EXHIBIT 99.6

  
                              VOTING AGREEMENT
  
      This VOTING AGREEMENT, dated June 11, 1998, between ING (U.S.)
 Investment Corporation, a Delaware corporation ("ING"), and Davel
 Communications Group, Inc., an Illinois corporation (the "Company"). 
  
      WHEREAS, concurrently with the execution and delivery of this
 Agreement, PhoneTel Technologies, Inc., an Ohio corporation ("PhoneTel"),
 the Company, Davel Holdings, Inc., a Delaware corporation and a wholly
 owned subsidiary of the Company ("New Davel"), D Subsidiary, Inc., an
 Illinois corporation and a wholly owned subsidiary of New Davel ("D Sub"),
 and PT Merger Corp., an Ohio corporation and a wholly owned subsidiary of
 New Davel ("P Sub"), have entered into an Agreement and Plan of Merger and
 Reorganization (the "Merger Agreement"), dated the date hereof, pursuant to
 which (i) D Sub will be merged with and into the Company with the Company
 surviving as a wholly owned subsidiary of New Davel (the "Davel Merger")
 and (ii) P Sub will be merged with and into PhoneTel with PhoneTel
 surviving as a wholly owned subsidiary of New Davel (the "PhoneTel
 Merger"). 
  
      WHEREAS, the consummation of the PhoneTel Merger, and the other
 transactions contemplated by the Merger Agreement (the "Transaction"), is
 subject to certain conditions, including the approval of the Merger
 Agreement and the PhoneTel Merger by the holders of at least a majority of
 the outstanding shares of common stock, par value $.01 per share, of 
 PhoneTel ("PhoneTel Common Stock"). 
  
      WHEREAS, ING is the holder of warrants (the "Warrants") to purchase
 shares of Series A Special Convertible Preferred Stock, par value $.20 per
 share (the Preferred Stock), of PhoneTel at an exercise price of $.20 per
 share of Preferred Stock.   
  
      WHEREAS, the Preferred Stock is convertible into an aggregate of
 2,041,590 shares of PhoneTel Common Stock (such shares, upon acquisition
 thereof by ING, being herein referred to as the "Warrant Shares" and the
 Warrant Shares, together with any other shares of capital stock of PhoneTel
 acquired by ING after the date hereof and during the term of this Agreement
 being collectively herein referred to as the "Shares"). 
  
      WHEREAS, under the terms of the Warrant Purchase Agreement dated March
 15, 1996 (the "Warrant Agreement") between PhoneTel and ING pursuant to
 which the Warrants were issued, the Warrants are immediately exercisable
 for the Preferred Stock; and, under the terms of the Preferred Stock, as
 set forth in the Articles of Incorporation of PhoneTel, upon issuance, the
 Preferred Stock will be immediately convertible into the Shares. 
  
      WHEREAS, as a condition to the willingness of the Company to enter
 into the Merger Agreement, and as an inducement to it to do so, ING has
 agreed for the benefit of the Company as set forth in this Agreement. 
  
      NOW, THEREFORE, in consideration of the representations, warranties,
 covenants and agreements contained in this Agreement, the parties hereby
 agree as follows: 
  
                                 ARTICLE I 
  
                              COVENANTS OF ING 
  
      Section 1.1    Agreement to Exercise Warrants.  ING covenants and
 agrees with the Company that, prior to the record date for the PhoneTel
 Shareholders Meeting (as hereinafter defined), ING will exercise the
 Warrants for all of the shares of Preferred Stock issuable upon exercise of
 the Warrants and will pay the exercise price payable in respect thereof. 
  
      Section 1.2    Agreement to Convert Preferred Stock.  ING covenants
 and agrees with the Company that, prior to the record date for the PhoneTel
 Stockholders Meeting, ING will convert the Preferred Stock into all of the
 shares of PhoneTel Common Stock issuable upon conversion of  the Preferred
 Stock  and will continue to hold the Shares through such record date so
 that ING is a holder of record of PhoneTel Common Stock entitled to vote
 the Shares at the PhoneTel Stockholders meeting. 
  
      Section 1.3    Agreement to Vote.  At any meeting of the shareholders
 of the Company held prior to the Termination Date (as hereinafter defined),
 however called ("PhoneTel Shareholders Meeting"), and at every reconvened
 meeting following any adjournment or postponement thereof prior to the
 Termination Date, or in connection with any written consent of the
 shareholders of the Company executed prior to the Termination Date, ING
 shall vote the Shares in favor of the approval of the Merger Agreement, the
 PhoneTel Merger and each of the actions contemplated by the Merger
 Agreement to be performed by PhoneTel in connection with the Transaction
 and any actions required in furtherance thereof.  Prior to the Termination
 Date and subject to Section 1.5, ING shall not enter into any agreement or
 understanding with any person, directly or indirectly, to vote, grant any
 proxy or give instructions with respect to the voting of the Shares in any
 manner inconsistent with the preceding sentence. 
  
      Section 1.4    Proxies.  (a) ING hereby revokes any and all previous
 proxies granted with respect to matters set forth in Section 1.3 for the
 Shares. 
  
      (b)  Prior to the Termination Date, ING shall not grant any proxies or
 powers of attorney with respect to matters set forth in Section 1.3,
 deposit any of the Shares into a voting trust or enter into a voting
 agreement, other than this Agreement, with respect to any of the Shares, in
 each case with respect to such matters. 
  
      Section 1.5    Transfer of Shares by ING.  Prior to the Termination
 Date, ING shall not (a) pledge or place any encumbrance on any Shares,
 other than pursuant to this Agreement, or (b) transfer, sell, exchange or
 otherwise dispose of any Shares, in each case, unless the pledgee,
 encumbrance holder, transferee, purchaser or acquiror of such Shares enters
 into a Voting Agreement with the Company containing substantially the same
 terms as this Agreement. 
  
      Section 1.6    Action in Shareholder Capacity Only.  ING makes no
 agreement or understanding herein in any capacity other than its capacity
 as a record holder of the Warrants and a beneficial owner of the Warrants,
 the Preferred Stock and the Shares, and nothing herein shall limit or
 affect any actions taken in any other capacity. 
  
                                 ARTICLE II 
  
                      REPRESENTATIONS, WARRANTIES AND 
                        ADDITIONAL COVENANTS OF ING 
  
      ING represents, warrants and covenants to the Company that: 
  
      Section 2.1    Ownership.  As of the date hereof, ING has the right,
 under the terms of the Warrants and the Preferred Stock, to acquire, in the
 aggregate, the 2,041,590 Warrant Shares.  Upon exercise of the Warrants and
 subsequent conversion of the Preferred Stock, ING will be the beneficial
 and record owner of the Warrant Shares and, subject to Section 1.3, ING
 will have the sole right to vote the Warrant Shares and there will be no
 restrictions on rights of disposition or other liens pertaining to the
 Warrant Shares.  ING has not agreed to subject any Shares to any voting
 trust or other agreement, arrangement or restriction with respect to the
 voting of the Shares. 
  
      Section 2.2    Authority and Non-Contravention.  ING has the right,
 power and authority to enter into this Agreement and, subject to the
 issuance to ING of the Warrant Shares, to consummate the transactions
 contemplated by this Agreement.  The execution and delivery of this
 Agreement by ING and the consummation of the transactions contemplated by
 this Agreement have been duly authorized by all necessary action on the
 part of ING.  This Agreement has been duly executed and delivered by ING
 and constitutes a valid and binding obligation of ING, enforceable against
 ING in accordance with its terms, subject to general principles of equity
 and as may be limited by bankruptcy, insolvency, moratorium, or similar
 laws affecting creditors' rights generally.  Neither the execution and
 delivery of this Agreement by ING nor the consummation by ING of the
 transactions contemplated hereby will (i) materially violate, or require
 any consent, approval or notice under, any provision of any judgment,
 order, decree, statute, law, rule or regulation applicable to ING or, upon
 issuance thereof to ING,  the Shares or (ii) violate or conflict with the
 certificate of incorporation or bylaws of ING or constitute a material
 violation of or default under any contract, commitment, agreement,
 understanding, arrangement or other restriction of any kind to which ING is
 a party or by which ING or its assets are bound. 
  
      Section 2.3    Total Shares.  As of the date hereof, ING does not own,
 beneficially (other than through ownership of the Warrants) or of record,
 any shares of capital stock of the Company.  Other than the Warrants, ING
 does not have any option to purchase or right to subscribe for or otherwise
 acquire any securities of the Company and has no other interest in or
 voting rights with respect to any other securities of the Company. 
  
      Section 2.4    Notifications.  Prior to the Termination Date, ING will
 notify the Company promptly of the number of any shares of capital stock of
 PhoneTel acquired by ING after the date hereof. 
  
      Section 2.5    Delivery of Affiliate Letter.  In the event that
 counsel to the Company reasonably determines that ING is an affiliate of
 PhoneTel for purposes of Rule 145 under the Securities Act of 1933, as
 amended, or for purposes of pooling accounting, ING agrees to execute and
 deliver to the Company not later than 30 days prior to the effective time
 of the PhoneTel Merger an Affiliate Letter substantially in the form
 attached hereto as Exhibit A. 
  
                                ARTICLE III 
  
                REPRESENTATIONS, WARRANTIES AND COVENANTS OF 
                                THE COMPANY 
  
      The Company represents, warrants and covenants to ING that: 
  
      Section 3.1    Authority and Non-Contravention.  The Company has the
 right, power and authority to enter into this Agreement and to consummate
 the transactions contemplated by this Agreement.  The execution and
 delivery of this Agreement by the Company and the consummation of the
 transactions contemplated by this Agreement have been duly authorized by
 all necessary action on the part of the Company.  This Agreement has been
 duly executed and delivered by the Company and constitutes a valid and
 binding obligation of the Company, enforceable against the Company in
 accordance with its terms, subject to general principles of equity and as
 may be limited by bankruptcy, insolvency, moratorium or similar laws
 affecting creditors' rights generally.  Neither the execution and delivery
 of this Agreement nor the consummation by the Company of the transactions
 contemplated hereby will (i) materially violate, or require any consent,
 approval or notice under, any provision of any judgment, order, decree,
 statute, law, rule or regulation applicable to the Company or (ii) violate
 or conflict with the certificate of incorporation or by laws of the Company
 or constitute a material violation of or default under any contract,
 commitment, agreement, understanding, arrangement or other restriction of
 any kind to which the Company is a party or by which the Company or its
 assets are bound. 
  
                                 ARTICLE IV 
  
                               MISCELLANEOUS 
  
      Section 4.1    Expenses.  All costs and expenses incurred in
 connection with this Agreement shall be paid by the party incurring such
 costs or expenses; provided, however, that the Company shall pay reasonable
 fees and expenses of counsel to ING incurred in connection with the
 negotiation and execution of this Agreement. 
  
      Section 4.2    Further Assurances.  From time to time, at the request
 of the Company, in the case of ING, or at the request of ING, in the case
 of the Company, and without further consideration, each party shall execute
 and deliver or cause to be executed and delivered such additional documents
 and instruments and take all such further action as may be reasonably
 necessary or desirable to consummate the transactions contemplated by this
 Agreement. 
  
      Section 4.3    Specific Performance.  ING agrees that the Company
 would be irreparably damaged if for any reason ING fails to perform any of
 ING's obligations under this Agreement, and that the Company would not have
 an adequate remedy at law for money damages in such event.  Accordingly,
 the Company shall be entitled to seek specific performance and injunctive
 and other equitable relief to enforce the performance of this Agreement by
 ING.  This provision is without prejudice to any other rights that the
 Company may have against ING for any failure to perform its obligations
 under this Agreement. 
  
      Section 4.4    Amendments, Termination.  This Agreement may not be
 modified or amended except by an instrument or instruments in writing
 signed by each party hereto.  The representations, warranties, covenants
 and agreements set forth in Article I, Article II and Article III shall
 terminate, except with respect to liability for prior breaches thereof,
 upon the earliest to occur of (i) December 7, 1998, (ii) termination of the
 Merger Agreement in accordance with its terms, (iii) the Closing Date and
 (iv) the date, if any, upon which PhoneTel's Board of Directors withdraws,
 modifies or changes its recommendation or approval of the Merger Agreement
 or the PhoneTel Merger in a manner adverse to the Company (the "Termination
 Date"). 
  
      Section 4.5    Assignment.  Subject to Section 1.5 hereof, neither
 this Agreement nor any of the rights, interests or obligations under this
 Agreement shall be assigned, in whole or in part, by operation of law or
 otherwise by any of the parties without the prior written consent of the
 other parties.  Subject to the preceding sentence, this Agreement shall be
 binding upon, and inure to the benefit of, the parties hereto and their
 respective successors and assigns. 
  
      Section 4.6    Certain Events.  ING agrees that this Agreement and the
 obligations hereunder shall attach to the Warrants, Preferred Stock and
 Shares and shall be binding upon any person to which legal or beneficial
 ownership of such shares shall pass, whether by operation of law or
 otherwise. 
  
      Section 4.7    Entire Agreement.  This Agreement (including the
 documents referred to herein) (a) constitutes the entire agreement, and
 supersedes all prior agreements and understanding, both oral and written
 between the parties with respect to the subject matter of this Agreement
 and (b) is not intended to confer upon any person other than the parties
 hereto any rights or remedies. 
  
      Section 4.8    Notices.  All notices and other communications
 hereunder shall be in writing and shall be deemed given if delivered
 personally, sent by documented overnight delivery service or telecopied
 with confirmation of receipt, to the parties at the addresses specified
 below (or at such other address or telecopy or telex number for a party as
 shall be specified by like notice): 
  
           If to the Company, to: 
  
                Davel Communications Group, Inc. 
                1429 Massaro Boulevard 
                Tampa, Florida  33619 
                Attention:  Theodore C. Rammelkamp, Jr. 
                Facsimile:  (813) 626-9610 
  
           with a copy to: 
  
                Kirkland & Ellis 
                200 East Randolph Drive 
                Chicago, Illinois  60601 
                Attention:  R. Scott Falk 
                Facsimile:  (312) 861-2200 
  
           If to ING, to: 
  
                Internationale Nederlanden 
                (U.S.)  Capital Corporation 
                135 East 57th Street 
                New York, NY 10022 
                Attention:  Chief Credit Officer 
                Facsimile:  (212) 750-8935 
  
           with a copy to: 
  
                King & Spalding 
                191 Peachtree Street 
                Atlanta, GA  30300-1763 
                Attention:  William R.  Spalding 
                Facsimile:  (404) 572-5100 
  
      Section 4.9    Governing Law.  This Agreement shall be governed by,
 and construed in accordance with, the laws of the State of New York
 regardless of the laws that might otherwise govern under applicable
 principles of conflicts of laws thereof. 
  
      Section 4.10   Counterparts.  This Agreement may be executed in two or
 more counterparts, all of which shall be considered one and the same
 agreement, and, shall become effective when one or more counterparts have
 been signed by each of the parties and delivered to the other parties in
 original or facsimile form. 
  
      Section 4.11   Interpretation.  The headings contained in this
 Agreement are inserted for convenience of reference only and shall not
 affect in any way the meaning or interpretation of this Agreement. 
  
      Section 4.12   Severability.  Any provision hereof which is invalid or
 unenforceable shall be ineffective to the extent of such invalidity or
 unenforceability, without affecting in any way the remaining provisions
 hereof. 
  
      Section 4.13   Consent to Jurisdiction.  Each party hereto irrevocably
 submits to the nonexclusive jurisdiction of (a) the state courts of the
 State of New York and (b) the United States federal district courts located
 in the State of New York for the purposes of any suit, action or other
 proceeding arising out of this Agreement or any transaction contemplated
 hereby. 
  
      Section 4.14   Attorney's Fees.  If any action at law or in equity is
 necessary to enforce or interpret the terms of this Agreement, the
 prevailing party shall be entitled to reasonable attorneys' fees, costs and
 necessary disbursements, in addition to any other relief to which such
 party may be entitled. 
  

      IN WITNESS WHEREOF, this Agreement has been signed by or on behalf of
 each of the parties as of the date first above written. 

  
                               ING, (U.S.) INVESTMENT CORPORATION 
  
  
                               By:________________________________
                               Name: 
                               Title: 
  
  
                               DAVEL COMMUNICATIONS GROUP, INC. 
  
  
                               By:________________________________
                               Name: 
                               Title: