Exhibit
4.3


NEGOTIABLE PROMISSORY
      NOTE





$1,747,012
            New
      York, New YorkAs
      of January 1, 2009





FOR VALUE
RECEIVED, PORTA SYSTEMS CORP., hereinafter referred to as “Borrower”, with an
address at 6851 Jericho Turnpike, Syosset, New York, 11791, hereby promises to
pay to the order of CHEYNE SPECIAL SITUATIONS FUND, L.P., hereinafter referred
to as “Lender”, with an address at P.O. Box 908 GT, Walker House, Mary Street,
Grand Caymans, Cayman Islands, or at such other place as the Lender or any
holder hereof may from time to time have designated, the principal sum of ONE
MILLION SEVEN HUNDRED FORTY SEVEN THOUSAND TWELVE AND NO/100 ($1,747,012)
DOLLARS, which shall be due and payable on April 30, 2010, together with any
accrued interest, unless prepaid in accordance with the terms of this
note.  Interest shall accrue and be payable on the outstanding
principal balance of this Note at an amount equal to the six-month rate of LIBOR
as reported in the Money Rate Section of the Wall Street Journal on a “Payment
Date” (as hereafter defined) or if such Payment Date is not a business
publication date of the Wall Street Journal, the first such publication date
immediately prior to the Payment Date, plus 10%, payable as set forth herein
(this “Note”).  This Note supersedes and replaces in its entirely that
certain Negotiable Promissory Note between the Borrower and the Lender dated
November 11, 2008, as amended, in the principal amount of one million seven
hundred forty seven thousand and twelve dollars ($1,747,012) (the “Prior
Note”).  As of the date hereof, accrued interest on the Prior Note as
of December 31, 2008 is $29,608, which is hereby added to the amounts due and
owing under this Note. For avoidance of doubt, the Prior Note superseded and
replaced in its entirety those certain Negotiable Promissory Notes between the
Borrower and the Lender dated October 23, 2007 in the principal amount of
$1,000,000 which was subsequently amended and restated on November 11, 2008 in
the principal amount of $1,747,012.





1.           Payment of Principal and
Interest.   Principal and interest payments of an
aggregate amount of $125,000 monthly shall be paid commencing on the last day of
January 2009, and the last day of each month thereafter with any unpaid
principal and accrued interest due on April 30, 2010.  Borrower
payments shall be allocated as follows: first, to accrued interest, then to
principal, and then until the accrued interest and principal are paid in full.
The Borrower may prepay the principal due under this Note, together with accrued
interest thereon, in whole or in part, without penalty.  Interest
shall be calculated on the basis of a year of 365 days, and charged for the
actual number of days elapsed.





2.           Default.  The
following shall be events of default (“Events of Default”)
hereunder:





(a)           If
any payment of principal, interest or other sum due hereunder shall not be made
as and when the same shall become due and payable;





(b)           If
Borrower defaults under that certain Amended and Restated Loan and Security
Agreement (the “Loan Agreement”), as amended from time to time, dated as of
November 28, 1994, between Borrower and Wells Fargo Foothill, Inc. (“Foothill”),
whereby Lender is the successor in interest of the obligations of Borrower to
Foothill, pursuant to an assignment dated February 7, 2007, between Lender and
SHF IX, LLC, a Delaware limited liability company (“SHF IX”), Foothill’s
successor in interest pursuant to an assignment between Foothill and SHF IX
dated October 7, 2004;








(c)           A
default by Borrower under this Note shall constitute an Event of Default under
the Loan Agreement.





3.           Collateral.  All
Collateral (as defined in the Loan Agreement) shall secure prompt payment in
full of all of Borrower’s obligations in connection with this Note as well as
all obligations in connection with the Loan Agreement.





4.           Due Upon Event of
Default.   This Note (the entire remaining principal
balance, interest and any other sums due hereunder) shall automatically become
immediately due and payable, without further notice or demand, upon the
occurrence of any Event of Default described in Section 2 above.





5.           Collection Costs. The
Borrower shall be liable for any and all out-of-pocket costs (including
reasonable attorneys’ fees and court costs) incurred by the Lender in connection
with Lender’s enforcement of, or collection of amounts owed by the Lender under,
this Note or any other documents contemplated hereby (any and all such sums,
“Collection
Costs”).





6.           Application of
Payments.  Any payments made by Borrower hereunder shall be
applied by Lender in the following priority:  first, to unpaid or
unreimbursed Collection Costs, next to accrued but unpaid interest, and finally,
to reduction of principal.





7.           Transfers;
Prepayment.  This Note may be transferred, assigned, pledged,
hypothecated or negotiated by the Lender at any time without notice or consent
of Borrower.  This Note shall be binding upon the Borrower, its
representatives, successors and permitted assigns.  The Borrower shall
not assign this Note or any of its rights or obligations hereunder without the
prior written consent of Lender.





8.           Waiver.  Except
as otherwise expressly required herein, the Borrower hereby waives presentment,
demand for payment, notice of dishonor, protest, notice of protest and
non-payment, notice of intention to accelerate, notice of acceleration and any
and all other notices or demands whatsoever in connection with the delivery,
acceptance, performance, default or enforcement of this Note.  In any
action, suit or proceeding arising out of or relating to this Note, the Borrower
hereby waives the right to interpose any defense, set-off or counterclaim of any
kind or nature whatsoever.  No release of any security for the Note or
extension of time for payment of this Note or any payment installment hereof,
and no alteration, amendment or waiver of any provision of this Note or other
agreement relating to the Note or the obligations of Borrower hereunder between
the Lender or any other person or company shall release, modify, amend, waive,
extend, change, discharge, terminate or affect the liability of the Borrower,
and any other person or entity who may become liable for the payment of all or
any part of this Note, except as otherwise specifically provided in writing by
any such alterations, amendments or waivers of this Note or such other
agreements.  No notice to or demand on the Borrower shall be deemed to
be a waiver of the obligation of the Borrower or of the right of the Lender to
take further action without further notice or demand as provided for in this
Note.





9.           Delay No Waiver; No Oral
Changes.  No delay on the part of the Lender in exercising any
right or remedy under this Note or any other agreement relating to the
obligations of Borrower under the Note or failure to exercise the same shall
operate as a waiver in whole or in part of any such right or
remedy.  No amendment or waiver of any provision of this Note shall be
effective unless the same shall be in writing and signed by the Lender and the
Borrower, and then such waiver or consent shall be effective only in the
specific instance and for the specific purpose for which given.





2


10.           Governing Law; Consent to
Jurisdiction.  This Note shall be governed by, and construed
and enforced in accordance with, the laws of the State of New York, without
regard to principles of conflicts or choice of law (or any other law that would
make the laws of any state other than the State of New York applicable
hereto).   Borrower hereby (a) waives any defense of forum non conveniensand
irrevocably consents and agrees that any legal or equitable action or proceeding
arising under or in connection with this Note or any document or instrument
delivered with respect to this Note, may be brought in any federal or state
court in the County of New York, State of New York, (b) agrees that any
process in any action commenced in such court under this Note may be served upon
such party either (i) by certified or registered mail, return receipt requested,
or by an overnight courier service which obtains evidence of delivery, with the
same full force and effect as if personally served upon him in such county or
(ii) any other method of service permitted by law.  Notice shall be
deemed given three days after mailing and one after delivery to any overnight
courier.





BORROWER:PORTA
      SYSTEMS CORP.By: 
      /s/ Edward B.
      KornfeldEdward
      B. KornfeldChief
      Executive Officer
 
 
 STATE
      OF NEW YORK
              ))
      ss.:COUNTY
      OF NASSAU
              )
 
 On this
10th
day of March, 2009, before me, the undersigned, personally appeared Edward B.
Kornfeld, Chief Executive Officer of Porta Systems Corp., personally known to me
or proved to me on the basis of satisfactory evidence to be the individual whose
name is subscribed to the within instrument that he executed the same and that
by his signature on the instrument.
  
 /s/ KEVIN
      MCHALEKEVIN MCHALENotary PublicState of New YorkQualified in Nassau
  CountyNo. 01MC6198994My commission expires Jan. 5,
      2013





[additional
signatures on next page]




3


CONSENT AND
RATIFICATION




Each of
the undersigned affiliates of Porta Systems Corp. (“Porta”) is aware of the
terms of the above attached Negotiable Promissory Note, dated as of January 1,
2009 (the “Note”), and hereby consents to the Note and guarantees the
obligations of Porta under the Note.








ASTER
      CORPORATION
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:
      Edward B.
      Kornfeld
              Title:CPI
      HOLDING CORP.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:CRITERION
      PLASTICS, INC.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:DISPLEX,
      INC.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:MIROR
      TELEPHONY SOFTWARE, INC.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:




4






PORTA
      FOREIGN SALES CORP.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:PORTA
      SYSTEMS OVERSEAS CORP.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:LERO
      INDUSTRIES LTD.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:PORTA
      SYSTEMS, LIMITED
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:PORTA
      SYSTEMS EXPORT CORP.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:PORTA
      SYSTEMS INTERNATIONAL CORP.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:




5




PORTA
      SYSTEMS LEASING CORP.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:VANDERHOFF
      BUSINESS SYSTEMS LTD.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:VANDERHOFF
      COMMUNICATIONS LTD.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:PORTA
      SYSTEMS S.A. de C.V.
              
              
              By:  /s/ Edward B.
      Kornfeld
              Name:  Edward B.
      Kornfeld
              Title:




6