<PAGE>

                                   ACE*COMM's
                            Master Support Agreement





                                  PREPARED FOR:

                        LOGIX COMMUNICATIONS CORPORATION
                     A SUBSIDIARY OF DOBSON WIRELINE COMPANY









                                  PREPARED BY:

                                    ACE*COMM
                             704 Quince Orchard Road
                          Gaithersburg, Maryland 20878









                            PROPRIETARY RIGHTS NOTICE

All rights reserved. This material contains the valuable properties and trade
secrets of ACE*COMM of Gaithersburg, Maryland, United States of America
embodying substantial creative efforts and confidential information, ideas, and
expressions. no part of which may be reproduced or transmitted in any form or by
any means, electronic, mechanical, or otherwise, including photocopying and
recording or in connection with any information storage retrieval system without
the permission in writing from ACE*COMM.


                          GOVERNMENT RESTRICTED RIGHTS

Use, duplication, or disclosure by the Government is subject to restrictions
as set forth in subparagraph (c)(i)(ii) of the Rights in Technical Data and
Computer Software clause DFARS 52.227-7013. Manufacturer is ACE*COMM 704
Quince Orchard Road, Gaithersburg, MD 20878.

                                      -1-
<PAGE>

                            MASTER SUPPORT AGREEMENT


This Agreement is made as of June____, 1998, by and between ACE*COMM
Corporation, located at 704 Quince Orchard Road, Gaithersburg, Maryland 20878,
hereinafter called "ACE*COMM", and LOGIX Communications Corporation, a
subsidiary of Dobson Wireline Company located at 13439 N. Broadway Extension,
Oklahoma City, OK 73114 hereinafter referred to as "Customer", for the purchase
by Customer of certain system support services under the following terms and
conditions:

ARTICLE I SCOPE OF AGREEMENT


ACE*COMM agrees to provide Customer support services, hereinafter called
"Support", for items listed in Schedules A through F hereof. Scheduling of such
Support will be decided by mutual agreement.

Contingent upon the terms specified in Article II hereof, Support under this
Agreement will include the following:

         A.1      Customer Telephone Support

                           The Customer Telephone Support Service is offered
                           from 8:30 a.m. to 10:00 p.m. Monday - Thursday and
                           8:30 a.m. to 6:00 p.m. Friday Eastern Time weekdays
                           except holidays. The current holidays are New Year's
                           Day, Memorial Day, Independence Day, Labor Day,
                           Thanksgiving Day and the following Friday, and
                           Christmas Day. After hours support is available via
                           paging service.

         A.2      Product support services for the NetPlus Software as listed in
                  Schedule A which shall include the following:

                  1.       Resolution of problems associated with generic and
                           custom application software provided by ACE*COMM.

                  2.       Improvements made available through new releases of
                           the application software features that resolve
                           problems or potential problems inherent in the
                           customer's software set.

                  3.       Installation of the new software release via remote
                           dial-up access.

                  4.       Old version to new version conversion tools as
                           necessary.


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<PAGE>

                  5.       Documentation updates and improvements.

                  6.       Coverage of the installed operating system. All sites
                           listed must be operating at the same revision level,
                           of the operating system.

                  7.       This coverage does not include maintenance required
                           for third party software products.

         A.3      Operating System support, as listed in Schedule B, includes:

                  1.       problem identification and resolution.

                  2.       assistance with system start-up and shutdown
                           procedures, disk management procedures, such as disk
                           defragmentation, and other system administrative
                           housekeeping procedures.

                  3.       site configuration setup and modification, as
                           required, for approved device software connections,
                           such as printers, modems, terminals, and switch
                           interfaces.

                  4.       assistance with backup procedures, including
                           standalone backups, incremental backups, and
                           application software backups, and with file
                           restoration procedures.

                  5.       This coverage does not include the cost of software
                           modifications to the Operating System, required as a
                           result of equipment modifications installed by
                           parties other than ACE*COMM.

                  6.       This coverage does not include maintenance required
                           for third party software products other than the
                           Operating System unless such product is provided by
                           ACE*COMM.

         A.4      Product support services for the hardware systems as listed in
                  Schedule C, which includes the following:

                  1.       Maintenance of the installed equipment.

                  2.       Replacement of all defective applicable hardware
                           parts (labor included). Shipment will be made via
                           next day air service within eight (8) normal business
                           hours of identification of defective parts.

                  3.       Six (6) hour response. Upon notification of a
                           hardware or software failure by the customer,
                           ACE*COMM will provide response within the next
                           business day.

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<PAGE>

         A.5      Optional software support as described in Schedule D.

         A.6      Time and Materials Support

                  If a Customer does not choose to purchase these services on a
                  fixed price basis, ACE*COMM can provide Support under our Time
                  and Materials Program. Before the work may begin, the
                  Customer must provide a Purchase Order for at least $1,000 for
                  each problem to obtain Telephone Support. ACE*COMM will
                  investigate the problem and either resolve the problem or
                  provide a cost estimate for the resolution of the problem
                  under this Purchase Order. If the problem has not been
                  resolved and Customer wants ACE*COMM to resolve the problem,
                  the Customer will issue a Purchase Order for the full amount
                  of the estimate. ACE*COMM will invoice the Customer for the
                  full cost to resolve the problem including parts and labor at
                  the currently applicable rates. The invoiced amount will not
                  be less than $600 nor greater than the amount of the
                  Customer's Purchase Order. All Customers covered under
                  Technical Support Agreements will have priority over Time and
                  Materials Customers in the event of a conflict for resources.
                  The current Labor Rates are given in Schedule E.

         B.       Problem Resolution

                  A problem is defined as the failure of any unaltered software
                  or unaltered hardware listed in Schedules A through D hereof
                  to comply with customer-level documentation, when operating
                  within the specified or operational environment established at
                  the customer site or ACE*COMM service Center, at the time of
                  initial installation or as a failure of the documentation to
                  adequately document the operations of the software. The
                  supplied software or hardware systems should not have been
                  expanded nor otherwise altered, except by ACE*COMM, since the
                  time of installation. Similarly, any host interfacing or
                  associated systems, not supplied by ACE*COMM, shall be
                  unaltered and operating in accordance with the manufacturer's
                  specifications, at the time of installation. Connection of any
                  equipment in the installed system without prior written
                  approval from ACE*COMM shall render this agreement void.

                  Problem Resolution support shall include the-following:

                  1.       Assisting the Customer in isolating problems and
                           preparing problem documentation.


                                      -3-
<PAGE>

                  2.       Providing problem resolution by one or more of the
                           following methods:

                           Replacement of appropriate hardware components or
                           corrected executable code as necessary.

                           Corrected documentation

                           Published feature limitations

         C.       Support Outside Scope

                  Support provided outside the Scope of this Agreement (such as
                  additional operator training, Hardware or Software not listed
                  in Schedules A to E, problems induced by malfunctions of
                  systems not covered under this agreement, or data recovery)
                  will be charged at ACE*COMM's current time and expense rates
                  as listed in Schedule E.

ARTICLE II CUSTOMER RESPONSIBILITIES

To receive the support outlined in Article I hereof, the customer must provide
the following items:

         A.       A dial-up/dial-out communications line to/from
                  Gaithersburg, Maryland to Customer's site and
                  communications hardware at the Customer's site to allow
                  ACE*COMM personnel to access the Customer's computer
                  hardware, software and database for problem analysis and
                  resolution. The customer shall provide appropriate
                  security procedures to control access to this line and
                  any sensitive data.

         B.       All expendable items, i.e., printer ribbons, magnetic tapes,
                  drums, diskettes, batteries, etc.

         C.       Sufficient notification and applicable documentation on any
                  problem to allow duplication of the problem on ACE*COMM
                  equipment and software, when necessary.

         D.       Appropriate magnetic data storage media for the transportation
                  of computer software between ACE*COMM and Customer's site.

         E.       Access to the hardware site if on-site maintenance is
                  required.

         F.       ACE*COMM and the Customer will be responsible for
                  implementing and following procedures to conduct full
                  backups of the system. In the event


                                      -4-
<PAGE>

                  of database loss or of a system failure that causes a database
                  loss, ACE*COMM will assist in restoring the database from the
                  latest backup tape created and archived. ACE*COMM and the
                  Customer will be responsible for re-entering any system
                  updates not recovered from the latest backup tape.

ARTICLE III MOVEMENT OF EQUIPMENT

         A.       Customer shall notify ACE*COMM ten (10) days prior to moving
                  or reconfiguring any equipment covered by this Maintenance
                  Agreement. ACE*COMM shall be under no obligation to continue
                  service if the equipment is moved without notification to
                  ACE*COMM.

         B.       ACE*COMM, if requested to by customer, shall supervise
                  the deinstallation and reinstallation of the equipment
                  that the Customer shall wish to move. Monthly charges
                  shall be suspended when the equipment is deinstalled.
                  Charges will be adjusted and/or reinstated on the date
                  following the equipment's reinstallation. The Customer
                  shall pay for all labor, materials and travel costs
                  provided to facilitate or remedy problems caused by the
                  movement of the equipment at ACE*COMM's current rates,
                  terms and conditions.


ARTICLE IV TERM OF AGREEMENT

The initial term of this Agreement shall be sixty (60) months from the date
indicated above. Following the sixty (60) months period, Customer shall have the
opportunity to renew this Support Agreement in a minimum of twelve (12) month
increments. Any subsequent renewal will remain in effect until it expires or
until terminated by either party upon sixty (60) days prior written notice.

ARTICLE V PRICE

         A.       Customer shall pay ACE*COMM in the annual amount(s) listed in
                  Schedule G of this Agreement for the Support specified herein.

         B.       Should travel be necessary, Customer will be charged for all
                  travel expenses incurred by ACE*COMM in addition to amount(s)
                  listed in Schedules A, B, C, and D.

         C.       For services required at a time other than those set
                  forth in this Agreement and for services required because
                  of damages resulting from accident, transportation,
                  neglect, or misuse, operation of the equipment outside of
                  the manufacturer's environmental specifications, failure
                  of electrical

                                      -5-
<PAGE>

                  power, air conditioning or humidity control, said
                  service charges shall be at the per call rate in effect at the
                  time service is rendered.

         D.       Remedial service calls wherein the problem is determined to be
                  other than as covered by this Maintenance Agreement shall be
                  billed to the Customer at the per call rate in effect at the
                  time of call.


         E.       Charges not covered by this Maintenance Agreement are
                  Customer's responsibility and the Customer shall pay for
                  sales, use and like taxes.

ARTICLE VI  PAYMENT TERMS

         A.       Customer agrees to pay ACE*COMM for the Support specified in
                  Article I of this agreement within thirty (30) days.

         B.       All other charges not included in paragraph A Article I will
                  be invoiced upon completion of any services rendered. Payment
                  shall be due upon receipt of invoice. All payments shall be
                  made to ACE*COMM at:

                           ACE*COMM
                           P.O. Box 79201
                           Baltimore, MD 21279-0201

         C.       Nonpayment of any amounts over ninety (90) days past due to
                  ACE*COMM under this or any other Agreement between the parties
                  shall give ACE*COMM the right to discontinue the Support
                  specified herein until all such delinquent invoices are paid
                  in full.

         D.       Late Payments - Payments not received within thirty days of
                  the date of invoice will be assessed a late payment penalty of
                  1 1/2% per month on the unpaid balance.

ARTICLE VII WARRANTY AND REMEDIES

ACE*COMM warrants that the Licensed Software and/or applicable hardware
improvements, additions and enhancements when delivered will conform to the user
level documentation for each item thereof. However, customer understands that it
may have inherent defects and agrees that ACE*COMM's sole liability and
Licensee's sole remedy is for ACE*COMM to provide all reasonable services to
correct such defects which ACE*COMM's diagnosis indicates are caused by a defect
in an unaltered version of the delivered Licensed Software or applicable
hardware. This constitutes the sole warranty made by ACE*COMM and is in lieu of
all other warranties, expressed, implied, or statutory, including but not
limited to the implied warranties of mercantile and fitness for


                                      -6-
<PAGE>

a particular purpose, and of any other warranty obligation on the part of
ACE*COMM regarding licensed software and/or applicable hardware.

ACE*COMM's sole and exclusive liability under this warranty or under any
obligation assumed hereunder shall be to provide the services specified herein.

ARTICLE VIII DAMAGE LIMITATIONS

ACE*COMM shall not be liable for any loss of profits, loss of data, loss of use,
or any indirect, special, incidental or consequential damages, of any kind, in
connection with or arising out of ACE*COMM's performance under this Agreement
unless ACE*COMM's actions are found to be willful, wanton or grossly negligent.
No obligation or liability shall arise or flow out of ACE*COMM's rendering
technical or other advice unless ACE*COMM's actions are found to be willful or
wanton or grossly negligent. ACE*COMM's maximum liability regardless of the
form of action taken shall not in any event exceed the individual transaction
charges paid under this Agreement unless ACE*COMM's actions are found to be
willful or wanton or grossly negligent.

ARTICLE IX CONTINGENCIES

ACE*COMM shall not be liable for any delay in performance or for
non-performance, in whole or in part, caused by the occurrence of any
contingency beyond the control either of ACE*COMM or ACE*COMM's suppliers,
including by way of illustration but not limiting, war (whether an actual
declaration thereof is made or not), sabotage, insurrection, riot or other act
of civil disobedience, act of a public enemy, failure or delay in
transportation, act of any government or any agency or subdivision thereof,
judicial action, labor dispute, accident, fire, explosion, flood, storm or other
act of God, shortage of labor, fuel, raw material or machinery or technical
failure where ACE*COMM exercised ordinary care in the prevention thereof.

ARTICLE X ASSIGNMENT

Neither party may assign this Agreement without the written consent of the other
party which shall not be unreasonably withheld except that Customer may, upon
notice, assign its rights and obligations to any parent company or subsidiary
company.

ARTICLE XI APPLICABLE LAW

This Agreement shall be governed by the laws of the State of Texas, United
States of America.


                                      -7-
<PAGE>

ARTICLE XII SOFTWARE RIGHTS

ACE*COMM shall have unlimited rights to further use or market all software
problem solutions arising out of this Agreement.

ARTICLE XIII PROPRIETARY INFORMATION

ACE*COMM does not desire to receive proprietary information. In those instances
where it is mutually desirable for ACE*COMM to do so, such information will only
be accepted under the terms of a definitive Non-Disclosure Agreement signed by
an officer of ACE*COMM. Under no other circumstances will ACE*COMM agree to keep
confidential, secret, or proprietary any ideas, concepts, know-how, or
techniques or any other information relating to data processing, whether
submitted to ACE*COMM or developed under this Agreement.

ARTICLE XIV NOTICES

All notices, requests, demands, and other communications required or permitted
under this Contract and the transactions contemplated herein shall be in writing
and shall be deemed to have been duly given, made and received when sent by
United States registered or certified mail, return receipt requested, postage
prepaid, addressed to the parties as set forth above. Either party may alter the
address of which communications or copies are to be sent by giving notice of
such change of address in conformity with the provisions of this paragraph for
giving notice.

ARTICLE XV LICENSED SOFTWARE

This Agreement in no way alters either party's obligations under any existing
Program License Agreement between ACE*COMM and Customer.

ARTICLE XVI SUBCONTRACTING

ACE*COMM with notice to Customer may, subcontract for any On-site Service
provided to Customer. Such subcontract will not release ACE*COMM from any of its
obligations in this Agreement, and there will be no further assignment to any
third or subsequent subcontractor without the consent of Customer.


                                      -8-
<PAGE>

ARTICLE XVII SEVERABILITY

In the event any part of this Agreement is held to be unenforceable, the balance
of this Agreement shall not be affected and shall remain in full force and
effect during the terms of the Agreement.

ARTICLE XVIII COMPLETE AGREEMENT

No other agreement, representations, or understandings, expressed or implied,
not specified herein, apply to this Agreement or services furnished hereunder.
No change to this Agreement shall take effect until approved in writing by both
parties.



LOGIX COMMUNICATIONS                        ACE*COMM CORPORATION
CORPORATION
A subsidiary of Dobson Wireline
Company

By:    /s/ William Hoffman                  By:   /s/ Dr. Thomas V. Russotto
   --------------------------------            -----------------------------
         William Hoffman                           Dr. Thomas V. Russotto


Title:                                      Title:
      -----------------------------               --------------------------
         Chief Operating Officer                        Vice President


Date:           6/30/98                     Date:           6/30/98
     ------------------------------              ---------------------------


                                      -9-
<PAGE>

                            MASTER SUPPORT AGREEMENT
                                   SCHEDULE D
                          OPTIONAL SERVICES PRICE LIST


DESCRIPTION                                        PRICE
-----------                                        -----

24 Hour Reporting Service                          $40 per month (Note 1)

Emergency Service Request                          $1,000 each request (Note 2)


Note 1: This service allows the customer to report problems for 24 hours per day
seven days per week. Unless an Emergency Service Request (ESR) is authorized,
work to correct the problem will commence with the next business day. This
option must be included in the agreement, either initially or by amendment
before it can be invoked.

Note 2: Emergency Service Request entitles the customer to up to four hours of
support outside the normal support hours (8:30 A.M. to 5:00 P.M. Eastern Time)
to correct a reported problem. ESRs may only be invoked in conjunction with 24
hour telephone reporting service.


                            MASTER SUPPORT AGREEMENT
                                   SCHEDULE E
                              CURRENT LABOR RATES*

                      REMOTE SOFTWARE/HARDWARE MAINTENANCE

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------
                         Customer Under Continuing Maintenance        All Others
-------------------------------------------------------------------------------------
                           Work Covered       Work Not Covered
                         Under Agreement      Under Agreement
-------------------------------------------------------------------------------------
         SCHEDULE        RATE    MINIMUM      RATE     MINIMUM      RATE    MINIMUM
-------------------------------------------------------------------------------------
<S>                      <C>     <C>          <C>      <C>          <C>     <C>
8-5 M/F EDT               0        None       $150       $600       $150      $600
-------------------------------------------------------------------------------------
After Hours              $150      $600       $150       $600       $250     $1,000
-------------------------------------------------------------------------------------
Emergency                $150      $600       $150       $600       $300     $1,200
-------------------------------------------------------------------------------------
</TABLE>

and Living Expenses

                                      -2-
<PAGE>

                            MASTER SUPPORT AGREEMENT
                                   SCHEDULE F
                        MAXIMUM SOFTWARE MAINTENANCE COST


PERIOD OF SUPPORT                   6/10/98   through       6/8/03

<TABLE>
<CAPTION>

      DESCRIPTION                      YEAR 3       YEAR 4       YEAR 5
      -----------                      ------       ------       ------
<S>                                  <C>          <C>           <C>
APPLICATIONS SOFTWARE SUPPORT        $500,000     $500,000      $500,000
</TABLE>









                                      -3-
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                                                                        ACE*COMM
                                                  An ISO 9001 Registered Company

                        LOGIX COMMUNICATIONS CORPORATION,
                     a Subsidiary of Dobson Wireline Company


                        Master Preferred Escrow Agreement
--------------------------------------------------------------------------------


Escrow Agreement attached


















                                                                             1
<PAGE>

                            Master Number __________


This Agreement is effective _______, 19__ among Data Securities International,
Inc. ("DSI"), ACE*COMM Corporation ("ACE*COMM") and any party signing the
Acceptance Form attached to this Agreement ("Logix Communications Corporation,
a subsidiary of Dobson Wireline Company"), who collectively may be referred to
in this Agreement as "the parties".

A.       Depositor and Preferred Beneficiary have entered or will enter into a
license agreement, development agreement, and/or other agreement regarding
certain Proprietary technology of Depositor (referred to in this Agreement as
"the license agreement").

B.       Depositor desires to avoid disclosure of its proprietary technology
except under certain limited circumstances.

C.       The availability of the proprietary technology of Depositor is
critical to Preferred Beneficiary in the conduct of its business and,
therefore, Preferred Beneficiary needs access to the proprietary technology
under certain limited circumstances.

D.       Depositor and Preferred Beneficiary desire to establish an escrow
with DSI to provide for the retention, administration and controlled access
of certain proprietary technology materials of Depositor.

E.       The parties desire this Agreement to be supplementary to the license
agreement pursuant to 11 United States [Bankruptcy] Code, Section 365(n).

ARTICLE 1 - DEPOSITS

1.1      OBLIGATION TO MAKE DEPOSIT. Upon the signing of this Agreement by the
parties, including the signing of the Acceptance Form, Depositor shall deliver
to DSI the proprietary information, including source code media and relevant
documentation commentary, and other materials ("deposit materials") required to
be deposited by the license agreement or, if the license agreement does not
identify the materials to be deposited with DSI, then such materials will be
identified on an Exhibit A. If Exhibit A is applicable, it is to be prepared and
signed by Depositor and Preferred Beneficiary. DSI shall have no obligation with
respect to the preparation, signing or delivery of Exhibit A.

1.2      IDENTIFICATION OF TANGIBLE MEDIA. Prior to the delivery of the deposit
materials to DSI, Depositor shall conspicuously label for identification each
document, magnetic tape, disk, or other tangible media upon which the deposit
materials are written or stored. Additionally, Depositor shall complete Exhibit
B to this Agreement by listing each such tangible media by the item label
description, the type of media and the quantity. The Exhibit B must be signed by
Depositor and delivered to DSI with the deposit materials. Unless and until
Depositor makes the initial deposit


                                                                             1
<PAGE>


with DSI, DSI shall have no obligation with respect to this Agreement, except
the obligation to notify the parties regarding the status of the deposit account
as required in Section 2.2 below.

1.3      DEPOSIT INSPECTION. When DSI receives the deposit materials and the
Exhibit B, DSI will conduct a deposit inspection by visually matching the
labeling of the tangible media containing the deposit materials to the item
descriptions and quantity listed on the Exhibit B. In addition to the deposit
inspection, Preferred Beneficiary may elect to cause a verification of the
deposit materials in accordance with Section 1.6 below.

1.4      ACCEPTANCE OF DEPOSIT. At completion of the deposit inspection, if DSI
determines that the labeling of the tangible media matches the item descriptions
and quantity on Exhibit B, DSI will date and sign the Exhibit B and mail a copy
thereof to Depositor and Preferred Beneficiary. If DSI determines that the
labeling does not match the item descriptions or quantity on the Exhibit B, DSI
will (a) note the discrepancies in writing on the Exhibit B; (b) date and sign
the Exhibit B with the exceptions noted; and (c) provide a copy of the Exhibit B
to Depositor and Preferred Beneficiary. DSI's acceptance of the deposit occurs
upon the signing of the Exhibit B by DSI. Deliver of the signed Exhibit B to
Preferred Beneficiary is Preferred Beneficiary's notice that the deposit
materials have been received and accepted by DSI.

1.5      DEPOSITOR'S REPRESENTATIONS. Depositor represents as follows:

         a.       Depositor lawfully possesses all of the deposit materials
                  deposited with DSI;

         b.       With respect to all of the deposit materials, Depositor has
                  the right and authority to grant to DSI and Preferred
                  Beneficiary the rights as provided in this Agreement;

         c.       The deposit materials are not subject to any lien or
                  other encumbrance; and

         d.       The deposit materials consist of the proprietary information
                  and other materials identified either in the license agreement
                  or Exhibit A, as the case may be.

1.6      VERIFICATION. Preferred Beneficiary shall have the right, at Preferred
Beneficiary's expense, to cause a verification of any deposit materials. A
verification determines, in different levels of detail, the accuracy,
completeness, sufficiency and quality of the deposit materials. If a
verification is elected after the deposit materials have been delivered to DSI,
then only DSI, or at DSI's election an independent person or company selected
and supervised by DSI, may perform the verification.

1.7      DEPOSIT UPDATES. Unless otherwise provided by the license agreement,
Depositor shall update the deposit materials within: 15 days of each release of
a new version of the product which is subject to the license agreement. Such
updates will be added to the existing deposit. All deposit updates shall be
listed on a new Exhibit B and the new Exhibit B shall be signed by Depositor.
Each Exhibit B will be held and maintained separately within the escrow account.
An independent record will be created which will document the activity for each
Exhibit B. The processing of all deposit updates shall be in accordance with
Sections 1.2 through 1.6 above. All references in this Agreement to the deposit
materials shall include the initial deposit materials and any updates.


                                                                             2
<PAGE>


1.8      REMOVAL OF DEPOSIT MATERIALS. The deposit materials may be removed
and/or exchanged only on written instructions signed by Depositor and
Preferred Beneficiary, or as otherwise provided in this Agreement.

ARTICLE 2 - CONFIDENTIALLY AND RECORD KEEPING

2.1      CONFIDENTIALITY. DSI shall maintain the deposit materials in a secure,
environmentally safe, locked receptacle which is accessible only to authorized
employees of DSI. DSI shall have the obligation to reasonably protect the
confidentiality of the deposit materials. Except as provided in this Agreement
DSI shall not disclose, transfer, make available, or use the deposit materials.
DSI shall not disclose the content of this Agreement to any third party. If DSI
receives a subpoena or other order of a court or other judicial tribunal
pertaining to the disclosure or release of the deposit materials, DSI will
immediately notify the parties to this Agreement. It shall be the responsibility
of Depositor and/or Preferred Beneficiary to challenge any such order; provided,
however, that DSI does not waive its rights to present its position with respect
to any such order. DSI will not be required to disobey any court or other
judicial tribunal order. (See Section 7.5 below for notices of requested
orders.)

2.2      STATUS REPORTS. DSI will issue to Depositor and Preferred Beneficiary
a report profiling the account history at least semi-annually DSI may provide
copies of the account history pertaining to this Agreement upon the request of
any party to this Agreement.

2.3      AUDIT RIGHTS. During the term of this Agreement, depositor and
Preferred Beneficiary shall each have the right to inspect the written
records of DSI pertaining to this Agreement. Any inspection shall be held
during normal business hours and following reasonable prior notice.

ARTICLE 3 - GRANT OF RIGHTS TO DSI

3.1      TITLE TO MEDIA. Depositor hereby transfers to DSI the title to the
media upon which the proprietary information and materials are written or
stored. However, this transfer does not include the ownership of the
proprietary information and materials contained on the media such as any
copyright, trade secret, patent or other intellectual property rights.

3.2      RIGHT TO MAKE COPIES. DSI shall have the right to make copies of the
deposit materials as reasonably necessary to perform this Agreement. DSI
shall copy all copyright, nondisclosure, and other proprietary notices and
titles contained on the deposit materials onto any copies made by DSI. With
all deposit materials submitted to DSI, Depositor shall provide any and all
instruction as may be necessary to duplicate the deposit materials including
but not limited to the hardware and/or software needed.

3.3      RIGHT TO SUBLICENSE UPON RELEASE. As of the effective date of this
Agreement, Depositor hereby grants to DSI a nonexclusive, irrevocable,
perpetual, and royalty-free license to sublicense


                                                                             3
<PAGE>


the deposit materials to Preferred Beneficiary upon the release, if any, of the
deposit materials in accordance with Section 4.5 below. Except upon such a
release, DSI shall not sublicense or otherwise transfer the deposit materials.


ARTICLE 4 - RELEASE OF DEPOSIT

4.1      RELEASE CONDITIONS. As used in this Agreement, "Release Conditions"
shall mean the set of conditions set forth in ACCEPTANCE FORM.

4.2      FILING FOR RELEASE. If Preferred Beneficiary believes in good faith
that a Release Condition has occurred, Preferred Beneficiary may provide to
DSI written notice of the occurrence of the Release Condition and a request
for the release of the deposit materials. Upon receipt of such notice, DSI
shall provide a copy of the notice to Depositor, by certified mail, return
receipt requested, or by commercial express mail.

4.3      CONTRARY INSTRUCTIONS. From the date DSI mails the notice requesting
release of the deposit materials, Depositor shall have ten business days to
deliver to DSI Contrary Instructions. "Contrary Instructions" shall mean the
written representation by Depositor that a Release Condition has not occurred
or has been cured. Upon receipt of Contrary Instructions, DSI shall send a
copy to Preferred Beneficiary by certified mail, return receipt requested, or
by commercial express mail. Additionally, DSI shall notify both Depositor and
Preferred Beneficiary that there is a dispute to be resolved pursuant to the
Dispute Resolution section of this Agreement (Section 7.3). Subject to
Section 5.2, DSI will continue to store the deposit materials without release
pending (a) joint instructions from Depositor and Preferred Beneficiary, (b)
resolution pursuant to the Dispute Resolution provisions, or (c) order of a
court.

4.4      RELEASE OF DEPOSIT. If DSI does not receive timely Contrary
Instructions from the Depositor, DSI is authorized to release the deposit
materials to the Preferred Beneficiary or, if more than one beneficiary is
registered to the deposit, to release a copy of the deposit materials to the
Preferred Beneficiary. However, DSI is entitled to receive any fees due DSI
before making the release. This Agreement will terminate upon the release of
the deposit materials held by DSI.

4.5      USE LICENSE FOLLOWING RELEASE. Unless otherwise provided in the license
agreement, upon release of the deposit materials in accordance with this Article
4, Preferred Beneficiary shall have a non-exclusive, non-transferable,
irrevocable right to use the deposit materials for the sole purpose of
continuing the benefits afforded to Preferred Beneficiary by the license
agreement. Preferred Beneficiary shall be obligated to maintain the
confidentiality of the release deposit materials.


                                                                             4
<PAGE>


ARTICLE 5 - TERM AND TERMINATION

5.1      TERM OF AGREEMENT. The initial term of this Agreement is for a
period of one year. Thereafter, this Agreement shall automatically renew from
year-to-year unless (a) Depositor and Preferred Beneficiary jointly instruct
DSI in writing that the Agreement is terminated; or (b) the Agreement is
terminated by DSI for nonpayment in accordance with Section 5.2. If the
Acceptance Forms has been signed at a date later than this Agreement, the
initial term of the Acceptance Form will be for one year with subsequent
terms to be adjusted to match the anniversary date of this Agreement. If the
deposit materials are subject to another escrow agreement with DSI, DSI
reserves the right, after the initial one year term, to adjust the
anniversary date of this Agreement to match the other prevailing anniversary
date of such other escrow arrangements.

5.2      TERMINATION FOR NONPAYMENT. In the event of the nonpayment fees owed
to DSI, DSI shall provide written notice of delinquency to all parties to
this Agreement. Any party to this Agreement shall have the right to make the
payment to DSI to cure the default. If the past due payment is not received
in full by DSI within one month of the date of such notice, then DSI shall
have the right to terminate this Agreement at any time thereafter by sending
written notice of termination to all parties. DSI shall have no obligation to
take any action under this Agreement so long as any payment due to DSI
remains unpaid.

5.3      DISPOSITION OF DEPOSIT MATERIALS UPON TERMINATION. Upon termination
of this Agreement by joint instruction of Depositor and Preferred
Beneficiary, DSI shall destroy, return, or otherwise deliver the deposit
materials in accordance with such instructions. Upon termination for
nonpayment, DSI may, at its sole discretion, destroy the deposit materials,
or return them to Depositor. DSI shall have no obligation to return or
destroy the deposit materials if the deposit materials are subject to another
escrow agreement with DSI.

5.4      SURVIVAL OF TERMS FOLLOWING TERMINATION. Upon termination of this
Agreement, the following provisions of this Agreement shall survive:

         a.       Depositor's Representations (Section 1.5).

         b.       The obligations of confidentiality with respect to the deposit
                  materials.

         c.       The licenses granted in the sections entitled Right to
                  Sublicense Upon Release (Section 3.3) and Use License
                  Following Release (Section 4.5), if a release of the deposit
                  materials has occurred prior to termination.

         d.       The obligation to pay DSI any fees and expenses due.

         e.       The provisions of Article 7.

         f.       Any provisions in the Agreement which specifically state they
                  survive the termination or expiration of this Agreement.

ARTICLE 6 - DSI'S FEES


                                                                             5
<PAGE>


6.1      FEE SCHEDULE. DSI is entitled to be paid its standard fees and expenses
applicable to the services provided. DSI shall notify the party responsible for
payment of DSI's fees at least 90 days prior to any increase in fees. For any
service not listed on DSI's standard fee schedule, DSI will provide a quote
prior to rendering the service, if requested.

6.2      PAYMENT TERMS. DSI shall not be required to perform any service
unless the payment for such service and any outstanding balances owed to DSI
are paid in full. All other fees are due upon receipt of invoice. If invoiced
fees are not paid, DSI may terminate this Agreement in accordance with
Section 5.2. Late fees on past due amounts not paid within 30 days from
receipt of invoice shall accrue at the rate of one and one-half percent per
month (18% per annum) from the date of the invoice.

ARTICLE 7 - LIABILITY AND DISPUTES

7.1      RIGHT TO RELY ON INSTRUCTIONS. DSI may act in reliance upon any
instruction, instrument, or signature reasonably believed by DSI to be
genuine. DSI may assume that any employee of a party to this Agreement who
gives any written notice, request, or instruction has the authority to do so.
DSI shall not be responsible for failure to act as a result of causes beyond
the reasonable control of DSI.

7.2      INDEMNIFICATION. DSI shall be responsible to perform its obligations
under this Agreement and to act in a reasonable and prudent manner with
regard to this escrow arrangement. Provided DSI has acted in the manner
stated in the preceding sentence, Depositor and Preferred Beneficiary each
agree to indemnify, defend and hold harmless DSI from any and all claims,
actions, damages, arbitration fees and expenses, costs, attorney's fees and
other liabilities incurred by DSI relating in any way to this escrow
arrangement.

7.3      DISPUTE RESOLUTION. Any dispute relating to or arising from this
Agreement shall be resolved by arbitration under the Commercial Rules of the
American Arbitration Association. Unless otherwise agreed by Depositor and
Preferred Beneficiary, arbitration will take place in Texas, U.S.A. Any
determination made by the arbitrator shall be final, binding, and conclusive
on the parties for all purposes. Any court having jurisdiction over the
matter may enter judgment on the award of the arbitrator(s). Service of a
petition to confirm the arbitration award may be made by First Class mail or
by commercial express mail, to the attorney for the party or, if
unrepresented, to the party at the last known business address.

7.4      CONTROLLING LAW. This Agreement is to be governed and construed in
accordance with the laws of the State of Texas, without regard to its conflict
of law provisions.

7.5      NOTICE OF REQUESTED ORDER. If any party intends to obtain an order
from the arbitrator or any court of competent jurisdiction which may direct
DSI to take, or refrain from taking any action that party shall:


                                                                             6
<PAGE>


         a.       Give DSI at least two business days' prior notice of the
                  hearing;

         b.       Include in any such order that, as a precondition to DSI's
                  obligation, DSI be paid in full for any past due fees and be
                  paid for the reasonable value of the services to be rendered
                  pursuant to such order; and

         c.       Ensure that DSI not be required to delivery the original (as
                  opposed to a copy) of the deposit materials if DSI may need to
                  retain the original in its possession to fulfill any of its
                  other escrow duties.


ARTICLE 8 - GENERAL PROVISIONS

8.1      ENTIRE AGREEMENT. This Agreement, which includes the Acceptance Form
and the Exhibits described herein, embodies the entire understanding between
all of the parties with respect to its subject matter and supersedes all
previous communications, representations or understandings, either oral or
written. No amendment or modification of this Agreement shall be valid or
binding unless signed by all the parties hereto, except Exhibit A need not be
signed by DSI and Exhibit B need not be signed by Preferred Beneficiary.

8.2      NOTICES. All notices, invoices, payments, deposits and other
documents and communications shall be given to the parties at the addresses
specified in the attached Exhibit C and Acceptance Form. It shall be the
responsibility of the parties to notify each other as provided in this
Section in the event of a change of address. The parties shall have the right
to rely on the last known address of the other parties. Unless otherwise
provided in this Agreement, all documents and communications may be delivered
by First Class mail.

8.3      SEVERABILITY. In the event any provision of this Agreement is found
to be invalid, voidable or unenforceable, the parties agree that unless it
materially affects the entire intent and purpose of this Agreement, such
invalidity, voidability or unenforceability shall affect neither the validity
of this Agreement nor the remaining provisions herein, and the provision in
question shall be deemed to be replaced with a valid and enforceable
provision most closely reflecting the intent and purpose of the original
provision.

8.4      SUCCESSORS. This Agreement shall be binding upon and shall inure to the
benefit of the successors and assigns of the parties. However, DSI shall have no
obligation in performing this Agreement to recognize any successor or assign of
Depositor or Preferred Beneficiary unless DSI receives clear, authoritative and
conclusive written evidence of the change of parties.


                                                                             7
<PAGE>


         ACE*COMM CORPORATION           DATA SECURITIES INTERNATIONAL, INC.


By: /s/ Thomas V. Russotto              By:
   ------------------------------          ----------------------------------

Name:   Thomas V. Russotto              Name:
     ----------------------------            --------------------------------

Title: Vice President                   Title:
      ---------------------------             -------------------------------

Date:  6/30/98                          Date:
     ----------------------------            --------------------------------




                                                                             8
<PAGE>

                                 ACCEPTANCE FORM

                        Account Number __________________

LOGIX Communications Corporation, a subsidiary of Dobson Wireline Company,
hereby (I) acknowledges that it is the Preferred Beneficiary referred to in the
Master Preferred Escrow Agreement effective _____________, 19____ with Data
Securities International, Inc. as the escrow agent and ACE*COMM Corporation as
the Depositor and (ii) agrees to be bound by all provisions of such Agreement.

                                        LOGIX COMMUNICATIONS CORPORATION,
                                        A SUBSIDIARY OF DOBSON WIRELINE COMPANY

                                        By: /s/ WILLIAM HOFFMAN
                                           ------------------------------------

                                        Name:   WILLIAM HOFFMAN
                                             ----------------------------------

                                        Title:   CHIEF OPERATING OFFICER
                                              ---------------------------------

                                        Date:          6/30/98
                                             ----------------------------------

Notices and communication               Invoices should be
should be addressed to:                 addressed to:

Company Name: ------------------        ----------------------------------------

Address:
        ------------------------        ----------------------------------------

        ------------------------        ----------------------------------------

        ------------------------        ----------------------------------------

Designated Contact:                     Contact:
                   -------------        ----------------------------------------

Telephone:
          ----------------------        ----------------------------------------

Facsimile:
          ----------------------        ----------------------------------------




                                                                             9
<PAGE>

Depositor hereby enrolls Preferred Beneficiary to the following accounts(s):


                  ACCOUNT NAME                               ACCOUNT NUMBER

LOGIX COMMUNICATIONS CORPORATION, A
SUBSIDIARY OF DOBSON WIRELINE COMPANY
------------------------------------

------------------------------------                -------------------------

------------------------------------                -------------------------


ACE*COMM CORPORATION                                DATA SECURITIES
                                                    INTERNATIONAL, INC.
Depositor

By:                                                 By:
   --------------------------------                    ----------------------

Name:                                               Name:
     ------------------------------                      --------------------

Title:                                              Title:
      -----------------------------                       -------------------

Date:                                               Date:
     ------------------------------                      --------------------



                                                                            10
<PAGE>


ACCEPTANCE FORM - Continued

Designated Contract Conditions of Release:

As used in the Master Preferred Escrow Agreement, "Release Conditions" shall
mean the following:

         a.       Breach of license agreement that is not cured by the Depositor
                  within 60 days and that can be corrected by the Preferred
                  Beneficiary upon Release of the deposit materials. (Such
                  Release shall be the complete settlement for any such breach);
                  or

         b.       Depositor's failure to continue to do business in the
                  ordinary course; or

         c.       Depositor is voluntarily or involuntarily dissolved, or
                  becomes insolvent; or

         d.       Depositor files for bankruptcy, make a general assignment
                  for the benefit of its creditors, or if an involuntary
                  proceeding seeking the entry of an order for relief under
                  any bankruptcy or related laws is filed or if a receiver
                  is appointed on account of the insolvency of Depositor
                  and Depositor or its successor in interest fails to
                  perform its obligations under the License Agreement
                  within sixty (60) days after such filing or appointment.


                                                                            11
<PAGE>

                                                                       EXHIBIT A

                            MATERIALS TO BE DEPOSITED

                            Account Number _________

                                    ACE*COMM
                               ESCROW DELIVERABLES
                                       for
                                LICENSE AGREEMENT
             FOR DELIVERY OF THE LOGIX COMMUNICATIONS CORPORATION, A
                                  SUBSIDIARY OF
                             DOBSON WIRELINE COMPANY
                                 IMPLEMENTATION
                              OF NETPLUS PRO*VISION

DEFINITIONS


         CURRENT RELEASED VERSION means the latest version of NetPlus Pro*Vision
         that was used to create the most recent version of the LOGIX
         Communications Corporation, a subsidiary of Dobson Wireline Company,
         implementation of the NetPlus Pro*Vision software.

ESCROW ITEMS
1.       CURRENT RELEASED VERSION, available electronically, of NetPlus
         Pro*Vision software and components used for LOGIX
         Communications Corporation, a subsidiary of Dobson Wireline
         Company, Communications Implementation of NetPlus Pro*Vision,
         includes but is not limited to all ACE*COMM developed
         currently available items that could be used in support of the
         LOGIX Communications Corporation, a subsidiary of Dobson
         Wireline Company, Implementation of NetPlus Pro*Vision such
         as;

                  -        Source code (Server and Client)
                           -        Application Software
                           -        Application libraries

                  -        Documentation

                           -        All published user documentation for
                                    released version

                           -        All currently developed systems
                                    documentation, process flows, system design,
                                    program designs, and system testing scripts

                           -        All internal documentation used by ACE*COMM
                                    staff in support of 3rd party software

                           -        Hardware configuration documentation as it
                                    applies to Logix Communications Corporation,
                                    a subsidiary of Dobson Wireline Company

                           -        All developed interface documentation to
                                    Logix Communications Corporation, a
                                    subsidiary of Dobson Wireline Company,
                                    proprietary interfaces


                                                                            12
<PAGE>


                           -        Database

                                    -        All currently available database
                                             schemas, definitions, entity
                                             relationships etc.


ACE*COMM CORPORATION                       LOGIX COMMUNICATIONS CORPORATION, A
DEPOSITOR                                  SUBSIDIARY OF DOBSON WIRELINE
                                           COMPANY
                                           Preferred Beneficiary

By: /s/ THOMAS V. RUSSOTTO                   By: /s/ WILLIAM HOFFMAN
   --------------------------------             ------------------------------

Name:   THOMAS V. RUSSOTTO                   Name:   WILLIAM HOFFMAN
     ------------------------------               ----------------------------

Title:  VICE PRESIDENT                       Title:  CHIEF OPERATING OFFICER
      -----------------------------                ---------------------------

Date:      6/30/98                            Date:      6/30/98
     ------------------------------               ----------------------------



                                                                            13
<PAGE>

                                                                     EXHIBIT B

                        DESCRIPTION OF DEPOSIT MATERIALS


Account Number_____________________________________________________________
Depositor Company Name ACE*COMM Corporation

DEPOSIT TYPE:   ____________ Initial       ___________ Supplemental

ENVIRONMENT:
Host System CPU/OS __________________ Version____________  Backup__________

Source System CPU/OS __________ Version __________ Compiler _______________
Special Instructions:______________________________________________________

DEPOSIT COPYING REQUIREMENT;
Hardware needed:___________________________________________________________
Software needed/Instructions:______________________________________________

DEPOSIT MATERIALS:
Exhibit B Name __________________________ Version___________________________

Item label description               Media                          Quantity






For Depositor, I certify that the above     For DSI, I certify that the deposit
described deposit materials have been       inspection has been completed
transmitted to DSI:                         (any exceptions are noted above):

By:                                         By:
    -----------------------------------         -------------------------------

Print Name:                                 Name:
           ----------------------------           -----------------------------
Date:                                       Date:
     ----------------------------------           -----------------------------
                                            ISE            EX.B#
                                                -------------------------------

Send materials to: DSI, 9555 Chesapeake Driver, #200, San Diego, CA 92123


                                                                            14
<PAGE>

                                                                       EXHIBIT C

                               DESIGNATED CONTACT


                            Master Number __________


Notices and communications
should be addressed to:                         Invoices should be addressed to:

Company Name ACE*COMM CORPORATION               ACE*COMM CORPORATION

Address:  704 QUINCE ORCHARD ROAD               704 QUINCE ORCHARD ROAD

          GAITHERSBURG, MD 20878                GAITHERSBURG, MD 20878

Designated Contact: DR. THOMAS RUSSOTTO         Contact: ACCOUNTS PAYABLE

Telephone: 301-721-3116
          ------------------------------        -----------------------------
Facsimile: 301-258-6241
          ------------------------------        -----------------------------

Requests to change the designated contact should be given in writing by the
designated contact or an authorized employee.


Contracts, deposit materials and notices to       Invoice inquiries and fee
DSI should be addressed to:                       remittances to DSI should be
                                                  addressed to:

DSI                                               DSI
Contract Administration                           Accounts Receivable
Suite 200                                         Suite 1450
9555 Chesapeake Drive                             425 California Street
San Diego, CA 92123                               San Francisco, CA 94104

Telephone: (619) 694-1900                         (415) 398-7900
Facsimile: (619) 694-1919                         (415) 398-7914


Date: _________________________________________



                                                                            15
<PAGE>

                       ADDITIONAL ESCROW ACCOUNT AMENDMENT
                      TO MASTER PREFERRED ESCROW AGREEMENT


                         Master Number ________________


                    New Account Number ______________________



ACE*COMM Corporation ("Depositor") has entered into a Master Preferred Escrow
Agreement with Data Securities International, Inc. ("DSI"). Pursuant to that
Agreement, Depositor may deposit certain deposit materials with DSI.

Depositor desires that new deposit materials be held in a separate account and
be maintained separately from the existing account. By execution of this
Amendment, DSI will establish a separate account for the new deposit materials.
The new account will be referenced by the following name:
                                                         -----------------------

Depositor hereby agrees that all terms and conditions of the existing Master
Preferred Escrow Agreement previously entered into by Depositor and DSI will
govern this account. The termination or expiration of any other account of
Depositor will not affect this account.




ACE*COMM CORPORATION                     DATA SECURITIES INTERNATIONAL, INC
Depositor


By:                                                 By:
   --------------------------------                    ----------------------

Name:                                               Name:
     ------------------------------                      --------------------

Title:                                              Title:
      -----------------------------                       -------------------

Date:                                               Date:
     ------------------------------                      --------------------



                                                                            16
<PAGE>

                          SYSTEM ACQUISITION AGREEMENT


         THIS SYSTEM ACQUISITION AGREEMENT (the "AGREEMENT") is hereby entered
into between ACE*COMM, Corporation ("ACE*COMM") located at 704 Quince Orchard
Road, Gaithersburg Maryland 20878 and LOGIX COMMUNICATIONS CORPORATION. A
SUBSIDIARY OF DOBSON WIRELINE COMPANY. ("CUSTOMER") with offices at 13439
NORTH BROADWAY EXTENSION, OKLAHOMA CITY, OKLAHOMA 73114 on the following terms
and conditions:

                                   Article I.
                                   DEFINITIONS


         "ACE*COMM DELIVERABLE SOFTWARE AND HARDWARE" means the deliverable
software and hardware identified on the document number T98.JMT.0676, Rev. 2
and includes NetPlus Pro*Vision, N*Vision, CANS,and the DCMS Call Collection
Device.

         "CUSTOM WORK PRODUCT" means all original work product arising out of
professional services rendered by ACE*COMM hereunder including, without
limitation, functional and technical design documentation, software programs,
modules, routines, algorithms and associated user documentation, authorized
custom enhancements; modifications, interfaces and changes to Third Party
Software Products, Standard Software Products or Embedded Software in
furtherance of the Specifications, including without limitation the NetPlus
Pro*Vision software, N*Vision software, CANS software and DCMS CDR Collection
hardware as identified in the T98.JMT.0676, Rev. 2 document called Statement
of Work/Pricing. Custom Work Product does not include any Embedded Software,
Standard Software Products or Third Party Software Products.

         "DELIVERABLES" means all equipment, cabling, Third Party Software
Products, Standard Software Products, Embedded Software, Custom Work Product,
documentation, goods, supplies, services, training, "know how," technology or
other things provided under this Agreement by or through ACE*COMM.

         "EMBEDDED SOFTWARE" means any pre-existing computer software
programs, modules, routines, algorithms and related documentation owned by
ACE*COMM and provided to Customer for the purpose of incorporating or
"embedding" it in whole or in part into Custom Work Product.

         "MAJOR ALARM" means a warranty call under Section 11 concerning an
error, malfunction or other problem with a Deliverable covered by warranty
that prevents the Deliverable from operating at a level of Substantial
Functionality and causes an immediate and significant disruption of Customer's
business operation. "Minor Alarm" means any warranty call that is not a Major
Alarm.

<PAGE>

         "SOFTWARE" means, collectively, the Third Party Software Products,
the Standard Software Products, Embedded Software and the Custom Work Products.

         "SPECIFICATIONS" means all descriptions of Deliverables, including
associated functional and technical designs, drawings, samples, ACE*COMM's
proposal and other material information created or specifically adopted by
ACE*COMM as the basis for discharging its responsibilities hereunder.

         "STANDARD SOFTWARE PRODUCTS" means computer software programs and
related documentation owned by ACE*COMM and provided to Customer in a form
generally available to the public without substantial customization or
modification, including those products listed in the attached Statement of
Work/Pricing.

         "STATEMENT OF WORK" means the description of professional services,
software products, equipment and devices identified on Statement of
Work/Pricing document T98.JMT.0676, Rev. 2 (project work schedule to be
determined by Customer and ACE*COMM program managers), job categories, prices,
special payment terms, special license terms, and other Deliverables or
relevant descriptions of what ACE*COMM is to provide hereunder.

         "SUBSTANTIAL FUNCTIONALITY" of a Deliverable means it operates
substantially in accordance with the Specifications, but does not mean it is
entirely free from errors or defects. A defect threatens Substantial
Functionality if it relates to a function that Customer's business actually
depends on and which cannot be accommodated or "worked around" through
relatively minor adjustments in work habits, operating procedures or otherwise.

         "THIRD PARTY SOFTWARE PRODUCTS" means software programs, modules,
routines and related documentation of third party vendors (other than
ACE*COMM), including operating system software and application software.

         "WARRANTY PERIOD" means the 365 day period commencing upon Acceptance
of the Deliverables.

                                   Article II.
                               GENERAL UNDERTAKING

1.       TERM OF AGREEMENT. The term of this Agreement ("Term") shall
commence on the date last below written and shall continue in full force and
effect until terminated in accordance with Section 15.

2.       SCOPE OF WORK

(a) GENERALLY. ACE*COMM agrees to provide, and Customer agrees to obtain and
pay for, the Deliverables described in document numbered T98.JMT.0676, Rev. 2
at the prices set forth therein according to the Specifications and this
Agreement.

(b) CHANGES IN SCOPE OF WORK. Customer may request changes to ACE*COMM
Software release 1.2 or may request additional or different work ("CHANGE
ORDER"). If any Change Order

                                                                     2

<PAGE>

??? increase in the price of, or the time required for performance, ACE*COMM
shall ??? Customer of the additional time required for performance and/or
increase in price resulting from the Change Order and shall proceed with work
under the Change Order only upon written approval of such changed terms and/or
prices by Customer. If a Change Order will not cause an increase in the price
of or the time required for performance, ACE*COMM shall proceed with the
Change Order. Upon the approval by Customer of the changed terms and/or prices
that are caused by such Change Order, such Change Order shall be included in
the applicable portion of the Specifications.

3.       PRICES. Pricing is provided in document number T98.JMT.0676, Rev. 2.

         (a)     Item I. The first item requires ACE*COMM to deliver
Customer's initial business and technical needs, providing a current,
operational version of the NetPlus Pro*Vision software product along with
hardware, as more fully explained in the Statement of Work. The NetPlus
Pro*Vision software product will include, but not be limited to the
functionality described in the Statement of Work. The NetPlus Pro*Vision
system will be installed and operational on Customer server hardware at
ACE*COMM data processing center by June 22. 1998.

                 Item II. ACE*COMM shall begin processing Customer
transactions as defined in the Data Processing Agreement and deliver a
current, operational version of the ACE*COMM NetPlus Pro*Vision version 1.2.

         (b)     The NetPlus Pro*Vision software product shall include all the
functionality set forth in the T98.JMT.0676, Rev. 2 document. ACE*COMM shall
deliver all of the Item II services at the price set forth in T98.JMT.0676,
Rev. 2.

         (c)     Item III. Consists of certain work described in the Statement
of Work. For processing extensions (if any).

         (d)     Customer shall be responsible for any state and local sales
or use tax based on Customer's payment of fees, and use of the Software, under
this Agreement. ACE*COMM shall be responsible for taxes based on ACE*COMM's
net income, gross income, receipts, capital or net worth as well as all
minimum taxes, doing business taxes and franchise taxes.

4.       CERTAIN OUT-OF-POCKET COSTS. Except as otherwise specifically set
forth in this Agreement, prices quoted do not include and Customer shall
reimburse ACE*COMM for its actual cost of travel (air & cab fare, lodging, or
auto rental).

5.       SHIPPING, RISK OF LOSS. Unless otherwise set forth herein, all
equipment purchased by Customer shall be shipped FOB Gaithersburg, Md. to
Customer according to ACE*COMM's (or the manufacturer's) normal procedures,
and Customer shall pay all associated shipping, insurance and handling charges.

6.       INSTALLATION & ACCEPTANCE. ACE*COMM shall install the products in
ACE*COMM's facility in Gaithersburg, Maryland. Title of Software license shall
transfer to Customer upon

                                                                     3

<PAGE>

such installation and ACE*COMM thereby grants and Customer accepts a perpetual
license to use the Software to process Customer's own billing, subscriber and
network data.

7.       INVOICES, PAYMENT AND LATE CHARGES. Payment schedule shall be as
stated in the Statement of Work/Pricing for all equipment, Third Party
Software Products and Standard Software Products and Services provided
hereunder. Except for the payment with order which shall be paid with the
order, payments shall be made within thirty (30) days from receipt of invoice.
Customer may not withhold or "setoff" any amounts due hereunder and ACE*COMM
reserves the right to cease work without prejudice if amounts are not paid
when due. ACE*COMM retains a purchase money security interest and the right
to assert appropriate liens with respect to all Deliverables until all amounts
due are paid in full. Any late payment shall be subject to any costs of
collection (including reasonable legal fees) and shall bear interest at the
rate of one and one-half (1.5) percent per month or fraction thereof until
paid.

8.       TRAINING & DOCUMENTATION. ACE*COMM shall provide training and
technical or user documentation in support of the Deliverables to the extent
and at the prices provided. Any additional training or documentation shall be
provided at ACE*COMM's then prevailing rates or at such other rates as the
parties may agree with in writing. Any right to source code and related
software design documentation must be specifically set forth herein or in a
separate source code license agreement.

9.       OWNERSHIP AND LICENSING OF TECHNOLOGY.

         (a)     THIRD PARTY SOFTWARE PRODUCTS. In the case of Third Party
Software Products, Customer hereby agrees to be bound and governed by the
terms and conditions of the original vendor's license agreement accompanying
such products or, if no such license agreement is included, by the vendor's
standard license terms generally applicable to the particular product provided
that such terms are typical and ordinary.

         (b)     ACE*COMM'S STANDARD SOFTWARE PRODUCTS. In the case of
Standard Software Products provided by ACE*COMM, Customer is granted a
paid-up, nonexclusive license to make and use as many copies as it deems
necessary, but only for use in support of its (and its affiliates') internal
business operations at the single office building (or contiguous set of
buildings) at which the Standard Software Product is first installed for
license volume purchased. Such license shall be for a perpetual term, in
object code form. Such license shall be transferable by Customer in object
code form upon advance notice to ACE*COMM, and the transferee's written
agreement to be bound by the terms and conditions applicable to the license
hereunder (the transfer of any license in source code form shall always
require ACE*COMM's prior written approval). If transferred, Customer shall
destroy all copies of the transferred Standard Software Products in its
possession and cease all further use.

         (c)     ACE*COMM'S CUSTOM WORK PRODUCT. It is hereby agreed that
ACE*COMM shall own all right, title and interest to all Custom Work Product.
Customer expressly acknowledges and agrees that in no event shall Custom Work
Product be deemed to constitute "work made for hire" under the Federal
copyright laws (17 U.S.C. Sec. 101) and, alternatively, Customer hereby
irrevocably assigns all ownership or other rights it might have in Custom Work

                                                                     4

<PAGE>

Product to ACE*COMM. Subject to any applicable limitations in the preceding
subparagraphs concerning Customer's use of any underlying Third Party Software
Products or Standard Software Products, Customer is granted a paid-up,
perpetual, nonexclusive, license in object code form. Customer may use one (1)
copy of the Custom Work Product and Embedded Software in support of its
internal business operations on the system on which the software is originally
installed. The software may be relocated to another system of Customer,
provided no more than one (1) copy per license is installed or used at any one
time. In any case, such system may be a networked or distributed system
(including a client/server system) provided that no more than one (1) copy is
stored in permanent (i.e., magnetic or optical) format and "use" and
"installation" as such term is used in this Section shall include use and
installation in connection with such networked or distributed system. In
addition, Customer may make one (1) copy of the Custom Work Product and
Embedded Software for archival and back-up purposes only. Such back-up and
archival copy may be stored away from the Customer's site, Customer may
transfer any license in object code form upon advance notice to the ACE*COMM
but any license in source code form may not be transferred without ACE*COMM's
prior written consent. If the Customer transfers this license to another
entity, it shall notify the transferee of all restrictions applicable to this
license and shall destroy all whole or partial copies and cease all further
use thereof.

         (d)     CUSTOMER'S DATA. ACE*COMM understands and acknowledges that
Customer will (i) manage, modify, maintain and update substantial amounts of
pre-existing data and information, and (ii) generate, manage, modify, maintain
and update substantial amounts of additional data and information
(collectively, "Customer Data") using the Software. Customer shall retain all
right, title and interest in and to Customer Data. Nothing contained in this
Agreement shall be deemed or construed to limit or prevent Customer from using
the Software (or any other process, program or device) to copy, modify, sell,
license, distribute, transmit, reformat, reconfigure or manipulate Customer
Data in any way. Customer or any employee, third-party consultant, contractor
or subcontractor or temporary employee of Customer may at any time (including
after any termination of this Agreement) access by any means any program,
communications or computer equipment, network and/or database in which, or in
connection with which, Customer Data is then stored to do any of the foregoing
and nothing in this Agreement shall be deemed or construed to require that
Customer use Deliverables by ACE*COMM in order to access any Customer Data.
ACE*COMM agrees that it will not use Customer Data or allow anyone else to use
Customer Data for any purpose other than compliance with the obligations and
purpose of this Agreement.

10.      Confidential Information.

         (a)     ACKNOWLEDGMENT OF CONFIDENTIALITY. Each party hereby
acknowledges that it may be exposed to confidential and proprietary
information of the other party including, without limitation, any trade
secrets embodied in the source code for the Standard Software Products, the
Custom Work Product, the Embedded Software and other technical information
(including functional and technical specifications, designs, drawings,
analysis, research, processes, source code versions of computer programs,
algorithms, methods, ideas, "know how" and the like), business information
(sales and marketing research, materials, plans, accounting and financial
information, personnel records and the like) and other information that has
been clearly designated in writing as confidential ("CONFIDENTIAL
INFORMATION"). Confidential Information

                                                                     5

<PAGE>

does not include (i) information previously known or independently developed
by the recipient; (ii) information in the public domain through no wrongful
act of the recipient, or (iii) information received by the recipient from a
third party who was free to disclose it.

         (b)     COVENANT NOT TO DISCLOSE. With respect to the other party's
Confidential Information, the recipient hereby agrees that during the Term and
at all times thereafter it shall not use, commercialize or disclose such
Confidential Information to any person or entity, except to its own employees
(and temporary employees and to any contractors retained to perform related
services) having a "need to know" (and who are themselves bound by similar
nondisclosure restrictions), and to such other recipients as the other party
may approve in a signed writing; provided, that all such recipients shall have
first executed a confidentiality agreement in a form acceptable to the owner
of such information. Each party shall use at least the same degree of care in
safeguarding the other party's Confidential Information as it uses in
safeguarding its own confidential information, Neither party nor any recipient
may alter or remove from any software or associated documentation owned or
provided by the other party hereunder, any proprietary, copyright, trademark
or trade secret legend, nor may it attempt to decompile or reverse engineer
such software. The provisions of this Section 10 shall Survive termination
of this Agreement.

         (c)     REMEDIES FOR BREACH OF CONFIDENTIALITY. Each party
acknowledges that the unauthorized use, commercialization or disclosure of the
other party's Confidential Information would cause irreparable harm to such
other party. The parties acknowledge that remedies at law would be inadequate
to redress the actual or threatened unauthorized use, commercialization or
disclosure of such Confidential Information and that a party may seek
temporary and permanent injunctive relief to enforce the foregoing
restrictions. Each party shall pay its own costs and expenses (including
attorneys' fees) incurred in any proceeding arising under this Section.

         (d)     NORMAL USE. Nothing in Section 9 or in this Section 10 shall
be deemed to restrict Customer from using any Deliverable as set forth in
Section 9(d) and otherwise in the ordinary course of its business it being
understood that many employees, subcontractors and others will use the
Confidential Information in completing their duties for Customer and that it
may become necessary for Customer to interface Confidential Information
constituting software to other systems utilized by Customer, its customers,
its suppliers, and its consultants.

11.      Warranties.

         (a)     EQUIPMENT, THIRD PARTY SOFTWARE PRODUCTS. ACE*COMM hereby
assigns to Customer, to the extent assignable, all warranties and indemnities
provided by manufacturers of equipment and associated devices, and by vendors
of Third Party Software Products provided to Customer hereunder. Customer will
look solely to the applicable manufacturer or vendor of Third Party Software
Products for all warranty claims with respect to those items and shall hold
ACE*COMM harmless therefrom; provided; however, that ACE*COMM shall remain
obligated to Customer as set forth below for the performance of the
Deliverables as a system. ACE*COMM warrants that the Equipment and Third Party
Software Products when installed with the other Deliverables will be
sufficient to deliver the service levels and functionality described herein.

                                                                     6

<PAGE>

         (b)     NONINFRINGENMENT WARRANTY: INDEMNIFICATION. ACE*COMM
represents and warrants that during the Term hereof (a) the Deliverables (not
including the Third Party Software Products), when properly used as
contemplated herein will not infringe or misappropriate any United States
copyright, trademark, patent, or the trade secrets of any third persons, and
(ii) the use of the Third Party Software Products in combination or in
connection with the remaining Deliverables when properly used as contemplated
herein, will not infringe or misappropriate any United States copyright,
trademark, patent, or the trade secrets of any third persons. ACE*COMM shall
indemnify and hold Customer harmless for any damages, suits, claims, actions,
costs, expenses, settlements arising out of the breach of ACE*COMM's
representation and warranty in the preceding sentence provided that (i)
ACE*COMM is given prompt written notice of such Claim; (ii) ACE*COMM is given
the right to control and direct the investigation, preparation, defense or
settlement of any claim; (iii) Customer fully cooperates with ACE*COMM in the
investigation, preparation, defense or settlement of any claim; and (iv)
Customer has in all respects complied with the terms of this Agreement, and
(v) the alleged infringement was not caused by Customer's alteration of the
product or use of it in combination with other software, equipment or
technology not supplied or authorized by ACE*COMM. In the event that an
injunction is sought or obtained preventing Customer's use of the Deliverables
as contemplated herein, ACE*COMM shall do one or more of the following, )such
choice being in ACE*COMM's sole description: (i) defend through litigation or
obtain through negotiation the right of Customer to continue; using the
product; (ii) rework the product so as to make it noninfringing while
preserving the original functionality and performance; or (iii) replace the
product with software having substantially equivalent functionality. If
ACE*COMM determines that none of the foregoing alternatives provide an
adequate remedy, ACE*COMM may terminate this Agreement with respect to such
infringing product upon advance written notice to Customer and, in discharge
of its obligations, refund an equitable portion of license fees actually paid
by Customer for the infringing product. THESE ARE THE SOLE AND EXCLUSIVE
REMEDIES AVAILABLE FOR BREACH OF THE WARRANTY PROVIDED IN THIS SUBSECTION.

         (c)     LIMITED PERFORMANCE WARRANTY. ACE*COMM represents and
warrants that during the Warranty Period, any Standard Software Products,
Embedded Software or Custom Work Product provided hereafter shall operate
together at a level of Substantial Functionality and shall operate with and/or
interface with the Third Party Software at a level of Substantial
Functionality provided that (i) the applicable Software is installed and
implemented substantially in accordance with all written user or technical
documentation previously supplied by ACE*COMM; (ii) Customer notifies ACE*COMM
of such defect; (iii) Customer has properly installed and paid all applicable
fees for all updates made available with respect to the products and any
updates recommended by ACE*COMM with respect to any other equipment or
software that materially affects the performance of the products; (iv)
Customer has properly maintained all associated equipment, software and
environmental conditions in accordance with applicable Specifications and
industry standards; (v) Customer has not introduced other equipment or
software creating an adverse impact on ACE*COMM's products; (vi) Customer has
paid all amounts due hereunder and is not in default of any provision of this
Agreement; (vii) any functional or technical design provided by Customer is an
accurate and complete rendering of the relevant features, applicable
interfaces and associated operating environment, and (viii) Customer has made
no changes (nor permitted any changes to be made other than by or with the

                                                                     7

<PAGE>

express approval of ACE*COMM) to the Software source code. ANY UNAUTHORIZED
CHANGES TO PRODUCT SOURCE CODE WILL VOID THE WARRANTY PROVIDED UNDER THIS
SUBSECTION.

         (d)     ACE*COMM warrants that the products provided by ACE*COMM are
fully Y2K compliant and will be able to correctly process date and
date-related data into and between the year 1999 and 2000, including leap year
calculations.

         (e)     WARRANTY RESPONSE.

                        (i)    GENERAL. During the Warranty Period, upon being
         notified by Customer in accordance with ACE*COMM's standard "trouble
         report" procedures (written copies of which have been or shall be
         provided to Customer) of a Major Alarm that is covered by the warranty
         set forth in Section 11(c), ACE*COMM shall respond by telephone to
         acknowledge the Major Alarm within 4 business hours and, with the
         cooperation of Customer (including installation of dial-in contact via
         modem), shall promptly commence diagnosis and error correction efforts
         and shall use all commercially reasonable efforts to correct such
         Major Alarm.

                        (ii)   MINOR ALARMS. Minor Alarms shall be diagnosed
         and corrected by ACE*COMM within twenty-four (24) hours by telephone
         support or through the issuance of periodic updates. ACE*COMM
         acknowledges that a large accumulation of Minor Alarms may
         collectively be characterized and treated by Customer as a Major
         Alarm if not corrected within a reasonable time. All corrections
         issued in response to Major Alarms and Minor Alarms shall during the
         original Warranty Period only be warranted against defects to the
         same extent as the original Deliverable.

                        (iii)  OUT OF POCKET EXPENSES; Out-of-pocket travel
         expenses and reasonable costs of labor incurred by ACE*COMM in
         providing on-site assistance required to correct problems not covered
         by warranty shall be borne by Customer and, in any event Customer
         shall bear all travel expense associated with problems that are
         covered by warranty.

         (f)     WARRANTY DISCLAIMER. EXCEPT AS SPECIFICALLY PROVIDED IN THIS
SECTION 11, ACE*COMM HEREBY DISCLAIMS WITH RESPECT TO ALL DELIVERABLES
PROVIDED HEREUNDER, ALL EXPRESS AND IMPLIED WARRANTIES, INCLUDING ANY IMPLIED
WARRANTIES OF MERCHANTABILITY, TITLE OR FITNESS FOR A PARTICULAR PURPOSE.

DISCLAIMER REGARDING GOVERNMENTAL LAWS AND REGULATIONS. THE PARTIES HEREBY
AGREE THAT, TO THE EXTENT ANY DELIVERABLE HEREUNDER IS USED FOR THE PURPOSE OF
GENERATING OUTPUT USED IN COMPLYING WITH GOVERNMENTAL LAWS AND REGULATIONS
(INCLUDING TAX LAWS AND REGULATIONS), CUSTOMER SHALL ASSUME ALL RESPONSIBILITY
FOR HAVING THE DELIVERABLES THOROUGHLY TESTED BY QUALIFIED PROFESSIONALS TO
ENSURE THE OUTPUT IS ACCURATE AND COMPLETE.

                                                                     8

<PAGE>

12.      LIMITATION OF REMEDIES & LIABILITIES. The parties acknowledge that
the following provisions have been negotiated by them and reflect a fair
allocation of risk:

         (a)     REMEDIES. Except for (i) certain injunctive relief authorized
under Section 6 and (ii) indemnification authorized under Sections 11(b), 17
and 25, Customer's sole and exclusive remedies for ACE*COMM's default
hereunder shall be to obtain the repair, replacement or correction of the
defective Deliverable, or, if ACE*COMM reasonably determines that such remedy
is not economically or technically feasible to obtain in accordance with the
specific provisions of this Agreement an equitable partial or full credit of
amounts paid with respect to the defective item.

         (b)     LIMITATION ON ACE*COMM'S LIABILITY. EXCEPT FOR DAMAGES
ARISING FROM BODILY INJURY CAUSED SOLELY BY THE NEGLIGENCE OF ACE*COMM, AND
DAMAGES COVERED BY THE INDEMNIFICATION AUTHORIZED UNDER SECTIONS 11(b), 17;
AND 25, ACE*COMM SHALL NOT BE LIABLE FOR ANY AMOUNT EXCEEDING THE PORTION OF
THE TOTAL CONTRACT PRICE ACTUALLY PAID BY CUSTOMER. IN NO EVENT SHALL ACE*COMM
BE LIABLE, WHETHER IN CONTRACT, TORT (INCLUDING NEGLIGENCE) OR OTHERWISE, FOR
ANY INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING LOST PROFIT OR
BUSINESS INTERRUPTION EVEN IF ACE*COMM IS NOTIFIED IN ADVANCE OF SUCH
POSSIBILITY) ARISING OUT OF OR PERTAINING TO THE SUBJECT MATTER OF THIS
AGREEMENT, PROVIDED THAT THE INDEMNIFICATION AUTHORIZED UNDER SECTIONS 11(b),
17, AND 25 SHALL NOT BE CONSIDERED "CONSEQUENTIAL DAMAGES."

         (c)     LIMITATION ON CUSTOMER'S LIABILITY. EXCEPT FOR DAMAGES
ARISING FROM BODILY INJURY CAUSED SOLELY BY THE NEGLIGENCE OF CUSTOMER, AND
DAMAGES COVERED BY THE INDEMNIFICATION AUTHORIZED UNDER SECTION 17, CUSTOMER
SHALL NOT BE LIABLE FOR ANY AMOUNT EXCEEDING THE TOTAL CONTRACT PRICE DUE FROM
CUSTOMER. IN NO EVENT SHALL CUSTOMER BE LIABLE, WHETHER IN CONTRACT, TORT
(INCLUDING NEGLIGENCE) OR OTHERWISE, FOR ANY INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES (INCLUDING LOST PROFIT OR BUSINESS INTERRUPTION EVEN IF
CUSTOMER IS NOTIFIED IN ADVANCE OF SUCH POSSIBILITY) ARISING OUT OF OR
PERTAINING TO THE SUBJECT MATTER OF THIS AGREEMENT, PROVIDED THAT THE
INDEMNIFICATION AUTHORIZED UNDER SECTION 17 SHALL NOT BE CONSIDERED
"CONSEQUENTIAL DAMAGES."

                                                                     9

<PAGE>

                                  Article III.
                             RESOLUTION OF DISPUTES

13.      NOTICES. Notices sent to either party shall be effective when
delivered in person or when transmitted in good form by telecopier ("fax")
machine; one (1) day after being sent by overnight courier, or two (2) days
after being sent by first class mail postage prepaid to the address set forth
below, or to such other address as the parties may from time to time give
notice:

         Customer Address:                         ACE*COMM Address

         Mr. Stephen Dobson                        Dr. Thomas V. Russotto
         President                                 Vice President
         LOGIX Communications Corporation,         ACE*COMM, Corporation
         a subsidiary of Dobson Wireline           704 Quince Orchard Road
         Company                                   Gaithersburg, MD 20878
         13439 N. Broadway Extension
         Oklahoma City, OK 73114

14.      DEFAULT. Either Party may be declared in default of this Agreement if
it breaches any material provision hereof and fails within ten (10) days after
receipt of notice of default to correct such default or to commence corrective
action reasonably acceptable to the other party and proceed with due diligence
to completion. Either party shall be in default hereof if it becomes
insolvent, makes an assignment for the benefit of creditors, a receiver is
appointed or a petition for Bankruptcy is filed with respect to it and such
proceeding is not dismissed within thirty (30) days. Any notice of default
shall be sent in accordance with Section 13 ("Notices") and shall identify the
contract provision at issue and describe in reasonable factual detail how the
other party has materially violated the provision. If timely corrective action
is not forthcoming, the aggrieved party may then terminate the Agreement
pursuant to Section 15 ("Termination") and pursue all other available remedies.

15.      TERMINATION. This Agreement shall terminate when the Term expires or,
if earlier, upon one party's giving written notice of termination after
following the procedures in Section 14 ("Default"). Termination shall have no
effect upon the parties' rights and obligations: (i) under Section 10
("Confidential Information"), or (ii) under Section 9 ("Ownership and
Licensing of Technology")(so long as Customer has paid all amounts due with
respect to such technology and is otherwise not in default of any provision of
Section 9).

16.      DISPUTES, CHOICE OF LAW. Except for certain emergency judicial relief
authorized under Section 10 ("Confidential Information") which may be brought
at any time, the parties agree that all disputes between them shall first be
subject to the procedures in Section 14 ("Default") and then shall be
submitted for informal resolution to their respective chief operating
officers. Any remaining disputes shall be submitted to &panel of three (3)
arbitrators, with each party choosing

                                                                    10

<PAGE>

one (1) panel member and the third member chosen by the first two (2) panel
members. The proceedings shall be conducted in accordance with the Commercial
Arbitration.

17.      ESCROW OF SOURCE CODE.

         (a)     ACE*COMM shall place the source code into escrow in
accordance with an approved Escrow Agreement. Cost of this Escrow agreement
will be borne by Customer.

18.      Rules of the American Arbitration Association. The award of the
arbitrators shall include a written explanation of their decision. If the
parties are still unable to reconcile their differences after the arbitration
panel issues its award the dispute may then be taken to court by either party.
THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
SUBSTANTIVE LAWS OF TEXAS AND ANY PROCEEDING SHALL BE INITIATED AND MAINTAINED
IN A FORUM OF COMPETENT JURISDICTION IN SUCH STATE.


                                   Article IV.
                            MISCELLANEOUS PROVISIONS

19.      INDEPENDENT ACE*COMM STATUS. Each party and its people are
independent contractors in relation to the other party with respect to all
matters arising under this Agreement. Nothing herein shall be deemed to
establish a partnership, joint venture, association or employment relationship
between the parties. Each party shall remain responsible for and shall
indemnify and hold harmless the other party for the withholding and payment of
all Federal, state and local personal income, wage, earnings, occupation,
social security, unemployment, sickness and disability insurance taxes,
payroll levies or employee benefit requirements (under ERISA, state law or
otherwise) now existing or hereafter enacted and attributable to themselves
and their respective people.

20.      ENTIRE AGREEMENT, AMENDMENT. This document, the accompanying
Specifications and any applicable provisions under Section 26, which are
hereby incorporated by reference, constitute the entire agreement between the
parties and supersede all other representations, understandings or
communications, whether written or verbal, with respect to the subject matter
hereof. This Agreement is expressly limited to its terms and any different or
additional provisions of any purchase order, invoice or similar documentation
or printed form are specifically rejected and shall have no effect. Any
amendment, modification or waiver of this Agreement, or any part hereof, shall
be binding upon the parties only if such amendment, modification or waiver
specifically references this agreement and has been signed by representatives
of both parties specifically authorized to execute such binding amendments.
Waiver of any provision of this Agreement in one instance shall not preclude
future enforcement of it in future situations.

21.      SEVERABILITY. If any provision hereof is determined by a tribunal of
competent jurisdiction to be illegal or unenforceable, it shall automatically
be deemed conformed to the minimum requirements of law and, along with all
other provisions hereof, shall thereupon be given full force and effect.
Headings are for reference purposes only and have no substantive effect.

                                                                    11

<PAGE>

22.      ASSIGNMENT, SUBCONTRACTING. Neither party may assign this Agreement
without the written consent of the other party which shall not be unreasonably
withheld except that Customer may, upon notice, assign its rights and
obligations to any parent company or subsidiary company.

23.      FAX COUNTERPARTS. A facsimile of this Agreement and notices sent
according to Section 13 generated in good form from a telecopier "fax" machine
(as well as a photocopy thereof) shall be treated as "original" documents
admissible into evidence unless a document's authenticity is genuinely placed
in question.

24.      FORCE MAJEURE. ACE*COMM shall not be liable for delays or failure to
perform as a direct result of causes beyond its reasonable control, including
acts of god (such as fire, storm, earthquake), electrical outages, labor
disputes or delay or failure by others to provide proper site or environmental
conditions, or in the performance of any co-contractor or subcontractors
selected by Customer.

25.      NONSOLICITATION. During the Term and for a period of one (1) year
thereafter, each party agrees not to solicit, nor attempt to solicit, me
services of any employee of the other party without the prior written consent
of the other party. If this provision is violated, the violating party shall
pay liquidated damages equal to one hundred fifty (150) percent of the
solicited person's annual compensation,

26.      SECURITY, NO CONFLICTS. Each party agrees to inform the other party
of any information made available to it that is classified or restricted data,
agrees to comply with the security requirements imposed by any State or local
government, or by the United States Government, and shall return all such
material upon request Each party represents that its participation in this
Agreement does not create any conflict of interest prohibited by the United
States Government or any other domestic or foreign government and shall
promptly notify the other party if any such conflict arises during the Term.

27.      INSURANCE, INDEMNITY. ACE*COMM shall maintain during the Term hereof
reasonable insurance protection for ACE*COMM's workers and their work
hereunder and shall to the extent of such coverage indemnify Customer for
bodily injury and physical property damage directly and solely attributable to
the negligent or intentional acts of its employees occurring within the scope
of their employment Customer shall maintain secure, up-to-date archival copies
of all valuable data, software programs and the like, as well as adequate
liability, casualty and business interruption insurance and appropriate
disaster recovery plans.

28.      COMPLIANCE WITH EXPORT REGULATIONS. Customer has or shall obtain in a
timely manner all necessary or appropriate licenses, permits or other
governmental authorizations or approvals; shall indemnify and hold ACE*COMM
harmless from, and bear all expense of, complying with all foreign or domestic
laws, regulations or requirements pertaining to the importation, exportation,
or use of the technology to be developed or provided herein.

Customer shall take no action, nor omit to take any required action, which
would cause either party to violate the Foreign Corrupt Practices Act of 1977
or the U.S. Export Administration Regulations.

                                                                    12

<PAGE>

         IN WITNESS THEREOF, and intending to be legally bound, the parties
hereto have caused this Agreement to be executed by their duly authorized
representatives.

LOGIX COMMUNICATIONS CORPORATION,                 ACE*COMM CORPORATION
a subsidiary of Dobson Wireline Company


By:    /s/ William Hoffman                        By:    /s/ Thomas V. Russotto
   ------------------------------------              --------------------------

Name:  WILLIAM HOFFMAN                            Name:  THOMAS V. RUSSOTTO
     ----------------------------------                ------------------------

Title: CHIEF OPERATING OFFICER                    Title: VICE PRESIDENT
      ---------------------------------                 -----------------------

Date:  6/30/98                                    Date:  6/30/98
     ----------------------------------                ------------------------








                                                                    13
<PAGE>

1.       ACE*COMM shall deliver the ACE*COMM Deliverable software and hardware
         products as outlined in the attached schedule and document number
         T98.JMT.0676 Rev. 2, dated May 8, 1998 (Training, Setup, and On-Site
         Support) in the integration and installation of the implementation of
         the ACE*COMM Software System. In addition, ACE*COMM will provide for
         the Host Platform, Client Workstation and the ACE*COMM Deliverable
         software.


2.       EQUIPMENT & DEVICES. ACE*COMM shall provide the following equipment and
         associated devices:

                                    CUSTOMER
                                 SERVER PLATFORM

3.       SCHEDULE OF WORK: The document number T98.JMT.0676, Rev. 2 document for
         each phase is included within the scope of this document. Included are
         Attachments B (Engineering and Support Labor Costs), Attachment C (Cost
         Estimate for Interfaces), Attachment E (Unix Platform Description),
         Attachment F (Source code Escrow Agreement), Attachment J (Pricing
         Workbook with Five Year Valuation)

4.       DELIVERY AND PAYMENT SCHEDULE

         The Delivery and Payment Schedule is as follows:

         A.       Delivery Schedule

<TABLE>
<CAPTION>

                  CONTRACT MILESTONES                                      ESTIMATED DATE
                  -------------------                                      --------------

                 <S>                                                       <C>
                 1.   Receipt of Purchase Order                            June 4, 1998
                 2.   Delivery of System to Site                           June 18, 1998
                 3.   Installation of Software at ACE*COMM                 June 23, 1998
                 4.   First Billing Calendar Cycle Begins                  Jan. 1, 1999

         B.       Payment Schedule - Customer agrees to pay ACE*COMM in
                  accordance with the following schedule:


                                                                            14
<PAGE>

                  SYSTEM PAYMENTS                                      PAYMENT AMOUNT
                  ---------------                                      --------------
                  Licensed Software                                      $2,143,431
                  Hardware                                                  570,342

                  SERVICES
                  --------
                  Set-up/training                                           156,500
                  Other one-time costs                                      288,000
                  Custom development based on time & materials              250,000
                  Total with discount:                                   $3,408,273


                  The amount above to be paid as follows:

                  Forty percent (40%) with order                          $1,363,311
                  Ten percent (10%) on July 31, 1998                         340,827
                  Ten percent (10%) on August 31, 1998                       340,827
                  Ten percent (10%) on September 30, 1998                    340,827
                  Ten percent (10%) on October 31, 1998                      340,827
                  Ten percent (10%) on November 30, 1998                     340,827
                  Ten percent (10%) upon completion of first
                  Live billing cycle production run begins.                  340,827


                  CONTRACT MILESTONES                                      ESTIMATED DATE
                  -------------------                                      --------------

                  1.   Purchase Order received by ACE*COMM                 June 4, 1998
                  2.   Contract signed                                     June 10, 1998
                  3.   Installation of NetPlus Pro*Vision                  June 23, 1998
                  4.   First Live Billing Cycle production run begins      January 31, 1999
</TABLE>


                                                                            15
<PAGE>

                                  Attachment B

                        ENGINEERING AND SUPPORT SERVICES
                                TIME AND EXPENSES



1.       Engineering and support services are available on a time and expenses
         basis. Services may be provided on fixed price quotation basis or on
         actual time and expenses as they are incurred.

2.       Labor is charged for work time.

3.       The following table presents current labor rates by labor category.

4.       Overtime billed at standard rates.

<TABLE>
<CAPTION>

RATE CATEGORY      LABOR TITLE                                  RATE PER HOUR
<S>                <C>                                          <C>
         A         Program Manager                              185
         A         Software Applications                        160
                   Engineer/Programmer IV
         A         Software Development Manager                 160
         A         Technical Support Manager                    160
         A         Technical Training Manager                   160
         B         Project Manager                              140
         B         Senior Technical Training Instructor         140
         B         Software Applications                        140
                   Engineer/Programmer III
         B         Systems Engineering Manager                  140
         B         Technical Support Engineer III               140
         C         Quality Assurance Technician III             110
         C         Software Applications                        110
                   Engineer/Programmer II
                   Technical Support Engineer II                110
         C         Technical Training Instructor II             110
         D         Software Applications                        90
                   Engineer/Program I
         D         Technical Support Engineer I                 90
         F         Data Entry Operator                          55
</TABLE>


                                                                            16
<PAGE>

                                  Attachment E

Desc.:  SUN Enterprise 3500 Servers

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                    Unit       Client
Line                                                                                List        Unit      Extended       Client
 No.   Qty.   Manufacturer   Description                          Item #           Price        Cost     List Price     Ext Cost
---------------------------------------------------------------------------------------------------------------------------------
<S>    <C>    <C>            <C>                                  <C>           <C>          <C>         <C>          <C>
  1              Note:       This configuration is for 2 Sun
                             Enterprise 3500 Servers set up to
                             share the Tape Backup Services
---------------------------------------------------------------------------------------------------------------------------------
  2
---------------------------------------------------------------------------------------------------------------------------------
  3     2         SUN        Enterprise 3500 Server Base          E3500-C64      79,800.00   57,456.00   159,600.00   114,912.00
                             Package, Tower Enclosure, One
                             SunCD32, Two Power/Cooling
                             Modules. Two CPU/Memory Boards,
                             Four 336-MHz/4-MB UltraSPARC
                             Modules, Solaris Server License
---------------------------------------------------------------------------------------------------------------------------------
  4     8         SUN        256-Mbyte Memory Expansion (8 X      7022A           3,200.00    2,304.00    25,600.00    18,432.00
                             32-Mbyte Memory Module)
---------------------------------------------------------------------------------------------------------------------------------
  5    16         SUN        Internal 9.1-Gbyte 7200 RPM FC-AL    6709A           2,500.00    1,800.00    40,000.00    28,800.00
                             Disk Drive. 1.6" High
---------------------------------------------------------------------------------------------------------------------------------
  6     2         SUN        EXX00 SBus I/O Board w/Three         2612A           6,500.00    4,680.00    13,000.00     9,360.00
                             Empty SBus slots, two empty 100
                             MB/sec FC-AL sockets, one 10/100
                             MB/sec Ethernet (Twisted Pair or
                             MIDI) Interface
---------------------------------------------------------------------------------------------------------------------------------
  7     2         SUN        Optional FC-AL Interface Board,      2652A           1,500.00    1,080.00     3,000.00     2,160.00
                             includes two GBIC modules, one 2
                             meter FC-AL cable
---------------------------------------------------------------------------------------------------------------------------------
  8     2         SUN        2-meter Fibre Optic Cable            X973A             150.00      150.00       300.00       300.00
---------------------------------------------------------------------------------------------------------------------------------
  9     2         SUN        SunFastEthernet 10/100 SBus          1059A             795.00      572.40     1,590.00     1,144.80
                             Adapter 2.0 SBus Card,
                             Media, Documentation
                             and Single-SBus License
                             SunFastEthernet 10/100
                             SBus Adapter 2.0
---------------------------------------------------------------------------------------------------------------------------------
 10     4         SUN        FC-AL 100 MB/sec GBIC module         6731A             600.00      432.00     2,400.00     1,728.00
---------------------------------------------------------------------------------------------------------------------------------
 11     2         SUN        TurboGX 8-bit color graphics         7110A             830.00      730.40     1,660.00     1,460.80
                             card, cables and documentation
---------------------------------------------------------------------------------------------------------------------------------
 12     2         SUN        17-inch Entry Color Monitor          X7103A            710.00      624.80     1,420.00     1,249.60
---------------------------------------------------------------------------------------------------------------------------------
 13     2         SUN        Type 5 Country Kits for U.S. and     X3540A
                             Canada only, UNIX
---------------------------------------------------------------------------------------------------------------------------------
 14     2         SUN        Solaris 25.1 Hardware 11/97 US       SOLS-2.51NO       100.00       72.00       200.00       144.00
                             English Server Media Kit
---------------------------------------------------------------------------------------------------------------------------------
 15     2         SUN        Second Peripheral Power Supply,      9698A           1,500.00    1,080.00     3,000.00     2,160.00
                             195W
---------------------------------------------------------------------------------------------------------------------------------
 16     2         SUN        SERVERSTART Install Services         NF-INST-SS      2,000.00    2,000.00     4,000.00     4,000.00
---------------------------------------------------------------------------------------------------------------------------------
 17     2         SUN        SPARCstorage Array Installation      NF-INST-SSA     1,800.00    1,800.00     3,600.00     3,600.00
                             Service
---------------------------------------------------------------------------------------------------------------------------------
 18     2         SUN        (RTU License Only) Sun Enterprise    EVM-2.5-DS-L    6,995.00    5,036.40    13,990.00    10,072.80
                             Volume Manager 2.5 for
                             Departmental Servers RTU only
---------------------------------------------------------------------------------------------------------------------------------
 19     2         SUN        Solstice Database Module for         BU09S-210.99    5,000.00    4,250.00    10,000.00      8500.00
                             Oracle 2.1 for Solaris/SPARC
                             Media, Docs RTU
---------------------------------------------------------------------------------------------------------------------------------
 20                                                                                             SUBTOTAL 2 SERVERS   $208,024.00
---------------------------------------------------------------------------------------------------------------------------------
 21                                                                                               PRICE PER SERVER   $104,012.00
---------------------------------------------------------------------------------------------------------------------------------
 22
---------------------------------------------------------------------------------------------------------------------------------
 23     1         SUN        SBus Differential Fast/wide          1062A           1,295.00      932.40     1,295.00       932.40
                             Intelligent SCSI-2 Host Adapter
                             (DWIS/S)
---------------------------------------------------------------------------------------------------------------------------------
 24     1         SUN        280-560 Gbyte StorEdge L280 Tape    SG-            19,500.00   14,040.00    19,500.00    14,040.00
                             Autoloader (Desktop)                 XLIBDLT1-
---------------------------------------------------------------------------------------------------------------------------------
 25     1         SUN        Solstice Backup 5.1 Network          BUW99-510-99    6,000.00    5,100.00     6,000.00     5,100.00
                             Edition for Solaris SPARC/Intel,
                             Media, Docs, RTU
---------------------------------------------------------------------------------------------------------------------------------

<PAGE>

                                  Attachment E

Desc.:  SUN Enterprise 3500 Servers

---------------------------------------------------------------------------------------------------------------------------------
                                                                                    Unit       Client
Line                                                                                List        Unit     Extended        Client
 No.   Qty.   Manufacturer   Description                          Item #           Price        Cost     List Price     Ext Cost
---------------------------------------------------------------------------------------------------------------------------------
<S>    <C>    <C>            <C>                                  <C>           <C>          <C>         <C>          <C>
 26     1         SUN        Solstice Backup 5.1 1-8 slot         BUJV9-          1,500,00    1,275.00     1,500.00     1,275.00
                             jukebox module for Solaris           510-999
                             SPARC/Intel. RTU
---------------------------------------------------------------------------------------------------------------------------------
 27     1         SUN        (Media and Documentation Sun         EVM-2-5-B         100.00      100.00       100.00       100.00
                             Enterprise Volume Manager 2.5
                             Base Pack
---------------------------------------------------------------------------------------------------------------------------------
                                                                                       SUBTOTAL ANCILLARY EQUIPMENT   $21,447.40
                             ----------------------------------------------------------------------------------------------------
                                                                                                     PURCHASE PRICE  $229,471.40
                             ----------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>

                        LOGIX COMMUNICATIONS CORPORATION
                           STATEMENT OF WORK/PRICING
                    Netplus Pro*Vision, N*VISION, CANS, DCMS
              ACE*COMM Deliverable Software, Hardware, and Services
                                  SUMMARY PAGE

         OFFEROR:

                  ACE*COMM Corporation
                  704 Quince Orchard Road                    Phone: 301-721-3000
                  Gaithersburg, Maryland 20878               Fax: 301-721-3001

<TABLE>

<S>      <C>      <C>
1.0      SOFTWARE PRO*VISION LICENSE
         1.1      Client Software License, plus annual warranty
         1.2      Server Software by Function Group
         1.3      Total Initial Software for 45,000 ANIs
         1.4      Incremental License Additions Costs
                  Initial software warranty is for 12 months from
                  delivery. Thereafter maintenance is for one year
                  durations at 18% of current license fee not to exceed
                  $500,000 in years 3 through 5. License includes
                  purchased modules plus all scheduled releases while
                  maintenance is in effect.
2.0      SETUP, SUPPORT, & TRAINING
3.0      SERVICE BUREAU --Outsource MIS/Data Processing
                  Logix licenses software and purchases Server located
                  at ACE*COMM. Server and Back Office bill processing
                  done at ACE*COMM Data Center Service. Bureau/MIS
                  Outsourcing pricing is available with a minimum
                  $12,500 per month fee against actual transaction
                  fees.
4.0      HARDWARE for Pro*Vision
                  Plus 15% ACE*COMM integration and testing charge.
                  Client hardware platform pricing not included in
                  Quote. Windows 95 workstation required for Developer
                  2000 bill production.
5.0      REAL TIME DATA MANAGEMENT
                  N*Vision-Real Time Network Surveillance, Reporting, Data Warehousing
                  DCMS Data collection device to feed Pro*Vision.
                  CANS Network Data storage and distribution package
                  Modification to software to be determined.
         5.1      Software Charge, Hardware Charge, Implementation and Training
6.0      ACE*COMM PRICING SUMMARY

</TABLE>



                                                                               1

<PAGE>

                        LOGIX COMMUNICATIONS CORPORATION
                           STATEMENT OF WORK/PRICING
                               NETPLUS PRO*VISION
          Multi-Services Customer Care, Service Management and Billing


OFFEROR:
         ACE*COMM
         704 Quince Orchard Road                             Phone: 301-721-3000
         Gaithersburg, Maryland 20878                        Fax: 301-721-3001
         Contact: Michael Kresloff

<TABLE>

<S>      <C>               <C>                                            <C>            <C>             <C>            <C>
1.0      PRO*VISION SOFTWARE REQUIREMENTS GENERAL:
         Software is provided on a per seat (client) and Site (server) license format

1.1      CLIENT            $250,000 one time payment (plus maintenance for years two and beyond)
                           for unlimited, perpetual Logix client workstations.
1.2      SERVER            Core Modules (systems admin., report writer, process security)                               $   360,895
                           Billing Customer Care                                                                        $   530,612
                           Service Creation, Facilities Management                                                      $   472,090
                           CDR Mediation (via FTP or Tape) w/o Collector                                                $    85,834
                           First Year Warranty                                                                           (included)
                                                                                                                        ===========
1.3                        Total Server Software 45,000 initial lines                                                   $ 1,449,431
                           (ANI's, Paging, Wireless, D50 Numbers)
                           --------------------------------------------------------------------------------------------------------
1.4                        GROWTH LICENSE INCREMENTS                          10,000+         25,000+        50,000+       100,000+
                           --------------------------------------------------------------------------------------------------------
                           INCREMENTS                                      40K - 100K         TO 100K        TO 200K
                           --------------------------------------------------------------------------------------------------------
                           Core Modules                                   $    38,672    $     82,178    $   143,811    $   251,669
                           --------------------------------------------------------------------------------------------------------
                           Billing Customer Care                          $    55,000    $    116,875    $   204,531    $   357,930
                           --------------------------------------------------------------------------------------------------------
                           Service Creation, Facilities
                           Management                                     $    49,844    $    105,918    $   185,356    $   324,374
                           --------------------------------------------------------------------------------------------------------
                           Call Mediation w/o collector                   $    10,313    $     21,914    $    38,350    $    67,112
                           --------------------------------------------------------------------------------------------------------
                           INCREMENT TOTAL                                $   153,828    $    326,885    $   572,048    $ 1,001,085
                           --------------------------------------------------------------------------------------------------------

1.5      One Year Software Warranty included with initial license pricing.
         Pro*Vision is tested for year 2000 operability. If faults are found
         concerning the year 2000, they will be fixed free of charge.
         Server Software Maintenance provided an 18% of License fee. Hardware
         warranty can be extended to one year with hardware vendor. Client
         Software Maintenance is provided at 18% of client licenses per year.
         Customization/Modification costs to be determined.

1.6      For item Growth License documents for Pro*Vision, N*Vision and CANS,
         Customer Shall be entitled to a 20% discount in years 2 through 5 and
         shall not pay more than $1,500,000, $1,500,000, and $700 for such
         Growth Licenses in years 3, 4 and 5 respectively.

</TABLE>



                                                                               2


<PAGE>
--------------------------------------------------------------------------------
                        LOGIX COMMUNICATIONS CORPORATION
--------------------------------------------------------------------------------
                           STATEMENT OF WORK/PRICING

                               NETPLUS PRO*VISION

          Multi-Services Customer Care, Service Management and Billing

--------------------------------------------------------------------------------

OFFEROR:
         ACE*COMM
         704 Quince Orchard Road             Phone: 301-721-3000
         Gaithersburg, Maryland 20878        Fax: 301-721-3001
         Contact: Mike Kresloff
--------------------------------------------------------------------------------

2.0      TRAINING AND SETUP RECOMMENDATIONS.
         Software is provided on a per seat (client) and Site (server) license
         format. Charges will be based on actual time and materials in
         accordance with Attachment B.

<TABLE>
                  <S>                                                      <C>
                  Estimated Site Setup (Install)                           $  30,000
                  Estimated Training (Basic level course instruction)      $  30,000
                  Estimated Support (Data Fill and implementation)
                  For actual hourly rates, see Attachment B.
                                                                           $ 288,000
                                                                           ---------
                  TOTAL PRO*VISION TRAINING,                               $ 348,000
                                                                           =========

                  SET-UP AND SUPPORT
</TABLE>


                                                                              3
<PAGE>
--------------------------------------------------------------------------------
                        LOGIX COMMUNICATIONS CORPORATION
--------------------------------------------------------------------------------
                           STATEMENT OF WORK/PRICING

                      NETPLUS PRO*VISION AND N*VISION/CANS

          Multi-Services Customer Care, Service Management and Billing

         OFFEROR:

                ACE*COMM
                704 Quince Orchard Road                Phone: 301-721-3000
                Gaithersburg, Maryland 20878           Fax: 301-721-3001


4.0      HARDWARE PRICING ESTIMATE

<TABLE>
                <S>                                                      <C>
                UNIX Ultra 3500 Server Hardware w/Ancillary Eqmt.        $125,459.40
                ACE*COMM Integration                                      $18,818.91
                                                                         -----------

                                                            SUB TOTAL    $144,278.31
                                                                         -----------



                NT Server for print engine, networked to UNIX server.
                Pentium II Processor
                Optimally configured                        SUB TOTAL    $    10,000
                                                                         -----------
                                             TOTAL PRO*VISION HARDWARE   $154,278.31
                                                                         ===========
</TABLE>


                                                                              4
<PAGE>

--------------------------------------------------------------------------------
                        LOGIX COMMUNICATIONS CORPORATION
--------------------------------------------------------------------------------
                           STATEMENT OF WORK/PRICING

              NETWORK SURVEILLANCE, CDR COLLECTION AND REFORMATTING

                       Enhanced, Real Time CDR Management



OFFEROR:

         ACE*COMM Corporation
         704 Quince Orchard Road                       Phone: 301-721-3000
         Gaithersburg, Maryland 20878                  Fax: 301-721-3001

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------
                                                                   HARDWARE     IMPLEMENTATION/SET
           PRODUCT                              SOFTWARE COST        COST                UP             TRAINING
  <S>                                           <C>                <C>          <C>                     <C>
------------------------------------------------------------------------------------------------------------------
  N*VISION (See note (1))                          $300,000                           $20,000*           $5,000*
  DCMS* - CDR Collection--Redundant-One per                          $45,000           $3,500*           $7,500*
    switch unless BX.25 from DMS 500
  Discounts for 3rd to 5th - 5%
  Discounts for 6th to 10th - 10%
  Discounts for 11th to 15th - 15%
  Discounts for 16th to 20th - 20%
  CANS, Network Collection and CDR Distribution                                       $10,000*          $15,000*
  Up to 8 switches at                              $144,000
  9-16 switches at                                 $256,000
  17-24 switches at                                $368,000
  25-32 switches                                   $448,000
  Site Survey per site                                                                 $3,000*




  UNIX Server Component for N*Vision                             $119,613.80           $5,000*          $10,000*
   w/integration
==================================================================================================================
</TABLE>

(1) Price of $300K is for up to 500K daily CDRs. For 500K - 1 million daily
CDRs, additional $150K; for 1 - 2 million daily, additional $150K; for 2
million to 3 million, additional $150K; for 3 - 5 million, additional $375K;
for 6 - 10 million, additional $375K; for 11 - 20 million, additional $375K.

Note: N*Vision, DCMS, and CANS are tested for year 2000 operability. If faults
are found concerning year 2000, they will be fixed free of charge.

*Implementation and training will be completed on a time and material basis at
the rates listed in Attachment B.


                                                                              5
<PAGE>

--------------------------------------------------------------------------------
                        LOGIX COMMUNICATIONS CORPORATION
--------------------------------------------------------------------------------
                            STATEMENT OF WORK/PRICING

                    NETPLUS PRO*VISION, N*VISION, CANS, DC&MS

          Multi-Services Customer Care, Service Management and Billing
                             Initial Contract Price

         OFFEROR:
                  ACE*COMM Corporation
                  704 Quince Orchard Road              Phone: 301-721-3000
                  Gaithersburg, Maryland 20878         Fax: 301-721-3001
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>
<S>      <C>                                                   <C>
6.0      ACE*COMM Pricing Summary
         SOFTWARE
         Pro*Vision Server Software License                                   $        1,449,431
         Pro*Vision Client Software License                                   $          250,000
         N*Vision                                                             $          300,000
         CANS (6 switch license)                                              $          144,000
                                                                              ------------------
                                                               TOTAL SOFTWARE $        2,143,431
                                                                              ==================
         HARDWARE
         Pro*Vision UNIX Server with Ancillary Equipment                      $          144,2&8
         DCMS - (six sites, redundant)                                        $          258,750
         N*Vision UNIX Server                                                 $          119,614
         NT Server for Bill Print Engine                                      $           10,000
         Hardware Maintenance 9 months for servers                            $           37,700
                                                                              ------------------
                                                               TOTAL HARDWARE $          570,342
                                                                              ==================

         INSTALLATION AND SETUP
         Pro*Vision Setup/training                                            $           60,000
         N*Vision                                                             $           40,000
         DCMS (six setups, one training)                                      $           28,500
         CANS                                                                 $           28,000
                                                                              ------------------
                                                               TOTAL SERVICES $          156,500
                                                                              ==================

         OTHER ONE TIME COST
         Pro*Vision Support Six Months                                        $          288,000
         Development Estimate                                                 $          250,000
                                                                              ------------------
                                                               TOTAL SERVICES $          538,000
                                                                              ==================

                                                               OVERALL TOTAL $         3,408,273
                                                                              ==================

         Payment Terms       40% with order                                            1,363,311
                             10% on July 31, 1998                                        340,827
                             10% on August 31, 1998                                      340,827
                             10% on September 30, 1998                                   340,827
                             10% on October 31, 1998                                     340,827
                             10% on November 30, 1998                                    340.827
                             10% upon completion of first live billing cycle.            340,827
</TABLE>

Service Bureau processing charges are not included in this summary and are
payable monthly from the start of first live billing cycle production run.

                                                                              6
<PAGE>

                       DATA PROCESSING SERVICES AGREEMENT


         THIS AGREEMENT (the "Agreement") is hereby entered into between
ACE*COMM Corporation ("ACE*COMM") located at 704 Quince Orchard Road,
Gaithersburg, Maryland 2,0878, and LOGIX COMMUNICATIONS CORPORATION, A
SUBSIDIARY OF DOBSON WIRELINE COMPANY ("Customer") with offices at 13439 N.
BROADWAY EXTENSION. OKLAHOMA CITY, OKLAHOMA 73114, on the following terms and
conditions:

1.       GENERAL UNDERTAKING.

(a)      COMPUTER PROCESSING SERVICES. ACE*COMM shall provide Customer with the
computer processing services described in the Schedule of Processing Services
(the "Processing Services")' to process Customer's internal information (the
"Data"), which may include Internal information of Customer's parent, subsidiary
or other affiliate controlled by any of the foregoing (where "control" for
purposes of this Section 1 means a 50% ownership interest), in accordance with
Section 2(d) ("Performance Goals") and this Agreement. ACE*COMM will provide the
Processing Services from its data processing center, located in Gaithersburg,
Maryland (the "Processing ACE*COMM Data Center"), at the prices set forth in
Section 4 ("Service Fees & Other Charges").

(b)      COMMUNICATIONS SYSTEM. ACE*COMM shall deliver Processing Services to
a "Point of Connection" located within the communications room at the
Processing ACE*COMM Data Center. The Customer shall at its own expense
provide or arrange dedicated telecommunications circuits and transmission
services linking the Point of Connection with the Customer's central and
various remote locations (the "Communications System"). ACE*COMM's ability to
provide Processing Service's in accordance with this Agreement is expressly
conditioned on the adequacy and availability of the Communications System
supplied by Customer, which will initially be an adequate connection from a
vendor selected by Customer and may be modified from time to time at the
election of Customer.

(c)      REMOTE ACCESS EQUIPMENT. The parties shall provide the following
equipment during the Term of this Agreement:

(i)      SUPPLIED BY ACE*COMM. ACE*COMM shall provide, install and maintain
at the prices set forth in the Schedule of Prices the computer hardware and
telecommunications devices identified on Subpart A of the attached Schedule
of Remote Access Equipment at the locations specified therein (the "ACE* COMM
Equipment:

(ii)     SUPPLIED BY CUSTOMER. Except as specified in Clause (i) above, the
Customer shall provide, install and maintain at its own expense all other
remote computer terminals, modems, printers and other hardware and
telecommunications services (including leased lines and circuits) and devices
required to obtain access to the Processing ACE*COMM Data Center and to make
effective use of the Processing Services at the level of activity and
performance contemplated herein (the "Customer Equipment").


                                                                        Page 1
<PAGE>


(d)      SOFTWARE. The software used by ACE*COMM to provide the Processing
Services shall be supplied as follows:

(i)      OPERATIONS SOFTWARE. ACE*COMM shall, as specified in the Schedule of
Software, provide the "Standard Library of Software" at no additional charge and
shall provide the "Software Subject to Surcharge" at the surcharge rates set
forth in the Schedule of Prices.

(ii)     APPLICATIONS SERVICES. Unless specified in the Schedule of Application
Services, the work contemplated hereunder does not include software applications
development, maintenance or conversion of programs or data.

(e)      OTHER BILLABLE SERVICES. ACE*COMM shall be reasonably available from
time to time during the Term hereof to assist Customer with "Other Billable
Services" outside the scope of Processing Services. Such services could
include assistance in the design or procurement of additional or different
telecommunications circuits, implementation or consolidation of other
Customer data processing operations, software development or conversion
services and general troubleshooting of problems with Customer-supplied
application software or problems interfering with Processing Services not
caused by ACE*COMM. Other Billable Services shall be subject to a signed
amendment hereto or separate agreement between the parties.

2.       PROCESSING ACE*COMM DATA CENTER OPERATIONS.

(a)      INITIATING PROCESSING AT THE PROCESSING ACE*COMM DATA CENTER. Within
fifteen (15) days after execution of this Agreement, the parties shall each
appoint a Coordinator responsible for coordinating and facilitating the
implementation of Customer's data processing operations at the Processing
ACE*COMM Data Center. ACE*COMM shall plan, manage and execute the
implementation according to a plan and schedule approved by the parties (the
"Implementation Plan").

(b)      COMMENCEMENT OF PROCESSING SERVICES. Upon completion of
implementation, the parties shall test the Processing Services to determine
whether the level of performance complies with the criteria set forth in the
IMPLEMENTATION PLAN. The "Commencement Date" of the Processing Services shall
be determined by the respective Service Coordinators of ACE*COMM and
Customer. Thereafter, each anniversary of the Commencement Date shall be
considered a separate "Processing Year" for purposes of this Agreement.

(c)      OPERATIONS MANAGEMENT.

(i)      CUSTOMER ACCOUNT MANAGER. ACE*COMM shall appoint a Customer Account
Manager to serve as Customer's key point of contact with ACE*COMM for any
questions, problems or service issues during the Term hereof, as more fully
explained in ACE*COMM's Customer Guide (the "Customer Guide"). The Customer
Guide will be completed 15 days after commencement and will be delivered in a
form mutually agreed to by the parties.

(ii)     DOCUMENTATION. ACE*COMM shall, at its own expense, provide Customer
two (2) copies of the Customer Guide, one in electronic MS Word format, and
related documentation


                                                                        Page 2
<PAGE>


pertaining to ACE*COMM supplied software. (collectively, the
"Documentation"). The Customer may copy the Documentation. Upon termination
of this Agreement, the Customer shall either return to ACE*COMM all copies of
Documentation under its possession or control, or destroy such copies with
confirmation of such to ACE*COMM within a reasonable period of time.

(iii)   TRAINING. ACE*COMM shall, at its proposed rates, provide Customer such
training and instruction at a mutually convenient location as may reasonably be
needed by managers and technicians of general proficiency to make effective use
of the Processing Services.

(iv)     OPERATING PROCEDURES. After receipt of the Customer Guide, the
Customer shall at all times comply with ACE*COMM's operational and security
procedures, as reflected in the Customer Guide, as from time to time revised
by ACE*COMM. ACE*COMM reserves the right in its sole discretion to upgrade or
reconfigure system components, hardware or software and otherwise to arrange
its location or method of operations and procedures, in a manner that
maintains its compatibility with existing systems, as it deems necessary or
helpful in meeting the requirements of this Agreement.

(d)      PERFORMANCE GOALS.

(i)      PROCESSING SERVICES PERFORMANCE OBJECTIVES. ACE*COMM shall meet the
minimum performance objectives for the Processing Services (the "Performance
Goals"), as follows:

               (a)   TIMELINESS OF SUBSCRIBER INVOICES. ACE*COMM shall send
                     out all subscriber invoices, as described in Section
                     1(c) of the Schedule of Processing Services, generated
                     by the Processing Services (the "Subscriber Invoices")
                     with the following schedule. ACE*COMM shall send out the
                     Subscriber Invoices for charges incurred during a
                     billing cycle within nine (9) calendar days of the end
                     of the billing cycle, including one-half of a business
                     day for billing cycle verification by Customer, as
                     defined in the Customer Guide. In the event the Customer
                     uses more than one-half of a business day for cycle
                     verification, the excess time beyond one-half of a business
                     day shall be added onto the nine (9) day deadline for
                     sending out the Subscriber Invoices described herein.
                     Subscriber Invoices must be sent to the correct address,
                     physical or electronic, for each account as provided by
                     Customer in order to fulfill the requirement of timeliness
                     set forth by this Subsection (a).

               b)    METHOD OF DELIVERY FOR SUBSCRIBER INVOICES. ACE*COMM
                     shall deliver Subscriber Invoices in accordance with the
                     method specified by Customer for the billing of each
                     account. Where not otherwise specified by Customer,
                     ACE*COMM shall deliver Subscriber Invoices by
                     first-class mail postage prepaid.

               c)    ACCURACY OF SUBSCRIBER INVOICES. ACE*COMM shall bill
                     parties for


                                                                        Page 3
<PAGE>

                     the full and exact amount indicated as owing by the Data
                     provided by Customer unless otherwise instructed in
                     writing by Customer.

(ii)     OPERATIONAL PARAMETERS. After commencement of Processing Services, the
Performance Goals shall be conditioned on the Customer not exceeding fifteen
percent (15%) or more transaction growth," as described below, in any month, If
this occurs, the Parties shall negotiate in good faith an appropriate adjustment
to the Processing Services and/or Performance Goals for that month. Transaction
growth shall be calculated as the percentage increase in "Billable Transactions"
(Billable Transactions are defined as any call transaction message that is input
through electronic and manual means to a ACE*COMM managed process or processes
that will result in direct or indirect invoicing by ACE*COMM or any third party
company, account cycle processing, tape input and output handling and material
cost etc. as defined in Schedule of Prices -- Billable Transactions), required
by the Customer in a given month as compared to the average number of
Billable Transactions required over the previous two (2) months.

(iii)    OTHER MATTERS. The Performance Goals (and any specific goals for
Particular System functions described in any attachment hereto) shall be
considered objectives only and not representations, warranties or guarantees of
performance, The performance objective, as described above, shall not apply
during the first sixty (60) days following the Commencement Date. ACE*COMM shall
make its best efforts to Provide the maximum performance possible during this
sixty (60) day period and throughout the term of this contract.

(e)      MIGRATION FROM ACE*COMM. Upon termination of this Agreement for any
reason, at Customer's request, ACE*COMM shall provide support staff, services
and shall cooperate fully with Customer to plan and execute an orderly
migration of hardware, software and Processing Services to the destination of
Customer's choice according to a migration plan and schedule supplied by
Customer in mutually agreeable form. The services described in this Section
2(e) shall be subject to a fee as described in the Schedule of Prices (the
"Migration Fee").

3        TERM. TERMINATION. This Agreement shall be effective from the date
         last below written and, unless terminated earlier under this Section 3
         or under Section 14 ("Default"), shall continue in full force and
         effect for a period of four (4) years from the Commencement Date. The
         Term shall be renewed for successive one (1) year periods unless either
         party notifies the other party at least sixty (60) days prior to
         expiration of the then current Term that the Agreement shall not be
         renewed. Notwithstanding the foregoing, Customer may terminate this
         Agreement at any time after Completion of the second (2nd) Processing
         Year, upon sixty (60) days' notice and payment of the "Termination Fee"
         described in the Schedule of Prices. Such termination shall have no
         effect on Customer's obligation to pay for all amounts due hereunder or
         the parties' rights and obligations under Section 6 ("Proprietary
         Rights"), Section 7 ("Confidential Information"), Section 8
         ("Nonsolicitation"), Section 11 ("Limitation of Remedies &
         Liabilities") or Section 21 ("Compliance with Export Regulations").
         Notwithstanding the foregoing, in the event ACE*COMM fails during four
         (4) of any eight (8) consecutive months to meet the Performance Goals
         described in Section 2(d) ("Performance Goals") Customer shall have an
         unrestricted right to terminate this agreement and shall thereafter
         incur no obligations under the Agreement. Such termination shall have
         no effect on the parties' rights and


                                                                        Page 4
<PAGE>

         obligations under Section 6 ("Proprietary Rights"), Section 7
         ("Confidential Information"), Section 8 ("Nonsolicitation"), Section 11
         ("Limitation of Remedies & Liabilities") or Section 21 ("Compliance
          with Export Regulations").

4.       SERVICE FEES & OTHER CHARGES. Beginning with the Commencement Date and
         in consideration of the Processing Services and other technology or
         services provided under Section 1 ("General Undertaking"), the Customer
         agrees to pay ACE*COMM the following compensation in accordance with
         Section 5 ("Invoices & Payment"):

(a)      MONTHLY SERVICE FEES.

         Customer shall pay ACE*COMM the greater of either:

                      (i)   MINIMUM MONTHLY SERVICE FEE. a Minimum Monthly
                      Service Fee in the amount of twelve thousand five hundred
                      dollars ($12,500.00) for the Processing Services.

                      (ii)  TRANSACTION PROCESSING FEE. a Transaction Processing
                      Fee as calculated in accordance with the SCHEDULE OF
                      PRICES.

(b)      CERTAIN OTHER CHARGES. If the data submitted by Customer is incorrect,
incomplete or not in the format specified by ACE*COMM, Customer agrees to pay
ACE*COMM their then current standard hourly rates for additional work required
to correct, complete or otherwise prepare the data for processing where Customer
has provided prior approval for such work to be undertaken by ACE*COMM.

                  Once production control release's approval for cycle printing,
                  all costs for transaction processing, and/or cycle printing
                  will be the responsibility of Customer (this includes restarts
                  and reruns) unless such costs are incurred through the
                  negligence of ACE*COMM.

                  The price for Other Billable Services, if any, rendered by
                  ACE*COMM shall be ACE*COMM's then current proposed standard
                  price for the services rendered or such price as the parties
                  otherwise agree in writing. Unless otherwise stated, the price
                  for Other Billable Services does not include and Customer
                  shall reimburse ACE*COMM for all associated out-of-pocket
                  costs for travel, long distance telephone, shipping, supplies
                  and other related costs, subject to reasonable reporting and
                  substantiation requirements.

(c)      CERTAIN TAXES. The Customer shall be responsible for any state and
local sales or use tax based on the Customer's payment of fees and use of
Processing Services or other deliverables provided hereunder. ACE*COMM shall
be responsible for taxes based on ACE*COMM's net income, gross income,
receipts, capital or net worth as well as all minimum taxes, doing business
taxes and franchise taxes.

5.       INVOICES & PAYMENT.


                                                                        Page 5
<PAGE>


(a)      MINIMUM MONTHLY SERVICE FEE. The Minimum Monthly Service Fee shall be
paid in arrears, without invoice or additional notice, on the first day of
each month beginning with the month following the month in which the
Commencement Date occurs. The Minimum Monthly Service Fee shall be prorated
during the first month of the first Processing Year and the last month of the
Term hereof based on the ratio of the actual number of days of Processing
Services utilization to the total number of days in each such month.

(b)      ADDITIONAL SERVICE FEE. ACE*COMM shall submit an invoice to Customer
for any Additional Service Fees by the fifteenth (15th) day of the month
following the month in which such Additional Service Fees are incurred by
Customer. Such Additional Service Fees shall be paid no later than the first
day of the month immediately following the month in which such invoice is
dated.

(c)      OTHER CHARGES. Any amounts due for Other Billable Services,
reimbursable out-of-pocket costs or other charges due hereunder shall be
invoiced monthly and paid by Customer within thirty (30) days from date of
invoice.

(d)      LATE CHARGES. Customer may not withhold or "setoff" any amounts due
hereunder and ACE*COMM reserves the right to assert appropriate liens to ensure
payment. Any late payment shall be subject to costs of collection (including
reasonable attorneys' fees) and shall bear interest at the rate of one and one
half percent (1-1/2%) per month or fraction thereof until paid.

6.       PROPRIETARY RIGHTS.

(a)      RIGHTS IN DATA. ACE*COMM agrees that all Data received, computed,
developed, used or stored pursuant to this Agreement shall remain the
exclusive property of the Customer and that immediately upon termination of
this Agreement, all such Data shall be furnished to Customer in machine,
readable form without additional charge, except for reasonable processing,
material and labor costs, provided Customer is current in its payment of all
amounts due hereunder. ACE*COMM further agrees that the Data will be used
only for the purposes expressly contemplated by this agreement and for no
other purpose.

(b)      RIGHTS IN SOFTWARE. All software of third party vendors (other than
ACE*COMM) supplied by ACE*COMM shall be governed by the terms and conditions of
the original vendor license agreement accompanying such software or, if no such
license agreement is included, by the vender's standard license terms generally
applicable to the particular product provided such terms are typical and
ordinary and, in all cases, do not impose any obligations upon the Customer in
addition to the Customer's obligations as set forth in this Agreement. Upon
payment of all fees associated thereto, the Customer is hereby granted the
nonexclusive right and license to use, execute and copy all software supplied by
ACE*COMM in object code form as an integral part of obtaining the Processing
Services and for no other purpose. Except as Provided by Section 19
("Assignment, Transfer"), Customer may not assign, transfer or sublicense this
license without ACE*COMM's prior written consent (which consent shall not be
unreasonably withheld) and any attempt to the contrary shall be void. With
respect to the Customer-supplied software, ACE*COMM is hereby granted the
nonexclusive right and license to use such software in the same form(s) provided
by Customer for use in providing the Processing Services and for no other


                                                                        Page 6
<PAGE>


purpose. ACE*COMM may not assign, transfer or sublicense this license without
the Customer's prior written consent (which consent shall not be unreasonably
withheld) and any attempt to the contrary shall be void. Unless otherwise agreed
in writing, any specially ordered software or modifications developed by
ACE*COMM at Customer's request shall be owned exclusively by ACE*COMM and
Customer shall receive a nonexclusive license conferring rights and obligations
equivalent to those provided for other ACE*COMM-supplied software, as described
in the second sentence of this Subsection.

7.       CONFIDENTIAL INFORMATION.

(a)      ACKNOWLEDGMENT OF CONFIDENTIALITY. Each party hereby acknowledges
that it may be exposed to confidential information belonging to or supplied
by the other party or relating to its affairs including, without limitation,
the Data, software, business plans and procedures, the terms of this
Agreement, the Customer Guide, and other information that may be marked as
confidential ("Confidential Information"). Confidential Information does not
include (i) information already known or independently developed by the
recipient outside the scope of this project; (ii) information in the public
domain through no wrongful act of the recipient, or (iii) information
received by the recipient from a third party who was free to disclose it.

(b)      COVENANT NOT TO DISCLOSE. With respect to the other party's
Confidential Information, and except as expressly authorized herein or as
required by a court of competent jurisdiction, the recipient hereby agrees
that during the Term hereof and at all times thereafter it shall not use,
commercialize or disclose such Confidential Information to any person or
entity, except to its own employees having a "need to know" (and who are
themselves bound by similar nondisclosure restrictions) and to such other
recipients as the other party may approve in writing. In no event shall
either party attempt to decompile, disassemble or reverse engineer the other
party's confidential or proprietary information and any information
discovered in violation of this provision shall be treated as Confidential
Information belonging exclusively to the other party. Each party shall use at
least the same degree of care in safeguarding the other party's Confidential
Information as it uses in safeguarding its own confidential information, but
in no event shall less than due diligence and care be exercised. ACE*COMM
shall not make use of any of the information received from the Customer for
any purpose not expressly contemplated by this Agreement. If requested by the
Customer, ACE*COMM's Personnel who are assigned to work on the Customer's
projects shall execute a document satisfactory to the Customer acknowledging
and agreeing to be bound by the terms of this Section 7 ("Confidential
Information").

(c)      NORMAL USE. Except as otherwise Specifically set forth in Section 6,
nothing in this Section 7 shall be deemed to restrict the Customer from using
any of the Customer's Data or any deliverable in the ordinary course of its
business it being understood that many employees, subcontractors and others
will use the Confidential Information in completing their duties for the
Customer and that it may become necessary for the Customer to interface
Confidential Information constituting software to other systems utilized by
the Customer, its customers, its suppliers, and its consultants.

8.       NONSOLICITATION. During the Term and for a period of one (1) year
         thereafter, each party


                                                                        Page 7
<PAGE>


         agrees not to solicit, nor attempt to solicit, the services of any
         employee of the other party without the prior written consent of the
         other party. If this provision is violated, the violating party shall,
         pay liquidated damages equal to one hundred fifty (150) percent of
         the Solicited person's annual compensation; provided that upon making
         such payment, the violating party shall not be in breach of this
         Agreement.

9.       INJUNCTIVE RELIEF; The parties acknowledge that violation by one party
         of the provisions of Section 6 ("Proprietary Rights"), Section 7
         ("Confidential Information") or Section 8 ("Nonsolicitation") would
         cause irreparable harm to the other Party not adequately compensable by
         monetary damages. In addition to other relief, it is agreed that
         temporary and permanent injunctive relief would be an appropriate
         remedy to prevent any actual or threatened violation of such provisions
         or to enforce such provisions according to their terms. Any party
         substantially prevailing in an action for injunctive relief under this
         Section 9 shall be entitled to recover its costs of enforcement,
         including reasonable attorneys' fees.

10.      WARRANTIES.

(a)      NONINFRINGEMENT WARRANTY. Each party (the "Indemnitor") represents and
warrants that the Data and any software supplied by it in accordance with
Section 1(d) ("Software"), when properly used as contemplated herein, will not
infringe or misappropriate any United States copyright, trademark, patent, or
the trade secrets of any third persons and will defend, indemnify and hold
harmless the other party (the "Indemnitee") from all damages, costs and expenses
(including reasonable attorneys' fees) incurred as a result of any third party
claim to the contrary. Upon being notified of such a claim, the Indemnitor shall
(i) defend through litigation or obtain through negotiation the right of
Indemnitee to continue using the Data or software; (ii) purge the Data of
tainted material or rework the software so as to make it noninfringing while
preserving the original functionality; or (iii) replace the software with
functionally equivalent software. If the Indemnitee reasonably determines that
none of the foregoing alternatives provide an adequate remedy, the Indemnitee
may, in addition to other relief, terminate all or any part of this Agreement.

(b)      LIMITED PERFORMANCE WARRANTY. ACE*COMM represents and warrants that
it shall make its best effort to ensure that the Processing Services are
compatible with industry standards and practices, including year 2000
compliance, are free from malfunctions, errors or loss of Data, achieve the
Performance Goals described in Section 2(d) ("Performance Goals"). However,
ACE*COMM does not represent or warrant that the Processing Services will be
entirely free from error or defect or that it will actually achieve the
Performance Goals. The foregoing warranty shall apply only if: (i) Customer
follows all operational instructions contained in the most current Customer
Guide; (ii) Customer notifies ACE*COMM of errors or defects within a
reasonable time after the appearance thereof; (iii) Customer has (to the
extent Customer bears responsibility under another provision of this
Agreement) provided and maintained adequate Remote Access Equipment,
software, the Communications System and environmental conditions in
accordance with applicable specifications and industry standards; (iv)
Customer has not introduced other equipment, software or unusual workloads
creating a materially adverse impact on the Processing Services or the
ACE*COMM's ability to achieve the Performance Goals; and


                                                                        Page 8
<PAGE>


(v) Customer has paid all amounts due hereunder and is not in default of any
material provision of this Agreement. Customer is solely responsible for the
adequacy and accuracy of all Data.

(c)      WARRANTY RESPONSE. Upon being notified by the Customer or otherwise
obtaining knowledge of a malfunction, error, or defect of the Processing
Services ACE*COMM shall respond within a reasonable time as stated within the
Processing Services Schedule (but not later than 12 hours of elapsed time), by
telephone support or through the issuance of periodic updates to acknowledge the
malfunction, error, or defect and, with the cooperation of the Customer, shall
promptly commence diagnosis and error correction efforts and shall use all
reasonable efforts to correct such problem before the subsequent billing cycle
commences.

(d)      WARRANTY DISCLAIMER. EXCEPT AS SPECIFICALLY, PROVIDED IN THIS.
SECTION 10 "WARRANTIES") ACE*COMM HEREBY DISCLAIMS WITH RESPECT TO ALL
PROCESSING OR OTHER SERVICES, EQUIPMENT, SOFTWARE, OR DELIVERABLES PROVIDED
HEREUNDER, ALL EXPRESS AND IMPLIED WARRANTIES, INCLUDING ANY IMPLIED
WARRANTIES OF MERCHANTABILITY, TITLE OR FITNESS FOR A PARTICULAR PURPOSE.

11.      LIMITATION OF REMEDIES & LIABILITIES. The parties acknowledge that the
         following provisions have been negotiated by them and reflect a fair
         allocation of risk:

(a)      REMEDIES. Except for certain injunctive relief authorized under
Section 9 ("Injunctive Relief"), Customer's sole and exclusive remedies for
ACE*COMM's default hereunder shall be to obtain repair, replacement or
correction of the defective services, software, equipment or deliverable to
the extent warranted under Section 10 ("Warranties") which, in the case of
Processing Services, means ACE*COMM shall at its own expense reinput the Data
or rerun the programs containing the error. If such remedy is not
economically or technically feasible or effective, then Customer may obtain
an equitable partial or full credit or refund of amounts paid with respect to
the defective services or deliverable, subject to the limitation set forth in
Subsection (b) below.

(b)      LIABILITIES. EXCEPT FOR DAMAGES ARISING FROM BODILY INJURY CAUSED
SOLELY BY THE NEGLIGENCE OF ACE*COMM, DAMAGES COVERED BY THE INDEMNIFICATION
AUTHORIZED UNDER SECTION 10(a) ("NONINFRINGEMENT WARRANTY"), DAMAGES ARISING
OUT OF AN INFRINGEMENT OF PROPRIETARY RIGHTS OR DISCLOSURE OF CONFIDENTIAL
INFORMATION, AMOUNTS DUE PURSUANT TO SUBSECTION 4(e) ("CERTAIN PRICE
CREDITS") AND ANY INJUNCTIVE RELIEF AUTHORIZED PURSUANT TO THIS AGREEMENT,
ACE*COMM SHALL NOT BE LIABLE FOR ANY AMOUNT EXCEEDING THE AMOUNT PAID BY
CUSTOMER UNDER THE CONTRACT DURING THE ONE (1) YEAR PRIOR TO THE EVENT GIVING
RISE TO THE ALLEGED CLAIM. NEITHER PARTY SHALL BE LIABLE TO THE OTHER PARTY
OR ANY THIRD PARTY, WHETHER IN CONTRACT, TORT (INCLUDING NEGLIGENCE) OR
OTHERWISE, FOR ANY INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING
LOST PROFIT OR BUSINESS INTERRUPTION EVEN IF NOTIFIED IN ADVANCE OF SUCH
POSSIBILITY) ARISING OUT OF OR PERTAINING TO THE SUBJECT MATTER OF THIS
AGREEMENT.


                                                                        Page 9
<PAGE>


12.      NOTICES. Notices sent to either party shall be effective when delivered
         in person or transmitted by telecopier ("fax") machine, one (1) day
         after being sent by overnight courier, or two (2) days after being sent
         by first-class mail postage prepaid to the addresses set forth below,
         or to such other address as the parties may from time to time give
         notice:


         CUSTOMER ADDRESS:                         ACE*COMM ADDRESS
         -----------------                         ----------------

         LOGIX Communications Corporation, a       Dr. Thomas V. Russotto
         subsidiary of Dobson Wireline Company     Vice President
         Mr. Stephen Dobson                        ACE*COMM Corporation
         13439 North Broadway Extension            704 Quince Orchard Road
         Oklahoma City, OK 73114                   Gaithersburg, MD 20878

13.      FAX COUNTERPARTS. A facsimile of this Agreement and notices generated
         in good form by a fax machine (as well as a photocopy thereof) shall be
         treated as "original" documents admissible into evidence unless a
         document's authenticity is genuinely placed in question.

14.      DEFAULT. Either party shall be in default of this Agreement if: (i) it
         breaches any material provision hereof and fails within ten (10) days
         after receipt of notice of default to correct such default or to
         commence corrective action reasonably acceptable to the aggrieved party
         and proceed with due diligence to completion, or (ii) it becomes
         insolvent, makes an assignment for the benefit of its creditors, a
         receiver is appointed or a petition in Bankruptcy is filed with respect
         to the party and is not dismissed within thirty (30) days.

15.      ARBITRATION, CHOICE OF LAW. Except for certain injunctive relief
         authorized under Section 9 ("Injunctive Relief"), which may be sought
         at any time, any dispute between the parties arising out of or relating
         to this Agreement or a breach hereof which dispute is not resolved
         within 10 days after receipt of notice by the allegedly breaching
         party, such dispute shall immediately be referred for resolution
         jointly by senior executives of the parties who are authorized to
         negotiate a resolution to such dispute. If such individuals are unable
         to agree upon a resolution within 20 days after referral of such
         dispute to them (such 20 day period together with the preceding 10 day
         period being referred to as the "RESOLUTION PERIOD;" provided, however,
         that the Resolution period shall in no event be less than 30 days),
         then either party may, upon notice to the other party pursuant to
         Section 12, refer the dispute for final, binding arbitration to
         J.A.M.S./Endispute or its successor organization for arbitration before
         a panel of three arbitrators (with each party choosing one arbitrator
         and the third arbitrator being chosen by the first two arbitrators) in
         Washington DC. Such arbitration shall be conducted under the
         administrative rules of J.A.M.S./Endispute; provided, however, that in
         the event of any conflict between such administrative rules and this
         Section 15, the provisions of this Section 15 shall govern. Each party
         shall bear its own coats and attorneys' fees with respect to such
         arbitration. The award of the arbitrators shall include a written
         explanation of their decision. The parties hereby agree that
         arbitration before J.A.M.S./Endispute pursuant to this Section 15


                                                                       Page 10
<PAGE>

         shall be the Parties' exclusive remedy and that the arbitration
         decision and award, if any, shall be final, binding upon, and
         enforceable against, the parties, and may be confirmed by the
         judgment of a court of competent jurisdiction. THIS AGREEMENT SHALL
         BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE SUBSTANTIVE LAWS
         OF TEXAS, AND ANY PROCEEDING SHALL BE INITIATED AND MAINTAINED IN
         SUCH STATE.

16.      INDEPENDENT CONTRACTOR STATUS. Each, Party and its people are
         independent contractors in relation to the other party with respect to
         all matters arising under this Agreement. Nothing herein shall be
         deemed, to establish a partnership, joint venture, association or
         employment relationship between the parties. Each party shall remain
         responsible, and shall indemnify and hold harmless the other party, for
         the withholding and payment of all Federal, state and local personal
         income, wage, earnings, occupation, social security, worker's
         compensation, unemployment, sickness, and disability insurance taxes,
         payroll levies or employee benefit requirement (under ERISA, state law
         or otherwise) now existing or hereafter enacted and attributable to
         themselves and their respective people.

17.      SECURITY, NO CONFLICTS. Each party agrees to inform the other of any
         information made available to the other party that is classified or
         restricted data, agrees to comply with the security requirements;
         imposed by any state or local government, or by the United States
         Government, and shall return all such material upon request. Each party
         warrants that its participation in this Agreement does not conflict
         with any contractual or other obligation of the party or create any
         conflict of interest prohibited by the U.S. Government or any other
         government and shall promptly notify the other party if any such
         conflict arises during the Term.

18.      INSURANCE INDEMNITY. Each party shall maintain adequate Insurance
         protection covering its respective activities hereunder, including
         coverage for statutory worker's compensation, comprehensive, general
         liability for bodily injury and tangible property damage, as well as
         adequate coverage for vehicles. Each party shall indemnify and hold the
         other harmless from liability for bodily injury, death and tangible
         property damage resulting from the acts or omissions of its officers,
         agents, employees or representatives acting within the scope of their
         work. The parties agree that they mutually wave any and all rights of
         subrogation; against the other party.

19.      ASSIGNMENT, TRANSFER. The Customer reserves the right to transfer or
         assign this Agreement, including the licenses granted hereunder, to any
         parent, subsidiary or other affiliate controlled by any of the
         foregoing (where "control" for purposes of this Section 19 means a 50%
         ownership interest); provided, however, that if such transfer or
         assignment by the Customer is done as part of a public offering of
         securities by the Customer, by an entity that directly or indirectly
         controls the Customer, or by an entity directly or indirectly
         controlled by the Customer, then the Customer shall provide written
         notice to ACE*COMM of such transfer or assignment, but ACE*COMM's
         consent to such transfer or assignment shall not be required. ACE*COMM
         shall not transfer, assign, subcontract or delegate its rights,
         licenses and obligations under this Agreement without the Customer's
         prior written consent (which consent shall not be unreasonably
         withheld)


                                                                       Page 11
<PAGE>


         and any attempt to the contrary shall be void. This Agreement is
         binding upon and is enforceable by the parties and their authorized
         successors and assigns. Except as otherwise provided in this Section
         19, neither party may assign this Agreement or any of its rights or
         obligations hereunder without the written consent of the other party
         and any attempt to do so shall be void and of no legal effect. In
         any permitted transfer, assignment or subcontracting of this
         Agreement, the transferring, assigning or subcontracting party shall
         remain liable and responsible for all transferred, assigned or
         subcontracted rights and obligations.

20.      FORCE MAJEURE. Excluding any of the Customer's payment obligations
         under this agreement, neither party shall be liable for delays or
         failure to perform as a direct result of causes beyond its reasonable
         control, including Acts of God (fire, storm, floods, earthquakes,
         etc.), civil disturbances or disruption of telecommunications or other
         essential services, or inability to use any third party-supplied
         software for the purposes contemplated herein.

21.      COMPLIANCE WITH EXPERT REGULATIONS.  Customer shall obtain in a timely
         manner all necessary or appropriate licenses, permits or other
         governmental authorizations or approvals and shall comply with all
         foreign or domestic laws, regulations or requirements pertaining to the
         importation, exportation, or use of the Processing Services, software,
         equipment, technology or Data to be provided herein. Absent such
         governmental authorization, the Customer shall not directly or
         indirectly export or re-export any such Processing Services, software,
         equipment, technology or Data to Afghanistan, the People's Republic of
         China or any Group Q.S.W.Y or Z country specified in Supplement 1 to
         Part 770 of the U.S. Export Administration Regulations. This provision
         and the assurances made herein shall survive termination of this
         Agreement.

22.      MISCELLANEOUS. This document and the accompanying Schedules, which are
         hereby incorporated by reference in its entirety, constitute the entire
         agreement between the parties with respect to the subject
         matter hereof and supersede all other communications, whether written
         or oral. This Agreement may be modified or amended only by a writing
         signed by the party against whom enforcement is sought. Any provision
         hereof found by a tribunal of competent jurisdiction to be illegal or
         unenforceable shall be automatically conformed to the minimum
         requirements of law and all other provisions shall remain in full force
         and effect. Waiver of any provision hereof in one instance shall not
         preclude enforcement thereof on future occasions. Headings are for
         reference purposes only and have no substantive effect.


                                                                       Page 12
<PAGE>


         IN WITNESS WHEREOF, and intending to be legally bound, the parties
hereto have caused this Agreement to be executed by their duly authorized
representatives.


LOGIX COMMUNICATIONS                             ACE*COMM CORPORATION
CORPORATION

A subsidiary of Dobson Wireline Company          By: /s/ THOMAS V. RUSSOTTO
                                                    ---------------------------

By: /s/ WILLIAM HOFFMAN                          Name:   THOMAS V. RUSSOTTO
   -----------------------------------                -------------------------

Name:   WILLIAM HOFFMAN                          Title:  VICE PRESIDENT
     ---------------------------------                 ------------------------

Title: CHIEF OPERATING OFFICER                   Date:      6/30/98
      --------------------------------                -------------------------

Date:        6/30/98
     ---------------------------------



                                                                       Page 13
<PAGE>

SCHEDULE OF REMOTE ACCESS EQUIPMENT

Subpart A. Supplied by ACE*COMM

            None identified at this time.


Subpart B. Supplied at this time.

            None identified at this time.



SCHEDULE OF EMPLOYEES


         COMPANY               POSITION                           NAME
         -------               --------                           ----

         ACE*COMM              Coordinator
                               Account Manager
         Customer              Point of Contact


SCHEDULE OF SOFTWARE

Subpart A. Standard Library of Software
ACE*COMM shall provide data center operations software as required to support
the Schedule of Processing Services (the "Standard Library of Software").
Operations software includes data processing support software such as tape
logging, bulk file transfer within ACE*COMM, database software for ACE*COMM
computers, applications/reports for transaction count verification etc.

Subpart B. Software Subject to a Surcharge
ACE*COMM shall also provide any third-party product as required to support the
Schedule of Processing Services (the "Software Subject to a Surcharge") at the
price indicated in the Schedule of Prices.


SCHEDULE OF APPLICATION SERVICES

Per document number T98JMT0786, REV. 2; Rev. 2 which may be modified from
time to time as mutually agreed by the parties.


                                                                     Page 14
<PAGE>

SCHEDULE OF PRICES

Per document number T98.JMT.0676, Rev. 2 Statement of Work/Pricing

Software Subject to a Surcharge: Customer Approved Software at Cost Plus 30%


Billable Transactions


Call Processing and Bill Invoicing Charges charged against $12,500 process
minimum

<TABLE>
<CAPTION>
                    ITEM                  DESCRIPTION
                    ----                  -----------
         <S>                              <C>                  <C>                       <C>

             Monthly CDR Volume           Price
         0-1,000,000                        $   0.008000
         1,000,001-3,000,000                $   0.007500
         3,000,001-5,000,000                $   0.007000
         5,000,001-10,000,000               $   0.006000
         10,000,001-15,000,000              $   0.005500
         15,000,001-25,000,000              $   0.005000
         25,000,001-50,000,000              $   0.004500
         50,000,001-100,000,000             $   0.004250
         100,000,001+                       $   0.004000

                                 INVOICE * CHARGES             MISC PROCESSING

         ITEM                                   PRICE          Tape Handling Charge      $20 In/Out
         Summary Page                       $      0.450
         Additional Page (B&W)              $      0.055       Tapes at Cost
                                                               Mail transport at Cost
                                                               Transmission/Network at Cost


         CDR                                      PRICE
         (AMA,EMI/EMR,CARE ETC.)
         OUTPUT
         Diskette                                  50.00
         CD                                        50.00
         Magnetic Cartridge                       125.00
</TABLE>

NOTE: MONTHLY MINIMUM OF $1.50 PLUS POSTAGE PER STATEMENT. POSTAGE IS NOT
INCLUDED IN THE MONTHLY MINIMUM.


                                                                     Page 15
<PAGE>


TRANSPORTATION CHARGES

As required at cost plus 10%

OTHER CHARGES

ACE*COMM Supplied Equipment as required plus 30%

Customer Supplied Equipment Plus 10%

Software and integration cost plus 30%

TERMINATION FEE

Total remaining Minimum Monthly Service Fees plus the Migration Fee, if any. The
Migration Fee shall be calculated in accordance with the following rates:

<TABLE>
<CAPTION>

     LABOR CATEGORY                 HOURLY RATE YEAR 1      HOURLY RATE YEAR 2-4
     --------------                 ------------------      --------------------
     <S>                            <C>                     <C>
     DATA PROCESSING PERSONNEL                              Current proposed standard
     Operations Project Manager     $100.00                 rates for data processing
     Operations Staff               $ 60.00                 services

     SYSTEMS PERSONNEL                                      Current proposed standard
     Project Manager                $ 150.00                rates for data processing
     Engineering Staff              $ 120.00                services
</TABLE>



                                                                     Page 16
<PAGE>

                         SCHEDULE OF PROCESSING SERVICES

The following represents the Processing Services referred to in Section 1(a)
("Computer Processing Services"):

1. OPERATIONS SUPPORT.

      (a) PRODUCTION. ACE*COMM shall monitor, schedule, or otherwise initiate
          batch jobs on behalf of the Customer as shown in the following
          Billing Data Processing Responsibility Matrix. Summary Reports and
          logs will be reviewed and the Customer will be notified of any
          problems.

      (b) PRODUCTION BATCH. Unless otherwise agreed in writing, the Customer's
          schedule for batch jobs will be the same schedule in existence prior
          to implementation of ACE*COMM processing or if none is in existence,
          as mutually agreed per Data Center Services Guide, as mutually
          agreed. Where input is required from the Customer for job scheduling
          functions, such input from Customer will be forwarded to ACE*COMM in
          hard copy form or via facsimile in a timely manner as scheduled.
          ACE*COMM reserves the right to automate the manual initiation of
          batch jobs where possible. ACE*COMM operators will notify the
          Customer of abnormal job termination and perform job reruns and
          restarts under established guidelines directed and approved by
          Customer.
          The Customer will review end-of-cycle reports and status and
          authorize close of each billing cycle in writing. Such authorization
          will be forwarded to ACE*COMM via facsimile or E-mail.
          Data Processing requirements for Access Billing have not yet been
          defined.
          ACE*COMM Data Center services rendered to support this function will
          be priced separately.
          The attached BILLING DATA PROCESSING RESPONSIBILITY MATRIX provides
          the specific run time activities.

      (c) CUSTOMER SERVER SYSTEM ADMINISTRATION. Per Responsibility Matrix,
          ACE*COMM shall address the following system administrator functions
          for the Customer NetPlus server within the Data Processing Services
          Guide:

                (I)    Maintain Network Configuration Files
               (II)    Maintain Netplus Configuration File
              (III)    Server Maintenance to include coordinating shutting down
                       and booting the server.
               (IV)    User Maintenance
                (V)    Maintain Access Control of Server Applications
               (VI)    Maintain Background Jobs
              (VII)    Monitor System Logs
             (VIII)    Maintain NetPlus Environment Variables
               (IX)    Database Management to include Starting and Stopping
                       ORACLE, mounting, dismounting the ORACLE database,
                       monitoring real-time use and performance of the ORACLE
                       database, and performing

                                                                     Page 17

<PAGE>

                       backup and recovery of database logs and data.
                (X)    Disk Management to include allocation and reallocation
                       of permanent, temporary, and work data sets, data
                       compression, data purging, and other required tasks.
                       Customer retains responsibility for network
                       administration and client workstation administration.

      (d) SUBSCRIBER INVOICES.  ACE*COMM shall perform printing, packaging, and
          mailing of the Customer invoices. Subscriber invoices will be
          printed two-sided on pre-printed 8 1/2" by 11" paper stock. The first
          page of each invoice shall be perforated with a logo banner
          pre-printed at the top of the page. The first page of each invoice
          section shall have a logo banner and a colored box for insert of the
          section title preprinted at the top of the page. The continuation
          pages of each section shall have only a logo banner pre-printed at
          the top of the page. Subscriber invoices shall be packaged unbound.
          ACE*COMM shall purchase from Customer approved vendors sufficient
          pre-printed paper stock, mailing envelopes, return envelopes, and
          magnetic media to support each bill run. The Customer is responsible
          for providing a camera-ready image of the logo banner to be printed
          on the pre-printed paper. Magnetic media shall include diskette,
          9-track tape, and CDROM. ACE*COMM reserves the right to outsource
          the printing, packaging, and mailing. Any customer requirements
          outside of this standard will be priced separately.

      (e) OUTGOING TAPE GENERATION. ACE*COMM shall perform all outgoing tape
          and other external media processing functions, including mounts and
          dismounts, and logging the tape generation and tape shipment to
          third parties.

      (f) EXTERNAL MEDIA MANAGEMENT. ACE*COMM shall perform all tape and other
          external media processing functions, including logging receipt and
          shipment, mounts, dismounts, on-site storage and off-site vaulting
          of tapes and other external media received from third parties for
          Customer processing. All such tapes and external media will be
          stored in a physically secured environment at the ACE*COMM Data
          Center. Processed tapes and external media will be archived to
          off-site vaulting on a weekly basis. The Customer will provide
          ACE*COMM with written instructions for retention of tapes in
          off-site vaulting.

      (g) CUSTOMER SERVER SYSTEM BACKUP AND RESTORE. ACE*COMM shall perform a
          weekly backup of the Customer NetPlus server database and data files
          to magnetic tape and a full backup of the NetPlus server monthly.
          The Customer shall provide for mounting and dismounting of tapes and
          shipment of monthly tapes to ACE*COMM for off-site vault archiving,
          All backup tape receipts and distributions will be logged. All
          backup and recovery operations will be coordinated with customer.
          Customer retains responsibility for client workstation backup and
          restore.

      (h) CUSTOMER DISASTER RECOVERY. ACE*COMM shall provide disaster recovery
          support for the Customer in the event of a catastrophe, ACE*COMM
          will make available

                                                                     Page 18

<PAGE>

          resources, including space, operations staff, and operations
          equipment at a cost to be determined when and if such support is
          required.

      (i) DATA CENTER ENVIRONMENT. ACE*COMM shall provide a secure processing
          environment for data center facilities. ACE*COMM shall provide
          secured access to operations equipment. Systems used for Customer
          processing shall be provided with a UPS system for system operation
          for not less than one hour for all data center equipment used in
          support of service level agreements.

      (j) DATA CENTER PROCESS CONTROL. ACE*COMM shall provide for logging of
          all processing tasks performed with reports each month to the
          Customer. This activity will provide the basis for billing/invoicing
          the Customer for services rendered under this contract. ACE*COMM and
          the Customer will establish-logging and monthly criteria prior to
          the commencement of operations for the Customer.

      (k) CUSTOMER SERVER STARTUP/SHUTDOWN. ACE*COMM will control the startup
          and shutdown of all NetPlus Server processing functions at the
          direction of Customer. ACE*COMM will notify Customer's users of any
          unscheduled startup or shutdown of server processing.

      (l) CUSTOMER SYSTEM AND SUBSYSTEM MONITORING AND MANAGEMENT. ACE*COMM
          will be responsible for installing, maintaining, and administering
          all system or subsystem level monitoring and management software.
          Customer retains responsibility for any application level monitoring
          and management such as database transaction logging to allow
          database restore.

      (m) CUSTOMER SYSTEM UPGRADES. Customer hardware and software upgrades
          shall be coordinated with ACE*COMM to ensure compatibility of
          operations between the Customer Site and the Data Center.

      (n) PRIORITIES. Customer will determine the task priorities for both
          batch and online processing services. ACE*COMM will administer
          services provided according to Customer priorities.

      (o) HELP DESK. ACE*COMM will provide the following Help Desk services:

            (i)   Customer will initiate trouble reports through its designated
                  representative(s) by contacting the Help Desk at the
                  telephone number listed in the Customer Guide;

            (ii)  ACE*COMM will log and classify all reported problems.
                  ACE*COMM will address all reported problems regarding
                  network and system availability, response time, terminal and
                  printer resets and any other such problem reasonably
                  classified by ACE*COMM as system related. ACE*COMM will
                  enlist Customer's information services staff when necessary
                  to assist in the resolution of these problems. For both
                  online and

                                                                     Page 19

<PAGE>

                  batch application problems, ACE*COMM will contact the
                  designated Customer personnel for resolution of such
                  application related problems. If the designated Customer
                  personnel are not available, the parties shall follow the
                  "escalation procedures" set forth in the Customer Guide;

            (iii) Terminal and printer hardware problems and any problems
                  related to Customer's applications will be forwarded to
                  Customer's operations or applications staff. If ACE*COMM
                  cannot contact the appropriate Customer personnel, the
                  parties shall follow the "escalation procedures" set forth
                  in the Customer Guide.

            (iv)  All reported problems will be entered into a shared problem
                  database accessible only by the Customer and the ACE*COMM
                  Data Center's operations and technical services staff. The
                  shared database will allow both ACE*COMM and the Customer to
                  track the resolution of reported problems.


      p. Additional Services.
            (i)   Professional Services. Any professional services specifically
      requested and approved in writing by the Customer will be billed at the
      ACE*COMM Data Center's then current proposed rates for such services.
      ACE*COMM will bill the Customer for its reasonable out-of-pocket expenses
      incurred in connection with providing professional services to the
      Customer.
            (ii)  Other Services. Additional hardware, software,
      telecommunications, travel or other services or deliverables beyond the
      scope of activities contemplated in this Schedule and which have been
      requested and approved by the Customer, will be billed separately by the
      ACE*COMM Data Center.






                                                                     Page 20
<PAGE>

                               BILLING DATA PROCESSING RESPONSIBILITY MATRIX

<TABLE>
<CAPTION>

==============================================================================================================
TASK                             RESPONSIBLE              PROCESSING            FREQUENCY            QUANTITY
                                                          LOCATION
--------------------------------------------------------------------------------------------------------------
<S>                              <C>                      <C>                   <C>                  <C>
Maintain Account Classes         Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain General Ledger Codes    Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Transaction Codes       Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Accounts                Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Change/Merge Accounts            Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Define Billing Hierarchy         Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Display Account Balances         Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Account Report          Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Account Roll-Up Report  Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Account Equipment       Customer                 Customer              As                   As
Summary Report                                                                  Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Tax Schemes             Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Associate Tax Schemes with       Customer                 Customer              As                   As
Accounts, Item Codes, or                                                        Required             Required
Transaction Types
--------------------------------------------------------------------------------------------------------------
Maintain Payments/Credits and    Customer                 Customer              As                   As
Supplemental Charge                                                             Required             Required
Transactions
--------------------------------------------------------------------------------------------------------------
Display Account Transactions     Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Account Activity        Customer                 Customer              As                   As
Report                                                                          Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Transaction Summary     Customer                 Customer              As                   As
Report                                                                          Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Transaction Detail      Customer                 Customer              As                   As
Report                                                                          Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain the Flat Rate Table     Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Dialing Plans           Customer                 Customer              As                   As
                                                                                Required             Required
==============================================================================================================

                                                                         Page 21

<PAGE>

==============================================================================================================
Load  Rate Tables                Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Time Period Tables      Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Currency Conversion     Customer                 Customer              As                   As
Rates                                                                           Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain From-Telephone Number   Customer                 Customer              As                   As
Translations                                                                    Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Country Rates           Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Polling Control         ACE*COMM                 Customer              As                   As
Parameters                                                                      Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Polling Jobs            ACE*COMM                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Show Polling Job Status          ACE*COMM                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Start Polling Jobs               ACE*COMM                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Stop Polling Jobs                ACE*COMM                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Polling Log       ACE*COMM                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Display the Polling Activity     ACE*COMM                 Customer              As                   As
Log                                                                             Required             Required
--------------------------------------------------------------------------------------------------------------
Delete the Polling Activity      ACE*COMM                 Customer              As                   As
Log                                                                             Required             Required
--------------------------------------------------------------------------------------------------------------
Display/Print the Rating         ACE*COMM                 Customer              As                   As
Log for Polling Activity                                                        Required             Required
--------------------------------------------------------------------------------------------------------------
Maintain Call Detail Records     Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Correct Rejected Call Records    Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------
Generate the Rejected Call       Customer                 Customer              As                   As
Record Reports                                                                  Required             Required
--------------------------------------------------------------------------------------------------------------
Recycle Rejected Calls           ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Generate Station Message Detail  Customer                 Customer              As                   As
Reports                                                                         Required             Required
--------------------------------------------------------------------------------------------------------------
Rate Calls Interactively         Customer                 Customer              As                   As
                                                                                Required             Required
--------------------------------------------------------------------------------------------------------------

==============================================================================================================

                                                                         Page 22

<PAGE>

==============================================================================================================
TASK                             RESPONSIBLE              PROCESSING            FREQUENCY            QUANTITY
                                                          LOCATION
--------------------------------------------------------------------------------------------------------------
Maintain Electronic Media Jobs   ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load Internet Usage Media        ACE*COMM                 Data                  As                   As
and Rate                                                  Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Internet Usage    ACE*COMM                 Data                  As                   As
Media Log                                                 Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Rating Log for    ACE*COMM                 Data                  As                   As
Internet Usage                                            Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load IXC Tape and Rate           ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the IXC Tape Log      ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Rating Log for    ACE*COMM                 Data                  As                   As
IXC                                                       Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load ILEC EMR Tape and Rate      ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the ILEC EMR Tape     ACE*COMM                 Data                  As                   As
Log                                                       Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Rating Log for    ACE*COMM                 Data                  As                   As
ILEC EMR                                                  Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load ILEC AMA Tape and Rate      ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the ILEC AMA Tape     ACE*COMM                 Data                  As                   As
Log                                                       Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Rating Log for    ACE*COMM                 Data                  As                   As
ILEC AMA                                                  Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load ILEC Tape and Rate          ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the ILEC Tape Log     ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Rating Log for    ACE*COMM                 Data                  As                   As
ILEC                                                      Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load DS1 Usage Media and Rate    ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the DS1 Usage Media   ACE*COMM                 Data                  As                   As
Log                                                       Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Rating Log for    ACE*COMM                 Data                  As                   As
DS1                                                       Center                Required             Required
--------------------------------------------------------------------------------------------------------------
Load Media and Rate              ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
--------------------------------------------------------------------------------------------------------------
View/Print the Media Log         ACE*COMM                 Data                  As                   As
                                                          Center                Required             Required
==============================================================================================================
</TABLE>

                                                                         Page 23

<PAGE>

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------
TASK                                   RESPONSIBLE      LOCATION    FREQUENCY    QUANTITY
----------------------------------------------------------------------------------------------
<S>                                    <C>              <C>         <C>          <C>
View/Print the Rating Log              ACE*COMM         Data        As           As Required
                                                        Center      Required
----------------------------------------------------------------------------------------------
Load Usage Media and Rate              ACE*COMM         Data        As           As Required
                                                        Center      Required
----------------------------------------------------------------------------------------------
View/Print the Usage Media Log         ACE*COMM         Data        As
                                                        Center      Required     As Required
----------------------------------------------------------------------------------------------
View/Print the Rating Log for Usage    ACE*COMM         Data        As
                                                        Center      Required     As Required
----------------------------------------------------------------------------------------------
Load EMR Tape and Rate                 ACE*COMM         Data        As
                                                        Center      Required     As Required
----------------------------------------------------------------------------------------------
View/Print Tape Log                    ACE*COMM         Data        As
                                                        Center      Required     As Required
----------------------------------------------------------------------------------------------
View/Print the Rating Log              ACE*COMM         Data        As
                                                        Center      Required     As Required
----------------------------------------------------------------------------------------------
Generate CMDS Tape                     ACE*COMM         Data        monthly      1 tape
                                                        Center
----------------------------------------------------------------------------------------------
Generate OUTCOLLECT Tapes              ACE*COMM         Data        monthly      1 tape
                                                        Center
----------------------------------------------------------------------------------------------
Generate CABS Tapes                    ACE*COMM         Data        monthly      1 tape
                                                        Center
----------------------------------------------------------------------------------------------
Generate Invoices for Carriers                                      monthly      As Required
----------------------------------------------------------------------------------------------
Load Rate Tapes                        ACE*COMM         Data        monthly      1 tape
                                                        Center
                                                        Customer
----------------------------------------------------------------------------------------------
Update the Billing Cycle               ACE*COMM         Customer    As           As Required
                                                                    Required
----------------------------------------------------------------------------------------------
Customize the Billing Statement Text   Customer         Customer    As           As Required
                                                                    Required
----------------------------------------------------------------------------------------------
Trial Billing Cycle Close              Customer         Customer    As           As Required
                                       ACE*COMM                     Required
----------------------------------------------------------------------------------------------
Close the Toll Cycle                   Customer         Customer    As           As Required
                                       ACE*COMM                     Required
----------------------------------------------------------------------------------------------
Show the Progress of                   ACE*COMM         Customer    As           As Required
End-of Cycle Process                                                Required
----------------------------------------------------------------------------------------------
Terminate the End-of-                  ACE*COMM         Customer    As           As Required
Cycle Process                                                       Required
----------------------------------------------------------------------------------------------
Display/Print/Review                   Customer         Customer    As           As Required
the Toll Close Report                  ACE*COMM                     Required
----------------------------------------------------------------------------------------------
Close the Billing Cycle                Customer         Customer    As           As Required
                                       ACE*COMM                     Required
----------------------------------------------------------------------------------------------
Show the Progress of                   ACE*COMM         Customer    As           As Required
Close Billing Cycle Processs                                        Required
----------------------------------------------------------------------------------------------
Review the Close Billing Cycle         Customer         Data        weekly       Once
Billing Cycle
----------------------------------------------------------------------------------------------

                                                                       Page 24
<PAGE>

----------------------------------------------------------------------------------------------
TASK                                   RESPONSIBLE      LOCATION    FREQUENCY    QUANTITY
----------------------------------------------------------------------------------------------
<S>                                    <C>              <C>         <C>          <C>
Report                                 ACE*COMM         Center
                                                        Customer
----------------------------------------------------------------------------------------------
Show On-Line Billing History Data      Customer         Customer    As           As Required
                                                                    Required
----------------------------------------------------------------------------------------------
Generate Printed Subscriber Bills      ACE*COMM         Data        weekly
                                                        Center
----------------------------------------------------------------------------------------------
Generate Subscriber Bills to           ACE*COMM         Data        weekly
Electronic Media                                        Center
----------------------------------------------------------------------------------------------
Generate the Aged Account Report       Customer         Customer    As           As Required
                                                                    Required
----------------------------------------------------------------------------------------------
Generate the Expense Recovery          Customer         Customer    As           As Required
Analysis Report                                                     Required
----------------------------------------------------------------------------------------------
File Transfer Usage Detail from Date   ACE*COMM         Data        daily        Once
Center to Customer Site                                 Center
                                                        Customer
----------------------------------------------------------------------------------------------
File Transfer BAF data from            ACE*COMM         Data        daily        Once
Customer Site to Data Center                            Center
                                                        Customer
----------------------------------------------------------------------------------------------
Transfer End of Cycle Data from        ACE*COMM         Data        weekly       Once
Customer Site to Data Center                            Center
                                                        Customer
----------------------------------------------------------------------------------------------
Transfer Invoice Image to Customer     ACE*COMM         Data        weekly       Once
site for Invoice Inquiry                                Center
----------------------------------------------------------------------------------------------
</TABLE>


                                                                       Page 25
<PAGE>

                              Amendment to Contract

IAW pare xxxx of contact yyyy between Logix Communications Enterprises, Inc. and
ACECOMM, Inc., the following amendments are agreed to supplement and/or extend
the provisions of the existing contract.

Purpose: The existing contract was structured to support a business model of
"customer and vendor." The speed of growth in the Competitive Local Exchange,
CLEC, market as well as changes in organization within both companies has
revealed the necessity of making fundamental changes in the relationship between
the two companies as documented in the initial contract. This amendment codifies
the new relationship.

1.       Logix and AceComm will enter a co-development effort to improve the
         purchased products as a CLEC Operational Support System, 0SS. AceComm
         shall have full and unrestricted intellectual property rights to the
         software code and concepts or ideas, implemented or not, of this
         amendment. AceComm shall maintain the right to make the 0SS available
         commercially without restriction. Logix will make available its
         subject matter experts (SMEs), provide testing of mutually agreed
         ideas and Logix developed software. As a co-development, both teams
         shall share ideas, concepts, methodology, software, and implementation
         towards the joint goal of improving and scaling the 0SS as the
         dominant, integrated system available in the market.

2.       AceComm/Logix shall establish a co-development team which shall review
         each concept and decide whether it is Logix only; AceComm only; or
         Team requirement; For company only requirements, the company desiring
         the change shall bear the costs of development. AceComm only ideas
         shall be available to Logix thru software maintenance updates. Logix
         only code shall be made available to AceComm for inclusion in the base
         product at their discretion. When AceComm develops Logix required
         software, it will be at the current contract rates. Team requirements
         will be funded by Logix on a cost (non-profit) basis and may be
         performed by either ACECOMM or Logix development staff.

3.       AceComm shall provide Logix complete access to the existing base
         program(s), their logic, development tools and support programs. Logix
         shall treat this access as AceComm proprietary and shall not release
         any information to outside sources without AceComm's specific
         permission. AceComm shall maintain configuration control of all
         software changes, regardless of origination.

4.       This agreement shall remain in place for a period of eighteen months
         unless terminated by mutual agreement.  At the end of the period of
         performance AceComm shall have the right to all developments,
         regardless of funding source or company of conception. Logix shall be
         given source code and all development information on the software
         version currently in use by Logix, including Logix work in process.
         This agreement may be extended in six month increments if mutually
         agreed.