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                                                                   EXHIBIT 10.15
                                                                   -------------



                              AMENDMENT NUMBER FOUR
                              ---------------------
                         TO LOAN AND SECURITY AGREEMENT
                         ------------------------------


          THIS AMENDMENT NUMBER FOUR TO LOAN AND SECURITY AGREEMENT (this
"Amendment") dated as of March 1, 2001, is entered into among PHONETEL
TECHNOLOGIES, INC., an Ohio corporation ("Phonetel"), CHEROKEE COMMUNICATIONS,
INC., a Texas corporation ("Cherokee," and together with Phonetel, each a
"Borrower" and collectively, jointly and severally, the "Borrowers"), on the one
hand, and, on the other hand, Agent (as hereinafter defined) and the financial
institutions (collectively, the "Lenders" and individually, a "Lender") that are
signatories to that certain Loan and Security Agreement, dated as of November
17, 1999 (as amended, restated, supplemented, or otherwise modified from time to
time, the "Loan Agreement"), entered into among the Borrowers, Lenders, and
FOOTHILL CAPITAL CORPORATION, a California corporation, as agent for the Lenders
(herein, in such capacity, referred to as "Agent"), in light of the following:


                                    RECITALS
                                    --------

          WHEREAS, Borrowers have requested that the Lenders amend the Loan
Agreement; and

          WHEREAS, Lenders are willing to amend the Loan Agreement under the
terms and conditions set forth in this Amendment.

          NOW, THEREFORE, in consideration of the foregoing and the mutual
covenants herein contained, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereby
agree as follows:


                                   AGREEMENT
                                   ---------

I.    DEFINITIONS. Capitalized terms not otherwise defined herein shall have the
      meaning ascribed thereto in the Loan Agreement.

II.   AMENDMENTS TO THE LOAN AGREEMENT. Upon the Fourth Amendment Effective
      Date, the parties agree to amend the Loan Agreement as follows:

      2.1 SECTION 1.1 of the Loan Agreement hereby is amended by inserting the
          following new defined terms in the proper alphanumerical order:



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          "FOURTH AMENDMENT" means that certain Amendment Number Four to Loan
          and Security Agreement, dated as of March 1, 2001, among Borrowers,
          Lenders and Agent.

          "FOURTH AMENDMENT EFFECTIVE DATE" means the date that all conditions
          set forth in SECTION 3 of the Fourth Amendment have been satisfied.

      2.2 SECTION 2.5 of the Loan Agreement hereby is amended and restated in
          its entirety to read as follows:

          2.5 OVERADVANCES. If, at any time or for any reason, the amount of
          Obligations owed by Borrower to the Lender Group pursuant to SECTIONS
          2.1 AND 2.12 exceeds the limitations set forth in SECTIONS 2.1 OR 2.12
          by an amount in excess of $2,410,000 (an "OVERADVANCE"), Borrower
          immediately shall pay to Agent, in cash, the amount of such excess,
          which amount shall be used by Agent to reduce the Obligations in
          accordance with the priority set forth in SECTION 2.4(b). In addition,
          Borrower hereby promises to pay the Obligations (including principal,
          interest, fees, costs, and expenses) in Dollars (except to the extent
          that Borrower has exercised its option to make payment in kind of
          certain interest and fees under the terms of this Agreement) in full
          to the Lender Group as and when due and payable under the terms of
          this Agreement and the other Loan Documents.

      2.3 SECTION 2.6 of the Loan Agreement hereby is amended by inserting the
          following new subsection (i) thereof:

          (i) PAYMENT IN KIND OF CERTAIN INTEREST OWING. Notwithstanding the
          provisions of subsections (c) and (h) above, interest accrued during
          the month of February, 2001, otherwise due and payable on March 1,
          2001, shall instead be added to principal as of March 1, 2001, and
          shall thereafter accrue interest at the rate then applicable to
          Advances hereunder.

      2.3 SECTION 7.20(f) of the Loan Agreement hereby is amended and restated
          in its entirety to read as follows:

          (f) MINIMUM NUMBER OF OPERATING TELEPHONES. Borrower will not permit
          the number of revenue producing operating Telephones which Agent has
          approved as Eligible Pay Telephones at any time to be less than 33,500
          such Telephones from the Closing Date through the Maturity Date.


III.  WAIVER TO THE LOAN AGREEMENT. Upon the Fourth Amendment Effective Date,
      the parties agree to certain waivers as follows:

      3.1 WAIVER OF SECTION 7.20(f) OF THE LOAN AGREEMENT. The parties hereby
          agree to waive Borrower's compliance with SECTION 7.20(f) of the Loan
          Agreement with respect to time periods before the Fourth Amendment
          Effective Date.



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      3.2 WAIVER OF CERTAIN FINANCIAL COVENANTS FOR THE QUARTER ENDED
          DECEMBER 31, 2000. Agent hereby waives any Default or Event of Default
          solely with respect to Borrower's failure to comply with SECTIONS
          7.20(a), 7.20(b), 7.20(c), 7.20(d), and 7.20(e), only for the period
          ending December 31, 2000.

IV.   CONDITIONS PRECEDENT TO AMENDMENT. The satisfaction of each of the
      following unless waived or deferred by Lenders, in their sole discretion,
      shall constitute conditions precedent to the effectiveness of this
      Amendment and each and every provisions hereof:

      4.1 Agent shall have received this Amendment, in form and substance
          satisfactory to Agent, duly executed by each party hereto, and in full
          force and effect;

      4.2 The representations and warranties in this Amendment, the Loan
          Agreement as amended by this Amendment, and the other Loan Documents
          shall be true and correct in all respects on and as of the date
          hereof, as though made on such date (except to the extent that such
          representations and warranties relate solely to an earlier date);

      4.3 No Default or Event of Default shall have occurred and be continuing
          on the date hereof, nor shall result from the consummation of the
          transactions contemplated herein; and

      4.4 No injunction, writ, restraining order, or other order of any nature
          prohibiting, directly or indirectly, the consummation of the
          transactions contemplated herein shall have been issued and remain in
          force by any Governmental Authority against either of the Borrowers,
          Agent or any of the Lenders.

V.    REPRESENTATIONS AND WARRANTIES. Each Borrower hereby represents and
      warrants to the Lenders that (a) the execution, delivery, and performance
      of this Amendment and of the Loan Agreement, as amended by this Amendment,
      are within such Borrower's corporate powers, have been duly authorized by
      all necessary corporate action, and are not in contravention of any law,
      rule, or regulation, or any order, judgment, decree, writ, injunction, or
      award of any arbitrator, court, or Governmental Authority, or of the terms
      of its Governing Documents, or of any contract or undertaking to which it
      is a party or by which any of its properties may be bound or affected, (b)
      this Amendment and the Loan Agreement, as amended by this Amendment,
      constitute such Borrower's legal, valid, and binding obligation,
      enforceable against such Borrower in accordance with its terms, and (c)
      this Amendment has been duly executed and delivered by such Borrower.

VI.   CHOICE OF LAW. THE VALIDITY OF THIS AMENDMENT, ITS CONSTRUCTION,
      INTERPRETATION AND ENFORCEMENT, THE RIGHTS OF THE PARTIES HEREUNDER, SHALL
      BE DETERMINED UNDER, GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH THE
      LAWS OF THE STATE OF NEW YORK.



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VII.  COUNTERPARTS; TELEFACSIMILE EXECUTION. This Amendment may be executed in
      any number of counterparts and by different parties and separate
      counterparts, each of which when so executed and delivered, shall be
      deemed an original, and all of which, when taken together, shall
      constitute one and the same instrument. Delivery of an executed
      counterpart of a signature page to this Amendment by telefacsimile shall
      be effective as delivery of a manually executed counterpart of this
      Amendment. Any party delivering an executed counterpart of this Amendment
      by telefacsimile also shall deliver a manually executed counterpart of
      this Amendment but the failure to deliver a manually executed counterpart
      shall not affect the validity, enforceability, and binding effect of this
      Amendment.

VIII. EFFECT ON LOAN AGREEMENT. The Loan Agreement, as amended hereby, shall be
      and remain in full force and effect in accordance with its respective
      terms and hereby is ratified and confirmed in all respects. The execution,
      delivery, and performance of this Amendment shall not operate as a waiver
      of or, except as expressly set forth herein, as an amendment of, any
      right, power, or remedy of Agent or any Lender under the Loan Agreement,
      as in effect prior to the date hereof.

IX.   FURTHER ASSURANCES. Each Borrower shall execute and deliver all
      agreements, documents, and instruments, in form and substance satisfactory
      to Agent, and take all actions as Agent may reasonably request from time
      to time, to perfect and maintain the perfection and priority of Liens in
      the Collateral held by Agent for the benefit of the Lenders and to fully
      consummate the transactions contemplated under this Amendment and the Loan
      Agreement, as amended by this Amendment.

X.    MISCELLANEOUS.

      A.      Upon and after the effectiveness of this Amendment, each reference
         in the Loan Agreement to "this Agreement", "hereunder", "herein",
         "hereof" or words of like import referring to the Loan Agreement, and
         each reference in the other Loan Documents to "the Loan Agreement",
         "thereunder", "therein", "thereof" or words of like import referring
         to the Loan Agreement, shall mean and be a reference to the Loan
         Agreement as modified and amended hereby.

      B.      The Loan Agreement and all other Loan Documents, are and shall
         continue to be in full force and effect and are hereby in all respects
         ratified and confirmed and shall constitute the legal, valid, binding
         and enforceable obligations of each Borrower to Agent and Lenders.


                            [signature page follows]



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          IN WITNESS WHEREOF, the parties have entered into this Amendment as of
the date first above written.

                                   PHONETEL TECHNOLOGIES, INC.,
                                   an Ohio corporation

                                   By /s/ John D. Chichester
                                      -------------------------------------
                                   Name: John D. Chichester
                                         ----------------------------------
                                   Title: Chief Executive Officer
                                          ---------------------------------


                                   CHEROKEE COMMUNICATIONS, INC.,
                                   a Texas corporation

                                   By /s/ John D. Chichester
                                      -------------------------------------
                                   Name: John D. Chichester
                                         ----------------------------------
                                   Title: Chief Executive Officer
                                          ---------------------------------


                                   FOOTHILL CAPITAL CORPORATION, a
                                   California corporation, as Agent and a Lender

                                   By /s/ Amy Lam
                                      -------------------------------------
                                   Name: Amy Lam
                                         ----------------------------------
                                   Title: Vice President
                                          ---------------------------------


                                   FOOTHILL PARTNERS III, L.P.,
                                   a Delaware limited partnership, as a Lender

                                   By /s/ Dennis R. Ascher
                                      -------------------------------------
                                   Name: Dennis R. Ascher
                                         ----------------------------------
                                   Title: Managing General Partner
                                          ---------------------------------


                                   ABLECO FINANCE LLC,
                                   a Delaware limited liability company,
                                   as a Lender and as agent for its successors
                                   and assigns

                                   By /s/ Kevin P. Genda
                                      -------------------------------------
                                   Name: Kevin P. Genda
                                         ----------------------------------
                                   Title: Senior Vice President and
                                          ---------------------------------
                                            Chief Credit Officer
                                            -------------------------------