<PAGE>

                                                                   Exhibit 10.20


(EDS LETTERHEAD)



December 16, 1996



Allin Communications Corporation
300 Greentree Commons
381 Mansfield Avenue
Pittsburgh, Pennsylvania 15220
Attention:  R. Daniel Foreman



     Re:    Authorization Letter No. 1996-01

Dear Mr. Foreman:

This letter will confirm the mutual understanding and agreement of Allin
Communications Corporation ("Customer") and Electronic Data Systems Corporation
("EDS") as to the terms on which EDS will provide to Customer the services and
resources described in this letter, which terms are as follows:

1.  This letter is entered into under the provisions of the Master Agreement,
    dated effective as of December 16, 1996, between Customer and EDS (the
    "Master Agreement"), and, except as otherwise provided in this letter, all
    applicable provisions of the Master Agreement are incorporated into this
    letter by this reference.

2.  The term of this letter will commence on January 6, 1997. (the "AL
    Effective Date"), and, unless earlier terminated as provided in this letter
    or in the Master Agreement, will continue thereafter until the tenth
    anniversary of the AL Effective Date.  The term of this letter may be
    extended by the mutual written agreement of the parties.

3.  During the term of this letter, EDS will provide to Customer the services
    and resources described in the attached Exhibit I.  The specific allocation
    of the services and resources will be set forth in separate written work
    orders (each a "Work Order") entered into from time to time by the parties
    during the term of this Authorization Letter.  Each Work Order shall contain
    the following: (a) a Statement of Work describing the services to be
    performed, resources to be allocated by EDS, specified performance criteria,
    and a list of appropriate deliverables with delivery dates; (b) a price
    schedule setting forth any modifications to the payment terms set forth on
    Exhibit III; (c) a designation of the Team Leader, as appropriate, and the
    Customer Team Leader, each of whom shall function as the point of contact
    for the respective parties for the services and resources identified in the
    Work Order; (d) any other terms and conditions appropriate to the services
    and resources provided under a given Work Order.  The EDS individual who
    will have management responsibility for EDS in connection with this letter
    is also designated in the attached Exhibit II.

4.  In connection with the provision of those EDS services and resources,
    Customer will provide to EDS the Customer support services and resources
    described in the attached Exhibit II. The specific Customer support
    services and resources will be set forth in the applicable Work Order.
    The Customer individual who will

                                       1
<PAGE>

    have management responsibility for Customer in connection with this letter
    is also designated in the attached Exhibit II.

5.  For the services and resources provided by EDS to Customer under this
    letter, Customer will pay to EDS the amounts specified in the attached
    Exhibit III.

6.  The services and resources provided to Customer by EDS under this letter
    will also be subject to the additional provisions set forth in the attached
    Exhibit IV.

7.  In the event of any express conflict or inconsistency between the provisions
    of a Work Order and the provisions of this Authorization Letter or the
    Master Agreement, the provisions of the Work Order will control with respect
    to the interpretation of that Work Order; provided, however, that the
    provisions of the Work Order will be so construed to give effect to the
    applicable provisions of the applicable Authorization Letter and Master
    Agreement to the fullest extent possible.

Please indicate your agreement to the foregoing by signing both copies of this
letter and returning one fully-executed copy to EDS.



                                    Sincerely,

                                    Electronic Data Systems Corporation


                                      By:      /s/ D. L. Stolkey
                                         -------------------------------------

                                    Name:     D. L. Stolkey
                                         -------------------------------------

                                   Title:     President GTSI
                                         -------------------------------------

                                    Date:     12-20-96





ACCEPTED AND AGREED:
--------------------

Allin Communications Corporation


   By:       /s/ Richard W. Talarico
      ----------------------------------------

 Name:     Richard W. Talarico
      ----------------------------------------

Title:     Chairman/CEO
        ----------------------------------

 Date:     12-16-96

                                       2
<PAGE>
                                   EXHIBIT I

                           EDS SERVICES AND RESOURCES
                           --------------------------


A. Installation of new and existing ships, consisting of the following
   components, and in conformance with the standards of performance set forth in
   Exhibit V.

     1.  Shipboard control center, including the following:

       a. Deployment Document

       b. Power requirements

       c. HVAC capabilities

       d.  Hardware

       e. Software interface development

     2.  Cabin

       a. Television Control Module ("TCM")

     3.  Plant

       a. Radio Frequency (RF) Cabling

       b. Network cabling

     4. Post Assembly Testing

B. Ongoing Support of Installed Ship-based Operations



                                      I-1
<PAGE>

                                   EXHIBIT II

                    CUSTOMER SUPPORT SERVICES AND RESOURCES
                    ---------------------------------------

1.  Make available to EDS, as reasonably requested by EDS, management decisions,
    personnel, information, approvals, acceptances and access to Customer's
    premises, as required by EDS to perform the services stated in the terms of
    this agreement and their related activities.

2.  Supply training and support for installation and post-installation shipboard
    personnel, as required by EDS to perform the services stated in the terms of
    this agreement and their related activities, until such time that both
    parties agree how and when such support shall be reduced.

3.  Supply EDS personnel with on-going support and training for new development
    services and critical problem resolution, as required by EDS to perform the
    services stated in the terms of this agreement and their related activities.

4.  Supply EDS with copies of Customer's operating processes and procedures as
    required by EDS to perform the services stated in the terms of this
    agreement and their related activities.

5.  Provide EDS personnel access to Customer's systems as required for EDS to
    perform the services stated in the terms of this agreement and their related
    activities.

6.  Cooperate with EDS in providing EDS personnel located at Customer's
    facilities access to all of EDS' internal systems via the methodologies
    requested by EDS.  EDS will reimburse Customer for any additional costs
    reasonably incurred by Customer as a result of providing EDS' employees with
    access to EDS' internal systems.

7.  Supply EDS with all pertinent documentation for the current platform and
    system for installation troubleshooting, problem resolution and post-
    installation activities required to perform the services stated in the terms
    of this agreement and their related activities.

8.  Provide the EDS Account Manager with facilities and related services (i.e.,
    office space, telephones, electric, water, temperature control, office
    supplies, etc.) equivalent to a Customer director.

9.  Provide EDS employees with facilities and related services (i.e., office
    space, telephones, electric, water, temperature control, office supplies,
    etc.) equivalent to individual performers employed by Customer.

10. Make provisions for the EDS Account Manager to attend and participate on
    regular staff meetings that regard sales, operations and other activities
    that affect his/her responsibilities and abilities to deliver services to
    Customer and/or Customer's customers, as stated in the terms of this
    agreement and their related activities.

11. Provide all travel and other transportation expenses required to provide the
    services set forth in this Authorization Letter and their related
    activities. Travel would be in accordance with Customer's current travel
    policy and guidelines for its employees. All such travel will be acquired by
    Customer through its vendors. Expense reports for travel and travel related
    expenses will be submitted directly to Customer for payment in accordance
    with Customer's existing policies; provided, however, that Customer would be
    required to reimburse EDS for such expenses within ten (10) days from the
    date EDS submits a request for reimbursement.

12. Supply EDS employees shipboard access, room, board and other reasonable
    accommodations and facilities as required to execute installation and post-
    implementation activities as required by EDS to perform the services stated
    in the terms of this agreement and their related activities.

13. Subject to Customer's discretion, supply EDS, to the extent that they are
    made available to Customer by its cruise line customers, with complimentary
    cruise passes.

                                      II-1
<PAGE>

                                  EXHIBIT III

                                PAYMENTS TO EDS
                                ---------------


A. Monthly Fee.
   -----------

   1. Beginning on the AL Effective Date, for a period of six months from the AL
      Effective Date (the "Initial Monthy Fee Period"), for each month during
      such period, Customer will pay to EDS an amount based upon the following
      rates for the following job categories as applicable (each such monthly
      fee shall be referred to herein as an "Initial Monthly Fee") and as
      adjusted pursuant to the applicable provisions of Exhibit IV:

<TABLE>
<CAPTION>

                                          Monthly
        Job Category                      Billing
                                          Rate Per
                                           Person
--------------------------------------------------------------
<S>                                        <C>
Account Manager                            $13,412
--------------------------------------------------------------
Administrative Assistant                   $ 3,815
--------------------------------------------------------------
Trainer/Documentation Mgr.                 $ 5,194
--------------------------------------------------------------
Project Manager                            $10,519
--------------------------------------------------------------
Site Survey Engineer                       $ 8,617
--------------------------------------------------------------
Radio Frequency Installer                  $ 8,617
--------------------------------------------------------------
Labor Technician                           $ 5,914
--------------------------------------------------------------
Software Engineer                          $ 8,321
--------------------------------------------------------------
Software/Interface Engineer                $ 5,914
--------------------------------------------------------------
Project Engineer                           $ 7,236
--------------------------------------------------------------
Shipboard Operator                         $ 6,266
--------------------------------------------------------------
</TABLE>

   2. Beginning on the first day following the conclusion of the Initial Monthly
      Fee Period, and for each month during the remaining term of this
      Authorization Letter (and any termination assistance period), Customer
      will pay to EDS the following amounts, as applicable (each, a " Base
      Monthly Fee"):

<TABLE>
<CAPTION>

 Base Monthly Fee    Contract
 (in $ per month)      Month
----------------------------------
<S>                 <C>
 To be determined       1-6
----------------------------------
     244,481            7-12
----------------------------------
     299,559           13-24
----------------------------------
     369,987           25-36
----------------------------------
     471,289           37-48
----------------------------------
     203,453           49-60
----------------------------------
     197,528           61-72
----------------------------------
     156,132           73-84
----------------------------------
     152,526           85-96
----------------------------------
     148,084           97-108
----------------------------------
     143,771          109-120
----------------------------------

</TABLE>

     EDS may adjust the Base Monthly Fee for any additional resources that
     Customer utilizes in any applicable month.  Such adjustments will be based
     upon the rates and job categories described above.  The Initial Monthly Fee
     and the Base Monthly Fee will be due and payable within 30 days after
     receipt of the invoice

                                     III-1
<PAGE>


     by Customer.  From time to time, but no more often than once each calendar
     year, Customer and EDS agree to meet to discuss merit adjustments to each
     job category comprising the Base Monthly Fee, which merit adjustments will
     be no more than three percent (3%) per year.

B.  Adjustment to the Base Monthly Fee.  Customer may permanently adjust the
    ----------------------------------
    Base Monthly Fee by requesting an adjustment to the staff resources
    allocated hereunder by providing EDS, in the event of an increase in the
    staff resources allocated with one hundred twenty (120) days prior written
    notice of the adjustment, and in the case of a decrease in the staff
    resources allocated with ninety (90) days prior written notice of the
    adjustment, (each a "Resource Adjustment Notice"); provided, however, that
    (i) only one Resource Adjustment Notice may be in effect at any time, and
    (ii) Customer may provide EDS with no more than two Resource Adjustment
    Notices in any calendar year. The Base Monthly Fee will be adjusted to
    reflect Customer's request set forth in the Resource Adjustment Notices as
    follows: (i) in the case of a Resource Adjustment Notice requesting
    additional staff, the Base Monthly Fee will be adjusted on the date the
    additional staff are performing services; (H) in the case of a Resource
    Adjustment Notice requesting a reduction in staff, the Base Monthly Fee,
    will be adjusted on the earlier to occur of (a) the redeployment of the
    personnel by EDS or (b) ninety days from the date of the Resource Adjustment
    Notice. If during the term of this Authorization Letter, the Customer's use
    of the services and/or resources described on Exhibit 1, for any three (3)
    consecutive months, varies by an amount equal to or greater than 30% and any
    unutilized services and resources cannot reasonably be allocated pursuant to
    paragraph C below, then EDS shall have the option to either (i) terminate
    this Authorization Letter. or (ii) Customer and EDS shall mutually agree
    upon an adjustment to the services or resources allocated to Customer with a
    corresponding adjustment to the applicable charges.

C.  Other Resource Utilization.  Notwithstanding anything contained herein to
    --------------------------
    the contrary, to the extent the parties have not entered into an
    Authorization Letter with respect to a specific industry, Customer and EDS
    may mutually agree to allocate the services and resources set forth herein
    to projects outside of the cruise line industry.


                                     III-2
<PAGE>

                                   EXHIBIT IV

                                OTHER PROVISIONS
                                ----------------


Cost of Living Adjustment.  If the Consumer Price Index for all Urban Consumers,
-------------------------
U.S. City Average, for All Items (1982-84 = 100), as published in the Bureau of
Labor Statistics of the Department of Labor (the "CPI"), is at any anniversary
of the AL Effective Date (the "Current Index") higher than the CPI at the
previous anniversary of the AL Effective Date or at the AL Effective Date, as
the case may be (the "Base Index"), then, effective as of such anniversary, all
charges under this Authorization Letter will be increased by the percentage that
the Current Index increased from the Base Index; provided, that in any such
twelve month period, Customer will pay increases in the charges for any increase
of the Current Index over the Base Index up to and including 4% and provided
further that during such period, Customer will not be charged for any increases
of the Current Index over the Base Index which are greater than 4%.  In the
event that the Bureau of Labor Statistics should stop publishing the CPI or
should substantially change the content or format thereof, the parties will
substitute therefor another comparable measure published by a mutually agreeable
source; provided, however, that if such change is merely to redefine the base
        -----------------
year for the CPI from 1982-84 to some other year, the parties will continue to
use the CPI but will if necessary, convert either the Base Index or the Current
Index to the same basis as the other by multiplying such index by the
appropriate conversion factor.

Taxes.  Customer will pay all Taxes (as defined below) to EDS at the same time
-----
and in the same manner that it pays those amounts due to EDS under this
Authorization Letter to which the Taxes relate, and EDS will remit such Taxes to
the appropriate taxing authority.  EDS and Customer will cooperate to minimize
and properly calculate any applicable Taxes and, in connection therewith,
Customer will provide any applicable direct pay certificates, resale
certificates, information regarding out-of-state use of materials, services or
sales or other exemption certificates or information reasonably requested by
EDS.  EDS will notify Customer of, and will coordinate with Customer, the
response to and settlement of any claims for Taxes that may be asserted by
applicable taxing authorities, it being understood that with respect to any
claim for Taxes arising out of a form or return signed (or which should have
been signed) by a party, such party will have the right to elect to control the
response to and settlement of the claim, but the other party will have the right
to participate in the responses and settlements that are appropriate to its
potential responsibilities or liabilities.  If Customer requests EDS to
challenge the imposition of any Tax, Customer will reimburse EDS for the
reasonable legal fees and expenses, including additional tax, penalty and
interest if assessed, that EDS incurs.  Customer will be entitled to any refunds
or rebates of Taxes (including additional tax, penalty, and interest) granted to
the extent such refunds or rebates are of Taxes (including additional tax,
penalty, and interest) that were paid by Customer.  For purposes of this
Authorization Letter, "Taxes" means any taxes, however designated or levied,
based upon amounts payable to EDS pursuant to this Authorization Letter, upon
this Authorization Letter or upon the services, resources, equipment or other
property provided pursuant to this Authorization Letter, including state and
local taxes, use taxes and any taxes or amounts in lieu thereof paid or payable
by EDS in respect of the foregoing, exclusive in each case, however, of any tax
(including additional tax, penalty, and interest) in respect of any salary,
wage, pension, retirement benefit, or other compensation, or fringe benefit paid
by EDS, of EDS' franchise taxes and taxes based upon the net worth, or any loan,
of EDS, property owned or leased by EDS or gross or net receipts or the net
income of EDS.  For purposes of this paragraph, EDS shall include EDS and its
affiliates.

Significant Changes.  The charges set forth in Exhibit III are based on there
-------------------
being no significant changes to the services or resources contemplated by this
Authorization Letter.  Without limitation of the foregoing, a significant change
to such services or resources would be deemed to occur upon (i) a significant
decrease in the number of installations [ships], (ii) a significant increase in
the amount of personnel resources necessary to complete an installation as
described in Exhibit 1, or (iii) significant change to the nature of Customer's
business or operations.  With respect to any such significant change, EDS and
Customer would meet to discuss a reasonable adjustment to charges.  Any
adjustment win require the consent of the other party, which consent may not be
unreasonably withheld.

                                      IV-1
<PAGE>

Insurance Requirements.
----------------------

Subject to review and confirmation by Allin, EDS will provide the following:

     General Liability Insurance.

     Longshoreman's and Harbor Workers Compensation Insurance (USL&H).




                                      IV-2
<PAGE>
                                   EXHIBIT V

                              PERFORMANCE CRITERIA
                              --------------------


EDS and Customer agree that the performance criteria set forth below are subject
to additional due diligence by EDS during the six month start-up period.
Accordingly, EDS and Customer agree that the performance criteria set forth
below may be amended during such six month period by EDS, provided such
adjustments do not adversely impact on-going service agreements or commitments
to Customer's clients or customers and thereafter by mutual agreement.  The
following key criteria shall be used as performance standards by which a
Customer will be able to gauge the timeliness, quality and reliability of the
services and resources provided by EDS.  These key criteria are guidelines for
levels of timeliness, quality and reliability and are not all inclusive.  The
complete list of performance criteria are based upon the entire Customer
documentation library listed as part of this Exhibit as well as any Customer
Client shipboard policies and procedures.

A. Installation

   Technical Site Survey - The Technical Site Survey (the "Survey") should
   commence within 2 weeks of contract signing and be performed by a qualified
   RF Engineer and Project Engineer. The Survey should be 100% complete within
   one (1) week of the Survey start date. The Site Survey document and technical
   sections of the Deployment document, including all design drawings should be
   completed within two (2) weeks of completion of the Survey. The Customer
   shall receive five (5) hard copies and one (1) secure electronic copy of
   these documents within two (2) days of completion of the documents received
   by Customer personnel.

   RF Network Installation - The RF Network Installation (RF) should be
   completed by the contractually agreed-to completion date. The RF, including
   shipboard TV and ITV System RF components, combining network, amps, TCMs,
   TVs, connectors and cabling should be properly installed to provide
   distortion-free video and audio quality through the complete RF network.
   Acceptable signal levels, as agreed to for each design effort, should exist
   at each amp input, amp output, and TV RF connector. The initial signal level
   values for each amp input and output, at a working low band, midband and the
   highest working superband channel and at each TV tap should be provided as
   proof of completion as well as being used as the baseline values for
   maintenance efforts.

   ITV System Installation - The ITV System Installation (ITV) should be
   completed by the contractually agreed-to completion date. The ITV should have
   all components in proper working condition, including verification that the
   RF components of the system satisfy the RF Network Installation quality
   levels. RF and digital networking connections, including hubs, cables and
   interface cards and connectors should have a greater than 99% rate of
   successful packet communications between ITV network devices.

   ITV System Interfaces - The ITV System Interfaces (Interfaces), to non-ITV
   computers and networks, should be completed by the contractually agreed-to
   completion date. The Interfaces should have greater than a 99% rate of
   successful packet communications between network devices, with the ability to
   100% reliably receive guest information and communicate transaction
   information between ITV and non-ITV systems.

   Operational Software Installation - Operational Software Installation should
   be completed by the contractually agreed-to completion date. All ITV software
   should be operational, with all ship specific content installed, including
   all operational software, audio, video, graphics and database files.

   Installation Specific Documentation - All Installation Specific Documentation
   (Specifics) should be completed within one (1) week of the ITV installation.
   The Specifics should include all information unique to the ITV installation,
   including but not limited to, as built drawings for the RF combining and ship
   networks, ITV system rack elevations, layouts, trunk and channel
   configurations, channel lineup, and initial RF readings.

                                      V-1
<PAGE>
B. Operations

   Operator Boarding - The Operator responsible for maintaining proper operation
   of the ITV System should have successfully completed the landbased portion of
   the ITV System Training and board the ship no later than two (2) weeks prior
   to the go-live date of the ITV System. The Operator should become an integral
   part of the installation team and completely understand the unique aspects of
   the ITV installation before the go-live date.

   Operator Answers to Master of the Ship - The Operator is under the authority
   of the Master of the Ship and the officers designated to oversee the
   operation of the Systems and Services. The Operator shall use his/her best
   efforts to comply with the operations manual and other shipboard guidelines
   set forth by the Customer Client.

   Operational Procedures - The Operator shall understand and effectively
   execute the Operational Procedures required to run the ITV system maintaining
   a greater than 90% level of guest satisfaction, based upon random guest
   surveys initiated by the Customer.

   System Operation - Through proper maintenance and servicing, the ITV System
   shall be maintained at a 98% average uptime for Interactive Services, with a
   98% average rate of equipment operation within each month of operation.

   Maintenance Procedures - The Operator shall perform all on-going maintenance
   procedures and record the results of maintenance procedures in the Ship's
   Log. The maintenance procedures shall include, but not be limited to, RF
   amplifier input and output readings at specified low, mid and superband
   channels, ITV System audio and video quality levels, proper component
   operations, backups, reporting and reconciliation.

   Service and Notification Procedures - The Operator shall immediately begin
   the investigation of any guest reported problems, or any problems discovered
   during normal system operation or maintenance. Problems and resolutions
   should be recorded as part of the Ship's Log. Any ITV System failure should
   be resolved or reported to Level 2 - Landside Technical Support personnel
   within a specified time frame, based upon the following ITV System failure
   levels:

        .  Disabling more than 10% of the ITV System    I hour

        .  Between I and 10% of the ITV System         2 hours

        .  Less than 1% of the ITV System             24 hours

   Decorum and Professionalism - The Operator shall maintain a high level of
   decorum and professionalism as the representative of both EDS and the
   Customer at each installation.

   Other Shipboard System Installations and Operations - For any other type of
   shipboard installations, including but not limited to Broadcast Centers,
   Information Systems, Property Management Systems, Point of Sale Systems,
   Kiosks, Digital Photography Systems, similar levels of timeliness, quality
   and reliability apply.

   Standards and Practices - All work shall be done in compliance with standards
   set forth by the Society of CATV Engineers, Society of Broadcast Engineers,
   Electronic Industries Association, and SOLAS maritime regulations.



                                      V-2