<PAGE>   1
                                                                   EXHIBIT 10.38




                            OEM/VAR SUPPLY AGREEMENT



                              SOFTWARE SUPPORT AND
                              MAINTENANCE SERVICES
                                    AGREEMENT


                                     Between
                                SUMMA FOUR, Inc.
                                       and
                                  NEWNET, Inc.




<PAGE>   2


                            OEM/VAR SUPPLY AGREEMENT

This OEM/VAR Supply Agreement (the "Agreement") is effective on February 17,
1997, by and between NewNet, Inc. ("NEWNET"), a Connecticut corporation with
offices at Two Enterprise Drive, Shelton, CT 06484 and Summa Four, Inc.,
("Customer") a Delaware corporation with offices at 25 Sundial Avenue,
Manchester, New Hampshire 03103-7251.

Hereinafter NEWNET and Customer, may be referred to as the "Party" or "Parties."
All defined terms in this Agreement shall have the meanings given to them in the
NEWNET Terms of Sale ("Terms of Sale"), Appendix 1 hereto, and

WHEREAS, Customer desires to obtain licensing and distribution rights to certain
NEWNET systems developed by NEWNET and NEWNET wishes to grant such rights to
Customer pursuant to the following terms and conditions,

NOW, THEREFORE, in consideration of the mutual covenants and promises contained
herein, the receipt and adequacy of which are acknowledged, the Parties contract
and agree as follows:

1.       TERMS OF SUPPLY

         1.1      NEWNET SYSTEMS AND SOFTWARE. Customer agrees to buy and NEWNET
                  agrees to sell to Customer NEWNET Systems and Software
                  pursuant to the terms of this Supply Agreement and the Terms
                  of Sale attached hereto as Appendix 1 and incorporated herein
                  by reference. Hereinafter, the Supply Agreement and its
                  attachments shall be referred to as the "Supply Agreement."
                  Any conflict between the terms of the Supply Agreement and any
                  of Customer's purchase documentation shall be resolved in
                  favor of the Supply Agreement. In the event of a conflict
                  between the main body of the Supply Agreement and the appended
                  Terms of Sale, the main body of this Agreement shall prevail.

         1.2      NEWNET SYSTEM SUPPORT SERVICES.  Customer agrees to buy System
                  Support Services pursuant to the System Support Service
                  Agreement attached hereto as Appendix 2.

2.       PRICES AND DISCOUNTS

         2.1      NEWNET SYSTEMS AND SOFTWARE. NEWNET will, throughout the term
                  of this Agreement, sell and license NEWNET Systems and
                  Software to Customer and Customer will purchase such NEWNET
                  products at the agreed upon discounts off of the relevant
                  price in NEWNET's price list ("Promotional Partner Pricing")
                  attached hereto as Appendix 3.



                                       -1-
<PAGE>   3


                  NEWNET may from time to time decrease its published OEM/VAR
                  prices and volume discount standard schedule. Should NEWNET
                  issue a new OEM/VAR standard price list for its Products, and
                  should that list contain a volume discount schedule, Customer
                  may have the lower of the prices that are (i) calculated by
                  reference to the new price list, using the new volume discount
                  schedule at Customer's then volume of purchases and (ii) the
                  prices that are calculated using the prices and discounts
                  found in this Agreement.

         2.2      Orders entered between the effective date of this Agreement
                  and March 31, 1997, have been processed under NEWNET's former
                  pricing. Summa Four shall be credited against future orders
                  with the difference between the prices stated in such orders
                  and the applicable pricing described in Appendix 3 hereto as
                  follows:

                  2.2.1    The aggregate difference in price for all such orders
                           is $87,783.50 and shall be credited against Summa
                           Four purchases hereunder in two (2) equal, quarterly
                           installments beginning April 1, 1997 as follows;
                           $43,891.75 in NewNet 2Q97 (ending June 31, 1997) and
                           $43,891.75 in NewNet 3Q97 (ending Sept. 30, 1997).

                  2.2.2    The quarterly credits shall not accrue to a later
                           quarter.

         2.3      The AccessMANAGER pricing referenced in Appendix 3 attached
                  hereto will apply to all current and future Releases of the
                  AccessMANAGER product, excluding Releases which incorporate
                  the distributed redundancy architecture. During the term of
                  this Agreement, Summa Four will have access to, at mutually
                  agreed upon prices, all fixes, Revisions, and Updates as well
                  as all new country variants of such current AccessMANAGER
                  products.

3.       PURCHASE COMMITMENT. In consideration for the above NEWNET discount,
         Customer will Purchase no less than three million US dollars (US$3M) of
         NEWNET Systems and Software over an eighteen (18) month period
         beginning on the date of this Agreement. NEWNET services, including
         customization and modification of its Software and System Support
         Services shall not be used to complete Customer's purchase commitment.
         At the end of the eighteen (18) month period, should Customer have not
         fulfilled the firm purchase commitment described for reasons not
         primarily attributable to NEWNET or NEWNET products, Customer shall pay
         to NEWNET the outstanding balance of the commitment within seven (7)
         days.




                                       -2-


<PAGE>   4


4.       WARRANTY. Article 5.2 of Appendix 1 hereto, NEWNET Terms of Sale, shall
         be amended to read that NEWNET's warranty offered to Customer shall be
         one (1) year from date of delivery to Customer.

5.       NOTICES AND OTHER COMMUNICATIONS. Notices shall be in writing (unless
         otherwise designated herein) and shall, for all purposes, be deemed to
         be fully given and received if delivered personally, or if sent by
         facsimile with a copy sent by Express, certified or registered mail,
         postage prepaid, to the other Party at its address stated below or to
         such other address as the respective Party shall advise in writing:

                         NEWNET:           President
                                           NewNet, Inc.
                                           2 Enterprise Drive
                                           Shelton, CT 06484
                                           Fax No. (203) 926-2664

                             cc:           George C. McKinnis, Esq.
                                           40 Oriole Avenue
                                           Bronxville, NY 10708
                                           Fax No. (914) 793-9433

                       CUSTOMER:           John Shaw
                                           25 Sundial Avenue
                                           Manchester, New Hampshire 03103-7251
                                           Fax No. (603) 668-4491

6.       CONFIDENTIALITY. All Confidential Information exchanged hereunder shall
         be subject to the terms of the Mutual Nondisclosure Agreement entered
         by the Parties and attached hereto as Appendix 4. Notwithstanding the
         termination date of the attached Mutual Nondisclosure Agreement, it
         shall remain in effect for so long as this Agreement and any renewal or
         successor agreement are in effect and the obligation of confidentiality
         shall survive the termination of this Agreement pursuant to the terms
         of the Mutual Nondisclosure Agreement.

7.       TERM OF AGREEMENT

         7.1      The term of this Agreement shall begin on the Effective Date
                  and unless otherwise terminated as provided herein, shall
                  continue in full force and effect until the expiration of the
                  initial term of this Agreement, which shall occur eighteen
                  (18) months from the Effective Date.

         7.2      Unless otherwise terminated as provided herein, the initial
                  term of this Agreement shall be renewed for successive
                  eighteen (18) month terms


                                       -3-



<PAGE>   5


                  after the initial eighteen (18) month term, unless either
                  Party gives written notice to the other Party not less than
                  ninety (90) days before the end of the initial or each
                  successive term that it elects not to extend the Agreement for
                  the next eighteen (18) month term. Notwithstanding any terms
                  to the contrary in this Agreement, including all appendices
                  thereto, NewNet shall not have the right to terminate this
                  Agreement for convenience only; however, should Customer
                  desire to terminate this Agreement for convenience, it may due
                  so subject to its payment in full on the proposed termination
                  date of the its minimum purchase commitment described in
                  Article 3, above.

         7.3      This Agreement replaces and supersedes the Purchase Agreement,
                  as subsequently amended by the parties.

8.       CONTRACT ADMINISTRATION REVIEW. Appropriate senior management personnel
         of Customer and NEWNET shall meet on a quarterly basis, at mutually
         agreeable times and locations, to review each parties compliance with
         the terms of this Agreement and to recommend appropriate changes
         thereto or other action.

9.       SOURCE CODE ESCROW. NewNet and Customer agree to enter the Source Code
         Escrow Agreement attached hereto as Appendix 5 for such NEWNET Software
         as Customer purchases hereunder, at such cost to customer as is
         described in Appendix 3 hereto. The Source Code Escrow Agreement shall
         survive the termination of this OEM/VAR Supply Agreement provided that
         Customer pays the yearly escrow fees and the Support and Maintenance
         fees both described in Appendix 3 hereto.

IN WITNESS WHEREOF, EACH PARTY HERETO HAS AGREED TO THE ABOVE PROVISIONS THROUGH
ITS DULY AUTHORIZED REPRESENTATIVE AS OF THE ABOVE DATE:




NEWNET, INC.                                             CUSTOMER:


By: /s/ Dilip Singh                     By: /s/ B.R. Gorsun    /s/ John H. Shaw
    --------------------------              ------------------------------------
    Name: Dilip Singh                       Name: B.R. Gorsun  John H. Shaw
    Title: President                        Title: Chairman VP Business 
                                                   Development



                                       -4-


<PAGE>   6


APPENDIXES
OEM/VAR SUPPLY AGREEMENT


Appendix 1    Terms of Sale


Appendix 2    System Support Service Agreement


Appendix 3    Price List


Appendix 4    Mutual Nondisclosure Agreement


Appendix 5    Escrow Agreement






                                       -5-


<PAGE>   7


                                    ADDENDUM
                                       to
                              NEWNET TERMS OF SALE


THIS ADDENDUM to the NEWNET Terms of Sale entered between Summa Four, Inc. and
NewNet, Inc. amends the NEWNET Terms of Sale as of the date it is entered by the
parties hereto; the below numbering scheme follows the numbers used in the
NEWNET Terms of Sale:

Art. 1. 11        The last line of this Article is amended to add the following
                  phrase: "--which is appended to the Supply Agreement as an
                  independent contract."

Art. 2.1          Delete the second sentence of this Article reading, "Each
                  Purchase Order shall be irrevocable upon acceptance by NEWNET"
                  and substitute therefore the following sentence:

                  "Each Purchase Order shall be irrevocable upon acceptance by
                  NEWNET, except that Summa Four may cancel a purchase order for
                  NEWNET products on NEWNET's prior written approval and payment
                  by Customer of cancellation charges as follows; however,
                  nothing herein shall compromise or lessen the Customer's firm
                  purchase commitment found in Article 3 of the Supply
                  Agreement:


<TABLE>
<CAPTION>
                      Days Remaining Until            Cancellation Charges
                       Scheduled Shipment           (Percentage Purchase Price)
                       ------------------           ---------------------------
                    <S>                               <C>

                    2.1.1   HARDWARE:

                         Six (6) weeks or more        zero percent (0%)
                         Less than six (6) weeks      one hundred percent (100%)

                    2.1.2   SOFTWARE:

                         six to ten days              ten percent (10%)
                         Two to five days             thirty percent (30%)
                         Zero to one day              one hundred percent (100%)
</TABLE>

Art. 2.2          The last sentence of this Article, reading as follows, is
                  deleted: "-- and cease providing Support Services until such
                  payment is made."

Art. 3            Delete the first sentence of this Article which reads, "The
                  prices quoted to Customer in the Agreement to which this
                  Appendix is attached may be changed by NEWNET on ninety (90)
                  days advanced notice to Customer."



                                       -1-

<PAGE>   8


                  The last sentence of the first paragraph of this Article,
                  reading as follows, is deleted: "Customer shall pay NEWNET's
                  costs of collection, including reasonable attorney's fees."

                  The last sentence of the second unnumbered paragraph of this
                  Article is amended to read as follows: "--NEWNET's fees shall
                  be due and payable--."

Art. 5.2          The last two lines of the first paragraph of this Article are
                  amended to read as follows: "-- for the warranty period
                  described in Article 4 of the Supply Agreement (the "Warranty
                  Period")."

Art. 7. 1(a)      This Article is amended to read, "NEWNET's adjustment or
                  repair of the NEWNET System or, at NEWNET's option, NEWNET
                  shall correct errors therein, or"

Art. 7.2          Amend line 7 to read "--through the period of time ending
                  twelve (12) months from delivery--."

Art. 8. 1         Amend the last sentence of the first paragraph of this Article
                  as follows: "Customer shall use reasonable effort to ensure
                  that the protections of any such sublicense shall inure to the
                  benefit of NewNet."

                  Modify the second sentence of paragraph two of this Article to
                  read as follows: "The Customer shall be permitted to market
                  and sublicense the Software to End Users as stand alone
                  software or integrated into Customer's hardware."

Art. 9. 1         Amend lines 7-9 of the first paragraph to read as follows:
                  "--Software violates said third party's patent, copyright,
                  trademark, trade secret or other proprietary right."

                  Insert the following new unnumbered paragraph as a substitute
                  for subparagraph (c):

                  (c)      In the event that NEWNET in its sole discretion
                           determines that none of the foregoing options are
                           procurable on reasonable terms, on written notice to
                           Customer, Customer shall have the option to (i)
                           immediately take the infringing NEWNET Software out
                           of use and service and promptly return the infringing
                           NEWNET Software to NEWNET, and NEWNET's sole
                           liability shall be to refund to Customer the amount
                           paid therefore by Customer, less an amount for
                           depreciation equal to twenty-five (25%) per year,
                           without prejudice to the provisions set forth in the
                           above option



                                       -2-


<PAGE>   9


                           or (ii) should Customer be unable to cause its End
                           User to immediately take the infringing NEWNET
                           Software out of use and service as described above,
                           Customer shall bear from that point of time all
                           liabilities and costs associated with its End User's
                           continued use of the infringing NEWNET Software.

Art. 9.2 (a)      Amend this subparagraph in its entirety as follows,
                  "modification to the NEWNET system made by the Customer or
                  allowed to be made by Customer, or"

Art. 9.2          Add the following sentence to the end of Article 9.2:

                  "CUSTOMER SHALL NOT BE SUBJECT TO LIABILITY TO NEWNET FOR AN
                  AMOUNT UNDER THIS ARTICLE 9.2 THAT IS MORE THAN THE AGGREGATE
                  ROYALTIES PAID BY THE CUSTOMER TO NEWNET UP TO THE DATE OF THE
                  LIABILITY."

The Parties signify their agreement to the above amendments to the NEWNET Terms
of Sale by having their duly authorized representatives sign where indicated
below:


NewNet, Inc


By: 
    ------------------------------
    Its:


Summa Four, Inc.


By:
    ------------------------------
    Its:






                                       -3-


<PAGE>   10

                                   Appendix 1

                              NEWNET TERMS OF SALE


1.       DEFINITIONS. For the purposes of these Terms of Sale, the below terms
shall have the following definitions:

1.1 "Confidential Information" shall have the
meaning defined in the Nondisclosure Agreement in force between the Parties.

         1.2      "End Users" shall mean Customer's direct end- user customers,
distributors, dealers, resellers and/or their end-user customers.

         1.3      "Customer's Systems" shall mean any computer driven switch,
voice or information processing system used or distributed by Customer or any
reseller of Customer.

         1.4      "Documentation" shall mean the installation and user manuals
and the specifications contained therein, maintenance manuals, training
materials, and other technical and user documentation to be delivered by NEWNET
pursuant to each NEWNET System provided under a Purchase Order.

         1.5      "Effective Date" shall mean the latest date on which duly
authorized representatives of NEWNET and Customer have signed and delivered this
Agreement.

         1.6      "Hardware" shall mean hardware supplied by NEWNET hereunder.

         1.7      "NEWNET System" shall mean NEWNET Software and Hardware
delivered to Customer as a System.

         1.8      "Purchase" shall mean the acquisition by Customer of licenses
to NEWNET Software, and the payment of purchase, license and royalty fees for
Software, hardware and services.

         1.9      "Purchase Order" shall mean an order for one or more NEWNET
Systems that is submitted by Customer to NEWNET's Connecticut office and duly
accepted by NEWNET in writing.

         1.10     "Software" shall mean the programs, data and supporting
documentation owned or licensed by NEWNET and licensed or sublicensed to
Customer for operation and use on or with the Customer's Systems, as further
defined in each Purchase Order. The term "Software" shall also include any
modifications made thereto by NEWNET as may be specified in each Purchase Order.

         1.11     "Supply Agreement" shall mean the OEM/VAR Supply Agreement to
which these Terms of Sale are appended.

         1.12     "Support Services" shall mean the NEWNET System and Hardware
support services and training services agreed to be provided by NEWNET as set
forth in the System Support Services Agreement, hereinafter called the "Support
Service Agreement" as amended from time to time, and which is appended to the
Supply Agreement.

2.       PURCHASE OF NEWNET SYSTEMS

         2.1      NEWNET hereby agrees to deliver, and Customer agrees to
Purchase each NEWNET System set forth in each Purchase Order. Each Purchase
Order shall be irrevocable upon acceptance by NEWNET. These terms of sale and
the terms of the



                                       -1-


<PAGE>   11

                                   Appendix 1

                              NEWNET TERMS OF SALE

Supply or Purchase Agreement to which these Terms of Sale are appended shall
take precedence over all other documentation of sale, including Customer's
standard terms of purchase printed on or appended to Customer's purchase orders.


         2.2      If Customer fails to pay any sum due hereunder that is not
reasonably disputed by Customer, NEWNET may, without prejudice to any other
remedy and upon ten (10) days' prior notice in writing to Customer, cease all
work in progress, if any, in respect of any NEWNET Systems yet to be delivered,
cease delivery of any undelivered NEWNET Systems, and cease providing Support
Services until such payment is made.

3.       PRICES AND PAYMENT TERMS. The prices quoted to Customer in the
agreement to which this Appendix is attached may be changed by NEWNET on ninety
(90) days advanced notice to Customer. Customer agrees to pay all sums when due.
If Customer fails to pay any sum due hereunder and such sum is not reasonably
disputed by Customer, interest shall be charged on such overdue amount at the
rate of one and one half (1 .5%) percent per calendar month or the maximum rate
permitted by applicable law, whichever is lower. Customer shall pay NEWNET's
costs of collection, including reasonable attorneys' fees.
        
         Customer agrees to pay all taxes levied or based upon the Fees, or any
part thereof, including any property, sales or use tax, except for any tax
levied or based upon the income of NEWNET. NEW NET's royalties shall be due and
payable in full within thirty (30) days from date of invoice.

4.       INSTALLATION. Unless otherwise agreed by the Parties in a specific
Purchase Order, Customer shall be solely responsible for installation of the
NEWNET Systems. Deployment of NEWNET staff involved in the installation of the
NEWNET Systems on Customer's or Customer's End User's site shall be at the sole
discretion of NEWNET unless otherwise agreed to by NEWNET pursuant to NewNet's
Terms of System Support and Maintenance Service.

5.       WARRANTY. NEWNET grants to Customer the following sole and exclusive
warranties concerning each NEWNET System supplied by NEWNET to Customer; these
warranties supersede any other oral or written representations, warranties,
marketing presentations or other information submitted to Customer:


         5.1      NEWNET warrants that it has the full right and authority to
enter into and perform its obligations under this Agreement.

         5.2      NEWNET warrants to Customer that each NEWNET System will
perform under normal usage substantially in accordance with its applicable
Documentation for a period of ninety (90) days from its date of delivery to
Customer (the "Warranty Period.")

         During the Warranty Period, NEWNET will, at no extra charge,



                                       -2-


<PAGE>   12

                                   Appendix 1

                              NEWNET TERMS OF SALE

correct any material defect discovered in the NEWNET System so that it will
perform substantially according to its Documentation. Customer may enhance
and/or extend this warranty cove rage, provided Customer has paid for Support
Services or extended warranty coverage, as set forth in the Support Service
Agreement. 

         5.3      NEWNET does not warrant that during the Warranty Period the
NEWNET System will meet all of the Customer's or End User's needs, that the
operation of the NEWNET System will be error-free or uninterrupted, or that all
non-material errors in programming will be corrected.

         5.4      The obligations of NEWNET under Article 5.2, above, shall be
dependent upon:

                  (a)      Customer using proper skill and care in following
         fault finding procedures required by NEWNET,
       
                  (b)      Full cooperation with NEWNET in aiding NEWNET in
         reproducing faults and in diagnosing and rectifying any error
         (including, without limitation, at NEWNET' request, the submission of
         reasonable documentary evidence of such error and the provision of
         access to all agreed facilities during normal office hours).
      
                  (c)      Customers prompt report to NEWNET of any breach of
         warranty upon discovery.

         5.5      The foregoing warranties cover normal use and do not cover
damages incurred in shipping or failure due to abuse, misuse, or misapplication,
or as a result of service or modification of NEWNET System other than by NEWNET
or by any employee or agent of Customer who has not followed the procedures
recommended by NEWNET.

         5.6      NEWNET shall have up to ninety (90) days to cure any customer
identified non-conformities to this warranty that are reproducible at will by
NEW NET at NEWNET's site in Connecticut and agreed to by NEWNET to be in breach
of NEWNET's warranty described herein. Customer will then have up to thirty (30)
days to retest to determine whether the non- conformities were cured.
Notwithstanding this cure period, NEWNET will use all reasonable efforts to cure
such nonconformity in the shortest time possible.

         5.7      EXCEPT AS SET FORTH HEREIN, NEWNET MAKES NO WARRANTIES WITH
RESPECT TO THE NEWNET SYSTEM, EITHER EXPRESS OR IMPLIED, AND SPECIFICALLY
EXCLUDES ANY WARRANTY THAT THE HARDWARE OR SOFTWARE IS FIT FOR A PARTICULAR
PURPOSE AND ANY IMPLIED WARRANTY OF MERCHANTABILITY.

6.       RISK OF LOSS. Risk of loss of the NEWNET System shall pass to Customer
upon shipment thereof to Customer, and all shipments shall be made FOB Shipping
Point. Whenever NEWNET shall deliver or cause to be delivered to a common
carrier any



                                       -3-


<PAGE>   13

                                   Appendix 1

                              NEWNET TERMS OF SALE

NEWNET System or Hardware ordered by Customer, NEWNET shall not be responsible
for any delays or damages in shipment. 

7.       LIMITATION OF LIABILITY. NEWNET's entire liability and Customer's
exclusive remedy under this Agreement and the warranties set forth above, and
under the Object License, shall be as follows:

         7.1      In all situations involving performance or non-performance of
the NEWNET System, Customer's exclusive remedy shall be limited as follows:

                  (a)      NEWNET's adjustment or repair of the Software or, at
         NEWNET's option, NEWNET shall correct programming errors therein, or
      
                  (b)      if, after repeated efforts, as reasonably permitted
         by Customer, NEWNET is unable to provide one of the foregoing remedies
         and make the NEWNET System operate as warranted, Customer shall be
         entitled to terminate this Agreement and/or any applicable Purchase
         Order.

         7.2      NEWNET's liability for damages to Customer for any cause
whatsoever, and regardless of the form of action, whether in contract or in tort
including negligence and strict liability, with respect to each NEWNET System
shall be limited to damages incurred through the period of time ending ninety
(90) days from delivery of the NEWNET System to Customer. In no event will
NEWNET be liable for any damage caused by Customer's failure to perform its
responsibilities.

         7.3      IN NO EVENT SHALL EITHER PARTY HAVE ANY LIABILITY TO THE OTHER
PARTY, (A) FOR ANY CLAIM, LOSS, DAMAGE IN EXCESS OF THE AGGREGATE VALUE OF ALL
SYSTEMS AND SERVICES AT ANY TIME PURCHASED UNDER THIS AGREEMENT, OR (B) FOR ANY
INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES OR LOST PROFITS, BUSINESS REVENUE OR
GOOD WILL, HOWEVER CAUSED AND WHETHER ARISING UNDER CONTRACT, TORT OR OTHER
THEORY OF LIABILITY. THESE LIMITATIONS SHALL APPLY NOTWITHSTANDING THE FAILURE
OF THE ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.

8.       INTELLECTUAL PROPERTY RIGHTS

         8.1      Subject to the terms of this Agreement, NEWNET grants to
Customer a world-wide, non-exclusive, non-transferable license ("License") to
use, market, make one (1) backup copy of each item to NewNet Software for which
NEWNET has supplied Customer the key, sublicense and distribute (directly or
indirectly through its resellers and distributors) the Software to End Users.
The protections of any such sublicense shall inure to the benefit of NewNet.
     
         The Customer shall only acquire copies of the Software for distribution
by sublicense pursuant to the terms of this Agreement. The Customer shall



                                       -4-


<PAGE>   14

                                   Appendix 1

                              NEWNET TERMS OF SALE

only be permitted to market and sublicense the Software as stand alone Software
to End Users or as Composite Software. The Customer shall not distribute the
Software in any other manner without having first obtained written consent from
NEWNET.
     
         Once Software is sublicensed under this grant, the sublicense granted
with respect to such Software shall become perpetual and shall survive
termination of this Agreement. Any sublicense by Customer hereunder shall be
supported by a license agreement between Customer and the End User or other
sublicensee in form and content reasonably agreeable to NEWNET.
      
         In addition, NEWNET hereby grants to Customer a royalty-free license to
use and sublicense the Software for the sole purpose of demonstration and
training by Customer, its resellers and agents. It is understood that such use
includes customer trials and demonstrations conducted by Customer, its resellers
and agents, subject to the entering of a license agreement between Customer and
its resellers and agents in form and terms reasonably satisfactory to NEWNET.

         8.2      Title to the Software, all copies thereof and all rights
therein, including all rights in patents, copyrights, and trade secrets
applicable thereto, shall remain exclusively vested in NEWNET. Customer agrees
to obtain NEWNET's prior written permission before disclosing, transferring,
providing, or other-wise making available in any form, Software or any portion
thereof to any person other than employees of Customer or a sublicensee, as
authorized herein, who enter a license agreement.

         8.3      Customer agrees not to reverse compile or disassemble the
Software.

         8.4      Any permitted copy of the Software shall state that it is the
property of NEWNET in the following language:

         This copy of ________________ (insert name of SW or manual) is the
property of NewNet, Inc., 2 Enterprise Drive, Shelton, CT 06484, and is
protected under the copyright, trade secret and confidentiality laws of the
United States.

         8.5      To maintain the confidentiality of the Software and its
related documentation, Customer shall at a minimum take those precautions in
protecting the Software and related documentation it employs to protect its own
confidential information.

         8.6      All intellectual property rights in and to each NEWNET System
and NEWNET modifications thereto, if any, shall be owned by NEWNET, and none of
the NEWNET Systems, modifications thereto, or Documentation are to be construed
to be works for hire, unless expressly agreed to by NEWNET in writing.

         8.7      Unless otherwise provided in a Purchase Order, NEWNET hereby
grants to Customer a non-exclusive right to use, modify, translate, reproduce
and distribute copies of the Documentation to Customer's End



                                       -5-


<PAGE>   15

                                   Appendix 1

                              NEWNET TERMS OF SALE

Users, solely for the purpose of marketing, selling and servicing Customer's
Systems that include the NEWNET System and for no other
purpose.

         Customer agrees not to delete or remove any copyright or other
proprietary notice of NEWNET on each copy of the NEWNET System, and
Documentation (whether or not modified by Customer) and agrees to ensure that
such notice is reproduced upon each copy of the NEWNET System and the
Documentation made by it. NEWNET shall be the owner of all copyrights in any
modifications made to the Documentation by Customer. 

         8.8      Translations of the Documentation not available on mutually
agreeable terms from NEWNET and required by Customer shall be arranged and paid
for by Customer. The copyright in each such translation shall belong to NEWNET,
and Customer shall retain a non-exclusive license to such translation, however,
NEWNET may not use any Customer created translation without paying to Customer a
reasonable and mutually agreeable fee.

         8.9      Should Customer incorporate a portion(s) to the Documentation
into documentation produced and owned by Customer to describe Customer's
product, Customer agrees to place a notice at the beginning of such
documentation that the document contains NEWNET copyright protected material.


         8.10     NEWNET grants Customer a license to use the NEWNET logotype,
trade name and trademark in its Documentation, during the term of this
Agreement. Customer shall display prominently the NEWNET name and logotype in
any delivery of NEWNET System or Documentation and in any promotional material
with respect to the NEWNET System.

         NEWNET shall have the right to inspect customer sales literature and
product information and to require such changes as NEWNET may deem necessary or
appropriate to protect its logotype, trade name and trademark. 8.11 Subject to
use of the NEWNET copyright notice required in Article 8.4, above, NEWNET hereby
acknowledges and agrees that Customer may, in its absolute and sole discretion,
private label or brand any and all NEWNET Systems acquired under this Agreement.

         If Customer determines to private label or brand any such NEWNET
System, Customer may do so using any name, mark, trade name, brand and/or
trademark that it chooses. Any such names, marks, trade names, brands and/or
trademarks may be displayed on or with the NEWNET System in any manner chosen by
Customer.

         Customer will have no obligation to in any way display or use any name,
mark, trade name, brand or trademark of NEWNET on or with any



                                       -6-


<PAGE>   16

                                   Appendix 1

                              NEWNET TERMS OF SALE


products that Customer chooses to private label or brand, other than to use the
NEW NET copyright notice, as described above.

         Nothing herein will in any way convey to either Party any right, title
or interest in any names, marks, trade names, brands and/or trademarks of the
other Party. Customer may also, if it so chooses, display any name, mark, trade
name brand or trademark of NEWNET according to any reasonable instructions
conveyed to Customer in writing according to the notice provisions of this
Agreement. All goodwill in any mark or brand name of Customer shall belong
exclusively to Customer.

9.       INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS

         9.1      NEWNET INDEMNITY. NEWNET agrees to defend, indemnify and hold
harmless Customer from and against any and all loss, damage, liability or
expense (including reasonable attorneys' fees) assessed against Customer, or
incurred by Customer, arising out of any claim being made or suit brought by any
third party alleging that the Software violates said third party's United States
patent, copyright, trademark, trade secret or other proprietary right in the
United States.

         This indemnity shall not apply to the extent that the third party
infringement is caused by modifications to the Software not made by NEWNET, the
combination of such Software with a NEW NET System or equipment not provided by
NEWNET or reasonably contemplated by this Agreement, or NEW NET's modifications
to the Software in response to specifications provided by Customer (to the
extent the Software would not have been infringing but for such specifications).
 
        NEWNET excludes from this indemnity all Hardware. However, NEWNET shall
pass to Customer any Hardware manufacturer's or supplier's intellectual property
indemnity received by NEWNET that arises out of NEWNET's purchase of hardware
that is resold to Customer hereunder as a part of a NEWNET System.
    
         If Software becomes or is likely to become the subject of a suit or
claim of patent, trademark or other intellectual property right or copyright
infringement, NEWNET shall, in its sole discretion and at its own expense,
perform one of the following options:

                  (a)      procure for Customer the right to continue to use
         such Software; or substitute the same with equally suitable Software;
         or

                  (b)      modify Software so that it no longer constitutes an
         infringement and maintains substantially the same or improved
         functionality, or
        
                  (c)      should none of the foregoing options be reasonably
         procurable, Customer shall return the NEWNET System containing the
         infringing Software to NEWNET, and NEWNET's sole liability shall be to
         credit Customer for amounts paid therefor by Customer, less an amount



                                       -7-


<PAGE>   17

                                   Appendix 1

                              NEWNET TERMS OF SALE


         for depreciation equal to twenty-five percent (25%) per year.

         With respect to any NEWNET System or Software provided by Customer to
an End User, NEWNET's obligation to indemnify Customer hereunder shall be no
broader than Customer's obligation to indemnify its End User against
intellectual property infringement.

         NEWNET SHALL NOT BE SUBJECT TO LIABILITY TO CUSTOMER FOR AN AMOUNT
UNDER THIS ARTICLE 9.1 THAT IS MORE THAN THE AGGREGATE ROYALTIES PAID BY
CUSTOMER TO NEWNET UP TO THE DATE OF THE LIABILITY.

9.2      CUSTOMER INDEMNITY

         Customer agrees to defend, indemnify and hold harmless NEWNET from and
against any and all loss, damage, liability or expense (including reasonable
attorneys' fees) assessed against NEWNET, or incurred by NEWNET, arising out of
any claim being made or suit brought by any third party alleging that the NEWNET
System violates said third party's United States patent, copyright, trademark,
trade secret or other proprietary right in the United States to the extent such
infringement is caused by

         (a)      modifications to the NEWNET System not made by NEWNET, or

         (b)      the combination of such NEWNET System with a NEWNET System or
equipment not provided by NEWNET or reasonably contemplated by this Agreement,
or

         (c)      NEWNET modifications to the NEWNET System in response to
Customer's specifications.

         Customer also indemnifies and holds NEWNET harmless against any claims
that any value-adding product of Customer that uses the NEWNET System infringes
any US patent, copyright, trademark or other proprietary rights of another in
the United States. 

9.3      GENERALLY. In the event of any claim or suit is brought against either
Party arising out of matters referred to in this Article 9, the indemnifying
Party shall be promptly notified thereof and may at its own expense and
discretion conduct all negotiations for the settlement of the same, and any
litigation that arises therefrom.

         The indemnified Party shall not make any admission which might be
prejudicial thereto, unless the indemnifying Party shall have failed within a
reasonable time after written notice to take over the conduct of the
negotiations or litigation.

         The indemnified Party shall make available to the indemnifying Party
all defenses against such claim or suit known to or available to the indemnified
Party.

         This Article 9 states the entire liability and the exclusive remedy of
each of the Parties regarding the infringement or alleged infringement by use of
any NEWNET System of any


                                       -8-


<PAGE>   18

                                   Appendix 1

                              NEWNET TERMS OF SALE

patent, trademark or copyright or other intellectual property right.

10.      TERMINATION

         10.1     TERMINATION FOR CONVENIENCE. This Agreement may be terminated
at any time after the initial term with or without cause by either Party upon
the giving of not less than ninety (90) days written notice to the other Party.

         10.2     TERMINATION FOR BANKRUPTCY.This Agreement shall automatically
be terminated should either Party

         (a)      apply for or consent to the appointment of or taking of
possession by a receiver, custodian, trustee, or liquidator of itself or of all
or a substantial part of its property, or

         (b)      make a general assignment for the benefit of creditors, or
commence a voluntary case under the Federal Bankruptcy Code (as now or hereafter
in effect) or any similar laws respecting debtors' and creditors' rights in any
other jurisdiction, or

         (c)      fail to contest in a timely or appropriate manner or acquiesce
in writing to any petition filed against it in an involuntary case under such
Bankruptcy Code or any similar laws or

         (d)      make any application for the appointment of a receiver,
custodian, trustee, or liquidation of itself or of all or a substantial part of
its property, or its reorganization, or dissolution or admit its inability to
pay its debts as they become due.

         References to the "Parties" in this Termination Clause shall be deemed
to include any firm or corporation controlling either Party. 

         10.3     TERMINATION FOR UNCURED BREACH. In the event that either Party
materially defaults in the performance of any of its duties and obligations
hereunder (other than a default described in Article 10.2, above, or a default
by Customer in the payment of money to NEWNET hereunder) which default is not
substantially cured within sixty (60) days after receipt of written notice by
the defaulting Party specifying the default, then the Party not in default may
terminate this Agreement as of the date specified in such notice.

         10.4     TERMINATION OF CUSTOMER FOR FAILURE TO PAY. The failure of
Customer to pay any sum due hereunder which is not reasonably disputed by
Customer for a period of thirty (30) days after written notice of such failure
is delivered by NEWNET to Customer, shall be deemed a material breach of this
Agreement, and grounds for termination by NEWNET without advance notice or a
period in which to cure the default.

         10.5     CONSEQUENCES OF TERMINATION. Upon termination of this
Agreement, it is expressly agreed by the Parties that:

                  (a)      all licenses previously and reasonably granted to
         Customer's End Users by Customer, if any, shall remain in full force
         and effect, subject to payment of any amounts due NEWNET in connection
         therewith; and

                  (b)      the license granted to Customer under the above
         Software



                                       -9-


<PAGE>   19

                                   Appendix 1

                              NEWNET TERMS OF SALE

License shall continue in effect only to the extent necessary to comply with
Customer's obligations to support existing and authorized sublicenses.

         The above license extensions are subject to payment of any amounts due
NEWNET in connection therewith.

         The remedies set forth in this Article 10 shall not be exclusive but
shall be in addition to any other remedies available to the nondefaulting Party
at law or in equity.

         The provisions of the following Articles of these Terms of Sale shall
survive the termination of the Supply or Purchase Agreement or to which these
Terms of Sale are appended: Articles 7, 8 and 9. The warranty provisions of
Article 5 shall survive the termination of this Agreement only if termination
was not due to a breach by Customer of its obligations under this Agreement.

11.      FORCE MAJEURE

         11.1     Neither Party shall be liable for any delay in meeting or for
failure to meet its obligations under this Agreement due to any cause outside
its reasonable control including, without limitation, strikes or lockouts, Acts
of God or of the public enemy, war, riot, malicious acts of damage, blizzards,
ice, lightning, floods, severe storms, fire, acts of governmental authority,
failure of the electricity supply, failure or delay on the part of any suppliers
or subcontractors attributable in themselves to Force Majeure as defined under
the law of the location of the supplier or subcontractor in question, or the non
availability or shortage of materials. The inability to pay money shall not be
deemed a cause outside the control of a Party.

         11.2     If a Party is prevented from meeting its obligations due to
any cause outside its reasonable control, it shall notify the other Party of the
circumstances and other Party shall extend the time for the nonperforming
Party's performance by the number of days by which it is so prevented.

12.      INDEPENDENT CONTRACTOR. The relationship of NEWNET and the Customer
established by this Agreement is that of independent contractors, and nothing
contained in this Agreement will be construed:

         12.1     to give either Party the power to direct and control the
day-to-day activities of the other,

         12.2     to constitute the Parties as partners, joint ventures,
co-owners or otherwise as participants in a joint or common undertaking, or

         12.3     to allow either Party to create or assume any obligation on
behalf of the other for any purpose whatsoever.

13.      ASSIGNMENT. This Agreement will be binding upon and inure to the
benefit of the Parties hereto and their permitted successors and assigns.
Notwithstanding the foregoing, neither this Agreement, nor any rights or
obligations hereunder, may be assigned or otherwise transferred, whether by
operation of law or otherwise by either Party, without prior written consent of
the other Party, which consent shall not



                                      -10-


<PAGE>   20

                                   Appendix 1

                              NEWNET TERMS OF SALE


be unreasonably withheld, and any assignment or other transfer without such
prior written consent will be invalid.

14.      APPLICABLE LAW. This Agreement shall be governed by and construed
according to the laws of the State of Connecticut.


15.      WAIVER AND SEVERANCE. No delay or failure of either Party in enforcing
against the other Party any provision of this Agreement, and no partial or
single exercise by either Party of any right hereunder, shall be deemed to be a
waiver of, or in any way prejudice, any right of that Party under this
Agreement. Should any part of this Agreement be illegal or unenforceable, it
shall be severed from this Agreement and the balance of the Agreement shall
continue in force.

16.      COMPLIANCE WITH US EXPORT LAWS. Customer agrees never to export,
directly or indirectly, proprietary products, technical data, Software or NEWNET
Systems, furnished by NEWNET to Customer pursuant to this Agreement, to any
country outside the United States which export may be in violation of Article
379.4 of the Export Administration Regulations, or any other US export control
law or regulation. Customer represents and warrants that in reexporting these
proprietary products, technical data or NEWNET Systems it will not violate this
export Administration Regulation or any other US export control law or
regulation. It will be the Customer's responsibility to acquire proper US export
licenses at Customer's expense.

17.      NO THIRD PARTY BENEFICIARIES. This Agreement is made and entered into
solely for the benefit and protection of the Parties and their successors and
permitted assigns, and no other person or entity shall have any cause of action
hereunder.



END



                                      -11-


<PAGE>   21


                                    ADDENDUM
                                       to
           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT

This Addendum consists of amendments to and explanations of the terms of the
NEWNET Software Support and Maintenance Services Agreement ("Support Agreement")
to which this Addendum is attached. All references in the Support Agreement to
"this Agreement" shall mean the Support Agreement. References to Article numbers
below follow the numbering scheme of the Support Agreement:

Art. 1.2   Amend to read, "Service Period" shall mean the warranty period
           described in the Support Agreement and the initial eighteen (18)
           month term of the Support Agreement, whichever is longer, and any
           subsequent period for which Customer has purchased and paid for
           Support Services or Support renewal on mutually agreeable prices
           therefore. Support Services shall include System Support Services,
           Software Support Services and Hardware Support Services as defined in
           Attachment 2."

Art. 1.3   Amend to read, ""Critical Error" shall mean an error that creates a
           condition which makes impossible the performance of one or more major
           functions of the NEWNET System."

Art. 1.5   Amend to read, "Art. 1.5 "Serious Error" shall mean an error that
           creates a condition which makes difficult the performance of one or
           more major functions of the NEWNET System, but which can be
           circumvented or avoided on a temporary basis."

Art. 1 6   Amend to read, "Art. 1.6 "Minor Error" shall mean an error that does
           not impair the performance or continued performance of one or more
           serious functions of the NEWNET System."

Art. 1.8   Add the following, "Art. 1.8 (a) "NEWNET System" shall mean the
           NEWNET Hardware and Software sold to Customer hereunder."

Art. 1.11  Amend to read, "Art. 1.11 "Response" shall mean the process and
           response times described in Attachment 4 hereto, entitled NewNet
           Escalation Process."

Art. 1.14  Amend to read, "Art. 1.14 "System Support Services" shall mean the
           training, technical and field service support provided to NEWET
           Systems for Customers who have paid NEWNET's support fees described
           in Attachment 5 hereto."

Art. 2     In the first line, delete the word, "System". Amend the third line to
           read, "--the original Customer for the NEWNET Systems- -."

Art. 4.1   Amend the fourth and sixth lines to read, "- -NEWNET Systems--."
           Amend eighth line to read, "- - found in Attachment 5 hereto."

Art. 4.2   Amend the fifth line to read, "- -at NEWNET's and Customer's
           discretion,--." Amend eighth line to read, "- - found in Attachment 5
           hereto."



                                       -1-


<PAGE>   22


Art. 4.3     Add article to read, "If at the end of a Service Period, certain
             NewNet products are still under warranty coverage, NewNet shall
             continue to honor warranty for such products until the end of such
             respective warranty term."

Art. 5       Amend the first paragraph to read in its entirety, "The Customer is
             entitled to the following services during the first eighteen (18)
             month term of this Agreement for the price described in Attachment
             5 hereto. Thereafter, Customer may purchase System Support Services
             at a mutually agreeable prices for services described in Attachment
             5 hereto."

             Amend the first sentence of the second paragraph as follows,
             "NEWNET System Support may be extended on an eighteen month term
             basis, subject to mutually agreeable cost of service." In the third
             paragraph, line 4, delete words, "in its discretion."

Art. 5.1     Amend to read, "NewNet TAC will provide telephone assistance to
             answer questions regarding usage of the NEWNET Systems, and
             clarification regarding any related documentation provided by
             NEWNET. During Out of Hours, NEWNET TAC engineers will carry pagers
             to alert them when their assistance is required and return
             Customer's page within such applicable time or times as are
             described in Attachment 4 hereto. During NEWNET's normal business
             hours, NewNet TAC will:"

Art. 5.1(g)  Delete in its entirety.

Art. 6       Amend to read, "Once NEWNET reasonably determines that a Critical,
             Serious or Minor Error exists in the Software, during Normal
             Business Hours, it will use reasonable commercial efforts to
             provide Customer with one of the following resolutions, in a manner
             consistent with the processes of Attachment 4 hereto:"

Art. 6.3(b)  Amend to read in its entirety, "If NEWNET cannot duplicate a
             reported software error using the above techniques, NEWNET and
             Customer will determine whether it is appropriate to send a service
             person to Customer's facility to work with Customer's personnel to
             duplicate said error. If the error is not NEWNET's exclusive fault
             or error, then Customer will pay NEWNET's time, material, living
             and travel expenses connected with such on-site support, at
             NEWNET's time and material rates described in Attachment 5 hereto."

Art. 6.3(c)  Amend line 2 to read, "--the Customer shall use reasonable
             commercial efforts to test and evaluate- -."

Art. 7       Amend to read, "NEWNET shall provide Hardware Support Services to
             Customer pursuant to Attachment 2 hereto, during the warranty term
             of each item of Hardware and at all other times in accord with
             Attachment 2 hereto."

Art. 8.1     Amend line two to read, "--Services are subject to Customer's
             reasonable commercial compliance with--."



                                       -2-


<PAGE>   23


Art. 8.2.4   Add the following text: "The Customer must have already tried to
             recreate the reported problem. If the Customer was not able to
             recreate the reported problem, all system logs, alarms, and
             configuration date must be forwarded to NEWNET to assist in
             resolution of the problem."

Art. 8.3.1   Add the following sentence: "Such new Software shall be accompanied
             by evidence that the error has been remedied. Patches will be
             provided with "read me" files, physical documentation and/or
             release notes, when available."

Art. 9       Add to the end of this Article: "NEWNET will notify Customer at
             least one year in advance prior to discontinuing a Product or
             support of a Product. In such event, NEWNET will offer Customer
             functionally equivalent Software on terms no less favorable than
             those of the OEM/VAR Agreement NEWNET, as a convenience only to
             Customer, offers the following examples of Version, Release and
             Revision of its Software:

<TABLE>
               Version      Release        Revision
                  <S>          <C>            <C>       <C>
                  3           .5              .3        = AccessMANAGER. 3.5.3
                  3           .5              .0        = AccessMANAGER. 3.5.0
                  3           .4              .1        = AccessMANAGER. 3.4.1"

</TABLE>
             Delete the last sentence of this Article and replace it with the
             following sentence, "This support is generally in the form of a
             patch, fix package or new Revision or Release or Version. NEWNET
             shall endeavor to take Customer's reasonable requests into
             consideration whenever practical in determining the form for the
             above support."

Art. 13.2    Amend line three and the balance of this Article to read, "--shall
             be renewed for successive eighteen (18) month terms for so long as
             Customer does not give NEWNET written notice of intent not to renew
             this OEM/VAR Agreement at least ninety (90) days prior to the end
             of the initial or each successive term, subject to mutual agreement
             on pricing. In the event of termination or nonrenewal of the
             OEM/VAR Purchase Agreement to which this System Support Agreement
             was originally appended, this System Support Agreement and the
             prices found in Attachment 5 hereto shall continue to be in full
             force and effect, subject to mutual agreement of the Parties as to
             pricing in the event of each renewal of this Agreement"

Attachment 2

Art. 1       Delete this entire Article and replace it with the following text:



                                       -3-


<PAGE>   24


             "Term of HW Support. The following Hardware Support Services shall
             be provided to Customer at no charge during the first one (1) year
             limited Hardware warranty period of all NewNet Hardware Products
             delivered to Customer. After such warranty term, the Customer may
             elect to purchase Hardware Support to extend these services to the
             end of the term for which the Software Service Agreement is
             purchased. During the initial and subsequent terms the Hardware
             warranty and Hardware Support Services may overlap. Should Customer
             decide not to purchase Hardware Support Services after the
             expiration of the Hardware warranty period, these Services are
             available on a per incident basis in accordance with the rates
             described in Attachment 5 to Appendix 2 to the Purchase Agreement.
             Hardware support shall be subject to the terms of the Purchase
             Agreement, including the appended Terms of Sale and Support
             Agreement. Should there be a conflict between the terms of that
             Agreement and any of its Appendixes and the terms of this
             Attachment 2, the terms of this Attachment shall prevail."

Art 2.4      Add the following new Article: "Art. 2.4 If a Hardware error is a
             Critical Error, NEWNET will promptly send a replacement board to
             Customer, who will promptly return the board which caused the
             Critical Error to NEWNET."

Appendix. 3  Replace the first paragraph of Appendix 3 with the following: "The
             AccessMANAGER. pricing referenced in this Agreement will apply to
             all current and future Releases of the AccessMANAGER. product,
             excluding Releases which incorporate the distributed redundancy
             architecture. During the term of this Agreement, Summa Four will
             have access to, at mutually agreed upon prices, all fixes,
             Revisions, and Updates as well as all new country variants of such
             current AccessMANAGER. products."

The Parties signify their agreement to the above amendments to the NEWNET System
Support Agreement by having their duly authorized representatives sign where
indicated below:



NEWNET, Inc.


By:
    -------------------------------
   Its:


Summa Four, Inc.

By:
    -------------------------------
   Its:



                                       -4-


<PAGE>   25

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



This NEWNET Software Support and Maintenance Services Agreement (the "System
Support Agreement") is entered by and between NEWNET, Inc. ("NEWNET"), and
Customer as of the Effective Date. NEWNET and Customer may be referred to herein
as the "Party" or "Parties". The definitions of NEWNET, Customer and Effective
Date are found in the OEM/VAR Agreement between the Parties.

The Parties covenant and agree as follows:

1.       Definitions. Definitions used in the OEM/VAR Agreement to which this
System Support Appendix is attached shall apply to this Appendix. The following
are additional defined terms used only in this Appendix:

         1.1      "NEWNET Facility" shall mean NEWNET engineering offices,
currently located in Shelton, Connecticut.

         1.2      Service Period" shall mean the period for which Customer has
purchased and paid for Support Services, or Service Renewal.

         1.3      "Critical Error" shall mean an error that creates a condition
which makes impossible the performance of one or more critical functions of the
NEWNET Software.

         1.4      "Hardware" shall mean hardware supplied by NEWNET.

         1.5      "Serious Error" shall mean an error that creates a condition
which makes difficult the performance of one or more critical functions of the
NEWNET Software, but which can be circumvented or avoided on a temporary basis.

         1.6      "Minor Error" shall mean an error that does not impair the
performance or continued performance of one or more critical functions of the
NEWNET Software.

         1.7      "Normal Business Hours" shall mean for services performed at
NewNet TAC, 8:30AM to 5:30PM USA Eastern Standard Time, Monday through Friday,
excluding NEWNET public holidays; for services performed at Customer's site,
Normal Business Hours shall mean Customer's normal daytime business hours at
Customer's site.

         1.8      "Software" and "NEWNET Software" shall mean the NEWNET
software licensed to Customer hereunder.

         1.9      "Out of Hours" shall mean for services performed at NewNet
TAC, 5:30PM to 8:30AM Monday through Friday USA Eastern Standard Time, and all
day Saturday, Sunday and NEWNET holidays; for services performed at Customer's
site, Out of Hours shall mean services that are not performed within the
Customer's Normal Business Hours.

         1.10     "Resolution" shall mean one or more fixes to errors reported
by the Customer, tested and delivered to



                                       -1-


<PAGE>   26

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


Customer in the form of a fix package, or patch, release, repair or replacement
of, Hardware or Software, or any portion thereof, and/or any other fixes deemed
mutually acceptable.

         1.11     "Response" shall mean the time taken to respond to the
Customer, sufficient to discuss and conduct initial analysis of an error
reported by the Customer in the Hardware or Software.

         1.12     "Release" shall mean a fix package or upgrade to a Version
that improves product attributes, capabilities or usability or contains
enhancements thereto, and may also incorporate corrections to Critical, Serious,
and Minor Errors thereto.

         1.13     "Revision" shall mean an update to a Version that remedies
existing Critical, Serious, or Minor Errors or contains minor enhancements
thereto.

         1.14     "System Support Services" shall mean the training, technical
and field support services to be provided by NEWNET to a Customer hereunder who
has paid NEWNET"s support fees.

         1.15     "NewNet TAC" shall mean the NEWNET Technical Assistance
Center, which is currently located in Shelton, Connecticut.

         1.16     "User" shall mean the Customer and any permitted End User.

         1.17     "Version" shall mean the software platform that the current
Revision and Release is based upon.

2.       General. The System Support Services described in this Agreement will
be provided only to the original Customer for the NEWNET Software unless
otherwise agreed in writing.

3.       Confidentiality. All Confidential Information exchanged hereunder shall
be subject to the terms of the Mutual Nondisclosure Agreement entered by the
Parties and found as Appendix 4 to the OEM/VAR Agreement to which this Agreement
is attached.

         Notwithstanding the termination date of the Mutual Nondisclosure
Agreement, it shall remain in effect for so long as this Agreement and any
renewal or successor agreement are in effect and the obligation of
confidentiality shall survive the termination of this Agreement pursuant to the
terms of the Mutual Nondisclosure Agreement.

4.       NEWNET System Support Services:

         4.1      Installation. Unless otherwise agreed, the Customer is
responsible for the installation and post-warranty maintenance of the NEWNET
Software. System Support Services are available from NEWNET as outlined in the
following sections. NEWNET may install the NEWNET Software for the Customer, at
Customer's request, by paying NEWNET's on-site rates found in Appendix 3 to the
Purchase Agreement.

         4.2.     Field Service. NEWNET will provide System Support Services to
Customer's personnel at locations other than the NEWNET Facility, including
without limitation, hands-on



                                       -2-


<PAGE>   27

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


trouble shooting or system relocation, at NEWNET discretion, subject to
personnel availability, and payment of NEWNET on-site service rates found in
Appendix 3 to the Purchase
Agreement.

5.       Software Support Services. The Customer is entitled to the following
services during the Service Period for a particular NEWNET Software for the
applicable price found in Appendix 3 to the Purchase Agreement.

         NEWNET SYSTEM Support extends on a year to year basis. In the case of a
new Service Agreement, its initial term will begin on the date that the
applicable warranty expires. In the case of a Service renewal, the effective
date of the renewal will be the date the Service Renewal is executed and the
termination date will be as described in the Renewal Agreement. NEWNET may
modify any of the provisions of the Service Agreements described herein for
subsequent terms provided that it gives to the Customer no less than thirty (30)
days advance written notice prior to the renewal of such Agreement(s). It is the
Customer's responsibility to extend the Agreement(s) before the termination of
the existing term. Election to purchase or extend NEWNET Support Service must be
made to NEWNET in writing.

         If the System Support Services Agreement has lapsed, then the Customer
can purchase such Revisions, Releases and Versions at the regular list prices
offered by NEWNET in its discretion. Software Upgrades (if any) can be purchased
when available.

         5.1      7x24 Service. NewNet TAC will provide telephone assistance to
answer questions regarding usage of the NEWNET Software and clarification
regarding any documentation provided by NEWNET. During Out of Hours, NewNetTAC
engineers will carry pagers to alert them when their assistance is required and
return Customer's page within one (1) hour of receipt. During NEWNET's Normal
Business Hours, NewNetTAC will:

                  a.       Investigate and analyze all reported Critical,
         Serious, and Minor Errors and determine if such error(s) exist in the
         Hardware, Software or both.

                  b.       Make available the means by which Customer may, if it
         so elects, report errors through the electronic mail network.

                  c.       Monitor NEWNET Software(s) with a modem at Customer's
         site. If Customer provides modem access to a NEWNET Software, then
         NewNet TAC staff will remotely diagnose such NEWNET Software when
         errors are reported.

                  d.       Replace any defective media on which the Software has
         been provided, if necessary.

                  e.       Provide Software Revisions (if any) at no charge
         during the term of the System Support Agreement.



                                       -3-


<PAGE>   28

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


                  f.       Provide Software Releases (if any) at NEWNET's
         prevailing rates for Systems Support Customers.

                  g.       If the System Support Agreement has lapsed, then the
         Customer can purchase Releases, Versions, and Revisions at the list
         price offered by NEWNET in its discretion. Software Upgrades (if any)
         may be purchased when available.

6.       Resolution of Errors. Once NEWNET reasonably determines that a
Critical, Serious or Minor Error exists in the Software, during Normal Business
Hours, it will use reasonable commercial efforts to provide Customer with a
Resolution as follows:

         6.1      Provide telephone assistance regarding Critical, Serious, and
Minor Errors in the Hardware, Software or both as reported by Customer.

         6.2      Respond with a plan for correcting an error within the
following times:

<TABLE>
<CAPTION>
                     Error                    Response Times
                     -----                    --------------
                    <S>                 <C>
                    Critical            Within one (1) business day
                    Serious             Within two (2) business days
                    Minor               Within five (5) business days
</TABLE>


         6.3      Resolve each Critical and Serious Error reported in writing by
the Customer in the following steps:

                  (a)      NEWNET will attempt to duplicate a reported software
         error. If NEWNET can duplicate the reported software error at NEWNET's
         offices, or, if practical, by remote dial-up access to and manipulation
         of the NEWNET Software, then NEWNET will determine the necessary
         corrective action for Errors and use reasonable commercial efforts to
         deliver a Resolution for such Errors within a mutually agreed time.

                  (b)      If NEWNET cannot duplicate a reported software error
         using the above techniques, NEWNET will determine whether it is
         appropriate to send a service person to Customer's facility to work
         with Customer's personnel to duplicate said error. NEWNET will only
         send a service person if Customer so requests at Customer's additional
         cost for NEWNET's time, material, living and travel expense connected
         with such on-site support. Such on-site support will be provided at
         NEWNET's standard time and material rates prevailing at the time of the
         on-site support, plus reasonable travel and living expenses.

                  (c)      Upon delivery to the Customer of each Resolution
         pursuant to this Section, the Customer shall test and evaluate said
         Resolution in order to determine whether the error reported by the
         Customer has been corrected. The Customer shall have thirty (30) days
         from receipt of said Resolution to notify NEWNET in writing that it
         either accepts or rejects the Resolution. Customer's failure to report
         will be deemed acceptance. If said Resolution is not accepted by the
         Customer for a



                                       -4-


<PAGE>   29

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


         stated and appropriate reason, NEWNET and Customer may agree to repeat
         the procedures pursuant to this section.

7.       Hardware Support NEWNET shall provide Hardware Support Services should
Customer elect such services. NEWNET Hardware Support Services are described in
Attachment 2 hereto.

8.       Customer's Obligations

         8.1      NEWNET's System Support Services are subject to Customers
compliance with the obligations set forth below. If the Customer fails to comply
with these obligations, then NEWNET shall have the right to provide Support
Services at its regular time and materials rates.

         8.2      Customer shall file with NewNet TAC the Service Request Form,
Attachment 3 hereto, in order to complete a Purchase Order for System Support
Services.

                  8.2.1    Customer shall be responsible for the interface
         between software for which System Support Services is available and all
         other software used by Customer.

                  8.2.2    Customer shall provide prompt notice to NEWNET of any
         problems with the Hardware or the Software. All errors reported
         verbally reported by the Customer shall be promptly confirmed by the
         Customer in writing and shall be in sufficient detail to enable NEWNET
         to duplicate the error and to certify that the error has been remedied.

                  8.2.3    Service requests should be forwarded by fax, e-mail
         or other written form. Customer shall provide NEWNET with the name of
         the product and the version and the serial number. The request shall
         include, if feasible, a test or program fragment and any additional
         information that demonstrates the Customer's problem. If the Software
         or Hardware is failing, the Customer shall provide a copy of the output
         from the failing product, typically in the form of a diagnostic
         message. If feasible, the Customer shall report the exact manner in
         which the product was being used and the command line options.

                  8.2.4    Problems reported to NEWNET must be outside the
         ordinary course of maintenance and beyond the capability of Customer's
         support personnel trained in the NEWNET Products.

                  8.2.5    The Customer shall maintain operation and maintenance
         personnel capable of providing fault isolation and problem
         determination consistent with the training provided by NEWNET to
         Customer, following NEWNET training. Customer shall assure that such
         personnel are available at the site by telephone during periods when
         NEWNET system maintenance services are being performed.
         
                  8.2.6    In order to allow a Resolution, Customer must provide
         NEWNET with reasonable access to its Hardware and Software upon request



                                       -5-


<PAGE>   30

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


         by NEWNET. Customer shall provide necessary dial-up facilities and
         allow qualified NEWNET personnel to access and operate the Purchaser's
         equipment via a dial-up line. NEWNET's obligations hereunder are
         subject to the availability of this access. NEWNET shall treat any
         confidential information of Customer obtained hereunder as
         "Confidential Information" under the Mutual Nondisclosure Agreement
         attached hereto as Appendix 4.

                  8.2.7    Customer hereby grants NEWNET authorized
         representative access, subject to Customer's normal security
         restrictions, to the Customer's site, and all related equipment and
         facilities, for the purpose of providing System Support Services.
         NEWNET will comply with Customer's standard rules and regulations for
         access, a copy of which will be furnished to NEWNET by the Customer
         upon execution of this Agreement. Any delays or return calls resulting
         from lack of free access to perform the required services will be
         billed according to NEWNET Support Service rates for field work. In
         addition, Customer will provide NEWNET access to electrical power and
         other utilities, and telephone and fax access to NEWNET, all at
         Customer's expense.
        
         8.3      NEWNET shall not be responsible for Resolving an reported
error should Customer fail to carry out any of the below obligations:
     
                  8.3.1    Customer shall incorporate in the Software any new
         Version, Release or Revision that NEWNET has offered to provide to
         Customer to remedy the alleged error.
      
                  8.3.2    Customer shall comply with the maintenance and repair
         obligations set forth in the documentation provided with the NEWNET
         Software and in NEWNET's user interface, maintenance, troubleshooting,
         field installation and support manuals.

                  8.3.3    Customer shall not modify the NEWNET Software.

                  8.3.4    Customer shall not mishandle or damage the NEWNET
         Hardware other than by ordinary wear and tear.

9.       Support of Discontinued or Superseded Product. NEWNET reserves the
right to develop and introduce enhancements to products and to improve products
and to discontinue the design and manufacture of existing products. NEWNET will
use its reasonable efforts to notify Customer regarding availability of new
Versions, Releases and Revisions. Each new Release or Revision supersedes the
preceding Release or Revision. NEWNET provides support to:

<TABLE>
<CAPTION>
               Version            Release           Revision
               -------            -------           --------
               <S>                <C>                <C>
               Latest             Latest             Latest
               Latest             Latest             Preceding
               Latest             Preceding          Latest

</TABLE>



                                      -6-
<PAGE>   31
                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


This support is generally, in NEWNET's unilateral discretion, in the form of a
software patch, fix package or new Revision, or Release or Version. 10. Limited
Warranty; Limitation on Liability and Customer's Exclusive Remedy. If NEWNET
fails to fulfill its obligations under this System Support Agreement with
respect to any covered NEWNET Software, Customer's sole and exclusive remedy is
the right to terminate the relevant System Support Services order, in writing,
and receive reimbursement of the portion of the System Support Services for the
unused portion of the annual support contract plus one additional month's
support charge.

OTHER THAN AS EXPRESSLY SET FORTH HEREIN, NEWNET MAKES NO WARRANTIES WITH
RESPECT TO ITS SYSTEM SUPPORT SERVICES OR ANY RESOLUTION, PATCH, FIX PACKAGE,
REVISION, RELEASE OR VERSION PROVIDED HEREUNDER, EITHER EXPRESSED OR IMPLIED,
AND SPECIFICALLY EXCLUDES (i) ANY WARRANTY THAT THE SAME ARE FIT FOR A
PARTICULAR PURPOSE AND (ii) ANY IMPLIED WARRANTY OF MERCHANTABILITY. IN NO EVENT
SHALL NEWNET BE LIABLE FOR ANY LOST PROFITS OR SAVINGS, OR FOR INCIDENTAL,
INDIRECT OR CONSEQUENTIAL DAMAGES, REGARDLESS OF THE FORM OF ACTION, EVEN IF
NEWNET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM
AGAINST CUSTOMER BY ANY THIRD PARTY.

11.      License Limitations. The rights granted to Customer, the use
limitations and Customer's responsibilities to prevent unauthorized disclosure
specified in the License applicable to the NEWNET Software covered by System
Support Services hereunder apply equally to all System Support Service elements,
including Resolutions, patches, fix packages, Versions, Releases and Revisions
delivered to Customer hereunder.

12.      Notices and Other Communications. Notices shall be in writing (unless
otherwise designated herein) and shall, for all purposes, be deemed to be fully
given and received if delivered personally, or if sent by facsimile with a copy
sent by Express, certified or registered mail, postage prepaid, to the other
Party at its address stated in Attachment 1 hereto, or to such other address as
the respective Party shall advise in writing.

13.      Term of Agreement

         13.1     The term of this Agreement shall begin on the Effective Date
and unless otherwise terminated as provided herein, shall continue in full force
and effect until the expiration date of the initial term of this Agreement found
in Attachment 1 hereto.

         13.2     Unless otherwise terminated as provided herein, the initial
term of this Agreement shall be



                                       -7-


<PAGE>   32

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


renewed for successive one (1) year terms after the initial term, unless either
Party gives written notice to the other Party not less than thirty (30) days
before the end of the initial or each successive term that it elects not to
extend the Agreement for the next one (1) year term.


IN WITNESS WHEREOF, EACH PARTY HERETO HAS SIGNIFIED ITS AGREEMENT TO THE ABOVE
PROVISIONS THROUGH ITS DULY AUTHORIZED REPRESENTATIVE AS OF THE ABOVE DATE:


NewNet, Inc.                              Customer:


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

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

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






                                       -8-


<PAGE>   33

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



                                  ATTACHMENT 1
              Effective Date and Term of Software Support Agreement
                         Names and Addresses of Parties
                    Appointment of Person to Receive Notices

1.       The effective date of the System Support Agreement is February 17, 1997
         and it shall continue in force for a period of eighteen (18) months
         unless terminated earlier.

2.       Identification and Addresses of Parties

         2.1      NEWNET

                  2.1.1    Name and Address:           NewNet, Inc., 
                                                       2 Enterprise Drive,
                                                       Shelton, CT 06484

                  2.1.2    State of Incorporation:     Connecticut

         2.2      Customer

                  2.2.1    Name and Address:           Summa Four, Inc.
                                                       25 Sundial Avenue, 
                                                       Manchester, New
                                                       Hampshire 03103-7251

                  2.2.2    State of Incorporation:     Delaware

3.       Persons to whom all notices required by the Support Agreement shall be
         delivered:

         3.1      NEWNET     Vice President Sales
                             NewNet, Inc.
                             2 Enterprise Drive
                             Shelton, CT 06484

                    Copy to:
                             General Counsel
                             NEWNET Inc.
                             40 Oriole Avenue
                             Bronxville, NY 10708



                                       -9-


<PAGE>   34

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


         3.2      CUSTOMER:        John Shaw
                                   Summa Four, Inc.
                                   25 Sundial Avenue
                                   Manchester, New Hampshire 03103-7251





                                      -10-


<PAGE>   35

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



                                  ATTACHMENT 2

                            HARDWARE SUPPORT SERVICES

1.       Term of HW Support. If the Customer and NEWNET elect Hardware Support,
         then NEWNET's System Support Service will extend to cover Hardware from
         the end of the first one (1) year limited Hardware warranty period to
         the end of the term for which the Software Service Agreement is
         purchased. During the initial and subsequent terms, the Hardware
         warranty and Hardware support services may overlap. Hardware support
         shall be subject to the terms of the OEM/VAR Purchase Agreement,
         including the appended Terms of Sale and Support Agreement. Should
         there be a conflict between the terms of that Agreement and any of its
         Appendixes and the terms of this Attachment 3, the terms of this
         Attachment shall prevail.

2.       Resolution of Hardware Errors. Once NEWNET has made a reasonable
         determination that a Critical, Serious or Minor Error exists in the
         Hardware, NEWNET will provide the following Resolution for that Error:

         2.1      If the Hardware or a component thereof is defective, NEWNET
                  will provide Customer with a Return Material Authorization
                  (RMA) number prior to such defective Hardware or component
                  being returned. The RMA number shall be written legibly on the
                  outside of the shipping carton. Customer will ship such
                  defective Hardware or component to NEWNET with risk of
                  in-transit loss or damage and transportation charges being
                  borne by Customer. NEWNET then will use its reasonable efforts
                  to repair or replace said Hardware or component and ship it
                  ex-works Shelton, CT within sixty (60) business days from the
                  receipt of the defective Hardware or component by NEWNET.
                  Customer bears the risk of in-transit loss or damage for
                  shipments to Customer of any repaired or replaced Hardware or
                  components thereof. Any repaired Hardware or components are
                  warranted for the remainder of the unexpired period of the
                  warranty or for sixty (60) days, whichever is longer.
                  Replacement Hardware and components shall be warranted as new
                  Hardware, to the extent the manufacturer provides NEWNET with
                  such a warranty.




                                      -11-


<PAGE>   36

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


         2.2      When it is necessary to ship a replacement part before the
                  defective part is received, the Customer will be invoiced for
                  the replacement part at its full cost. Appropriate credit will
                  be given to the Customer when the defective part is received.
                  NEWNET must receive the defective part within thirty (30) days
                  from the date of the applicable RMA, or, on or after the
                  thirty-first (31st) day NEWNET will invoice the Customer for
                  an additional ten percent (10%) over NEWNET's standard price
                  for the replacement part. Customer also can request expedited
                  delivery of replacement Hardware and/or component parts at
                  NEWNET prevailing rates.

         2.3      If the Hardware or a component thereof cannot be repaired or
                  replaced, NEWNET will so notify Customer promptly and, unless
                  otherwise agreed, Customer may, at its option, elect either of
                  the following options: (1) allow NEWNET to substitute similar
                  replacement Hardware or components that conform to the
                  specifications for the defective Hardware or components, or
                  (2) terminate the Hardware portion of System Support Services
                  and obtain similar material(s) from another source, in which
                  case NEWNET shall have no further liability to the Customer
                  for Hardware under this System Support Services Agreement.



                                      -12-


<PAGE>   37

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



                                  ATTACHMENT 3

                          REGISTRATION FORM FOR SERVICE


DATA TO BE PROVIDED:


         1.       Customer Name

         2.       Customer Contact

         3.       Customer Telephone Number

         4.       Customer Fax Number

         5.       Customer E-mail Address

         6.       Software Release

         7.       Country Variant (if any)

         8.       ANSI or CCITT

         9.       License Number

         10.      Hardware SS7 I/F Medium

         11.      TAC Center Location

         12.      TAC Center Telephone Number

         13.      TAC Support Hours







                                      -13-


<PAGE>   38

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



                                  ATTACHMENT 4

                            NEWNET ESCALATION PROCESS


PROBLEM REPORTING PROCESS

Call 203-925-6100, NewNet TAC, 7 days per week, 24 hours per day.
Other channels for initiating problems are E-Mails and Fax. Out of hours call
will be answered by the NewNet answering service and forwarded to the
appropriate TAC Engineer to provide a response to the customer.

All calls will come to the NewNet TAC center and be issued a call request
number(CR). During regular business hours, all calls be handled immediately. Out
of hours, all calls will be responded to within 60 minutes.

If no Response is received for any call within a 60 minute period, the call will
be escalated to the Director of Support and Manufacturing by NewNet.

If no Response is received within 2 hours from initial call receipt, the call
will be escalated to the Vice President of Operations by NewNet.

If no Response is received within 2 hours after the escalation to the Vice
President of Operations, the call will escalated to the President of NewNet by
NewNet.

PROBLEM PRIORITY

Critical - Response with a resolution (target date) is within 24 hours - final
solution to problem is within 7 business days - on development systems.

For Runtime systems, if rebooting does not clear the problem, Engineering
resources will be called in to correct the problems or provide workaround within
24 hours.

Serious - Response with a resolution (target date) is within 48 hours - final
solution to problems is within 21 business days.

Minor - Response with a resolution (target date) is within 5 days - final
solution to Minor CR's will be in upcoming fix packages.




                                      -14-


<PAGE>   39

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT


In all situations mentioned above, if acceptable, workaround solutions can be
given to the customer as a temporary measure. Agreement between the customer and
NewNet must be met for all workarounds. Workarounds must be replaced by final
solutions.



                                      -15-


<PAGE>   40

                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



                                  ATTACHMENT 5

                      SUPPORT AND MAINTENANCE (18 MONTHS)*

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------
                                                               PROMOTIONAL PARTNER PRICING
-------------------------------------------------------------------------------------------------
<S>                                                           <C>           
Lab Development AccessMANAGER.  Licenses (up to 20)**         $180K - $60K Credit(1)  = $120,000
-------------------------------------------------------------------------------------------------
Run Time AccessMANAGER.  Licenses (current installed          $360K - $120K Credit(1) = $240,000
base plus up to $3M of NewNet Products)
-------------------------------------------------------------------------------------------------
</TABLE>

*    Support and Maintenance Discount based on a signed, valid Software Support
     and Maintenance Services Agreement between SummaFour and NewNet. Support
     and Maintenance prices revert to standard NewNet published pricing upon
     termination and/or expiration of said signed, valid Support Agreement.

**   Summa Four will identify the twenty (20) Lab Development system Host ID's
     covered under Support and Maintenance. Keyfile(s) for these Lab Development
     system(s) will be provided to Summa Four upon their request for each
     software version of AccessMANAGER. requested, at no additional charge.

(1)  Credits give due to overlap of Support and Maintenance from prior purchases
     and agreements.




                          ENGINEERING SUPPORT/TRAINING

<TABLE>
--------------------------------------------------------------------------------
<S>                                                    <C>
Strategic Engineering Support                          $240,000 per staff year
--------------------------------------------------------------------------------
                                                      ($20,000 per staff month)
--------------------------------------------------------------------------------
Field Support                                          $240,000 per staff year
--------------------------------------------------------------------------------
                                                      ($20,000 per staff month)
--------------------------------------------------------------------------------
AccessMANAGER.  Training @ NewNet                                       $9,500
(4 persons/3 days)
--------------------------------------------------------------------------------
</TABLE>




                                      -16-

<PAGE>   41
                                   Appendix 2

           NEWNET SOFTWARE SUPPORT AND MAINTENANCE SERVICES AGREEMENT



                       SYSTEM SUPPORT SERVICE LIST PRICES
               (as of effective date of System Support Agreement)

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------
<S>                                          <C>
A.   NEWNET TRAINING:

     NewNet TAC Training of up to            US $2,500 for each trainee 
     four (4) Customer Tier 2 TAC            (A private course requires a 
     support personnel at NEWNET's           minimum of four (4) trainees). 
     offices

     Trainee's travel, living and            Paid by Customer
     other out-of-pocket expenses

-------------------------------------------------------------------------------
B.   FIELD SERVICE:

     Field                                   Services US $1,000 per 8 hour day 
                                             of service       
                                             US $200 per hour above 8 hours
                                             service in one day
                                             US $5,000 per 40 hour work week
                                             US $200 per hour for hours 
                                             above a 40 hour work week

-------------------------------------------------------------------------------                                                 
C.   OUT-OF-POCKET COSTS OF FIELD
     SERVICE, INCLUDING INSTALLATION
     AND INTEGRATION

     Transportation, room, board and         Paid by Customer in US dollars
     communications expenses

-------------------------------------------------------------------------------
D.   SUPPORT FEES FOR NEWNET                 US $300 per staff hour, with a 
     SOFTWARE SUPPORT FOR                    minimum per call or assignment of 
     WHICH SOFTWARE SUPPORT                  two hours support.
     HAS NOT BEEN PURCHASED
                                             Customer will pay a license fee for 
                                             each patch, fix package and         
                                             Revision that it receives for each  
                                             NEWNET System that it has           
                                             purchased.                          

-------------------------------------------------------------------------------
E.   VERSIONS OR RELEASE UPGRADE             50% of NEWNET's List Price (while     
                                             a NewNet Software Support and        
                                             Maintenance Agreement is in        
                                             effect.)                           
                                             
-------------------------------------------------------------------------------
F.   OUT OF WARRANTY REPAIR OF               Not to exceed Summa Four's       
     HARDWARE                                Promotional Partner Price for the
                                             item of hardware (Shipping and   
                                             Handling NOT included) found in  
                                             Appendix 3 of the OEM/VAR        
                                             Agreement.                       

-------------------------------------------------------------------------------                                             
          
</TABLE>
          

                                      -17-



<PAGE>   42
                                   Appendix 3

                    NewNet Pricing (ANSI and CCITT Standards)
                 with Summa Four's Promotional Partner Discounts
================================================================================

The AccessMANAGER. 3.5.3 pricing referred to in this Agreement will apply to all
current and future Releases of that product, excluding Releases which
incorporate distributed redundancy architecture. During the term of this
Agreement, Summa Four will have access to, at the agreed upon pricing described
below, all fixes, Revisions and Updates, as well as new country variants of the
above described product as are current at the time this Agreement is entered.


<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------
                                                       PUBLISHED        PROMOTIONAL PARTNER
        ACCESSMANAGER. V3.5.3                          PRICE LIST             PRICING
-------------------------------------------------------------------------------------------
        DEVELOPMENT LICENSES
-------------------------------------------------------------------------------------------
<S>                                                     <C>                 <C>
ISUP, MTP-L3, API                                       $ 33,750            $21,937.50
-------------------------------------------------------------------------------------------
ISUP, MTP-L3, API (Fault Res. Copy)                     $ 13,500            $ 8,775.00
-------------------------------------------------------------------------------------------
TCAP-SCCP-ISUP, MTP-L3, API                             $ 51,250            $33,312.50
-------------------------------------------------------------------------------------------
TACP-SCCP-ISUP, MTP-L3, API (Fault Res. Copy)           $ 20,500            $13,325.00
-------------------------------------------------------------------------------------------
4 links MTP-L2                                          $ 12,000            $ 4,920.00
-------------------------------------------------------------------------------------------
4 Links MTP-L2 (Fault Res. Copy)                        $  4,800            $ 3,120.00
-------------------------------------------------------------------------------------------
AX7000 4 port Sbus RS-449 Card (each)                   $  4,500            $ 2,250.00
-------------------------------------------------------------------------------------------
4 input Selector Shelf Unit (Dual Power Supply)         $ 12,500            $ 6,250.00
-------------------------------------------------------------------------------------------
        RUN TIME (S/w + NewNet Supplied H/w)
-------------------------------------------------------------------------------------------
              ISUP Only Licenses
-------------------------------------------------------------------------------------------
ISUP, 4 links MTP-L2, -L3, APII,                        $ 45,750            $   12,000
1 AX7000 4 port Sbus Card (Simplex)
-------------------------------------------------------------------------------------------
ISUP, 4 links MTP-L2, -L3, API,                         $ 86,350            $   24,000
Dual Power Supply Selector Shelf Unit,
2 add'l Slave Cards,
2 AX7000 4 port Sbus Cards (Fault Resilient)
-------------------------------------------------------------------------------------------
ISUP, 8 links MTP-L2, -L3, API                          $ 66,750            $   16,000
2 AX7000 4 port Sbus Cards (Simplex)
-------------------------------------------------------------------------------------------
ISUP, 8 links MTP -L2, -L3, API,                        $114,950            $   31,500
Dual Power Supply Selector Shelf Unit,
6 add'l Slave Cards,
4 AX7000 4 port Sbus Cards (Fault Resilient)
-------------------------------------------------------------------------------------------
Upgrade ISUP System to TCAP/SCCP/ISUP                   $ 17,500            $    4,000
(Simplex-Simplex)
-------------------------------------------------------------------------------------------
Upgrade ISUP System to TCAP/SCCP/ISUP (F.               $ 24,500            $    4,300
Res. - F. Res.)
-------------------------------------------------------------------------------------------
Upgrade 4 Links MTP-L2 to 8 Links + 1 add'l             $ 16,500            $    4,000
AX7000 Card (Simplex-Simplex)
-------------------------------------------------------------------------------------------
</TABLE>



                                       -1-


<PAGE>   43

<TABLE>

-------------------------------------------------------------------------------------------
<S>                                                     <C>                 <C>

Upgrade 4 Links MTP-L2 to 8 Links + 2 add'l             $ 29,800            $ 7,500
AX7000 Cards + add'l Slave Cards (F. Res. - F. Res.)
-------------------------------------------------------------------------------------------
            TCAP/ISUP Licenses
-------------------------------------------------------------------------------------------
TCAP-SCCP-ISUP, 4 links MTP L-2, -L3, API 1             $ 67,750            $16,000
AX7000 4 port Sbus Card (Simplex)
-------------------------------------------------------------------------------------------
TCAP-SCCP-ISUP, 4 links MTP-L2, -L3, API, Dual          $110,850            $28,300
Power Supply Selector Shelf Unit,
2 add'l Slave Cards.
2 AX7000 4 port Sbus Cards (Fault Resilient)
-------------------------------------------------------------------------------------------
TCAP-SCCP-ISUP, 8 links MTP-L2, -L3, API 2              $ 84,250            $20,000
AX7000 4 port Sbus Cards (Simplex)
-------------------------------------------------------------------------------------------
TCAP-SCCP-ISUP, 8 links MTP-L2, -L3, API, Dual          $139,450            $35,900
Power Supply Selector Shelf Unit,
-------------------------------------------------------------------------------------------
6 add'l Slave Cards,
4 AX7000 4 port Sbus Cards (Fault Resilient)
-------------------------------------------------------------------------------------------
Upgrade 4 Links MTP-L2 to 8 Links - (refer to          see above          see above
ISUP only upgrade section above)
-------------------------------------------------------------------------------------------
</TABLE>


     *    Software Upgrade (to new Version/Release) without an existing, valid
          OEM/Support Agreement will be charged at Published Price List prices.





                                       -2-


<PAGE>   44


                                   Appendix 3

                    NewNet Pricing (ANSI and CCITT Standards)
                 with Summa Four's Promotional Partner Discounts
================================================================================


<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
                    CONNECT7 V2.0.0        PUBLISHED PRICE   PROMOTIONAL PARTNER 
                                                LIST               PRICING
--------------------------------------------------------------------------------
<S>                                           <C>                  <C>
DEVELOPMENT LICENSES/RUN TIME
--------------------------------------------------------------------------------
         (S/w only*)
--------------------------------------------------------------------------------
         ISUP Only Licenses
--------------------------------------------------------------------------------
Connect7 ISUP, 4 links MTP-L2 (Simplex)       $19,800              $12,000
--------------------------------------------------------------------------------
Connect7 ISUP, 4 links MTP-L2 (Fault          $39,600              $24,000
Resilient)
--------------------------------------------------------------------------------
         TCAP/ISUP Licenses
--------------------------------------------------------------------------------
TCAP-SCCP-ISUP, 4 links MTP-L22 (Simplex)     $33,075              $16,000
--------------------------------------------------------------------------------
TCAP-SCCP-ISUP, 4 links MTP-L2 (Fault         $66,150              $31,500
Resilient)
--------------------------------------------------------------------------------
</TABLE>


*    Connect 7 Hardware is the responsibility of the customer and is not
     included in the above pricing.



                             SOURCE CODE ESCROW FEES

     Should Customer desire for NEWNET to deposit the NEWNET Software source
     code in escrow, with NEWNET's Escrow Agent, it must pay the following fees
     to NEWNET:

--------------------------------------------------------------------------------
Establish Escrow:                 $5,000, payable thirty (30) days in advance
                                  of NEWNET's establishing an escrow account
                                  for Customer.
--------------------------------------------------------------------------------
Maintain Escrow:                  $3,000 per year, payable thirty (30) days in
                                  advance of new year of escrow coverage.
--------------------------------------------------------------------------------



                                       -3-


<PAGE>   45


                                   Appendix 4
                         MUTUAL NONDISCLOSURE AGREEMENT


THIS AGREEMENT made and effective as of February 17, 1997 by and between NewNet,
Inc. ("NEWNET"), a Connecticut corporation, having offices at 2 Enterprise
Drive, Shelton, CT, 06484 and Summa Four, Inc., ("Customer") a New Hampshire
corporation having an office at 25 Sundial Avenue, Manchester, New Hampshire
03103-7251. Hereinafter these parties maybe addressed individually and
collectively as the "Party" or "Parties."


                                WITNESSETH THAT:


WHEREAS, effective on even date, the Parties have entered a NEWNET OEM/VAR
Supply Agreement;

WHEREAS, it is expected that the OEM/VAR relationship and Agreement will involve
the mutual disclosure and communication by both Parties of Information not in
the public domain, including business and financial information, drawings,
samples, devices, demonstrations, computer programs, inventions and other
information, and all proprietary and novel features contained in any of the
foregoing ("Information");

WHEREAS, the Parties wish to define their rights with respect to Information
delivered to the other Party; and to protect any proprietary and novel features
contained therein;

NOW, THEREFORE, in consideration of the above premises, it is agreed as follows:

1.       Information delivered by the disclosing Party to the other Party shall
be considered confidential if (ii) the disclosing Party restricts it in a
reasonable manner to keep it confidential and (ii) such knowledge is clearly and
completely reduced to written or graphics form when disclosed and the documents
that contain such knowledge are clearly marked "confidential" or the information
is verbally identified as proprietary at the time of disclosure and within sixty
(60) days is subsequently furnished to the receiving Party in a document that is
clearly marked "confidential." Such information ("Confidential Information")
shall be subject to the restrictions of this Agreement.

2.       The receiving Party agrees that all rights to the proprietary and novel
features contained in the Confidential Information are reserved by the
disclosing Party; and the receiving Party will not use or disclose such
proprietary and novel features to the benefit of itself or the detriment of the



                                       -1-


<PAGE>   46


disclosing Party unless and until such use or disclosure is expressly authorized
in writing by the disclosing Party. The receiving Party shall perform no less
than that degree of reasonable care not to disclose such Confidential
Information to any third party that the Receiving Party normally accords its own
proprietary and confidential information. 

3.       The disclosing Party agrees that the receiving Party shall not be
liable for any disclosure or use of any knowledge contained in any of the
Confidential Information:

         3.1      if such knowledge is publicly available other than through a
breach by the receiving Party of this Agreement, or

         3.2      if such knowledge is subsequently lawfully obtained by the
receiving Party from a third party or parties, or

         3.3      if the receiving Party can prove by documentary evidence that
such knowledge was known to the receiving Party prior to such disclosure or is
independently developed by the receiving Party subsequent to such disclosure.

4.       The receiving Party agrees that no license under any patent, copyright
or other intellectual property right is granted by implication or otherwise to
the receiving Party under this Agreement.

5.       To facilitate transfer of Confidential Information between the Parties
hereto, NEWNET designates as its coordinator (name) ______________ and (name)
___________ designates as its coordinator (name). The disclosing Party shall not
make a disclosure of Confidential Information to the receiving Party unless the
disclosure is coordinated with the receiving Party's coordinator.

7.       All Confidential Information supplied to either Party hereunder shall
be disposed of by the receiving Party pursuant to the written instructions of
the disclosing Party.

8.       This Agreement shall be effective during the term of and all renewals
of the NEWNET Supply Agreement to which this Agreement is appended. Upon
termination or nonrenewal of the NEWNET Supply Agreement, the obligations
imposed by this Agreement shall expire five (5) years thereafter.

9.       This Agreement embodies all of the understandings between the Parties
concerning the subject matter hereof, and merges all prior discussions and
writing between them as to confidentiality of Information. Neither of the
Parties shall be bound by any conditions, warranties or representations with
respect to confidentiality of Confidential Information other than as expressly
provided in this Agreement, or as duly set forth subsequent to the date hereof
in writing and signed by both Parties. The Parties agree that Information
disclosed prior to the entering of the NEWNET Supply Agreement is proprietary
and shall be held in confidence under these terms.

10.      This agreement shall be governed by, and construed and interpreted in
accordance with the laws of the State of Connecticut.




                                       -2-


<PAGE>   47


Both Parties signify their agreement to the above terms by causing their
authorized representatives to sign this Agreement as of the date above written.


NEWNET, INC.


By:                                     By:
   -------------------------------          -------------------------------
   Title:                                   Title:





                                       -3-


<PAGE>   48


                                   APPENDIX 5

                           PREFERRED ESCROW AGREEMENT

                     Account Number ________________________

This Agreement is effective ___________________, 19__ among Data Securities
International, Inc. ("DSI"), NewNet, Inc. ("Depositor") and _________
("Preferred Beneficiary"), who collectively may be referred to in this Agreement
as "the parties."

A.       Depositor has entered into a licensing agreement with the Preferred
Beneficiary (the "License Agreement") covering the licensing to the Preferred
Beneficiary of certain software products and has entered into a support and
maintenance agreement with the Preferred Beneficiary regarding maintenance and
support of such software products (the "Support Services 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 the
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, Depositor shall deliver to DSI the proprietary information 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,



                                       -1-


<PAGE>   49


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 with DSI, DSI shall F 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.

                                   APPENDIX 5

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. Delivery 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;

         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; and



                                       -2-


<PAGE>   50


         e.       The deposit materials are readable and useable in their
                  current form or, if the deposit materials are encrypted, the
                  decryption tools and decryption keys have also been deposited.


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 60 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.

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 -- CONFIDENTIALITY AND RECORD KEEPING

2.1      CONFIDENTIALITY. DSI shall maintain the deposit materials in a secure,
environmentally safe, locked facility which is accessible only to authorized
representatives 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.



                                       -3-


<PAGE>   51


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 instructions as
may be necessary to duplicate the deposit materials including but not limited to
the hardware and/or software needed.

3.3      RIGHT TO TRANSFER UPON RELEASE. Depositor hereby grants to DSI the
right to transfer the deposit materials to Preferred Beneficiary upon any
release of the deposit materials for use by Preferred Beneficiary in accordance
with Section 4.5. Except upon such a release or as otherwise provided in this
Agreement, DSI shall not transfer the deposit materials.

ARTICLE 4 -- RELEASE OF DEPOSIT

4.1      RELEASE CONDITIONS. As used in this Agreement, "Release Conditions"
shall mean the following:

         a.       Depositor's material default under the support obligations
imposed on is pursuant to the Software Support Services Agreement and
Depositor's failure to cure such default within thirty (30) days of receipt of
notice from Preferred Beneficiary; or

         b.       Depositor's failure to continue to do business in the ordinary
course, unless Depositor has appointed a successor; or

         c.       If Depositor has appointed a successor to fulfill the support
obligations imposed on it pursuant to the Support Services Agreement, the
occurrence of the conditions set forth in clause (a) or (b) of this Section 4.4
with respect to such successor; provided, that if a successor is appointed
during a material breach of depositor's



                                       -4-


<PAGE>   52


obligations, then the cure period for such successor under clause (a) shall be
the difference between 30 days and the days elapsed since receipt of notice of
default by Depositor.

         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 (Section 7.3) of this Agreement.
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 Contrary
Instructions from the Depositor within the ten business days mentioned in
Section 4.3, 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      RIGHT TO USE 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 the right to use the Deposit
Materials for the sole purpose of providing support services that Depositor or
its successor has failed to provide under the Support Services Agreement.
Preferred Beneficiary shall be required to maintain the confidentiality of the
released Deposit Materials as provided in the Licensee Agreement, the Support
Services Agreement or any other confidentiality agreement with Depositor.

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



                                       -5-


<PAGE>   53


is terminated; or (b) the Agreement is terminated by DSI for nonpayment in
accordance with Section 5.2. 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 then
prevailing anniversary date of such other escrow arrangements.

5.2      TERMINATION FOR NONPAYMENT. In the event of the nonpayment of 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. APPENDIX
5

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 Depositor's 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 rights granted in the sections entitled Right to Transfer
Upon Release (Section 3.3) and Right to Use 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; and

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




                                       -6-


<PAGE>   54


ARTICLE 6 -- DSI'S FEES

6.1      FEE SCHEDULE. DSI is entitled to be paid its standard fees and expenses
applicable to the services provided. All DSI's fees will be paid by NewNet (the
Depositor). 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 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 not, by reason of its execution of this
Agreement assume any responsibility or liability for any transactions between
Depositor and Licensee other than for the performance of DSI's obligations with
respect to the deposit material held by it in accordance with this Agreement.
The party on whose behalf, or pursuant to whose directions DSI acts hereunder,
shall indemnify, defend, and hold harmless DSI from and against all claims,
actions and suits, whether in contract or in tort, and from and against any and
all liabilities, losses, damages, specifically including, without limitation,
third party claims, costs, charges, penalties, counsel fees, and other expenses
of any nature (including, without limitation, settlement costs) incurred by DSI
as a result of performance by DSI under this Agreement except in the event of a
judgment which specifies that DSI acted with gross negligence or willful
misconduct. Notwithstanding the foregoing indemnity, the Preferred Beneficiary
does not indemnify DSI against third party intellectual property claims arising
out of the deposit material.

7.3      DISPUTE RESOLUTION. Any dispute relating to or arising from this
Agreement shall be resolved by arbitration under the Commercial Arbitration
Rules of the American Arbitration Association. Unless otherwise agreed by
Depositor and Preferred Beneficiary, arbitration will take place in Boston,
Massachusetts, USA. 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



                                       -7-


<PAGE>   55


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 Commonwealth of Massachusetts, 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:

         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 deliver 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 duties.

ARTICLE 8 -- GENERAL PROVISIONS

8.1      ENTIRE AGREEMENT. This Agreement, which includes the Exhibits described
herein, embodies the entire understanding among 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 that Exhibit A need not be signed by DSI, Exhibit B need not be signed by
Preferred Beneficiary and Exhibit C need not be signed.

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. 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



                                       -8-


<PAGE>   56


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.



Depositor:  NewNet, Inc.                  Preferred Beneficiary:


By:                                       By:      
    ---------------------------------         ---------------------------------
                                                                               
Name:                                     Name:    
      -------------------------------           -------------------------------
                                                                               
Title:                                    Title:   
       ------------------------------            ------------------------------
                                                                               
Date:                                     Date:    
      -------------------------------           -------------------------------
                                 

         
                       Data Securities International, Inc.


                       By:                                      
                           ---------------------------------
                                                            
                       Name:                       
                             -------------------------------
                                                            
                       Title:                               
                              ------------------------------
                                                            
                       Date:                                
                             -------------------------------                  





                                      -9-


<PAGE>   57

                                   APPENDIX 5

                       
                                    EXHIBIT A
                            MATERIALS TO BE DEPOSITED

                     Account Number _______________________



Depositor represents to Preferred Beneficiary that deposit materials delivered
to DSI shall consist of the following:














Depositary:  NewNet, Inc.                 Preferred Beneficiary:



By:                                       By:        
    ---------------------------------         ---------------------------------
                                                                               
Name:                                     Name:      
      -------------------------------           -------------------------------
                                                                               
Title:                                    Title:     
       ------------------------------            ------------------------------
                                                                               
Date:                                     Date:      
      -------------------------------           -------------------------------







                                      -10-


<PAGE>   58


                                   Appendix 5


                                    EXHIBIT B


                        DESCRIPTION OF DEPOSIT MATERIALS


Depositor Company Name: _______________________________________________________

Account Number: _______________________________________________________________

PRODUCT DESCRIPTION: 

Product Name ______________________________________      Version ______________

Operating System ______________________________________________________________

Hardware Platform _____________________________________________________________

_______________________________________________________________________________

DEPOSIT COPYING INFORMATION:

Hardware required: ____________________________________________________________

Software required: ____________________________________________________________

DEPOSIT MATERIAL DESCRIPTION:

Qty        Media Type & Size            Label Description of Each Separate Item
           (excluding documentation)

______     Disk 3.5" or ____________

______     DAT tape ___mm

______     CD-ROM

______     Data cartridge tape _____

______     TK 70 or _____ tape

______     Magnetic tape ___________

______     Documentation

______     Other ___________________





                                      -11-


<PAGE>   59


I certify for Depositor that the above      DSI has inspected and accepted the
described deposit materials have been       above materials (any exception are
transmitted to DSI:                         noted above):

Signature ___________________________       Signature _________________________

Print Name: _________________________       Print Name: _______________________

Date: _______________________________       Date: _____________________________



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



                                      -12-


<PAGE>   60


                                   Appendix 5


                                    EXHIBIT C


                               DESIGNATED CONTACT

Account Number ___________________

Notices, deposit materials returns      Invoices to Depositor should be
and communications to Depositor         addressed to:
should be addressed to:

NewNet, Inc.                            NewNet, Inc.
2 Enterprise Drive                      2 Enterprise Drive
Shelton, CT 06584                       Shelton, CT 06484
Designated Contact:_______________      Contact: Mr. Roger Whitham

Telephone: _______________________      

Facsimile: _______________________


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

Company Name: ____________________      _______________________________________

Address: _________________________      _______________________________________

Designated Contact: ______________      _______________________________________

Telephone: _______________________      Contact: ______________________________

Facsimile: _______________________      _______________________________________


Requests from Depositor or Preferred Beneficiary to change the designated
contact should be given in writing by the designated contact or an authorized
employee of Depositor or Preferred Beneficiary.

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



                                      -13-


<PAGE>   61




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) 695-1900               (415) 398-7900
Facsimile: (619) 694-1919               (415) 398-7914

Date: ___________________





                                      -14-


<PAGE>   62


                                   Appendix 5


                                  Attachment 1
                                       to
                           Preferred Escrow Agreement


                             SOURCE CODE ESCROW FEES


Should Customer desire for NEWNET to deposit the NEWNET Software source code in
escrow, with NEWNET'S Escrow Agent, it must pay the following fees to NEWNET:

Establish Escrow:          $5,000, payable thirty (30) days in advance of
                           NEWNET's establishing an escrow account for Customer
                           

Maintain Escrow:           $3,000 per year, payable thirty (30) days in advance
                           of new year of escrow coverage.


Should customer elect NEWNET's source code escrow service, NEWNET's Escrow
Agreement, duly executed by NEWNET, Customer and NEWNET's escrow agent is
Appendix 1 to this Attachment 1.





                                      -15-


<PAGE>   63


                              ADDENDUM S4-97 to the
                            OEM/VAR SUPPLY AGREEMENT


This Addendum ("Addendum") to the OEM/VAR Supply Agreement dated 2/17/97 (the
"Agreement") is effective on December 15, 1997, by and between ADC NewNet, Inc.
("ADC NEWNET"), a Minnesota corporation with offices at Two Enterprise Drive,
Shelton, CT 06484 and Summa Four, Inc. ("Customer") a New Hampshire corporation
with offices at 25 Sundial Avenue, Manchester, New Hampshire 03103- 7251.

Hereinafter ADC NEWNET and Customer, may be referred to as the "Party" or
"Parties." All defined terms in this Addendum shall have the meanings given to
them in the ADC NEWNET Terms of Sale ("Terms of Sale"), Appendix 1 of the
Agreement, and

WHEREAS, Customer desires to obtain licensing and distribution rights to certain
ADC NEWNET systems developed by ADC NEWNET and ADC NEWNET wishes to grant such
rights to Customer pursuant to the following terms and conditions.

NOW, THEREFORE, in consideration of the mutual covenants and promises contained
herein, the receipt and adequacy of which are acknowledged, the Parties contract
and agree as follows:

1.       Objective of Addendum

         1.1      This Addendum is to extend the duration of the Agreement and
                  to include pricing for licensing and support of the Connect7
                  products.

         1.2      Customer commits that it will purchase a minimum of eighty-one
                  Units during the Contract Extension Period August 17, 1998
                  through August 17, 1999. This commitment will be updated on an
                  annual basis.

         1.3      "Unit" is defined as one (1) complete AccessMANAGER. ISUP,
                  TCAP or ISUP/TCAP software license or similar Connect7
                  software, regardless of availability (simplex, active/standby
                  or active/active) not including spares or hardware upgrades.

         1.4      "System" shall mean ADC NewNet Software and Hardware delivered
                  to Customer as a combined product or package.

         1.5      NewNet, Inc. was merged into ADC NewNet, Inc. As a consequence
                  of that statutory merger, ADC NewNet confirms that it is fully
                  and legally responsible for and possesses all of the rights,
                  duties, obligations, contracts and responsibilities of NewNet,
                  Inc.



                                       -1-


<PAGE>   64


2.       Terms of Supply

         2.1      ADC NEWNET SYSTEMS AND SOFTWARE. Customer agrees to buy and
                  ADC NEWNET agrees to sell to Customer ADC NEWNET Systems and
                  Software pursuant to the terms of this Addendum. Hereinafter,
                  the Addendum to the Agreement and its attachments shall be
                  referred to as the "Addendum." Any conflict between the terms
                  of the Addendum and any of Customer's purchase documentation
                  shall be resolved in favor of the Addendum. In the event of a
                  conflict between the main body of the Supply Agreement and the
                  Addendum, this Addendum shall prevail.

         2.2      ADC NEWNET SYSTEM SUPPORT SERVICES. Customer agrees to buy
                  System Support Services pursuant to the System Support Service
                  Agreement attached to the Agreement as Appendix 2 and the
                  pricing
                  outlined in this Addendum.

         2.3      ADC NEWNET LICENSING METHODS. ADC NewNet intends to migrate
                  towards an Internet-based method for issuing licenses. This
                  will allow direct access by Customer's manufacturing for
                  issuing licenses. This facility is expected to be in place by
                  4Q98.

3.       PRICES AND DISCOUNTS

         3.1      ADC NEWNET SYSTEMS AND SOFTWARE. ADC NEWNET will, throughout
                  the term of this Addendum, sell and license ADC NEWNET Systems
                  and Software to Customer and Customer will purchase such ADC
                  NEWNET products at the agreed upon discounts off of the
                  relevant price in ADC NEWNET's price list attached hereto as
                  Addendum Appendix 1. The attached price schedule for software
                  licenses may not be increased for a period of three years from
                  the date of this addendum.

         3.2      ADC NEWNET may from time to time decrease its published
                  OEM/VAR prices and volume discount standard schedule. Should
                  ADC NEWNET issue a new OEM/VAR standard price list for its
                  Products, and should that list contain a volume discount
                  schedule, from that time forward Customer may have the lower
                  of the prices that are (i) calculated by reference to the new
                  price list, using the new volume discount schedule at
                  Customer's then volume of purchases and (ii) the prices that
                  are calculated using the prices and discounts found in this
                  Addendum.




                                       -2-


<PAGE>   65


         3.3      The Connect7 pricing referred to in Addendum Appendix 1 will
                  apply to Release v2.0 and future 2.x Releases. During the term
                  of this Addendum, Summa Four will have access to, at the
                  agreed upon pricing described in Addendum Appendix 1, all
                  fixes, Revisions, and Updates, as well as new country variants
                  of the above described product.

         3.4      The Agreement includes A Purchase Commitment of three million
                  US dollars (US$3M) of ADC NEWNET Systems and Software over an
                  eighteen (18) month period. This Addendum represents an
                  addition to Customer's firm purchase commitment of eighty-one
                  (81) Units throughout the extended term of the agreement.

4.       NOTICES AND OTHER COMMUNICATIONS. Notices shall be in writing (unless
         otherwise designated herein) and shall, for all purposes, be deemed to
         be fully given and received if delivered personally, or if sent by
         facsimile with a copy sent by Express, certified or registered mail,
         postage prepaid, to the other Party at its address stated below or to
         such other address as the respective Party shall advise in writing:

                  ADC NEWNET: Pat Donnelly
                           ADC NewNet, Inc.
                           Enterprise Drive
                           Shelton, CT 06484
                           Fax No.: (203) 926-2664

                           George C. McKinnis, Esq.
                           Oriole Avenue
                           Bronxville, NY 10708
                           Fax No: (914) 793-9433

                  CUSTOMER: John Shaw
                           Summa Four, Inc.
                           Sundial Avenue
                           Manchester, New Hampshire 03103-7251
                           Fax No.: (603) 6684491

5.       CONFIDENTIALITY. All Confidential Information exchanged hereunder shall
         be subject to the terms of the Mutual Nondisclosure Agreement entered
         by the Parties as part of the Agreement. Notwithstanding the
         termination date of the attached Mutual Nondisclosure Agreement, it
         shall remain in effect for so long as this Addendum and any renewal or
         successor agreement or Addendum are in effect and the obligation of
         confidentiality shall survive the termination of this Addendum pursuant
         to the terms of the Mutual Nondisclosure Agreement.



                                       -3-


<PAGE>   66


         6.       TERM OF ADDENDUM

         6.1      This Addendum extends the current supply contract general
                  terms and conditions and support/maintenance terms and
                  conditions for one (1) year after the expiration date of the
                  initial term of said supply contract, until August 17, 1999.

         6.2      Unless otherwise terminated as provided herein, the Agreement
                  shall be renewed for successive Terms of twelve (12) months
                  after August 17, 1999 unless either Party gives written notice
                  to the other Party not less than thirty (30) days before that
                  date or the termination date of any successive twelve (12)
                  month Term thereafter that it elects to not extend the
                  underlying Agreement for the next twelve (12) months.
                  Notwithstanding any terms to the contrary in this Addendum,
                  including all appendices thereto, ADO NewNet shall not have
                  the right to terminate this Addendum for convenience only.

         6.3      This Addendum is an addendum to the Agreement and therefore is
                  subject to all terms and conditions of said Agreement which
                  are not replaced by terms in the Addendum.

7.       ADO NEWNET DELIVERABLES - ADDENDUM APPENDIX 2

                  The Addendum Appendix 2 ("Appendix 2") provides the high level
                  requirements for v2.0 of Connect7 and assigns a "requirement
                  id" to the requirements in the Summa Four presentation for
                  future reference.

IN WITNESS WHEREOF, EACH PARTY HERETO HAS AGREED TO THE ABOVE PROVISIONS THROUGH
ITS DULY AUTHORIZED REPRESENTATIVE AS OF THE ABOVE DATE:



ADO NEWNET, INC.                             CUSTOMER:


By:                                          By:
    ---------------------------------            -------------------------------
    Name: Dilip Singh                            Name:
    Title:  President, ADC New Net               Title:





                                       -4-


<PAGE>   67


APPENDIXES

ADDENDUM S4-97 TO THE OEM/VAR SUPPLY AGREEMENT




Appendix 1       Price List


Appendix 2       Response to Customer's Single Card SS7 Requirements






                                       -5-


<PAGE>   68


                               ADDENDUM APPENDIX 1
                               CONNECT7 PRICE LIST


SUPPORT SERVICES:

The Agreement includes support pricing for the AccessMANAGER. product. This
addendum requires simultaneous support of both AccessMANAGER. and Connect7. The
current annual Support Agreement and its current charges for AccessMANAGER.
($360,00 per year for both engineering and end customer support) will continue
to apply for each term of this addendum. Connect7 support will be in addition to
the current support provided to Customer for AccessMANAGER. Connect7 support
will cost one thousand two-hundred dollars ($1,200) per year per Connect7 unit,
beginning when the warranty period ends. Support prices for Connect7 may be
increased annually (on the Agreement anniversary, August 18, 1999) to account
for cost increases, but limited to no more than 7% per year.

ACCESSMANAGER PRICE ADJUSTMENTS:

When both products are simultaneously deployed, it is desirable that the market
price between AccessMANAGER. and Connect7 appear similar. Various events lead up
to 'simultaneous deployment', the events and the reduction in AccessMANAGER.
promotional package prices for redundant ISUP units are shown below:


<TABLE>
<CAPTION>

Event                                                           Price
<S>                                                            <C>    

Current                                                        $24,000

Addendum Signature                                              19,500

Summa Four accepts Connect7 2.0 Beta release,
         shipped by ADC NEWNET in April 1998                    17,000
         (If the April ship date is not met by ADO
         NEWNET, the price change will take
         effect irrespective of Summa Four
         acceptance)

First Summa Four customer shipment of
         Connect7 2.0                                           14,800


</TABLE>





                                       -1-


<PAGE>   69


LAB DEVELOPMENT:

One Connect7 Lab Development system will be provided at no charge. Subsequent
Lab Development systems will be priced at fifty percent (50%) of the list price
schedule shown below. Lab Development systems may only be used for Customer's
product development.

CONNECT7 VOLUME DISCOUNT SCHEDULE

THE DISCOUNT STRUCTURE SHOWN BELOW WILL BE APPLIED BASED UPON 81 UNITS FOR EVERY
PURCHASE ORDER RECEIVED DURING THE TWELVE (12) MONTH PERIOD STARTING WITH THE
DATE OF THE FIRST ORDER FOR CUSTOMER SHIPMENT (THE ANNIVERSARY DATE). ANY
COMMITTED UNITS NOT SHIPPED WITHIN TWELVE MONTHS OF THE ANNIVERSARY DATE WILL BE
SHIPPED AND BILLED ON THE NEXT ANNIVERSARY DATE. THE SOFTWARE LICENSES FOR A
GIVEN PURCHASE ORDER WILL TYPICALLY BE SCHEDULED TO SHIP WITHIN NINETY DAYS OF
RECEIPT. THE QUANTITY COMMITMENT CAN BE ADJUSTED ON THE TWELVE (12) MONTH
ANNIVERSARY DATE FOR THE FOLLOWING YEAR.

COMMITMENT LEVEL - 1-10 UNITS (0% DISCOUNT)

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------
                                                  Simplex                           Act/Act
                                       ------------------------------     ------------------------------
        Item                             List      Single       Multi       List      Single       Multi
--------------------------------------------------------------------------------------------------------
<S>                                    <C>        <C>         <C>         <C>        <C>         <C>
ISUP, -L3, 4 links -L2                 $12,000    $12,000     $15,000     $15,600    $15,600     $19,500
ISUP, -L3, 8 links -L2                 $15,000    $15,000     $18,750     $19,500    $19,500     $24,375
TCAP, SCCP, -L3, 4 links -L2           $14,000    $14,000     $17,500     $18,200    $18,200     $22,750
TCAP, SCCP, -L3, 8 links -L2           $18,000    $18,000     $22,500     $23,400    $23,400     $29,250
TCAP, SCCP, ISUP, -L3, 4 links -L2     $20,000    $20,000     $25,000     $26,000    $26,000     $32,500
--------------------------------------------------------------------------------------------------------

<CAPTION>
COMMITMENT LEVEL - 11-40 UNITS (10% DISCOUNT)

--------------------------------------------------------------------------------------------------------
                                                  Simplex                             Act/Act
                                       ------------------------------     ------------------------------
        Item                             List      Single       Multi       List      Single       Multi
--------------------------------------------------------------------------------------------------------
<S>                                    <C>        <C>         <C>         <C>        <C>         <C>
ISUP, -L3, 4 links -L2                 $12,000    $10,800     $13,500     $15,600    $14,040     $17,550
ISUP, -L3, 8 links -L2                 $15,000    $13,500     $16,875     $19,500    $17,550     $21,940
TCAP, SCCP, -L3, 4 links -L2           $14,000    $12,600     $15,750     $18,200    $16,380     $20,475
TCAP, SCCP, -L3, 8 links -L2           $18,000    $16,200     $20,250     $23,400    $21,060     $26,325
TCAP, SCCP, ISUP, -L3, 4 links -L2     $20,000    $18,000     $22,500     $26,000    $23,400     $29,250
--------------------------------------------------------------------------------------------------------
</TABLE>




                                       -2-


<PAGE>   70


COMMITMENT LEVEL - 41-80 UNITS (18% DISCOUNT)

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------
                                                  Simplex                             Act/Act
                                       ------------------------------     ------------------------------
        Item                             List      Single       Multi       List      Single       Multi
--------------------------------------------------------------------------------------------------------
<S>                                    <C>        <C>         <C>         <C>        <C>         <C>

ISUP, -L3, 4 links -L2                 $12,000    $ 9,840     $12,300     $15,600    $12,792     $15,990
ISUP, -L3, 8 links -L2                 $15,000    $12,300     $15,375     $19,500    $15,990     $19,988
TCAP, SCCP, -L3, 4 links -L2           $14,000    $11,480     $14,350     $18,200    $14,930     $18,655
TCAP, SCCP, -L3, 8 links -L2           $18,000    $14,760     $18,450     $23,400    $19,190     $23,985
TCAP, SCCP, ISUP, -L3, 4 links -L2     $20,000    $16,400     $20,500     $26,000    $21,320     $26,650
--------------------------------------------------------------------------------------------------------


<CAPTION>
COMMITMENT LEVEL - 81-120 UNITS (24% DISCOUNT)

--------------------------------------------------------------------------------------------------------
                                                  Simplex                             Act/Act
                                       ------------------------------     ------------------------------
        Item                             List      Single       Multi       List      Single       Multi
--------------------------------------------------------------------------------------------------------
<S>                                    <C>        <C>         <C>         <C>        <C>         <C>

ISUP, -L3, 4 links -L2                 $12,000    $ 9,120     $11,400     $15,600    $11,860     $14,820
ISUP, -L3, 8 links -L2                 $15,000    $11,400     $14,250     $19,500    $14,820     $18,525
TCAP, SCCP, -L3, 4 links -L2           $14,000    $10,640     $13,300     $18,200    $13,835     $17,290
TCAP, SCCP, -L3, 8 links -L2           $18,000    $13,680     $17,100     $23,400    $17,790     $22,230
TCAP, SCCP, ISUP, -L3, 4 links -L2     $20,000    $15,200     $19,000     $26,000    $19,760     $24,700
--------------------------------------------------------------------------------------------------------


<CAPTION>
COMMITMENT LEVEL - 121+ UNITS (29% DISCOUNT)

--------------------------------------------------------------------------------------------------------
                                                  Simplex                             Act/Act
                                       ------------------------------     ------------------------------
        Item                             List      Single       Multi       List      Single       Multi
--------------------------------------------------------------------------------------------------------
<S>                                    <C>        <C>         <C>         <C>        <C>         <C>

ISUP, -L3, 4 links -L2                 $12,000    $ 8,640     $10,800     $15,600    $11,235     $14,040
ISUP, -L3, 8 links -L2                 $15,000    $10,800     $13,500     $19,500    $14,040     $17,550
TCAP, SCCP, -L3, 4 links -L2           $14,000    $10,080     $12,600     $18,200    $13,110     $16,380
TCAP, SCCP, -L3, 8 links -L2           $18,000    $12,960     $16,200     $23,400    $16,850     $21,060
TCAP, SCCP, ISUP, -L3, 4 links -L2     $20,000    $14,400     $18,000     $26,000    $18,720     $23,400
--------------------------------------------------------------------------------------------------------

</TABLE>



                                       -3-


<PAGE>   71


                     RESPONSE TO SUMMA FOUR SINGLE CARD SS7
                                  REQUIREMENTS


                                  REVISION 1.0
















ADC NEWNET, INC.
2 ENTERPRISE DRIVE
SHELTON, CT  06484



THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OF ADC NEWNET, INC. AND SUMMA
FOUR. NO USE OR DISCLOSURE OF THE INFORMATION CONTAINED HEREIN IS PERMITTED
WITHOUT THE PRIOR WRITTEN CONSENT OF ADC NEWNET, INC. THE INFORMATION CONTAINED
IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. ADC NEWNET, INC. MAKES NO
WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL. ADC NEWNET, INC. SHALL NOT BE
LIABLE FOR ERRORS CONTAINED HEREIN OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN
CONNECTION WITH THE USE OF THIS MATERIAL.





                                       -4-


<PAGE>   72


1.       PURPOSE

The presentation titled "Single Card SS7 Requirements October 1997" by Summa
Four lists requirements to a single card SS7 solution. This document is a
response document to those requirements on behalf of the Connect7 product.

This document assigns a "requirement id" to the requirements in the Summa Four
presentation for future reference. The requirements are extracted out of the
presentation subject to the interpretation of the author of this document. Any
requirement which is left out or misinterpreted should be identified by the
audience of this document as such.

Each requirement is discussed in the "comments" section where potential problems
are raised. The "questions" section is meant to initiate a discussion on the
requirement.

All comments apply to Connect7 release 2.0 which is specifically focused on
Summa Four requirements. When this document indicates that a requirement is not
met, it means that it is not met in 2.0. Such requirement should be discussed
for releases that follow 2.0. We are planning a more fully distributed solution
in 1998 (release 2.1) that follows 2.0.

Release 2.1 will be introduced as beta in the fourth quarter of calendar year
1998. It will support active operation at all SS7 layer. In other words, the MTP
L2, MTPL3, SCCP, TCAP and SUP layers on both SS7 boards (could be more than 2
boards also) will be active. All layers on all boards will be operating
concurrently. With Release 2.1, there will not be a need to take the links
momentarily out to service when one of the boards is dead. No board shall be
designated the active board as all boards will be operating concurrently.

We recommend that Summa Four and ADC Newnet jointly develop a test plan that
will be used as the acceptance criteria for Release 2.0. The test plan should be
prepared such that successful completion of all the test cases should indicate
the fulfillment of the requirements discussed below.

2.       REVISION

The word "Summafour" has been changed as "Summa Four" from revision 0.3 to 1.0.
There are no other changes in 1.0.

1.       Requirements Review

REQUIREMENT LID: R-010
REQUIREMENT STATEMENT: Mated Pair STP Operation
COMMENTS: The figure that accompanies this requirement indicates that there can
be up to 16 SS7 links in each of the linksets to the STPs. Connect7 supports up
to 8 links per SS7 board. In an active-active redundancy solution, two boards
can provide 16 links. This is the maximum number of SS7 links that Connect7 2.0
will support. This means that Connect7 can be connected against a mated STP pair
with at most 8 SS7 links to each STP. Connect7 2.0 over two cards each
supporting up to 8 links will be tested for its ability to provide ISUP
signaling and TCAP signaling. Configurations of up to 16 links depend on board
capabilities which will also be tested.

The figure also indicates that there can be up to N boards in the redundant
solution. In 2.0, Connect7 will support two boards.




                                       -5-


<PAGE>   73


REQUIREMENT ID: R-020
REQUIREMENT STATEMENT: Multiple SS7 Network STP Operation
COMMENTS: The figure that accompanies this requirement indicates that one
linkset to one STP may be used for ANSI signaling while another linkset to
another STP is being used for ITU signaling. Connect7 supports this
configuration with its ability to run up to 4 SS7 stacks on the board.
Obviously, one stack can support ANSI signaling on some link sets and another
stack can support ITU signaling on different linksets.

REQUIREMENT ID: R-030
REQUIREMENT STATEMENT: Multiple switches without STP's.
COMMENTS: Requirement will be met as stated.

REQUIREMENT ID: R-040
REQUIREMENT STATEMENT: Distributed Multiple Stack Operation
COMMENTS: In Connect7 2.0, we plan to have the following capability. MTP L2 will
be active-active on both cards. MTP L3 and ISUP will be active-standby. The SS7
configuration between boards will not be shared. The Summa Four OA&M application
is expected to send the configuration message that results from an operator's
MML request to both boards keeping the SS7 configuration identical.

ISUP layer will be communicating with its peer so that the standby ISUP layer
can also keep track of the circuit states. Should a switch overtake place, all
calls in the conversation state will be preserved.
Calls in transient states will not be preserved.

The active board will be able to receive and send messages on the SS7 links on
the standby side. Should a switchover take place all links will go momentarily
out of service before they are back in service. Emergency alignment will be used
for link alignment so that the settle time for this operation is less than a
second. We will run load tests that include switchover scenarios to measure the
effects.

This design is expected to satisfy Summa Four's "active-active MTP-L2 with
preserved ISUP calls" requirement. The following figure represents these
concepts.


                                  INSERT GRAPH



THE CALLS THAT WILL BE SAVED BY THE STANDBY BOARD IN CASE OF A SWITCH OVER EVENT
ARE THE ONES IN THE CONVERSATION STATE. SAVING CALLS IN OTHER STATES IN FOR
FURTHER STUDY.

Release 2.0 is designed for two boards. However, there is nothing that prevents
one from installing multiple pairs of boards on the same bus with release 2.0.
One can install many pairs, but the pairs will not be aware of each other. Only
those boards that are part of the same pair will communicate with each other.
Other pairs would probably be used for other signaling points in such a
configuration. Release 2.1 of Connect7 plans to support more than two boards as
part of the same signaling point.

When Connect7 is improved to support more SS7 links on a single board, there
will be no impact on the applications. Source code backward compatibility will
be protected.

In release 2.0 applications can modify the configuration on the board on the
fly. The suggested method to do this is to update the standby board
configuration first and the active board configuration next. The process will
not require a switchover event. Joint design reviews should address this issue
in more detail.




                                       -6-


<PAGE>   74


REQUIREMENT ID: R-050
REQUIREMENT STATEMENT: Card must occupy a single card slot in a 6U shelf.
COMMENTS: Requirement will be met as stated. Assume board manufacturer
compliance.

REQUIREMENT ID: R-051
REQUIREMENT STATEMENT: Industry standard format - compact PCI
COMMENTS: Requirement will be met as stated. Assume board manufacture 
compliance.

REQUIREMENT ID: R-060
REQUIREMENT STATEMENT: Portable real-time card OS-Vx Works desirable
COMMENTS: Connect7 board software is based on VRTX. The sample source code
provided can be used as a model for the Summa Four development of a Vx Works
device driver on the host side.

REQUIREMENT ID: R-070
REQUIREMENT STATEMENT: All connections to card via backplane connectors (no
front panel)
COMMENTS: This requirement depends on the board manufacturer.

REQUIREMENT ID: R-080
REQUIREMENT STATEMENT: 16 links per card in 4 link increments (8 links
acceptable to meet density requirements)
COMMENTS: Up to 8 links per card will be supported in 2.0.

REQUIREMENT ID: R-081
REQUIREMENT STATEMENT: H.100 PCM required (interim SCSA acceptable to meet
time-to-market requirements)
COMMENTS: Current hardware selection is expected to support SCSA interface. This
requirement depends on the board manufacturer.

REQUIREMENT ID: R-090
REQUIREMENT STATEMENT: External links will be handled via Drop and Insert card
COMMENTS: If this requirement has to do with the ability to redirect time slots
carrying voice to the SCSA interface, our solution will be as described below.
Otherwise, please clarify the requirement.



                                  INSERT GRAPH



REQUIREMENT ID: R-100
REQUIREMENT STATEMENT: MTP-L2 will be distributed (active/standby or external
switch is not acceptable)
COMMENTS: The active-active solution described in R-040 will be implemented.

REQUIREMENT ID: R-101
REQUIREMENT STATEMENT: MTP operation must be SS7 network compliant.
Comments: Requirement will be met as stated.

REQUIREMENT ID: R-102
REQUIREMENT STATEMENT: Traffic loading on links should follow industry practice
so loss of links will not reduce system calculated capacity.
COMMENTS: Requirement will be met as stated.

REQUIREMENT ID: R-110




                                       -7-


<PAGE>   75


REQUIREMENT STATEMENT: First release must support 8,000 trunks; 16,000 in next
release.
COMMENTS: Requirement will be met as stated. Note that the number of ISUP trunks
supported should not be used to derive a conclusion on the Busy Hour Call
Attempt capacity. Connect7 1. 1 has been tested for up to 1.6 million BHCA on
360 based boards. Performance is expected to be better with the 360 based SS7
controller boards proposed by board manufacturer.

REQUIREMENT ID: R-120
REQUIREMENT STATEMENT: Card must be able to be operated in a non-redundant mode.
COMMENTS: Requirement will be met as stated. Note that the redundant nature of
Connect7 will be completely transparent to the call control application. This
means that Summa Four can start implementation immediately with release 1.1.

REQUIREMENT ID: R-130
REQUIREMENT STATEMENT: Distributed operation at MTP, ISUP/TUP and TCAP layers.
COMMENTS: Connect7 2.0 will operate as explained in R-040. The TUP layer is not
planned for 2.0. The availability date for the TUP layer should be discussed in
the context of the planned 2.1 release.

REQUIREMENT ID: R-131
REQUIREMENT STATEMENT: Minimum of 2 cards for redundancy.
COMMENTS: Connect7 2.0 will support 2 boards.

REQUIREMENT ID: R-132
REQUIREMENT STATEMENT: Maximum number of cards determined by card performance to
meet 30,000 port switch requirements.
COMMENTS: 2.0 is designed for a 2 card solution. Supporting more than 2 cards
will be addressed in the later 2.1 distributed release WHICH WILL BE AN N-BOARD
DISTRIBUTED SOLUTION.

REQUIREMENT ID: R-140
REQUIREMENT STATEMENT: Multiple stacks and end points on a per linkset basis.
COMMENTS: See response to R-141, R-142 and R-143.

REQUIREMENT ID: R-l41
REQUIREMENT STATEMENT: Minimum of 8 concurrent stacks per card.
COMMENTS: Connect7 currently supports 4 concurrent stacks. We believe that with
additional memory and performance testing, up to 8 stacks may be supported. This
will be confirmed with additional testing.

REQUIREMENT ID: R-142
REQUIREMENT STATEMENT: Any quantity of links per linkset (1-32 as defined by
stack) COMMENTS: Standards allow up to 16 links per Iinkset, not up to 32.
Connect7 supports up to 16 links per linkset over two boards or up to 8 links on
one board. ONE CAN HAVE A COMBINED LINKSET OF 32 LINKS WHERE EACH IINKSET IN THE
COMBINED LINKSET WOULD HAVE 16 LINKS. ALTHOUGH CONNECT7 SOURCE CODE SUPPORTS
THIS CONFIGURATION, THE CURRENT HARDWARE CANDIDATES ARE NOT EXPECTED TO
SUPPORTING MORE THAN 8 LINKS PER BOARD. THEREFORE, THE TOTAL NUMBER OF LINKS
BETWEEN TWO BOARDS WOULD BE LIMITED TO 16. THE POSSIBILITY OF SUPPORTING 16
LINKS PER BOARD AND 32 LINKS BETWEEN TWO BOARDS WILL BE EXPLORED.

REQUIREMENT ID: R-143
REQUIREMENT STATEMENT: All variants must be supported in a single compiled code
base.
COMMENTS: Requirement will be met as stated.

REQUIREMENT ID: R-150



                                       -8-


<PAGE>   76


REQUIREMENT STATEMENT: Single API must support all versions of ISUP, TUP and
TCAP concurrently.
COMMENTS: A consistent API is provided for protocol variants at all layers. The
API will work in the same way for all country variants. TUP layer will not be
provided in 2.0 but can be discussed for possible inclusion in 2.1.

REQUIREMENT ID: R-160
REQUIREMENT STATEMENT: Stack software must allow addition of new messages
without having to recompile software (except call control messages). COMMENTS:
The entire ADC Newnet country variant library will be available with Connect7
2.0. Additional variants may be quickly added. Advance planning of requested
country variants will allow for rapid introduction into new markets.

REQUIREMENT ID: R-170
REQUIREMENT STATEMENT: Performance requirement is 100 transactions per second
per 1,000 switch boards. (Transaction is equal to 2 MSU's) COMMENTS: The ISUP
call that we have modeled in our performance tests includes five MSUs as shown
below.

               SPA                        SPB

                  ------------- IAM ------------- [arrow]

          [arrow] ------------- ACM -------------

          [arrow] ------------- ANM -------------

                  ------------- REL ------------- [arrow]

          [arrow] ------------- RLC -------------


This call flow has been tested up to 1.6 million BHCA.

REQUIREMENT ID: R-180
REQUIREMENT STATEMENT: MTP, ISUP and TCAP per Bellcore NWT-246.
COMMENTS: Requirement will be met. GR-CORE-246 will be used as reference.

REQUIREMENT ID: R-181
REQUIREMENT STATEMENT: ISUP GR-317-CORE and ISUP GR-394-CORE
COMMENTS: These specifications specify rules for the call control. The
references to ISUP signaling are taken from corresponding sections in
GR-CORE-246. Connect7 will support ISUP procedures. However, call control
specifications in these documents are the responsibility of the Summa Four call
control application.

REQUIREMENT ID: R-190
REQUIREMENT STATEMENT: MTP. ISUP and TCAP 1988 Blue Book
COMMENTS: Requirement will be met as stated.

REQUIREMENT ID: R-191
REQUIREMENT STATEMENT: MTP. ISUP and TCAP 1992 White Book
COMMENTS: Requirement will be met as stated.

REQUIREMENT ID: R-192



                                       -9-


<PAGE>   77

REQUIREMENT STATEMENT: MTP and TUP 1988 Blue Book
COMMENTS: Requirement will not be met in 2.0 but can be discussed for 2.1.

REQUIREMENT ID: R-200
REQUIREMENT STATEMENT: Hong Kong, Thailand, Chile Q.767, Singapore (number
port.) at MTP and ISUP layers will be supported.
COMMENTS: Requirement will be met as stated.

REQUIREMENT ID: R-210
REQUIREMENT STATEMENT: ITU TUP variant stacks required.
COMMENTS: Requirement will not be met in 2.0 but can be discussed for 2.1.

REQUIREMENT ID: R-211
REQUIREMENT STATEMENT: China TUP
COMMENTS: Requirement will not be met in 2.0 but can be discussed for 2.1.

REQUIREMENT ID: R-212
REQUIREMENT STATEMENT: BT-NUP
COMMENTS: We have no active plans to support BT-NUP.

REQUIREMENT ID: R-220
REQUIREMENT STATEMENT: TTC (Japan) stacks required (MTP, ISUP and TCAP)
COMMENTS: Requirement will be met as stated. However. this is not yet provided
in release 1.1.

REQUIREMENT ID: R-230
REQUIREMENT STATEMENT: Future stacks may include A and A+, GSM-MAP and IS4IC
COMMENTS: Requirement will not be met in 2.0. However. the TCAP layer can be
used to carry IS4I-C or GSM-MAP signaling. A and A+ layers can be discussed for
2.1.





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