FOURTH AMENDMENT TO
                                CREDIT AGREEMENT

     This Fourth  Amendment is made as of June 24, 2002 among  SYNERGX  SYSTEMS,
INC. (f/k/a  Firetector Inc.), a Delaware  corporation (the "Company");  GENERAL
SOUND (TEXAS) COMP ANY , a Delaware corporation ("General"); CASEY SYSTEMS INC.,
a New  York  corporation  ("Casey");  and  PYROTECH  SERVICE  INC.,  a New  York
corporation  ("Pyrotech" and collectively  with the Company,  General and Casey,
the  "Borrowers")  as  co-borrowers  and CITIZENS  BUSINESS  CREDIT  COMPANY , a
division  of  Citizens   Leasing   Corporation,   a  Rhode  Island   corporation
(hereinafter referred to as "Citizens") as lender.

     WHEREAS, the Borrowers and Citizens are parties to a Credit Agreement dated
as June 28, 1998 (as amended, the "Credit Agreement");

     WHEREAS,  Firetector,  Inc. changed its name to Synergx Systems, Inc. as of
May 24, 2002;

     WHEREAS,  Firetector's former subsidiary,  Amco Maintenance  Corporation ("
Amco"), has been dissolved with its business  operations  transferred to Systems
Service Technology Corporation;

     NOW THEREFORE, the parties agree as follows:

     1. All  reference  to  "Firetector,  Inc." or the  "Company"  in the Credit
Agreement, Revolving Credit Note, Security Agreement, Pledge Agreement, Guaranty
(all of which are dated June 23, 1998) and related  documents shall mean Synergx
Systems, Inc.

     2. Citizens consents to the dissolution of Amco and waives any violation of
the Credit Agreement arising from such dissolution.

     3. Except as set forth in this Fourth Amendment,  the Third Amendment dated
as of May 14,  2002,  the Second  Amendment  dated as of October 1, 2001 and the
First  Amendment dated as of October 10, 2000, the Credit  Agreement  remains in
full force and effect.

IN WITNESS WHEREOF, the parties hereto have executed this Fourth Amendment under
seal as of the date first above written.

                                 BORROWERS:

                                 SYNERGX SYSTEMS, INC.

                                 (f/k/a Firetectr
                                 By:

                                 John A. Poserina . Chief Financial Officer


                                 GENERAL SOUND (TEXAS) COMPANY
                                 By:

                                 John A. Poserina . Chief Financial Officer


                                 CASEY SYSTEMS INC.
                                 By:

                                 John A. Poserina . Chief Financial Officer



                                 PYROTECH SERVICE INC.
                                 By:

                                 John A. Poserina . Chief Financial Officer


                                 LENDER:
                                 CITIZENS BUSINESS CREDIT COMPANY
                                 By:

                                 Vincent P. O'Leary
                                 Senior Vice President


Systems Service  Technology  Inc., a subsidiary of the Company,  consents to the
foregoing  amendment and  acknowledges  the continuing  validity of its Guaranty
dated June 23, 1998.

                                  Systems Service Technology Inc.
                                  By:

                                  John A. Poserina . Chief Financial Officer