MORTGAGE MODIFICATION AGREEMENT

     THIS  AGREEMENT  is entered  into on the 18th day of MARCH,  1998,  between
TELEBYTE  TECHNOLOGY,  INC., a New York  corporation  with is principal place of
business at 207 Pulaski Road, Greenlawn, New York 11740, hereinafter referred to
as "MORTGAGOR",  and HOME FEDERAL SAVINGS BANK, a National  Banking  corporation
with an office at 62 South Ocean Avenue, Patchogue, New York 11772, as successor
in interest to UNION SAVINGS BANK, hereinafter referred to as "MORTGAGEE";

                              W I T N E S S E T H:

     WHEREAS,  the  Mortgagee  is the holder and owner of the  following  of the
following mortgages and/or agreements:

(a) Mortgage made by Telebyte  Technology,  Inc. to The Union Savings Bank dated
09/30/85,  in the  original  principal  amount of  $850,000.00,  recorded in the
Suffolk County Clerk's Office on 10/10/85 in Liber 11085 mp 597; and

(b) Mortgage made by Telebyte  Technology,  Inc. to The Union Savings Bank dated
05/25/88,  in the  original  principal  amount of  $454,300.00,  recorded in the
Suffolk  County Clerk's office on 06/09/88 in Liber 14143 mp 444, which Mortgage
was  consolidated  with  Mortgage  recorded  in Liber  11085 mp 597 by a certain
Consolidation  Agreement dated 05/25/88,  recorded in the Suffolk County Clerk's
office on  06/09/88 in Liber 14143 mp 449 to form a single lien in the amount of
$1,275,000.00; and

WHEREAS,  the unpaid  principal  balance of said Mortgages,  as consolidated and
extended, as of the date of the execution of 'this Agreement is $965,827.88.

         NOW, THEREFORE, the parties covenant and agree as follows:

         1. Modification of Interest Rate: Commencing as of the

date hereof and continuing  until the first (lst) day of June,  2000, the unpaid
principal sum secured by the Mortgages as consolidated and extended,  shall bear
interest at the rate of Nine percent  (9.00%) per annum and the principal  shall
be amortized over a 10year payment  schedule.  On the lst day of June, 2000, the
interest  rate will be adjusted for the next ensuing three (3) years of the term
hereunder  to the three (3) year weekly  average US Treasury  Constant  Maturity
rate  in  effect  on  May 1,  2000,  plus  3.00%.  At  such  time,  the  monthly
amortization  payment due pursuant to the Promissory Note and Security Agreement
executed  simultaneously  herewith shall be adjusted using the new interest rate
and  amortizing  the then  principal  balance over an 8-year  payment  schedule.
Thereafter,  on the 1st day of June,  2003,  the  interest  rate shall  again be
adjusted for the next ensuing three (3) years of the term hereunder to the three
(3) year weekly  average US  Treasury  Constant  Maturity  rate in effect on May
1,.,2003,  plus  3.00%.  At such time,  the  monthly  amortization  payment  due
pursuant to the Promissory Note and Security Agreement  executed  simultaneously
herewith  shall be adjusted  using the new interest rate and amortizing the then
principal balance over a 5-year payment schedule.  Thereafter, on the lst day of
June, 2006, the

interest  rate shall again be adjusted  for the  remaining  two (2) years of the
term  hereunder  to the three  (3) year  weekly  average  US  Treasury  Constant
Maturity rate in effect on May 1, 2006,  plus 3.00%.  At such time,  the monthly
amortization  payment due pursuant to the Promissory Note and Security Agreement
executed  simultaneously  herewith shall be adjusted using the new interest rate
and amortizing the then principal  balance over a 2-year payment  schedule.  The
entire unpaid principal balance shall be due and payable on the lst day of June,
2008. Each of the said payments shall be applied first when received by the Bank
to the  payment of interest at the rate in effect at the time of the due date of
the said payment,  to be computed from the date hereof on the unpaid  balance of
the  principal  sum hereof to the date of payment;  and,  secondly,  towards the
reduction of the principal sum hereof.

II.  RESERVATION OF RIGHTS AGAINST THIRD PARTIES:  This Agreement is made on the
express condition that it shall not be construed as precluding Mortgagee, or the
successors or assigns of Mortgagee, from enforcing any rights against any person
liable on the obligation secured as maker, endorser, guarantor, or




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otherwise,  whose written  consent  hereto has not been  obtained.,  If or which
purpose  the debt  may be  treated  as  overdue  and  collected  immediately  in
accordance with the terms of the Mortgage Note as if this Agreement had not been
made.

III.  OPERATION AS MODIFICATION  ONLY: The parties to this Agreement intend this
instrument to operate only as a



                                   SCHEDULE A



          THE PREMISES IN WHICH THE INSURED HAS THE ESTATE OR INTERBST
                             COVERED BY THIS POLICY



All that certain plot, piece, or parcel of land,  situate,  lying and being near
Greenlawn, Town of Huntington,  County of Suffolk and State of Now York, bounded
and described an follows:

BEGINNING at a point on the northerly  aide of East Pulaski Road distant  392.54
feet easterly from the southeasterly end of a line connecting the said northerly
side of Bast Pulaski Road, and the easterly aide of Park Avenues

THENCE  North 20 degrees 02 minutes 10 seconds  West 7.03 feet to the true point
or place of beginning, and from said point or place of beginning

RUNNING THENCE 14orth-20 degrees 02 minutes 10 seconds West 559.37 feet to lands
now or formerly of N. Racanelli,

THENCE  North 75 degrees 00 minutes 20 seconds  East 260.72 feet to lands now or
formerly of Stanford B. Taylor;

THENCE  South 20 degrees 02 minutes 10  seconds  East  525.96  feet-to  the said
northerly aide of East Pulaski Road as widened, and

THENCE along the said  northerly  aide of East Pulaski Road an widened along the
arc of a curve bearing to the left having a radius of 2904.93 feet a distance of
259.99 feet to the point or place of BEGINNING.






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