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                                                                Exhibit 10.34
                           FIRST AMENDMENT TO LEASE

This First Amendment to Lease ("Amendment"), is made and entered  into this 
17th day  of  September,  1996 by  and  between  Berg & Berg Enterprises,  
Inc.,  a California corporation ("Berg"  or "Lessor") and Premisys 
Communications, Inc., a Delaware  corporation ("Premisys"  or "Lessee").   All 
capitalized  terms used in this Amendment shall have the definitions set 
forth in the Lease. 

RECITALS

A.  By that certain lease  dated October 24, 1996  (the "Lease"), Berg agreed to
    construct approximately  52,000   square  feet   of  space,  including all
    improvements  thereto,  at  48700  Milmont  Drive,  Fremont, California (the
    "Premises") and to lease the constructed space to Premisys.

B.  The parties to  the Lease hereby agree  to amend the  Lease according to the
    terms and conditions of this Amendment.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency
of  which  are acknowledged,  the parties  hereto agree  to amend the Lease as
follows:

     1.  ADDRESS: The address for the Premises is 48800 Milmont Drive, Fremont,
         California.

     2.  PREMISES: The  square footage  of the  Premises has increased to 53,000
         square feet. 
     
     3.  COMMENCEMENT DATE: Lessor and  Lessee agree that construction of the
         Premises has  been delayed due  to acts of God (rain and wet soil 
         conditions) for in excess of sixty (60) days  and therefore rent 
         abatement as  provided in Section 2 of the Lease,  if any, shall 
         commence November 30, 1996 rather  than September  30, 1996. It is 
         the  intention of  Lessor and  Lessee  that the Commencement Date as
         provided  in Section 1 of the  Lease shall be  October 1, 1996 rather
         than August 1, 1996.  
     
     4.  TI ALLOWANCE: The TI Allowance shall be increased to $1,325,000 rather
         than $1,300,000 as provided in Section 2 of the Lease.

     5.  BASE RENT: Base rent shall be increased to and payable at the following
         monthly rates:
          Months  1 through 12                     $46,640
          Months 13 through 24                      47,806
          Months 25 through 36                      49,001
          Months 37 through 48                      50,226
          Months 49 through 60                      51,482
          Months 61 through 72                      52,769
          Months 73 through 84                      54,088
          Months 85 through 96                      55,440

     6. LESSEE INTERIOR IMPROVEMENTS: Lessee is aware and acknowledges that 
        the cost of  the Lessee Interior Improvements  are expected to be 
        approximately two million three  hundred twenty-eight thousand one 
        hundred fifty-six dollars ($2,328,156) due  to the  special  HVAC, 
        electrical, data, and grounding requirements of Premisys, excluding
        security costs.  Based on the current estimated  total of the Lessee
        Interior  Improvements, Lessee  will be required to make cash payments
        to Lessor of approximately one million three thousand dollars 
        ($1,003,156) for  Lessee Interior Improvements plus the costs of 
        security.

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     7.  RATIFICATION OF LEASE:  Except as modified herein, the Lease is hereby
         ratified, approved and  confirmed upon all the terms, covenants,  and
         conditions.
     
     8.  AUTHORITY: Each party executing  this Amendment represents and warrants
         that he or she is duly authorized to execute and deliver this 
         Amendment. If executed on behalf of a corporation, that this Amendment
         is executed in accordance with  the by-laws of  said corporation (or a
         partnership that this Amendment  is executed in  accordance with  the 
         partnership  agreement of such partnership), that no other party's 
         approval  or consent to such execution and delivery is required,  and 
         that this Amendment is binding upon said individual, corporation  
         (or partnership) as the case may be in accordance with its terms.

         BERG & BERG ENTERPRISES, INC.,          PREMISYS COMMUNICATIONS, INC.,
         a California general partnership             a Delaware corporation


     By:  /s/ Carl E. Berg                   By:    /s/ Riley R. Willcox
         -------------------------                  -------------------------
            Carl E. Berg                              Riley R. Willcox

     Title:    President                     Title: Chief Financial Officer
            ----------------------                  -------------------------

     Date:     September 17, 1996            Date:     September 17, 1996
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In reference  to section 4,  TI Allowance of First  Amendment to Lease:   
Lessor prescribed herein  represents the lessors  best estimate  of cost at  
this time. Formal definition  of final cost as it relates to  monies owed by 
lessee will be defined at conclusion of construction.  Lessor shall provide 
lessee  with actual cost and provide supporting documentation as requested by 
lessee.

Acknowledged and accepted:


     By:  /s/ Carl E. Berg                   By:      /s/ Riley R. Willcox
         -------------------------                  -------------------------
            Carl E. Berg                                 Riley R. Willcox

     Title:    President                     Title:    Chief Financial Officer
            ----------------------                   --------------------------

     Date:     September 17, 1996            Date:     September 17, 1996
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