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                                                                   EXHIBIT 10.42

                                SUBORDINATED NOTE

$1,079,333.34                                                    October 1, 1998


        FOR  VALUE  RECEIVED,   PARAVANT  COMPUTER  SYSTEMS,   INC.,  a  Florida
corporation  (the  "Maker"),  promises to pay to the order of EDWARD W. STEFANKO
(the "Payee"),  in the manner  hereinafter  set forth,  the principal sum of One
Million  Seventy Nine  Thousand  Three Hundred  Thirty Three and 34/100  Dollars
($1,079,333.34).

        This Note is given as  consideration  for the purchase by the Maker from
the Payee of shares of common  stock of  Engineering  Development  Laboratories,
Incorporated,  an Ohio corporation  ("EDL") pursuant to that certain Acquisition
Agreement dated as of March 31, 1998 (the "Acquisition  Agreement")  between the
Maker, EDL, Signal Technology  Laboratories,  Inc., an Ohio corporation ("STL"),
the  shareholders  of EDL,  including the Payee,  and the  shareholders  of STL.
Payments  to be made  under this Note shall be made to the order of the Payee at
6020 S. Wheelock Road,  West Milton,  Ohio 45383,  or at such other place as the
Payee may designate to the Maker in writing.

        In addition to the aforementioned  principal amount, the Maker shall pay
to the  Payee  interest  on the  unpaid  principal  amount  from  time  to  time
outstanding under this Note interest at the rate of eight percent (8%) per annum
determined on the basis of a three hundred and sixty five (365) day year.

        This Note shall be payable in twelve (12) quarterly payments as follows:
(i) eleven (11)  payments in the  principal  amount of Eighty Nine Thousand Nine
Hundred  Forty  Four and  44/100  Dollars  ($89,944.44)  together  with  accrued
interest on the unpaid  principal  amount and (ii) one payment in the  principal
amount of Eighty  Nine  Thousand  Nine  Hundred  Forty Four and  50/100  Dollars
($89,944.50)  together with accrued interest on the unpaid principal amount. The
first  such  quarterly  payment  shall be due and  payable  on April 1, 1999 and
successive  quarterly payments shall be due and payable on July 1, 1999, October
1, 1999 and January 1, 2000 and on each April 1, July 1, October 1 and January 1
thereafter  until January 1, 2002, when the entire principal sum and all accrued
but unpaid interest,  if not sooner paid as aforesaid,  shall be due and payable
in full. In the event the Maker calls all or any of its outstanding warrants for
redemption,  cancellation, exercise or conversion, the Maker will be required to
apply a portion of the proceeds  therefrom to reduce the indebtedness  this Note
as  required,  and  subject to the  limitations  set forth in,  the  Acquisition
Agreement.

        The Maker  shall have the right to prepay  this Note in whole or in part
at any time  without  penalty.  The Maker  shall  also have the right to set-off
against any payment or payments due under this Note any amount or amounts due to
the Maker from the Payee as indemnification  under the Acquisition  Agreement or
as damages under the Covenant Not to Compete or the  Non-Disclosure  provisions,
paragraphs 6 and 7, respectively  (but only such provisions),  of the Employment
Agreement  between the Payee and the Maker dated as of the date of this Note and
given as a

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condition of the Closing under the Acquisition Agreement. Any such prepayment or
set-off shall be applied first to accrued but unpaid  interest,  and then to the
principal sums next maturing hereunder.

        All payments required hereby shall be made in lawful money of the United
States of America.

        By  acceptance  of this Note the Payee has agreed  that the right of the
holder of this  Note to obtain  payment  from the  Maker is  subordinate  to the
rights  of  National  City  Bank  (the  "Senior  Creditor")  in  respect  of any
indebtedness  of the Maker for  borrowed  money  payable to the Senior  Creditor
("Senior Debt"). This Note shall not be subordinate to any other indebtedness of
the Maker.

        Any failure of the Maker to make any payment  required  hereunder by not
later than ten (10) days after the same shall be due shall  constitute  an Event
of Default. Upon the occurrence of any Event of Default, the holder hereof shall
have the right, after written notice to the Maker of such Event of Default,  and
the failure of the Maker to cure such Event of Default  within  thirty (30) days
after Maker's  receipt of such notice,  to declare a Default under this Note and
to accelerate all principal and interest due hereunder. Following the occurrence
of any  Default,  the holder  hereof also shall have the right to  exercise  any
remedies  that it may have  hereunder.  If it becomes  necessary  for the holder
hereof to enforce  this Note,  the Maker shall pay the holder any and all costs,
expenses and reasonable  attorneys's and paralegals' fees and expenses  incurred
by  such  holder  in  connection  with  such   proceedings  and  any  associated
administrative,  appellate or bankruptcy proceedings.  During any Default or any
period  permitted for the curing of any Event of Default  interest will continue
to accrue  for the  benefit of the Payee at the rate of eight  percent  (8%) per
annum determined as hereinbefore provided.

        The Maker hereby waives presentment for payment, demand, protest, notice
of protest and notice of dishonor  and  expressly  agrees to remain and continue
bound for the payment of the principal and interest provided for by the terms of
this Note,  notwithstanding  any  extension or extensions of time of, or for the
payment of said principal or interest.

        This Note shall be governed and construed in accordance with the laws of
the  State of  Florida.  If any term or  provision  of this  Note  shall be held
invalid,  illegal  or  unenforceable,  the  validity  of  all  other  terms  and
provisions hereof shall in no way be affected thereby.

        IN WITNESS WHEREOF,  the Maker has caused this Note to be executed under
seal and  delivered  by its duly  authorized  officer as of the date first above
written.

                                             "MAKER"

                                              PARAVANT COMPUTER SYSTEMS, INC.

                                             By:       /s/   Krishan K. Joshi
                                                --------------------------------
                                                    Krishan K. Joshi
                                                   Chairman of the Board


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