. In order to induce the
         Lenders, the Agent and the Co-Agents to enter into this Amendment and
         to consummate the transactions contemplated herein, the Borrower hereby
         represents, warrants and covenants to and with the Agent, the Co-Agents
         and each Lender as follows:



                                      -8-
<PAGE>   9


                  (a) as of the date hereof, all representations and warranties
         set forth in Article 5 of the Credit Agreement and in all other Loan
         Documents are true and correct in all material respects, except to the
         extent described in Section 15 below;

                  (b) as of the date hereof and after giving effect to this
         Amendment, no Default or Event of Default exists under the Credit
         Agreement;

                  (c) no later than March 23, 1998, Borrower shall deliver to
         the Lenders, the Agent and the Co-Agents (i) an opinion letter from
         Skadden, Arps, Slate, Meagher & Flom, counsel to the Borrower and its
         Subsidiaries, and Tammy L. Martin, General Counsel to Borrower and its
         Subsidiaries, in form and substance satisfactory to the Required
         Lenders, as to the corporate authority of the Borrower to enter into
         this Amendment and the other documents required hereunder, the
         enforceability of this Amendment and the other documents required
         hereunder, and such other matters as the Lenders may request; and (ii)
         a secretary's certificate in form and substance satisfactory to the
         Required Lenders, certifying true and correct copies of the Borrower's
         certificate of incorporation, by-laws and resolutions of the Board of
         Directors approving this Amendment and the modifications set forth
         herein; and

                  (d) the breach of any representation, warranty or covenant set
         forth in this Section 14 shall constitute an Event of Default under the
         Credit Agreement.

15.      ACKNOWLEDGMENT OF MATERIAL ADVERSE CHANGE. (a) In July 1997, Borrower
         informed the Agent, the Co-Agents and the Lenders that the United
         States Court of Appeals for the District of Columbia Circuit, in Case
         No. 96-1394 entitled ILLINOIS PUBLIC TELECOMMUNICATIONS ASSOCIATION,
         PETITIONER, V. FEDERAL COMMUNICATIONS COMMISSION AND UNITED STATES OF
         AMERICA, RESPONDENTS, WITH COMPETITIVE TELECOMMUNICATIONS ASSOCIATION,
         ET AL, AS INTERVENORS, entered an order (the "Reversal") reversing and
         remanding to the Federal Communications Commission (the "FCC") for
         further consideration the dial-around compensation provisions of the
         Commission's Report and Order implementing Section 276 of the
         Communications Act of 1934, as amended by the Telecommunications Act of
         1996 (the "FCC Order"). More recently, the United States Court of
         Appeals for the District of Columbia vacated certain aspects of the FCC
         Order relating to compensation of pay phone providers by Interexchange
         Carrier Parties (1997 U.S. App. LEXIS 24440). On October 9, 1997, the
         FCC adopted and released its Second Report and Order implementing
         Section 276 of the Communications Act of 1934, as amended by the
         Telecommunications Act of 1996 (the "Second FCC Order") which addressed
         dial-around compensation for calls originating from pay phones in light
         of the foregoing Court decisions, establishing a rate of $0.284
         ($0.35-$0.066) per call for the first two years of per-call
         compensation, the market-base local coin rate, adjusted for certain
         costs defined by the FCC as $0.066 per call. The Second FCC Order is on
         appeal with the United States Court of Appeals for the District of
         Columbia Circuit. The


                                      -9-
<PAGE>   10

         Borrower hereby expressly acknowledges and agrees that the foregoing
         events constitute a Material Adverse Change, that except to the extent
         expressly provided in paragraph (b) below, the Lenders expressly
         reserve all rights with respect to such Material Adverse Change and
         that nothing contained in this Amendment waives such Material Adverse
         Change. The Borrower further acknowledges and agrees that as provided
         in Section 4.3.5 of the Credit Agreement, it is a condition precedent
         to the obligations of the Lenders to make any Loans, and the obligation
         of the Agent to issue and the obligations of the Lenders to purchase
         participations in Letters of Credit, that no Material Adverse Change
         shall have occurred since the Closing Date. Accordingly, the Lenders
         have no obligation to make Loans, the Agent has no obligation to issue
         Letters of Credit and the Lenders have no obligation to purchase
         participations in said Letters of Credit, and the making of any such
         Loans and the issuance of any such Letters of Credit are subject to the
         sole and absolute discretion of the Lenders, subject to subsection (b)
         below.

         (b) Notwithstanding that the Material Adverse Change described in
subparagraph (a) above has occurred and that the Lenders have no obligation to
make Loans, the Agent has no obligation to issue Letters of Credit and the
Lenders have no obligation to purchase participations in said Letters of Credit,
the Agent agrees to issue Letters of Credit and the Lenders agree to make
Revolving Credit Loans and to purchase participations in said Letters of Credit,
subject to all other terms and conditions of the Credit Agreement, as amended by
this Amendment; PROVIDED, HOWEVER, that the aggregate outstanding principal
amount of all Revolving Credit Loans, PLUS the aggregate amount of outstanding
Letter of Credit Obligations, may not exceed $10,300,000 at any time.

16.      EFFECTIVENESS. This Amendment shall become effective only upon (i)
         receipt by the Agent of a copy of this Amendment, duly executed by each
         of the Borrower, the Lenders, the Agent and the Co-Agents, and duly
         acknowledged and consented to by the Subsidiaries of the Borrower in
         the form attached to this Amendment; (ii) receipt by each Lender of a
         duly executed and delivered Expansion Note in a principal amount equal
         to such Lender's Percentage of the Expansion Loan Commitment Amount (as
         such terms are modified by this Amendment), in replacement and
         substitution of the Expansion Notes issued by Borrower on the Closing
         Date, (iii) receipt by each Lender of a duly executed and delivered
         Revolving Credit Note in a principal amount equal to such Lender's
         Percentage of the Revolving Credit Commitment Amount (as such terms are
         modified by this Amendment), in replacement and substitution of the
         Revolving Credit Notes issued by Borrower on the Closing Date; (iv)
         receipt by legal counsel to each Lender of payment for fees and
         expenses incurred to date; and (v) receipt by the Agent of the
         Amendment Fee required pursuant to Section 17 hereof.

 17.     AMENDMENT FEE. The Borrower agrees to pay to the Agent for the ratable
         account of each Lender, an amendment fee in an amount equal to $150,000
         (the "AMENDMENT FEE"). The Amendment Fee shall be payable by the
         Borrower upon the execution of this Amendment, and the Borrower hereby
         irrevocably authorizes the Agent to deduct from


                                      -10-
<PAGE>   11

         the proceeds of a Borrowing of Revolving Loans to be made on the date
         of this Agreement in the amount of $3,000,000, the sum of $150,000 for
         the ratable account of each Lender as payment in full of the Amendment
         Fee and the sum of $20,148.64 for the account of the Agent as payment
         of its billed and outstanding legal expenses.

 18.     CONTINUING EFFECTIVENESS OF CREDIT AGREEMENT. The Credit Agreement and
         each of the other Loan Documents shall remain in full force and effect
         in accordance with their respective terms, except as expressly amended
         or modified by this Amendment.

 19.     COST AND EXPENSES. The Borrower agrees to pay all reasonable
         out-of-pocket expenses of the Agent and each of the Lenders party to
         this Amendment for the negotiation, preparation, execution and delivery
         of this Amendment (including reasonable fees and expenses of counsel to
         the Agent and such Lenders).

 20.     HEADINGS. The various headings of this Amendment are inserted for
         convenience only and shall not affect the meaning or interpretation of
         this Amendment or any provision hereof.

 21.     COUNTERPARTS. This Amendment may be executed by the parties hereto in
         several counterparts, each of which shall be executed by the Borrower,
         the Lenders and the Agent and shall be deemed to be an original and all
         of which shall constitute together but one and the same agreement.

 22.     GOVERNING LAW. THIS AMENDMENT SHALL BE DEEMED TO BE A CONTRACT MADE
         UNDER AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW YORK.

 23.     SUCCESSORS AND ASSIGNS. This Amendment shall be binding upon and shall
         inure to the benefit of the parties hereto and their respective
         successors and assigns; PROVIDED, HOWEVER, that the Borrower may not
         assign or transfer its rights or obligations hereunder or under the
         Credit Agreement except in accordance with the terms of the Credit
         Agreement.



                                      -11-
<PAGE>   12



         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed by their respective officers thereunto duly authorized as of the day
and year first above written.


                                   PHONETEL TECHNOLOGIES, INC.


                                   By:  /s/ Tammy L. Martin
                                        --------------------------
                                   Name: Tammy L. Martin
                                   Title: Secretary

                                                     [CORPORATE SEAL]



Percentage: 26.6666667%            ING (U.S.) CAPITAL CORPORATION, in its
                                   capacity as Agent and Lender


                                   By:  /s/ Steven G. Fleenor
                                        --------------------------
                                        Steven G. Fleenor
                                        Vice President



Percentage: 26.6666667%            TRANSAMERICA BUSINESS CREDIT
                                   CORPORATION, in its capacity as Co-Agent
                                   and Lender



                                   By:  /s/  Terrell W. Harris
                                        --------------------------
                                        Terrell W. Harris
                                        Vice President





                                      -12-
<PAGE>   13


Percentage: 26.6666667%            FINOVA CAPITAL CORPORATION, in its
                                   capacity as Co-Agent and Lender



                                   By:  /s/ Marilyn Milam
                                        --------------------------
                                        Marilyn Milam
                                        Vice President


Percentage: 20.0%                  AMERICAN NATIONAL BANK, in its
                                   capacity as Lender



                                   By:  /s/ Richard Johnson
                                        --------------------------
                                        Name:  Richard Johnson
                                        Title: Vice President


                                      -13-
<PAGE>   14



                           ACKNOWLEDGMENT AND CONSENT

         The undersigned hereby acknowledge receipt of a copy of the foregoing
Amendment, consent to the terms and provisions set forth therein, and agree that
the Subsidiary Guaranty dated as of May 30, 1997 (the "SUBSIDIARY GUARANTY")
made by each of the undersigned, jointly and severally, in favor of ING (U.S.)
Capital Corporation ("ING"), the other lenders as are, or may from time to time
become, parties to the Credit Agreement (as defined in the Subsidiary Guaranty)
and ING in its capacity as Agent for such Lenders, will continue in full force
and effect without diminution or impairment notwithstanding the execution and
delivery of the Amendment. The undersigned further acknowledge and agree that,
upon effectiveness of the Amendment and from and after the date thereof, each
reference to the Credit Agreement in the Subsidiary Guaranty and each other Loan
Document (as such term is defined in the Credit Agreement) to which any of the
undersigned is a party shall mean and be a reference to the Credit Agreement as
amended by this Amendment.

CHEROKEE COMMUNICATIONS, INC.

By:  /s/ Tammy L. Martin
   -----------------------------------
     Name:  Tammy L. Martin
     Title: Secretary

            [CORPORATE SEAL]


PHONETEL V, INC.

By:    /s/ Tammy L. Martin
   -----------------------------------
     Name:  Tammy L. Martin
     Title: Secretary

            [CORPORATE SEAL]


PHONETEL ACQUISITION CORP.

By:    /s/ Tammy L. Martin
   -----------------------------------
     Name:  Tammy L  Martin
     Title: Secretary

            [CORPORATE SEAL]


                                      -14-