EXHIBIT 4.25

                 AMENDMENT NUMBER SEVEN TO AMENDED AND RESTATED
                           LOAN AND SECURITY AGREEMENT

      This  Amendment  Number  Seven to Amended and  Restated  Loan and Security
Agreement  ("Amendment")  is entered  into as of December 1, 1998 by and between
FOOTHILL CAPITAL CORPORATION,  a California corporation ("Foothill"),  and PORTA
SYSTEMS CORP., a Delaware corporation ("Borrower"), in light of the following:

      FACT ONE: Borrower and Foothill have previously  entered into that certain
Amended and Restated Loan and Security Agreement, dated as of November 28, 1994,
as amended as of February 13, 1995, March 30, 1995,  March 12, 1996,  August 26,
1997 and November 30, 1997 and August 1, 1998 (collectively, the "Agreement").

      FACT TWO:  Borrower and Foothill  desire to further amend the Agreement as
provided for and on the conditions herein.

      NOW,  THEREFORE,  Borrower  and  Foothill  hereby  amend the  Agreement as
follows:

      1. DEFINITIONS.  All initially  capitalized  terms used  in this Amendment
shall  have the  meanings  given to them in the  Agreement  unless  specifically
defined herein.

      2. AMENDMENT.

      A. The definition of the "Renewal Date" in Section 1.1 of the Agreement is
hereby amended to read as follows:

            "'Renewal Date' means January 2, 2001."

      B. Section 2.9 of the Agreement is hereby amended to read as follows:

            "2.9 Loan  Amortization.  In addition to all other payments required
      to be made by Borrower,  Borrower  shall make  payments to Foothill in the
      amount of $400,000 on the last day of each calendar quarter  commencing on
      December 31, 1998 and on the last day of each calendar quarter  thereafter
      during the term of the Agreement.  In addition to the foregoing  payments,
      in the event that  Borrower's  "Adjusted  Cash Flow Amount" for any of the
      above-referenced    calendar   quarter   exceeds   the   amount   of   the
      above-referenced  payment  to be made  in the  last  day of such  calendar
      quarter,  Borrower  shall pay Foothill  fifty percent (50%) of such excess
      amount by not later than 45 days after each such calendar  quarter  except
      that such excess amount shall be paid by not later than 90 days after each
      calendar quarter ending on December 31. For


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      purposes hereof, the "Adjusted Cash Flow Amount" for each calendar quarter
      shall be calculated in accordance  with the following  formula:  operation
      income  plus  depreciation  plus  amortization  plus  any  other  one time
      accounting  adjustments  that are non-cash  items minus all interest minus
      all fees paid to Foothill and minus  $625,000.  Borrower  shall deliver to
      Foothill  by no  later  than  45  days  after  each  calendar  quarter,  a
      certificate signed by Borrower's chief financial officer setting forth the
      calculation  of  Borrower's  Adjusted  Cash Flow Amount for such  calendar
      quarter except that such  certificate  may be delivered to Foothill by not
      later than 90 days after each calendar quarter ending on December 31."

      C. Section 3.4 of the Agreement is hereby amended to read as follows:

            "3.4 Term. This Agreement shall become  effective upon the execution
      and delivery  hereof by Borrower  and Foothill and shall  continue in full
      force and effect for a term ending  January 2, 2001, and the maturity date
      of the Term Note,  the Deferred  Funding Fee Note and the NEW Deferred Fee
      Note  shall  also be  January  2,  2001.  The  foregoing  notwithstanding,
      Foothill  shall have the right to  terminate  its  obligations  under this
      Agreement  immediately  and without  notice upon the occurrence and during
      the continuation of an Event of Default."

      3.  REPRESENTATIONS  AND  WARRANTIES.  Borrower hereby affirms to Foothill
that all of Borrower's  representation and warranties set forth in the Agreement
are true, complete and accurate in all respects as of the date hereof.

      4. NO  DEFAULTS.  Borrower  hereby  affirms to  Foothill  that no Event of
Default has occurred and is continuing as of the date hereof.

      5. CONDITION  PRECEDENT.  The effectiveness of this Amendment is expressly
conditioned upon receipt by Foothill of an executed copy of this Amendment.

      6. COSTS AND  EXPENSES.  Borrower  shall pay to Foothill all of Foothill's
out-of-pocket costs and expenses  (including,  without limitation,  the fees and
expenses of its  counsel,  which  counsel may include any local  counsel  deemed
necessary, search fees, filing and recording fees, documentation fees, appraisal
fees,  travel  expenses,   and  other  fees)  arising  in  connection  with  the
preparation,   execution,  and  delivery  of  this  Amendment  and  all  related
documents.

      7.  LIMITED  EFFECT.  In the  event of a  conflict  between  the terms and
provisions of this Amendment and the terms and provisions of the Agreement,  the
terms and provisions of this Amendment shall govern. In all other respects,  the
Agreement,  as amended and supplemented  hereby,  shall remain in full force and
effect.


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      8.  COUNTERPARTS;  EFFECTIVENESS.  This  Amendment  may be executed in any
number of counterparts and by different parties on separate  counterparts,  each
of which when executed and delivered shall be deemed to be an original. All such
counterparts,  taken together, shall constitute one and the same Amendment. This
Amendment  shall become  effective  upon the execution of a counterpart  of this
Amendment by each of the parties hereto.

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

                                            FOOTHILL CAPITAL CORPORATION, 
                                            a California corporation
                                                                          
                                            By: /s/ M. E. Stearns
                                               ---------------------------------
                                            M. E. Stearns
                                            Vice President
                                            
                                            
                                            PORTA SYSTEMS CORP.,
                                            a Delaware corporation
                                            
                                            By: William V. Carney
                                               ---------------------------------
                                            Title: CEO


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      Each of the  undersigned  affiliates of Porta  Systems Corp.  ("Porta") is
aware of the  terms of the  above  Amendment  Number  Seven to the  Amended  and
Restated  Loan and Security  Agreement,  dated as of December 1, 1998 (the "Loan
Agreement"), and acknowledges that all of such affiliate's obligations under any
of the  Collateral  Documents (as defined in the  Assignment  Agreement) are and
shall continue in full force and effect in favor of Foothill Capital Corporation
("Foothill"), including the obligations pursuant to the terms of such Collateral
Documents. "Assignment Agreement" shall have the meaning given to it on the Loan
Agreement.

                                              ASTER CORPORATION    
                                              
                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                              
                                             
                                              CPI HOLDING CORP.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                              
                                             
                                              CRITERION PLASTICS, INC.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                              
                                              
                                              DISPLEX, INC.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 


                                              MIROR TELEPHONY SOFTWARE, INC.
                                              
                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 


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                                              PORTA FOREIGN SALES CORP.
                                              
                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                              
                                              
                                              PORTA SYSTEMS EXPORT CORP.
                                              
                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                             
                                              
                                              PORTA SYSTEMS INTERNATIONAL CORP.
                                              
                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                             
                                              
                                              PORTA SYSTEMS LEASING CORP.
                                              
                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 


                                              PORTA SYSTEMS OVERSEAS CORP.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                              
                                              
                                              LERO INDUSTRIES LTD.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 


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                                              PORTA SYSTEMS, LIMITED

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                              
                                             
                                              VANDERHOFF BUSINESS SYSTEMS LTD.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 
                                             
                                              
                                              VANDERHOFF COMMUNICATIONS LTD.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: 


                                              PORTA SYSTEMS S.A. de C.V.

                                              By: William V. Carney
                                                 -------------------------------
                                              Name:
                                              Title: