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                                                              EXHIBIT NUMBER 4.2

                      AMENDMENT NO. 1 TO RIGHTS AGREEMENT


     THIS AMENDMENT NO. 1 TO RIGHTS AGREEMENT (this "Amendment"), dated as of
June 18, 1999, is between Stanford Telecommunications Inc., a Delaware
corporation (the "Company"), and BankBoston, N.A. (f/k/a The First National Bank
of Boston) (the "Rights Agent").

     WHEREAS, the Company and the Rights Agent are parties to a Rights Agreement
dated as of May 9, 1995 (the "Rights Agreement"); and

     WHEREAS, pursuant to Section 27 of the Rights Agreement, the Company and
the Rights Agent desire to amend the Rights Agreement as set forth below.

     NOW, THEREFORE, the Rights Agreement is hereby amended as follows:

     1.   Amendment of Section 1.

          Section 1 of the Rights Agreement is amended by adding thereto two new
definitions immediately after the definition of "Trading Day", which new
definitions shall read as follows:

               "(ee)  `Merger Agreement' shall mean the Agreement and Plan of
          Merger, dated as of June 22, 1999, by and among the Company, Newbridge
          Networks Corporation, and Saturn  Acquisition  Corp. as the same may
          be amended from time to time.

               (ff) 'Transaction Documents' shall mean the Merger Agreement, the
          Stock Option Agreement (as defined in the Merger Agreement), the
          Technology Option Agreement (as defined in the Merger Agreement), and
          the Voting Agreements (as defined in the Merger Agreement), as said
          Transaction Documents or any thereof may be amended from time to
          time."

     2.   Amendment of Section 2.

          Section 2 of the Rights Agreement is amended by adding the following
language after the word "desirable" in the second sentence:

          ", upon ten (10) days' prior written notice to the Rights Agent.  The
          Rights Agent shall have no duty to supervise, and shall in no event be
          liable for, the acts or omissions of any such co-Rights Agent."

     3.   Amendment of Section 7.

          Section 7(a) of the Rights Agreement is amended by amending the
definition of "Expiration Date" by deleting the word "or" immediately preceding
clause (iii) thereof and by adding

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the following new phrase immediately following clause (iii) thereof: "or (iv)
immediately prior to the Effective Time (as defined in the Merger Agreement)."

     4.   Amendment of Section 18.

          Section 18(a) of the Rights Agreement is amended by adding the word
"gross" immediately after the word "without" and immediately before the word
"negligence" in the second sentence.

     5.   Amendment of Section 20.

          Section 20(c) of the Rights Agreement is amended by adding the word
"gross" immediately after the word "own" and immediately before the word
"negligence."

     6.   Amendment of Section 26.

          Section 26 of the Rights Agreement is amended by deleting the address
for The First National Bank of Boston as set forth therein and substituting in
lieu thereof the following:

          "BankBoston, N.A.
          c/o EquiServe Limited Partnership
          150 Royall Street
          Canton, MA 02021
          Attn: Client Administration"

     7.   Addition of New Section 35.

          The Rights Agreement is amended by adding a Section 35 thereof which
shall read as follows:

          "Section 35.  Exception For Merger Agreement.   Notwithstanding any
          provision of this Agreement to the contrary, neither a Distribution
          Date, Flip-In Event, Flip-Over Event nor a Stock Acquisition Date
          shall be deemed to have occurred, neither Newbridge Networks
          Corporation, or Merger Sub (as defined in the Merger Agreement) nor
          any of their affiliates shall be deemed to have become an Acquiring
          Person, and no holder of any Rights shall be entitled to exercise such
          Rights under, or be entitled to any rights pursuant to, any of
          Sections 3(a), 7(a), 11(a) or 13 of this Agreement, in any such case
          solely by reason of (a) the approval, execution or delivery of the
          Transaction Documents or any amendments thereof, or (b) the
          performance or consummation of any the transactions contemplated by
          the Transaction Documents in accordance with the provisions of the
          Transaction Documents, including the Merger (as defined in the Merger
          Agreement)."

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     8.   Effectiveness.

     This Amendment shall be deemed effective as of, and immediately prior to,
the earlier of (i) execution and delivery of the Merger Agreement, (ii) the
execution and delivery of the Stock Option Agreement (as defined in the Merger
Agreement), the (iii) the execution and delivery of the Technology Option
Agreement (as defined in the Merger Agreement), and the (iv) the execution and
delivery of the Voting Agreements (as defined in the Merger Agreement), and all
references to the Rights Agreement shall, from and after such time, be deemed to
be references to the Rights Agreement as hereby amended.  Except as amended
hereby, the Rights Agreement shall remain in full force and effect and shall be
otherwise unaffected hereby.

     9.   Miscellaneous.

     This Amendment shall be deemed to be a contract made under the laws of the
State of Delaware and for all purposes shall be governed by and construed in
accordance with the laws of such state applicable to contracts to be made and
performed entirely within such state.  This Amendment may be executed in any
number of counterparts, each of such counterparts shall for all purposes be
deemed to be an original, and all such counterparts shall together constitute
but one and the same instrument.  If any term, provision, covenant or
restriction of this Amendment is held by a court of competent jurisdiction or
other authority to be invalid, illegal, or unenforceable, the remainder of the
terms, provisions, covenants and restrictions of this Amendment shall remain in
full force and effect and shall in no way be affected, impaired or invalidated.

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     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the date set forth above.

                         STANFORD TELECOMMUNICATIONS INC.

                         By:
                            ------------------------------------------------
                            Name:  Jerome F. Klajbor
                            Title: Vice President, Chief Financial Officer


                         BANKBOSTON, N.A.


                         By:
                            ------------------------------------------------
                            Name:  Geoffrey Anderson
                            Title: Director

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