<PAGE>
 
                                                                   EXHIBIT 10.57


                        LICENSE AND PURCHASE AGREEMENT
                        ------------------------------

          This Agreement made and entered into this 27th day of July, 1998
by and between The Whitaker Corporation, a Delaware corporation and a wholly
owned subsidiary of AMP Incorporated ("Licensee") and Vertel Corporation, a
California corporation ("Licensor").

                                  WITNESSETH:
                                  ----------

          WHEREAS, Licensor has designed and developed and is the owner of
various CDPD technology together with certain trade secrets, copyrights,
know-how and other information related thereto; and

          WHEREAS, Licensee desires to purchase certain assets related to such
CDPD technology described as Purchased Technology hereinafter and to obtain a
non-exclusive license in and to other assets of such technology and related
information (described as Background Technology hereinafter) and to obtain a
non-exclusive sublicense in and to the _________ as described hereinafter), and
Licensor is willing to sell the Purchased Technology and to grant such licenses,
subject to the terms and conditions contained herein;

          NOW, THEREFORE, in consideration of the foregoing and the mutual
covenants contained herein, the parties hereto hereby agree as follows:

          1.0  Definitions
               ----------- 

               When used herein, the following terms shall have the following
meanings:

               1.1  "AMP" shall mean AMP Incorporated.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

<PAGE>
 
               1.2  "Background Technology" shall mean the software programs
listed below and all related documentation and any and all proprietary data,
trade secrets, patents or patent rights, copyrights, whether registered or
unregistered, trademarks or service marks, whether registered or unregistered,
information, inventions, know-how, designs, products, processes, methods,
discoveries and other intellectual property relating thereto, as they exist as
of the date of this Agreement, which were designed and developed and are owned
by Licensor or designed and developed by third parties working under contract
for Licensor and legally or contractually obligated to assign all rights therein
to Licensor, in source code or binary format as follows:

Part Number         Description                 Version            Code Type
-----------         -----------                 -------            ---------   
S-3800085-00-D      TMN C                        2.1.2              Binary
                    Object Compiler

3800276-00-G        TMN Agent                    3.0, includes      Source
                    ToolKit (Source)             NMG 20

S-3800193-00-B      UTS Netlink                  3.1                Source
                    for Solaris


               1.3  ______  shall mean the software known as _____ which is
owned by _________

               1.4  "Derivative Works" shall have the meaning ascribed to such
term in the U.S. Copyright Act, 17 U.S.C..

               1.5  "Licensed Technology" shall mean the Background Technology
and the __________         

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       2
<PAGE>
 
               1.6  "Purchased Technology" shall mean the software programs
listed below and all related documentation and any and all proprietary data,
trade secrets, patents or patent rights, copyrights, whether registered or
unregistered, trademarks or service marks, whether registered or unregistered,
information, inventions, know-how, designs, products, processes, methods,
discoveries and any other intellectual property relating thereto , as they exist
as of the date of this Agreement, which were designed and developed and are
owned by Licensor or designed and developed by third parties working under
contract for Licensor and which third parties were legally or contractually
obligated to assign all rights therein to Licensor, all in source code format as
further defined in documents identified as PIA-96:112 dated March 11, 1996, as
follows, but excluding any Background Technology embedded therein:

                    1.6.1   CDPD MD-IS Product.

                    1.6.2   CDPD Network Management System product.

                    1.6.3   CDPD Customer Activation System product.

                    1.6.4   CDPD Accounting Server product.

                    1.6.5   pACT PD-IS Intermediate System product.

                    1.6.6   pACT Customer Activation System product.

                    1.6.7   Configuration Management Tool.

               1.7  The "Products" shall mean all products which utilize or are
based upon the Purchased Technology.


               1.8  "Reseller Agreements" shall mean the following third party
reseller software agreements:


                                       3
<PAGE>
 
               1.8.1 Agreement between Licensor and ____________________ dated
August 22, 1995, as amended.

               1.8.2 Agreement between Licensor and ____________________ dated
June 8, 1994.

               1.8.3 Agreement between Licensor and ____________________ dated
June 30, 1995.

          1.9  __________ Agreements shall mean reseller software agreements
between Licensor and third parties who themselves are resellers of the following
products of ___________________ Corporation.


                 ___________________________     

                 ___________________________        

                 ___________________________   
     
                 ___________________________     

                 ___________________________     

                 ___________________________       


     2.0  Purchase and Grant of License 
          ----------------------------- 

          2.1  Licensor hereby grants to Licensee, subject to the terms and
conditions of this Agreement, an unrestricted, non-exclusive, irrevocable, fully
paid up, perpetual, royalty free worldwide license (a) under the Background
Technology to make, have made, market, use, reproduce, and sell the Products
either standalone or as part of other products, (b) to use, reproduce, and
sublicense the Background Technology in the areas of CDPD or pACT technology,
and (c) to improve, make Derivative Works of, enhance, modify or otherwise
revise the Background Technology in the areas of CDPD or pACT technology
(collectively "Enchancements") and to use, reproduce, sublicense

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       4
<PAGE>
 
such Enhancements and to make, have made, market, use, reproduce, and sell
products which use or incorporate such Enhancements. Neither party hereto shall
be obligated to share with the other any Enhancements which it makes to the
Background Technology, unless the parties so agree in a separate written
agreement; provided, however, that if Licensor makes or releases any
Enhancements within six (6) months after the date hereof, Licensor shall provide
such Enhancements to Licensee at no additional charge in the format of code
specified in Section 1.2 hereof. Licensor shall provide support for the
Background Technology to Licensee pursuant to a certain support agreement
between the parties of even date herewith (the "Support Agreement").

          2.2  Licensor shall, simultaneously with the execution hereof and
pursuant to a mutually agreeable assignment agreement, assign to Licensee the
Reseller Agreements. Licensee shall assume no liability of Licensor under the
Reseller Agreements.

          2.3  Licensor hereby grants to Licensee, subject to the terms and
conditions of this Agreement, an unrestricted (except for the fact that all
copyright legends included on the _______________ are to be maintained thereon),
non-exclusive, irrevocable, fully paid up, perpetual, royalty free worldwide
sublicense (a) under the ________ ______________ to make, have made, market,
use, reproduce and sell the Products either standalone or as part of other
products, (b) to use, reproduce, further sublicense and sell the
__________________ in the areas of CDPD or pACT technology, and (c) to improve,
make Derivative Works of, enhance, modify or otherwise revise the
_______________________ the areas of CDPD or pACT technology (collectively
_________________ and to use, reproduce,

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       5
<PAGE>
 
sublicense such __________________________ and to make, have made, market, use,
reproduce and sell products which use or incorporate such _______________
Neither party hereto shall be obligated to share with the other, or with
__________________________ any __________________________ which it makes to the
_____________________ unless the parties so agree in a separate written
agreement.

          2.4  Licensor shall use its best efforts to assist Licensee in
entering into reseller agreements with third party resellers which are
counterparts of the _____ ____________________ Agreements.

          2.5  Licensor hereby sells, assigns, and conveys to Licensee all
right, title and interest in and to the Purchased Technology, and agrees to
execute simultaneously with the execution of this Agreement a mutually
acceptable assignment document evidencing the assignment, transfer, grant and
conveyance to Licensee of the Purchased Technology.

          3.0  Consideration
               ------------- 

               As the sole consideration for the purchases, licenses,
assignments and other transactions described in Section 2.0 hereof, Licensee
shall pay to Licensor the sum of $2,500,000 as follows, all by wire transfer
within five (5) business days after the designated dates:

               3.1  $750,000 simultaneously with the execution hereof.

               3.2  $750,000 on the delivery of the code under Section 6.0
hereof and the delivery of notice to such effect by Licensor to Licensee.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       6
<PAGE>
 
                   3.3 $1,000,000 upon the later to occur of (a) six (6) months
after the date hereof, or (b) the consummation of all transactions described
herein, including, without limitation, the obtaining by Licensee of the reseller
agreements described in Section 2.4 hereof (it being understood that Licensee
shall provide reasonable cooperation in connection therewith); and the delivery
of notice to such effect by Licensor to Licensee.

          4.0      AMP
                   --- 

                   Licensee is entering into this Agreement on behalf of AMP.
AMP, together with its divisions, subsidiaries, joint ventures, affiliates and
other related entities, shall at all times have the full right, power and
authority to exercise on its and their own behalf all license, sublicense and
other rights granted to Licensee hereunder. Each use of the word "Licensee" in
this Agreement shall be deemed to include AMP and its divisions, subsidiaries,
joint ventures, affiliates and other related entities.

          5.0      Other Agreement
                   ---------------

                   M/A-COM, a Division of AMP and Licensor have on even date
herewith entered into a certain Agreement (the "Other Agreement"). Even if the
Other Agreement by its terms or otherwise at any time becomes null and void,
there shall be no effect upon this Agreement and this Agreement shall remain in
full force and effect.

          6.0      Delivery
                   --------

                   No later than thirty (30) days after the date hereof,
Licensor shall deliver to Licensee two (2) full copies of the source code,
including all relevant documentation,


                                       7
<PAGE>
 
for the Purchased Technology, the source code for the _________ and the format 
of code specified in Section 1.2 hereof for the Background Technology.

          7.0      Technical Assistance
                   --------------------

                   Licensor shall provide Licensee with one hundred sixty (160)
of technical assistance regarding use of the Licensed Technology at no
additional charge. Licensee shall have the right to purchase additional
technical assistance from Licensor at the rate of ____________ for a period of
six (6) months after the date hereof. Licensee shall have the right to make
employment offers to and hire employees of Licensor who were previously involved
in the development and/or maintenance of the Purchased Technology.

          8.0      Ownership
                   ---------

                   8.1 Licensee shall at all times own the entire right, title
and interest in and to any Derivative Works made by Licensee and has the right
under Article 2 above to make such Derivative Works without any claim by
Licensor of infringement of any underlying work from which the Derivative Works
are derived.

                   8.2 Licensor shall at all times own the entire right, title
and interest in and to the Background Technology. Licensee shall at all times as
of the date set forth in the first paragraph of this Agreement own the entire
right, title and interest in and to the Purchased Technology.

                   8.3 In the event the __________ Agreement (as defined in the
Other Agreement) is not assigned by Licensor to M/A-COM, a Division of AMP in
accordance with the Other Agreement, Licensor shall retain the limited right to
use the Purchased

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       8
<PAGE>
 
Technology and the Licensed Technology to meet obligations previously agreed to
by Licensor under the ___________ Agreement including the release of source code
thereunder specifically for the use described thereunder, and which limited
right shall last only for the period of time until such obligations to _________
are fulfilled.

                   8.4 Licensor shall have the right to use the Purchased
Technology to meet its obligations under the Support Agreement.

          9.0      Technology
                   ----------

                   9.1 Licensor represents and warrants that the Purchased
Technology and the Licensed Technology represent, include and constitute all of
the technology of any nature whatsoever now or previously utilized by Licensor
in the conduct and operation of Licensor's line of business being assigned to
M/A-COM, a Division of AMP pursuant to the Other Agreement.

                   9.2 In the event Licensor at any time becomes party to any
proceeding under the U.S. Bankruptcy Code, Licensee shall retain all its license
rights hereunder pursuant to (S)365 of the U.S. Bankruptcy Code.

          10.0     Representations and Warranties 
                   ------------------------------

                   Licensor represents and warrants as follows:

                   10.1 The license and other rights granted to Licensee under
this Agreement do not require the consent of any person or entity other than
Licensor. The Purchased Technology and the Background Technology are owned
exclusively by the Licensor, are freely transferrable by Licensor and are free
and clear of any Liens (as defined in the Other Agreement).

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       9
<PAGE>
 
                   10.2 Except as set forth in Exhibit A attached hereto, no
third party or entity has an interest in or right or license to use, or the
right to license any other person or entity to use, any of the Purchased
Technology.

                   10.3 There are no claims or demands of any third party or
entity pertaining to the Purchased Technology or the Background Technology and
no proceedings have been instituted, or are pending or, to the knowledge of the
Licensor, are threatened, which challenge Licensor's rights in respect thereof
or with respect to the ___________, the Reseller Agreements or the ___________ 
Agreements.

                   10.4 To Licensor's knowledge, none of the Purchased
Technology or the Background Technology is being infringed by another person or
entity or is subject to any outstanding order, decree, ruling, charge,
injunction, judgment or stipulation.

                   10.5 No Claim (as defined in the Other Agreement) has been
made or has been threatened with respect to the Purchased Technology or the
Background Technology charging the Licensor with infringement of any third party
intellectual property.

                   10.6 Licensor has the full, complete and unrestricted right,
power and authority to sublicense the _____________ to Licensee as set forth in
Section 2.3 of this Agreement.

                   10.7 Licensor has good and marketable title to the Purchased
Technology, free and clear of all Liens (as defined in the Other Agreement) and
the sale and delivery of the Purchased Technology to Licensee pursuant hereto
shall vest in

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       10
<PAGE>
 
Licensee good and marketable title thereto, free and clear of any and all Liens
(as defined in the Other Agreement).

                   10.8 Neither the Licensor nor any other person or entity is
in default under the Reseller Agreements or the ____________ Agreements.
                                                                       
                   10.9 Licensor has the full, complete and unrestricted right,
power and authority to assign the Reseller Agreements to Licensee as set forth
in Section 2.2 of this Agreement.

          11.0     Infringement
                   ------------

                   11.1 Licensor shall defend, indemnify and hold harmless
Licensee from and against any Claim (as defined in the Other Agreement) that
Licensee's use of the Purchased Technology or the Background Technology
hereafter or hereunder infringes any patent of a country covered by the scope of
the _____________ Agreement (as defined in the Other Agreement) or the _________
Agreement. (as defined in the Other Agreement), copyright, trade secret or other
proprietary rights of any third party, provided that Licensor's liability under
this Section 11.1 shall not exceed an amount equal to two (2) times paid by
Licensee to Licensor under this Agreement.

                   11.2 Each party shall promptly notify the other party in
writing of any infringement of the Background Technology as it relates to the
Purchased Technology by a third party which it becomes aware of at any time.
Licensor shall have a period of ninety (90) days from its awareness of such
infringement or receipt of such notice to initiate legal proceedings against the
alleged infringer or to provide notice to Licensee

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       11
<PAGE>
 
that it will not initiate such proceedings. In the event Licensor does initiate
such proceedings, they shall be subject to the following:

                            11.2.1 Licensor shall be responsible for the control
of such proceedings and shall pay all expenses incurred in connection therewith.

                            11.2.2 Licensee shall provide to Licensor reasonable
cooperation in initiating or carrying on such proceedings.

                            11.2.3 Any monetary recovery obtained by Licensor as
a result of such proceeding shall be retained by Licensor.

                   11.3 In the event Licensor does not commence a proceeding
against, or otherwise stop, an alleged infringer in accordance with Section 11.2
hereof within the time period specified therein, Licensee shall have the option
to commence such a proceeding on its own behalf in Licensor's name. All such
proceedings brought by Licensee shall be subject to the following:

                            11.3.1 Licensee shall be responsible for the control
of such proceeding and shall pay all expenses incurred in connection therewith.

                            11.3.2 Licensor shall provide to Licensee reasonable
cooperation in initiating or carrying on such proceedings.

                            11.3.3 Any monetary recovery obtained by Licensee as
a result of such proceeding shall belong solely to Licensee.

          12.0     Damages
                   -------

                   Except with respect to Section 11.1 hereof, neither party
shall have any liability to the other for consequential, indirect or special
damages.


                                       12
<PAGE>
 
          13.0 Miscellaneous Provisions
               ------------------------

               13.1  The performance of each party hereunder shall be in
compliance with all applicable foreign, federal, state and local laws, rules and
regulations.

               13.2  Each party shall perform as an independent contractor
hereunder and nothing contained herein shall be construed as giving rise to a
joint venture; partnership or other form of business relationship.

               13.3  Neither party shall be liable to the other party for a
delay in performance arising out of causes beyond such party's control,
including, without limitation, strikes, riots, weather difficulties, fires and
acts of God or government.

               13.4  This Agreement shall be governed by and interpreted in
accordance with the laws of the State of Delaware.

               13.5  All notices given hereunder shall be in writing and shall
be sent by certified mail, return receipt requested, addressed to the other
party as follows, provided that either party may change such address by
providing written notice thereof:

     If to Licensee:            The Whitaker Corporation
                                4550 New Linden Hill Road, Suite 450
                                Wilmington, Delaware 19808

                                Attn:  Director of Licensing

     with copies to:            M/ACOM, a Division of AMP Incorporated
                                1011 Pawtucket Blvd.
                                P.O. Box 3295
                                Lowell, MA 018533295

                                Attn:  Ms. Jean L. Ribeiro 
                                       Contracts Manager


                                       13
<PAGE>
 
     If to Licensor:            Vertel Corporation
                                21300 Victory Blvd.
                                Suite 1200
                                Woodland Hills, CA 91367

                                Attn:  Mr. David Brock  
                                       Director of Contracts     
                                
               13.6  The headings of this Agreement have been inserted for
convenience of reference only and are to be of no force or effect in any
interpretation or construction of this Agreement.

               13.7  In the event that any provision of this Agreement shall be
held to be illegal or null and void by any court of competent jurisdiction, such
determination shall not affect the remainder of this Agreement and it shall
remain in full force and effect.

               13.8  Licensee shall have no responsibility for the payment of
any taxes arising out of or in connection with this Agreement.

               13.9  The failure of either party at any time or times to require
performance of any provision hereof shall not affect its right at a later time
to enforce the same. No waiver by either party of the breach of any provision
hereof shall be deemed to be a continuing or further waiver of any such breach.
This Agreement may be assigned in whole or in part by Licensee.

               13.10 This Agreement constitutes the entire agreement between the
parties concerning the subject matter hereof and supersedes, except for the
Other Agreement, any and all prior or contemporaneous agreements and
understandings in


                                       14
<PAGE>
 
connection therewith. This Agreement may be amended, modified or revoked only by
a written instrument executed by both parties hereto.

               13.11 This Agreement may be delivered by facsimile copies, and
such facsimile copies shall be deemed to be executed originals for all purposes.
This Agreement may be executed in a series of counterparts all of which, when
taken together, shall constitute one and the same instrument.

          IN WITNESS WHEREOF, this Agreement has been executed by the parties 
hereto under seal in duplicate originals as of the date first written above.

THE WHITAKER CORPORATION                     VERTEL CORPORATION


By:  /s/ [SIGNATURE ILLEGIBLE]               By:  /s/ James Brill
   ------------------------------               ------------------------------
Title:   PRESIDENT                           Title:   V P
      ---------------------------                  --------------------------- 


                                       15
<PAGE>
 
                                   AGREEMENT
                                   ---------


          Agreement dated as of July 27, 1998, by and between AMP Incorporated,
acting through its M/A-COM Division, a Pennsylvania corporation ("Buyer") and
Vertel Corporation, a California corporation ("Seller").

          This Agreement sets forth the terms and conditions upon which the
Buyer will obtain from the Seller and the Seller will assign to the Buyer
certain agreements of the Seller, subject to those liabilities of the Seller
which are specifically hereinafter described, for the consideration provided
herein.

          In consideration of the foregoing, the mutual representations,
warranties and covenants set forth herein, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties to this Agreement hereby agree as follows:

                              1.0    DEFINITIONS
                                     -----------

          1.1  Definitions.  For the purposes of this Agreement, all capitalized
               -----------
words or expressions used in this Agreement shall have the meanings specified in
this Section 1.0 (such meanings to be equally applicable to both the singular
and plural forms of the terms defined):

          ______ means _________________________

       _________ Agreement" means a certain Reseller Agreement between Seller
and ______ dated July 16, 1996, as amended September 16, 1997.

       _________ Backlog" means the unfilled balance of obligations against
orders placed with Seller by ____ under the __________ Agreement

     "Agreement" means this Agreement and all Exhibits hereto.
      ---------

     "Assigned Agreements" means the ___________ Agreement, the _________ 
      -------------------
Agreement and the __________ Agreement.

     "Assigned Backlog" means the __________ Backlog, the _________ Backlog and
      ----------------
the ________ Backlog.

     "Assigned Items" means the Assigned Agreements and the Assigned Backlog.
      --------------

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       16
<PAGE>
 
     "Charter" means the Certificate of Incorporation, Articles of Incorporation
      -------
or Organization or other organizational document of a corporation, as amended
and restated through the date hereof.

     "Claim" means an action, suit, proceeding, hearing, investigation,
      -----
litigation, charge, complaint, claim or demand.

     ______________ means ______________________.

     __________ Agreement" means a certain Agreement between __________ and 
Seller dated March 15, 1996, as amended March 16, 1998.

     __________ Backlog means the unfilled balance of obligations against orders
placed with Seller by __________________ under the __________ Agreement.

     ______________________ Agreement means ______________________

     ______________________ Agreement means a certain Software License Agreement
between ______________________ and Seller dated June 17, 1997.

     ___________ Backlog means the unfilled balance of obligations against 
orders placed with Seller by ______________________ under the __________ 
Agreement. 

          "License Agreement" means a certain License and Purchase Agreement of
           -----------------
even date herewith between Seller and The Whitaker Corporation.

          "Lien" means, with respect to any asset, any mortgage, deed of trust,
           ----
pledge, hypothecation, assignment, security interest, lien, charge, restriction,
adverse claim by a third party, title defect or encumbrance of any kind.

          "Person" means any individual, firm, partnership, association, trust,
           ------
corporation, limited liability company, governmental body or other entity.

          "Reseller Agreement" means a certain Reseller Agreement between Buyer
           ------------------ 
and Seller dated December 26, 1997.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       2
<PAGE>
 
                             2.0   ASSIGNED ITEMS
                                   --------------

     2.1  _______   Simultaneously with the execution hereof, Seller shall
request ____________ consent to the assignment of the _________ Agreement and 
the ____________ Backlog together with the Software Maintenance Agreement dated
July 1996 between Seller and ______, from Seller to Buyer, and the parties shall
proceed as follows in connection therewith:

          2.1.1     Immediately upon the receipt of such consent in form and
substance as set forth in Exhibit A attached hereto, (a) Seller shall execute in
favor of Buyer an assignment of the ____________ Agreement, ____________ Backlog
and such Software Maintenance Agreement in form and substance as set forth in
Exhibit B attached hereto, such assignment to include all right, title and
interest of Seller under the ____________ Agreement the ______________ Backlog
and such Software Maintenance Agreement, except for amounts due from _______ to
Seller for services performed or items delivered prior to the date of such
assignment, and (b) Buyer shall execute in favor of Seller an assumption of the
__________ Agreement, the _________ Backlog and such Software Maintenance
Agreement in form and substance as set forth in Exhibit B, such assumption to
include all obligations of Seller under the __________ Agreement the ________
Backlog and such Software Maintenance Agreement, except as set forth in Section
2.9 hereof.

          2.1.3     In the event such consent for all such items from
____________ is not received within ninety (90) days after the date hereof, this
Section 2.1 shall automatically be rendered null and void and of no further
force or effect.


     2.2  ____________ Simultaneously with the execution hereof, Seller shall
request consent to the assignment of the __________ Agreement, together with the
associated Escrow Agreement, and the ____________ Backlog from Seller to Buyer,
and the parties shall proceed as follows in connection therewith:

          2.2.1     Immediately upon the receipt of such consent in form and
substance as set forth in Exhibit A, (a) Seller shall execute in favor of Buyer
an assignment of the ______________ _____________ Agreement the __________
Backlog and such Escrow Agreement in form and substance as set forth in Exhibit
B, such assignment to include all right, title and interest of Seller under the
____________ Agreement the ___________ Backlog and such Escrow Agreement, except
for amounts due from ____________ to Seller for services performed or items
delivered prior to the date of such assignment, and (b) Buyer shall execute in
favor of Seller an assumption of the __________ Agreement the __________ Backlog
and such Escrow Agreement in form and substance as set forth in Exhibit B, such
assumption to include all obligations of Seller under the ___________ Agreement
the _________ Backlog and such Escrow Agreement, except as set forth in Section
2.9 hereof.

          2.2.2     In the event such consent from ____________ is not received
within ninety (90) days after the date hereof, this Section 2.2 shall
automatically be rendered null and void and of no further force or effect.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       3
<PAGE>
 
          2.2.3     In the event ____________ fails to provide such consent and
instead invokes its right to receive source code under the __________ Agreement
and such Escrow Agreement, (a) this Section 2.2 shall be null and void as
described in Section 2.2.3 hereof, and (b) Seller shall have the entire right,
title and interest in and to any amounts payable by ____________ under the
__________ Agreement as a result of ____________ receipt of such source code,
including, without limitation, any residual royalties.

     2.3 ____________ Prior to the execution hereof, Seller and Buyer have
obtained ____________ consent to the assignment of the __________ Agreement and
the __________ Backlog from Seller to Buyer in form and substance as set forth
in Exhibit A-1 attached hereto. Immediately upon the execution of this
Agreement, (a) Seller shall execute in favor of Buyer an assignment of the
__________ Agreement and the __________ Backlog in form and substance as set
forth in Exhibit B, such assignment to include all right, title and interest of
Seller under the __________ Agreement and the ___________ Backlog except for
amounts due from ____________ to Seller for services performed or items
delivered prior to the date of such assignment, and (b) Buyer shall execute in
favor of Seller an assumption of the __________ Agreement and the __________
Backlog in form and substance as set forth in Exhibit B, such assumption to
include all obligations of Seller under the __________ Agreement and the
__________ Backlog except as set forth in Section 2.9 hereof.

     2.4  Independent Obligations. The failure to obtain one of, but not
          -----------------------
both of, the desired consents from ____________ and ____________ shall not
affect this Agreement, except with respect to the items for which consent was
not obtained and with respect to the purchase price as described in Section 2.7
hereof.

     2.5  License Agreement. The parties acknowledge that on even date
          -----------------
herewith Seller has entered into the License Agreement. In the event this
Agreement is rendered null and void due to the failure to obtain all of the
required consents to the assignment to the Assigned Items, the License Agreement
shall not be affected thereby and shall remain in full force and effect.

     2.6  Additional Conditions. In the event ____________ or ____________
          ---------------------
require Buyer to enter into additional agreements or to agree to additional
conditions with respect to the assignment of any of the Assigned Items, Buyer
shall in its sole discretion have the right to accept or reject such conditions
and shall have no liability to Seller if such rejection causes ____________ or
____________ to refuse to provide the desired consent.

     2.7  Purchase Price. The purchase price for the Assigned Items shall be as
          --------------
follows:

          2.7.1 Within five (5) working days after the execution of the
assignment of the __________ Agreement and the __________ Backlog from Seller to
Buyer, Buyer shall pay Seller the sum of $1,000,000 by wire transfer; provided,
however, that Buyer shall withhold ____________ of such amount until the earlier
to occur of (a) Seller provides notice to Buyer from ____________ that all
credits in favor of ____________ under Section 4.2 of the ____________ Agreement
have been liquidated, or (b) February 28, 1999. In the event the assignment of
the __________ Agreement and the __________

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       4
<PAGE>
 
Backlog does not occur and ____________ seeks to recover such credits from
Buyer, Seller shall pay Buyer an amount not to exceed ____________ to cover such
credits.

          2.7.2  The only consideration for the assignment of the ____________
Agreement said Software Maintenance Agreement, the ____________ Backlog the
____________ Agreement and the ____________ Backlog shall be the Buyer's
assumption of Seller's obligations thereunder.

     2.8  Reseller Agreement. The parties hereby terminate and cancel in its
          ------------------
entirety and render null and void the Reseller Agreement.

     2.9  Existing Indemnities. Notwithstanding any provision of this
          --------------------  
Agreement or of any assignment of the Assigned Agreements to Buyer, Seller shall
remain fully responsible for, and shall indemnify Buyer against, any warranties
or indemnifications regarding intellectual property rights or related matters
contained in the Assigned Agreements. Such indemnification by Seller shall not
be subject to the time limitations set forth in Section 6.1 hereof, and such
indemnification shall be in an amount no greater than the larger of (a) the
amount of the indemnification provided for in the applicable Assigned Agreement,
or (b) (i) ____________ if the _____________________ Agreement and the
____________ Backlog are not assigned to Buyer, or (ii) ____________ if the
_________________ Agreement and the ____________ Backlog are assigned to Buyer.

               3.0  REPRESENTATIONS AND WARRANTIES OF THE SELLER
                    -------------------------------------------- 

     The Seller hereby represents and warrants to Buyer as follows:

     3.1  Organization and Qualification. Seller is a corporation duly
          ------------------------------
organized, validly existing and in good standing under the laws of the State of
California. Seller has full power and authority to own, use and lease its
properties and to conduct its business relating to or affecting the Assigned
Items as currently conducted and as proposed to be conducted. The copies of the
Seller's Charter and By-Laws, as amended to date, certified by its Secretary and
delivered to Buyer's counsel prior to the date hereof, are true, complete and
correct. The Seller is qualified to do business as a foreign corporation and is
in good standing in each jurisdiction in which it owns or leases property
relating to or affecting the Assigned Items or maintains inventories or where
the conduct of its business relating to or affecting the Assigned Items would
require such qualification.

     3.2  Authority: No Violation. Seller has all requisite corporate power
          -----------------------
and authority to enter into this Agreement and to carry out the transactions
contemplated hereby. The execution, delivery and performance of this Agreement
and the License Agreement by the Seller has been duly and validly authorized and
approved by all necessary corporate action. This Agreement and the License
Agreement constitute the legal and binding obligation of the Seller, enforceable
against it in accordance with its terms. To the best knowledge of Seller, the
entering into of this Agreement and the License Agreement by the Seller does
not, and the consummation by the Seller of the transactions contemplated hereby
and thereby will not, violate the provisions of

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       5
<PAGE>
 
(a) any applicable federal, state, local or foreign laws, (b) the Seller's
Charter or By-Laws, or (c) any provision of, or result in a default or
acceleration of any obligation under, or result in any change in the rights or
obligations of the Seller under, any Lien, contract, agreement, license, lease,
instrument, indenture, order, arbitration award, judgment, or decree to which
the Seller is a party or by which it is bound, or to which any property of the
Seller is subject.

     3.3  Title, Sufficiency and Condition of Assets. The Seller has good
          ------------------------------------------
and marketable title to the Assigned Items, free and clear of all Liens, and
free of any non-performance or Claims thereof, and the sale and delivery of the
Assigned Items to Buyer pursuant hereto shall vest in Buyer good and marketable
title thereto, free and clear of any and all Liens.

     3.4  Default.  Neither the Seller nor any other Person is in default
          -------
under any Assigned Item.

     3.5  Compliance with Laws. Seller has conducted and is conducting its
          --------------------
business in compliance with applicable federal, state, local or foreign laws,
statutes, ordinances, regulations, rules or orders or other requirements of any
governmental, regulatory or administrative agency or authority or court or other
tribunal relating to it as it relates to or affects the Assigned Items.

     3.6  Litigation. There is no Claim pending or, to the knowledge of the
          ----------
Seller, threatened (or, to the knowledge of the Seller, any facts which could
reasonably be expected to lead to such a Claim) by, against, affecting or
regarding the Assigned Item before any federal, state, local or foreign court or
any other governmental or administrative agency or tribunal or any arbitrator or
arbitration panel, and there are no judgments, orders, rulings, charges,
decrees, injunctions, notices of violation or other mandates against or
affecting the Assigned Items.

     3.7  Assigned Backlog. The Assigned Backlog constitutes, represents and
          ----------------
includes, together with the Reseller Agreement, all of the backlog of Seller
with respect to the Products (as defined in the License Agreement).

     3.8  Disclosure of Material Information. Neither this Agreement nor any
          ----------------------------------
document, certificate or instrument furnished in connection therewith contains,
with respect to the Seller, any untrue statement of a material fact or omits to
state a material fact necessary to make the statements therein not misleading.

     3.9 ____________ Agreement The amount of credits in favor of ____________
under Section 4.2 of the _________________ Agreement does not exceed
____________


                4.0   REPRESENTATIONS AND WARRANTIES OF BUYER
                      ---------------------------------------

     Buyer hereby represents and warrants to the Seller as follows:

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       6
<PAGE>
 
          4.1 Organization and Qualification. Buyer is a corporation duly
              ------------------------------
organized, validly existing and in good standing under the laws of the
Commonwealth of Pennsylvania, with full power and authority to own, use or lease
its properties and to conduct its business as such properties are owned, used or
leased and as such business is conducted.

          4.2 Authority. Buyer has the requisite corporate power and authority
              ---------
to enter into this Agreement and to carry out the transactions contemplated
hereby. The execution, delivery and performance of this Agreement by Buyer have
been duly and validly authorized and approved by all necessary corporate action
on the part of Buyer, and this Agreement constitutes the legal and binding
obligation of Buyer, enforceable against Buyer in accordance with its terms.
Assuming the accuracy of the representations and warranties of the Seller
hereunder, the entering into of this Agreement by Buyer does not, and the
consummation by Buyer of the transactions contemplated hereby will not, violate
the provisions of (a) any applicable federal, state, local or foreign laws or
any other state or jurisdiction in which Buyer does business, (b) the Charter or
By-Laws of Buyer, or (c) any provision of, or result in a default or
acceleration of any obligation under, or result in any change in the rights or
obligations of Buyer under, any mortgage, Lien, lease, agreement, contract,
instrument, order, arbitration award, judgment, or decree to which Buyer is a
party or by which Buyer is bound, or to which any property of Buyer is subject.

          4.3 Disclosure of Material Information. Neither this Agreement nor any
              ----------------------------------
document, certificate or instrument furnished in connection therewith contains,
with respect to Buyer, any untrue statement of a material fact or omits to state
a material fact necessary to make the statements therein not misleading.

                             5.0 OTHER CONDITIONS
                                 ----------------
          The Seller shall on the date hereof deliver to Buyer a certificate of
the Secretary of Seller certifying the truth and correctness of resolutions of
the Seller authorizing the entry by the Seller into this Agreement, the License
Agreement and the transactions contemplated hereby and thereby.

                              6.0 INDEMNIFICATION
                                  ---------------
          6.1 Survival of Representations and Warranties. Each and every such
              ------------------------------------------
representation and warranty set forth in this Agreement, and the right to bring
legal action with respect to its breach, shall survive until the third
anniversary of the date hereof.

          6.2 Indemnification by the Seller. Seller shall defend and hold Buyer,
              -----------------------------
its officers, directors, employees, owners, agents and affiliates, harmless from
and in respect of any and all losses, damages, costs and expenses (including,
without limitation, interest and penalties, reasonable expenses of investigation
and court costs, reasonable attorneys' fees and disbursements and the reasonable
fees and disbursements of other professionals) which may be sustained or
suffered by any of them (collectively "Losses"), arising out of, resulting from
or


                                       7
<PAGE>
 
pertaining to any breach or inaccuracy of any representation or warranty or the
breach of or failure to perform any warranty, covenant, undertaking or other
agreement of the Seller contained in this Agreement or any other document
executed in connection herewith. Seller's indemnification under this Section 6.2
shall not exceed (a) __________ if the ___________ Agreement and the ________
Backlog are not assigned to Buyer, or (b) ____________ if the _____________
Agreement and the ___________ Backlog are assigned to Buyer.

          6.3 Indemnification by Buyer. Buyer shall indemnify, defend and hold
              ------------------------
Seller and its officers, directors, employees, consultants, owners, agents and
affiliates, harmless from and in respect of any and all Losses which may be
sustained or suffered by any of them arising out of or resulting from any breach
or inaccuracy of any representation or warranty or the breach of or failure to
perform any warranty, covenant, undertaking or other agreement of Buyer
contained in this Agreement or any other document executed in connection
herewith. Buyer's indemnification under this Section 6.3 shall not exceed (a)
_________ if the __________ Agreement and the ________ Backlog are not assigned
to Buyer, or (b) _________ if the _________ Agreement and the ____________
Backlog are assigned to Buyer.

          6.4 Notice and Opportunity to Defend. If there occurs an event which a
              --------------------------------
party asserts is an indemnifiable event pursuant to Section 6.2 or 6.3, the
party seeking indemnification shall promptly notify the other parties obligated
to provide indemnification (collectively, the "Indemnifying Party"). If such
event involves (a) any Claim, or (b) the commencement of any action, suit or
proceeding by a third person, the party seeking indemnification will give such
Indemnifying Party prompt written notice of such Claim or the commencement of
such action, suit or proceeding; provided, however, that the failure to provide
                                 --------  -------
prompt notice as provided herein will relieve the Indemnifying Party of its
obligations hereunder only to the extent that such failure prejudices the
Indemnifying Party hereunder. In case any such action, suit or proceeding shall
be brought against any party seeking indemnification and it shall notify the
Indemnifying Party of the commencement thereof, the Indemnifying Party shall be
entitled to participate therein and, to the extent that it desires to do so, to
assume and control the defense thereof, with counsel reasonably satisfactory to
such party seeking indemnification and, after notice from the Indemnifying Party
to such party seeking indemnification of such election so to assume the defense
thereof, the Indemnifying Party shall not be liable to the party seeking
indemnification hereunder for any attorneys' fees or any other expenses, in each
case subsequently incurred by such party, in connection with the defense of such
action, suit or proceeding. The party seeking indemnification will cooperate
fully with the Indemnifying Party and its counsel in the defense against any
such action, suit or proceeding. In any event, the party seeking indemnification
shall have the right to participate at its own expense in the defense of such
action, suit or proceeding, provided the indemnifying party shall control such
defense. In no event shall an Indemnifying Party be liable for any settlement
or compromise effected without its prior consent.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       8
<PAGE>
 
                             7.0     MISCELLANEOUS
                                     -------------
          7.1 Fees and Expenses. Each of the parties hereto will pay and
              -----------------
discharge its own expenses and fees in connection of with the negotiation of and
entry into this Agreement and the consummation of the transactions contemplated
hereby. Buyer shall have no responsibility for the payment of any taxes arising
out of or in connection with this Agreement.

          7.2 Notices. All notices, requests, demands, consents and
              -------
communications necessary or required under this Agreement or any other document
executed in connection herewith shall be made in the manner specified, or, if
not specified, shall be sent by registered or certified mail, return receipt
requested to:

          if to Buyer:

          AMP, Incorporated, acting through its M/A-COM Division
          1011 Pawtucket Boulevard
          P.O. Box 3295
          Lowell, MA 01853-3295

          Attention:    Ms. Jean L. Ribeiro
                        Contracts Manager
          Facsimile Transmission Number: 978-442-4988

          if to the Seller:

          Vertel Corporation
          21300 Victory Blvd.
          Suite 1200
          Woodland Hills, California 91367

          Attention:   David Brock, Director of Contracts
          Facsimile Transmission Number: 818-598-0047

          All such notices, requests, demands, consents and other communications
shall be deemed to have been duly given or sent three (3) business days
following the date on which mailed addressed as aforesaid.

          7.3 Successors and Assigns. All covenants and agreements set forth in
              ----------------------
this Agreement and made by or on behalf of any of the parties hereto shall bind
and inure to the benefit of the successors and assigns of such party, whether or
not so expressed.


                                       9
<PAGE>
 
          7.4 Counterparts. This Agreement may be executed in any number of
              ------------
counterparts and by the different parties hereto on separate counterparts, each
of which when so executed and delivered shall be an original, but all of which
together shall constitute one and the same instrument, and it shall not be
necessary in making proof of this Agreement to produce or account for more than
one such counterpart. This Agreement may be delivered by facsimile copies, and
such facsimile copies shall be deemed to be executed originals for all purposes.
The headings of the sections and paragraphs of this Agreement have been inserted
for convenience of reference only and shall not be deemed to be part of this
Agreement. If any one or more of the provisions contained herein, or the
application thereof in any circumstances, is held invalid, illegal or
unenforceable in any respect for any reason in any jurisdiction, the validity,
legality and enforceability of any such provision in every other respect and of
the remaining provisions hereof shall not be in any way impaired or affected, it
being intended that each of parties' rights and privileges shall be enforceable
to the fullest extent permitted by law, and any such invalidity, illegality and
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

          7.5 Governing Law. This Agreement, including the validity hereof and
              -------------
the rights and obligations of the parties hereunder, shall be construed in
accordance with and governed by the laws of the Commonwealth of Pennsylvania
applicable to contracts made and to be performed entirely in such state (without
giving effect to the conflicts of laws provisions thereof).

          7.6 Entire Agreement. This Agreement is complete, and all promises,
              ----------------
representations, understandings, warranties and agreements with reference to the
subject matter hereof, and all inducements to the making of this Agreement
relied upon by all the parties hereto, have been expressed herein. This
Agreement may not be amended except by an instrument in writing signed on behalf
of the Seller and the Buyer.

          IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first set forth above.

AMP INCORPORATED, Acting
through its MIA-COM Division                     VERTEL CORPORATION



By: /s/ Richard R. Clark                         By: /s/ James Brill
   ----------------------                           --------------------------
Title:  President and CEO                        Title:  V.P
      -------------------                              -----------------------


                                      10
<PAGE>
 
                                   EXHIBIT A

                                FORM OF CONSENT


                                                           ________________ 1998

_____________________
_____________________
_____________________
_____________________

Gentlemen:

          We are writing to inform you that we have sold to AMP Incorporated,
acting through its M/A-COM Division ("M/A-COM") our CDPD software, as we intend
to exit such business and transfer all backlog from such business to M/A-COM. As
a result, we are hereby notifying you of this situation and requesting your
consent to our transfer to M/A-COM of our Agreement with you dated ______, all
orders placed by you with us thereunder and __________ .

          In addition, M/A-COM, by its countersignature of this letter, has
agreed to assume all of our obligations under all such Agreements.

          If the foregoing is acceptable to you, kindly execute three copies of
this letter in the space set forth below. Please retain one for your files,
please send one to us to the attention of __________ and please send one to
M/A-COM at 1011 Pawtucket Boulevard, P.O. Box 3295, Lowell, MA 01853-3295 to the
attention of Ms. Jean L. Ribeiro, Contracts Manager.

          Thank you very much for your consideration of this matter.

                                                Very truly yours,

                                                VERTEL CORPORATION

                                                ________________________

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.
<PAGE>
 
AMP Incorporated, acting through 
its M/A-COM Division hereby agrees 
to the foregoing assumption:

AMP Incorporated, acting through 
its M/A-COM Division


By:__________________________

Title:_______________________

The foregoing is hereby accepted 
and agreed to in its entirety:


By:__________________________

Title:_______________________

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       2
<PAGE>
 
                                  EXHIBIT A-1
                                  -----------

                          FORM OF __________  CONSENT


                                              _______, 1998

_____________________        
_____________________         
_____________________          
_____________________

Gentlemen:

     ____________________ consent is requested to the assignment of a certain
Software License Agreement between ____________ and Vertel Corporation
("Vertel") dated June 17, 1997 (the "Agreement") to M/A-COM, a Division of AMP
Incorporated ("M/A-COM") together with all unfilled balances of obligations
against orders placed with Vertel by _________ under the Agreement (the
"Backlog"). M/A-COM is willing to assume all remaining obligations under the
Agreement and all existing Backlog subject to ___________ consent and in
accordance with the conditions as outlined below.

     1.   _________________ consent shall automatically become effective only
when Vertel and M/A-COM execute certain agreements between them with regard to
the purchase of CDPA and mACT technology (the "Technology") as well as certain
other assets including the Agreement and the Backlog by M/A-COM from Vertel (the
"Transaction"). M/A-COM and Vertel shall notify ________________ on the date 
the Transaction is consummated by immediately returning a signed copy of this
consent agreement. However, nothing contained herein shall be construed as
requiring M/A-COM and Vertel to consummate that Transaction.

     2.   Promptly upon the receipt of such notice to ___________ by M/A-COM as
evidenced by a signed copy of this consent agreement, M/A-COM and ___________
shall undertake all good faith efforts to enter into an escrow agreement with 
_______________ with regard to the Technology in form and substance as required
by the Agreement (the "Escrow").

     3.   Commencing upon the date of the Transaction, ______________ shall pay
any further royalties under the Agreement and remaining Backlog to M/A-COM
separately and apart from the price of the radios M/A-COM sells to _______ under
existing and future agreements and orders between ______________ and M/A-COM. 
__________ and M/A-COM shall also discuss the possibility of terminating the
Agreement, but not the Escrow, at no cost or liability to either party and
adding the existing royalty payments to the price of the radios upon the
execution of such termination. ______________ shall owe no further payments to
Vertel after the Transaction, other than with respect to those royalties accrued
prior to the date of the Transaction.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.
<PAGE>
 
     4.   M/A-COM, by its countersignature of this consent agreement, agrees
to all of the foregoing.

          If the foregoing is acceptable to you, please execute three copies of
this Agreement in the space set forth below and return them to M/A-COM, a
Division of AMP Incorporated, at 1011 Pawtucket Boulevard, P.O. Box 3295,
Lowell, Massachusetts 01853, Attention of Jean L. Ribeiro, Contracts Manager.

          The foregoing is hereby accepted and agreed to in its entirety:


__________________________________        


By:_______________________________

Title:____________________________

Date:_____________________________

VERTEL CORPORATION


By:_______________________________

Title:____________________________

Date:_____________________________

M/A-COM, A DIVISION OF AMP INCORPORATED


By:_______________________________

Title:____________________________

Date:_____________________________

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       2
<PAGE>
 
                                   EXHIBIT B
                                   ---------

                           ASSIGNMENT AND ASSUMPTION


     Vertel Corporation, a California corporation, having its principal place of
business in Woodland Hills, California ("Assignor") in consideration of the
payment of One Dollar ($1.00) and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, by AMP, Incorporated,
acting through its M/A-COM Division with a place of business in Lowell,
Massachusetts ("Assignee"), does hereby assign, grant, sell, transfer, bargain,
convey and deliver unto Assignee its entire right, title and interest and all of
its rights, liabilities and obligations in and to the contracts listed in
Attachment I attached hereto (collectively the "Contracts").

     Assignor hereby covenants to and with Assignee that said right, title and
interest in the Contracts has not previously been sold, assigned or transferred
and that Assignor is the lawful owner of said right, title and interest in the
Contracts free from all liens, mortgages, security interests or encumbrances of
any nature whatsoever, contingent or otherwise. Assignor hereby further
covenants to and with Assignee that Assignor has obtained all necessary consents
of third parties to the assignments granted herein.

     Assignee, in consideration of the payment of One Dollar ($1.00) and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, by Assignor, hereby assumes all liabilities and obligations of
Assignor under the Contracts.

<PAGE>

     EXECUTED as an instrument under seal this _____ day of __________, 1998.


AMP INCORPORATED, Acting
through its M/A-COM Division                 VERTEL CORPORATION

By:________________________                  By:________________________
Title:_____________________                  Title:_____________________


     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                       2
<PAGE>
 
                                 ATTACHMENT I
                                 ------------

                                   CONTRACTS

          1.   A certain Reseller Agreement between Assignor and
________________ dated July 16, 1996, as amended September 16, 1997, together
with the unfilled balance of obligation against orders placed with Assignor
thereunder.

          2.   A certain Agreement between ______________________ and Assignor
dated March 15, 1996, as amended March 16, 1998, together with the unfilled
balance of obligations against orders placed with Assignor thereunder.

          3.   A certain Software License Agreement between Assignor and
_______________________ dated June 17, 1997, together with the unfilled balance
of obligations against orders placed with Assignor thereunder.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.
<PAGE>
 
                                   AMENDMENT
                                   ---------

          Amendment dated October 9th, 1998 by and between AMP Incorporated,
acting through its M/A-COM Division, a Pennsylvania corporation ("Buyer") and
Vertel Corporation, a California corporation ("Seller").

          Buyer and Seller entered into a certain Agreement dated as of July 27,
1998 (the "Agreement"). Buyer and Seller desire to amend the Agreement in
certain respects.

          In consideration of the foregoing and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereby amend the Agreement and agree as follows:

          1.   Delete the first sentence of Section 2.7.1 of the Agreement in
               its entirety and substitute therefor the following:

               Upon the execution of an agreement among Buyer, Seller and
               ________________________ dealing with when the assignment of the
               __________________ Agreement and the __________________ Backlog
               is to occur (the "Transfer Agreement"), or the completion and
               mutual agreement of the Attachment 1 list as described in the
               Transfer Agreement, whichever occurs later, Buyer shall pay
               Seller the sum of $500,000. Buyer shall pay Seller an additional
               $500,000 less $169,000 (representing advance payments made by
               __________ to Seller) for a net amount of $331,000 when Seller
               fulfills all of its remaining obligations under the Transfer
               Agreement or December 31, 1998 whichever occurs later. Buyer
               shall also withhold __________________ from the $331,000 until
               the earlier to occur of (a) Seller provides notice to Buyer from
               ____________ that all credits in favor of _____________________
               under Section 4.2 of the ___________________ Agreement have been
               liquidated, or (b) February 28,1999.

          2.   In the event of any conflict, inconsistency or ambiguity between
               the provisions of this Amendment and the Agreement, the
               provisions of this Amendment shall control and take precedence.

     ________ = CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND FILED
                SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
                REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.
<PAGE>
 
          3.   Each individual executing this Amendment on behalf of a party
               hereto has the full right, power and authority to bind the party
               on whose behalf such individual is signing, as such individual is
               an authorized representative of such party acting within the full
               scope of such individual's authority.

          IN WITNESS WHEREOF, the parties hereto have executed this Amendment in
duplicate originals as of the date first written above.

AMP INCORPORATION, Acting 
through its M/A-COM Division                 VERTEL CORPORATION

By: /s/ Richard P. Clark                     By:     /s/ Jeff Curtis 
    -----------------------------                 -------------------------
        Richard P. Clark
 
Title:  President and CEO                    Title:  Vice President
                                                    -----------------------