December 22, 1998

Base Ten Systems, Inc.
One Electronics Drive
Trenton, NJ  08619

                  Re:      Base Ten Systems, Inc. (the "Company")
                           9.01% Convertible Subordinated Debenture

         The  undersigned   holder  of  (i)  the  Company's  9.01%   Convertible
Subordinated Debenture in the principal sum of $4,500,000, dated August 12, 1996
and due August 31, 2003, and (ii) the Company's 9.01%  Convertible  Subordinated
Debenture  in the  principal  sum of  $5,500,000,  dated August 22, 1996 and due
August 31, 2003,  (collectively  referred to as the "9.01%  Debenture"),  hereby
consents to the following:

         1. The undersigned holder irrevocably consents to the conversion of the
entire 9.01% Debenture upon, and only upon, the exchange of all of the Company's
Series A, Convertible  Preferred Shares  outstanding as of December 1, 1998 into
the  Company's  Series B,  Convertible  Preferred  Shares.  The  original  9.01%
Debenture is being forwarded to the Company under separate cover in anticipation
of the aforementioned conversion.

         2. The  undersigned  holder  consents to the  modification of the 9.01%
Debenture  to decrease  the  conversion  price at which the 9.01%  Debenture  is
convertible  into  shares  of Class A Common  Stock  from  $12.50  to $4.00  (as
approved by the Company's  shareholders  at the Special Meeting held on November
10,  1998),  simultaneous  with the  conversion  of the 9.01%  Debenture  by the
undersigned in accordance with paragraph 1 above.

         3. The  undersigned  holder hereby  directs that the Company effect the
conversion of the 9.01%  Debenture  upon,  and only upon, the exchange of all of
the Company's Series A, Convertible  Preferred Shares outstanding as of December
1, 1998 into the Company's Series B, Convertible Preferred Shares.

                                 Very truly yours,

                                 TRUST C OF THE
                                 CONSTANCE J. UPCHURCH FAMILY TRUST

                                 JESSE L. UPCHURCH
                                 ------------------------------------------
                                 Jesse L. Upchurch, Trustee