EXHIBIT 10.9.1

                               Porta Systems Corp.
                             575 Underhill Boulevard
                             Syosset, New York 11791

                                December 18, 1996


Mr. Edward R. Olson, Principal
KPMG BayMark Strategies LLC
1921 Gallows Road, Suite 750
Vienna, Virginia 22182

Dear Ed:

     This letter by KPMG BayMark  Strategies  LLC's  ("BayMark")  signature  and
return shall constitute the amendment to the letter agreement (the "Agreement"),
dated October 2, 1995,  effective  November 3, 1995,  between  BayMark and Porta
Systems Corp. (the "Company").  Capitalized terms used herein without definition
shall have the meanings assigned thereto in the Agreement.

     For  good and  valuable  consideration,  the  receipt  of  which is  hereby
acknowledged, the parties hereby amend the Agreement as follows:

     1. The  termination  dare under the  Agreement  is January  31,  1997.  The
Agreement may be extended by the Company, one or more times, on a month-by-month
basis,  for an aggregate of up to six (6) months beyond the  expiration  date of
January  31,  1997.  Each  month for  which  the  Agreement  is  extended  is an
"Extension  Month".  If the Company exercises its right to extend the Agreement,
the  Company  will pay  BayMark  fifteen  thousand  dollars  ($15,000)  for each
Extension  Month,  plus  reimbursement  of mutually  agreed  upon  out-of-pocket
expenses.

     2. The  success  fees  (the  "Success  Fees")  payable  to  BayMark  on the
Company's Earning Before Interest and Taxes ("EBIT") shall be reduced during the
entire term of the Agreement  and during any  extension  thereof to four percent
(4%) of the Company's EBIT. The Success Fee for the year ended December 31, 1996
shall be computed on an annual  basis.  The Success  Fees for (i) the year ended
December 31,  1997,  and (ii) the ten (10) months  ended  October 31, 1998,  and
(iii) one additional  month for each Extension  Month shall be computed based on
calendar  quarters of March 31, June 30,  September 30 and  December 31,  during
each such period.  In the event any period  contains  less than a full  calendar
quarter,  EBIT for such period  shall be a fraction of the EBIT for the calendar
quarter  containing  such period,  the numerator of which shall be the number of
full  months  contained  in such  period and the  denominator  of which shall be
three. The parties agree that no Success Fee is due for 1995 or any period other
than those stated above.  The EBIT shall be  determined  in a manner  consistent
with the operating income or loss, as reported in the Company's annual 1996 Form
10-K report or the relevant Form 10-Q quarterly report for the calendar quarters
during 1997 and 1998 and, if applicable,  1999 and shall be determined  prior to
any deduction for

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Mr. Edward R. Olson, Principal
December 18, 1996
Page 2


interest and taxes, but after  depreciation and amortization,  and shall exclude
any one-time  credits such as reversal of the Ireland IDA  obligation or gain on
sale of the MRV Corporaiion common stock.

     3. The Success Fee, if any, for the year ended December 31, 1996,  shall be
paid in eight consecutive, equal monthly installments,  without interest, due on
the first day of the month, the first such payment being due on May 1, 1997. The
Success Fees, if any, due for any calendar  quarter  occurring during 1997, 1998
or, if applicable,  1999,  shall be aggregated  during each such year (but shall
not be reduced by any EBIT loss  reported  for any  calendar  quarter  occurring
during each such year) and shall be paid for each such year in eight consecutive
equal monthly  installments,  without interest,  commencing on May 1, 1998, 1999
and,  if  applicable,  2000,  for the Success  Fee due for any  preceding  year.
Provided,  however,  no monthly payment shall be less than $20,000. In the event
the monthly payment is less than $20,000,  the monthly payment schedule shall be
accelerated  by  dividing  the  Success  Fee due with  respect to such period by
$20,000, with the last month's payment being any remaining amount due; provided,
further, in no event  shall such  aggregate  monthly  payments  exceed the total
Success Fee due for any period.

     4. The Success Fee relating to inventory is eliminated.

     5. The  Success  Fee of  one-half  of one  percent  (.5%)  relating to debt
restructuring will only apply if (a) Foothill Capital Corporation is replaced by
another lender and (b) BayMark is an active pariicipant in such restructuring.

     6.  BayMark and Mr.  Edward Olson hereby agree to keep secret and retain in
the strictest confidence all confidential matters which relate to the Company or
any affiliate,  including,  without  limitation,  customer lists, trade secrets,
pricing policies and other business affairs of the Company or affiliate  learned
by it or him from the  Company  or any  affiliate  or  otherwise  heretofore  or
hereafter,  and not use or  disclose  any such  confidential  matter  to  anyone
outside the Company or any affiliate,  whether during or after BayMark's  period
of service  with the  Company,  except in the course of  performing  its duties.
Furthermore,  BayMark and Mr. Olson hereby agree not to make any statement which
is directly or indirectly  damaging to the reputation or standing of the Company
or any affiliate.

     7. This  Agreement and the rights and  obligations of the parties set forth
in this  Agreement  are  personal to the parties and may not be  transferred  or
assigned  except to a successor  in interest  which  acquires  the  Company's or
BayMark's  assets and  assumes  its  liabilities;  provided,  however,  that any
services to be performed  pursuant to this  Agreement  shall be performed by Mr.
Olson; and provided,  further, that in connection with any assignment by BayMark
any assignment shall be accompanied by (a) a certificate  executed by all of the
members of BayMark which states that (i) they are all of the members of BayMark;
(ii) they consent to the assignment of this

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Mr. Edward R. Olson, Principal
December 18, 1996
Page 3


Agreement,  and (iii) the  assignment is not being made with the view to hinder,
delay or defraud  creditors,  and (b) an indemnity executed by the transferee in
form and  substance  satisfactory  to the  Company,  agreeing to  indemnify  the
Company  and hold the Company  harmless  from and against any and all claims and
any and all manner of loss,  liability,  damage or expense  (including  fees and
expenses of counsel) incurred by the Company which arise out of or in connection
with any moneys previously paid or to be paid by the Company to such transferee.

     8. In the  event  of any  inconsistency  between  the  Agreement  and  this
Amendment, this Amendment shall prevail.

     If the  foregoing  terms  meet with your  approval,  please  indicate  your
acceptance  by signing and  returning to the Company the  enclosed  copy of this
letter.

                                               Very truly yours,

                                               PORTA SYSTEMS CORP.

                                               By  /s/ William V. Carney
                                                  -----------------------------
                                                   William V. Carney, Chairman

Agreed and Accepted:

KPMG BAYMARK STRATEGIES LLC

By: /s/ Edward R. Olson
   ----------------------------
   Edward R. Olson, Principal

Date: 12/18/96


Agreed for Purposes of Section 6, Only.

/s/ Edward R. Olson
-------------------------------
Edward R. Olson