Exhibit 10.2


                                JOINDER AGREEMENT
                                -----------------


     JOINDER TO LOAN DOCUMENTS  ("JOINDER") DATED THIS 14TH DAY OF JULY, 2006 BY
AND AMONG CompuDyne Corporation, A NEVADA CORPORATION, CompuDyne-Public Safety &
Justice, INC., A VIRGINIA CORPORATION,  Norment Security Group, INC., A DELAWARE
CORPORATION, Norshield Corporation, AN ALABAMA CORPORATION, Fiber Sensys, LLC, A
DELAWARE LIMITED LIABILITY COMPANY;  CompuDyne-Integrated  Electronics Division,
LLC, A DELAWARE LIMITED LIABILITY COMPANY ("CIED"),  CorrLogic,  LLC, A DELAWARE
LIMITED  LIABILITY  COMPANY  AND  Xanalys  Corporation,  A DELAWARE  CORPORATION
(COLLECTIVELY,  THE "EXISTING BORROWERS"),  Signami DCS, LLC, A DELAWARE LIMITED
LIABILITY  COMPANY,  ("NEW BORROWER") AND COLLECTIVELY  WITH EXISTING  BORROWERS
("BORROWER" OR "BORROWERS"),  AND PNC Bank, National  Association,  AS AGENT FOR
THE LENDERS (IN ITS CAPACITY AS AGENT,  THE "AGENT"),  AND EACH OF THE FINANCIAL
INSTITUTIONS  LISTED ON THE  SIGNATURE  PAGES HERETO IN ITS CAPACITY AS A LENDER
(EACH INDIVIDUALLY, A "LENDER" AND COLLECTIVELY "LENDERS").


                                   BACKGROUND
                                   ----------

          A.   Existing Borrowers, Agent and Lenders are parties to that certain
Second  Amended and  Restated  Revolving  Credit and Security  Agreement,  dated
December 19, 2005 ("Loan Agreement"),  and related  agreements,  instruments and
documents (all of the foregoing  collectively,  "Loan  Documents"),  pursuant to
which  Lenders  established  for the benefit of  Existing  Borrowers a revolving
credit  facility  in  a  maximum  aggregate  principal  amount  of  $20,000,000,
consisting of Revolving Loans and Letters of Credit.  Capitalized terms used but
not  defined  herein  shall  have the  meanings  given to such  terms  in, or by
reference in, the Loan Agreement.

          B.   New Borrower is a newly formed  wholly owned  Subsidiary of CIED.
Borrowers  have requested that Agent and Lenders enter into this Joinder so that
New Borrower may be a party to the Loan Agreement and be permitted thereunder to
acquire  certain assets of Signami,  LLC through an asset  purchase  pursuant to
that certain Asset Purchase Agreement ("Asset Purchase  Agreement") by and among
CompuDyne, New Borrower, Bert Jones, Gary Kenworthy and Apple Oak Farms dated on
or about July 14, 2006.

          C.   Lenders have  consented  to New Borrower  becoming a party to the
Loan Agreement, subject to the terms and conditions hereof.

                              TERMS AND CONDITIONS
                              --------------------

     NOW  THEREFORE,  with  the  foregoing  Background  deemed  incorporated  by
reference  herein and made part hereof and for good and valuable  consideration,
the receipt and adequacy of which is hereby  acknowledged,  the parties  hereto,
intending to be legally bound, promise and agree as follows:


<PAGE>


     1.   JOINDER
          -------

               (a)  New Borrower hereby joins in, assumes,  adopts and becomes a
Borrower  under the Loans and  under  the Loan  Documents,  expressly  including
without limitation the Loan Agreement.

               (b)  (i) The term "Borrowers"  under the Loan Agreement,  and all
other Loan Documents shall therefore hereinafter, for all purposes, refer to and
include New Borrower (as if it were an original signatory thereto).

                    (ii) Without  limiting the  generality of the  provisions of
subparagraph  b(i) above,  (i) New  Borrower is thereby  liable,  on a joint and
several  basis,  along  with  Existing  Borrowers  for all  existing  and future
Advances and other  liabilities and obligations  incurred at any time by any one
or more  Borrowers  under the Loan  Documents,  as  amended  hereby or as may be
hereafter  amended,  modified or replaced,  (ii) assigns and grants to Agent for
the benefit of  Lenders,  as security  for the  payment of all  Obligations  and
performances  of all  covenants  and  undertakings  in  the  Loan  Documents,  a
continuing first lien on and security  interest in all of the items and types of
Collateral of such New Borrower as more fully  described in the Loan  Agreement;
and (iii) agrees to execute and deliver to Agent any agreements, instruments, or
other  documents  reasonably  required by Agent to evidence,  perfect or protect
Lenders' Liens on and security  interest in the Collateral,  including,  without
limitation,  UCC-1 financing  statements for filing in all  jurisdictions  where
Agent may deem appropriate.

               (c)  The Allonge to Revolving  Credit Note  executed by Borrowers
hereunder in the form of Exhibit A hereto  shall amend that certain  Amended and
Restated  Revolving Credit Note issued by Existing  Borrowers in favor of Lender
dated as of December 19, 2005.

     2.   FURTHER ASSURANCES
          ------------------

     Borrowers  hereby  agree to take all such  actions  and to  execute  and/or
deliver  to  Agent  or  Lenders  all  such  documents,  assignments,   financing
statements and other  documents,  as Agent may  reasonably  require from time to
time, to effectuate and implement the purposes of this Joinder.

     3.   CONFIRMATION OF COLLATERAL
          --------------------------

     All  Borrowers  hereby  confirm  that all  security  interests  at any time
granted by them to Agent for the  ratable  benefit of Lenders  continue  in full
force and effect and secure and shall  continue  to secure the  liabilities  and
Obligations  of Borrowers and that all assets  subject  thereto  remain free and
clear of any liens or  encumbrances  other  than those in favor of Agent for the
ratable  benefit of Lenders or as  specifically  set forth in the Loan Agreement
and exhibits thereto.

     4.   REPRESENTATIONS AND WARRANTIES
          ------------------------------

          (a)  Existing  Borrowers  hereby  reaffirm  (and New  Borrower  hereby
asserts) all  representations and warranties made to Agent and Lenders under the
Loan  Agreement  and all of the other Loan  Documents  and confirms that all are
true and correct as of the date hereof.  Each Borrower  further  represents  and
warrants  that each has the  authority  and legal right to execute,  deliver and
carry out the terms of this Joinder,  that such actions were duly  authorized by
all  necessary  corporate  or  company  action  on the part of each and that the


<PAGE>


officers  or  managers  executing  this  Joinder  on its behalf  were  similarly
authorized  and  empowered,  and  that  this  Joinder  does not  contravene  any
provisions of its articles of incorporation or certificate of formation,  or its
by-laws or  operating  agreement,  or of any contract or agreement to which is a
party or by which any of its  properties  is bound.  Existing  Borrowers  hereby
reaffirm  and New  Borrower  hereby  assumes and  accepts  all of the  covenants
contained in the Loan  Agreement  and covenant to abide thereby until all of the
Advances  and  other  liabilities  and  Obligations  of  Borrowers  to Agent and
Lenders, of whatever nature and whenever incurred, are satisfied and/or released
by Agent and Lenders.

          (b) Existing  Borrowers and New Borrower have  delivered to Agent true
and correct  copies of the Asset  Purchase  Agreement and documents  executed in
connection  therewith,  which are (i) in full force and effect and have not been
modified in any way, and (ii) constitute the valid and binding obligation of the
parties thereto, enforceable in accordance with their respective terms except as
enforceability   may  be   limited   by   applicable   bankruptcy,   insolvency,
reorganization,  moratorium  and  similar  laws  affecting  the  enforcement  of
creditor's rights generally and by general equitable principles.

     5.   INTERRELATED OPERATIONS
          -----------------------

          THE BUSINESS  OPERATIONS  OF EXISTING  BORROWERS  AND NEW BORROWER ARE
INTERRELATED  AND  COMPLEMENT  ONE  ANOTHER,  AND SUCH  COMPANIES  HAVE A COMMON
BUSINESS PURPOSE. TO PERMIT THEIR UNINTERRUPTED AND CONTINUOUS OPERATIONS,  SUCH
COMPANIES  NOW REQUIRE AND WILL FROM TIME TO TIME  HEREAFTER  REQUIRE  FUNDS FOR
WORKING  CAPITAL AND OTHER  GENERAL  BUSINESS  PURPOSES.  THE MAKING OF ADVANCES
UNDER THE LOAN  AGREEMENT  WILL  DIRECTLY OR  INDIRECTLY  BENEFIT  EACH  COMPANY
HEREUNDER  SEVERALLY,  AND BOTH OF THEM  JOINTLY,  REGARDLESS  OF  WHICH  ENTITY
HEREUNDER RECEIVES PART OR ALL OF THE PROCEEDS OF ANY PARTICULAR ADVANCE.


     6.   CONDITIONS PRECEDENT
          --------------------

     The  obligation of Agent and Lenders to enter into this Joinder are subject
to, and this  Joinder  shall  become  effective  upon  ("Effective  Date"),  the
following conditions having been satisfied in full to the satisfaction of Agent:

          (a)  Existing Borrowers and New Borrower shall have delivered to Agent
on behalf of Lenders the  following  documents  (all to be in form and substance
acceptable in all respects to Agent):

               (i)  this Joinder properly executed by Existing Borrowers and New
Borrower; and

               (ii) the Allonge to Revolving Credit Note,  properly  executed by
Existing Borrowers and New Borrower;

          (b)  no Event of Default under the Loan Agreement  shall have occurred
or is existing.

     7.   PAYMENT OF EXPENSES
          -------------------

     Borrowers  shall pay or  reimburse  Agent  and/or  Lenders  for  reasonable
attorneys' fees and expenses in connection with the preparation, negotiation and
execution  of this  Joinder  and the  documents  provided  for herein or related
hereto.


<PAGE>


     8.   REAFFIRMATION OF EXISTING AGREEMENT
          -----------------------------------

     Except as modified by the terms hereof,  all of the terms and conditions of
the Loan Agreement,  as previously amended,  and all other of the Loan Documents
are hereby  reaffirmed  and shall  continue  in full force and effect as therein
written.

     9.   EFFECTIVE DATE
          --------------

     This Joinder shall have effect as of its date.



                                   * * * * * *


<PAGE>


     IN WITNESS WHEREOF, the parties have caused this Joinder to be executed and
delivered by their duly authorized officers as of the date first above written.


EXISTING BORROWERS:                COMPUDYNE CORPORATION
------------------

                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------


                                   COMPUDYNE-PUBLIC SAFETY & JUSTICE, INC.


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------


                                   NORMENT SECURITY GROUP, INC.


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------


                                   NORSHIELD CORPORATION


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------


                                   FIBER SENSYS, LLC


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------


<PAGE>


                                   COMPUDYNE-INTEGRATED
                                    ELECTRONICS DIVISION, LLC


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------

                                   Title:
                                         ---------------------------------------


                                   CORRLOGIC, LLC


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------


                                   XANALYS CORPORATION


                                   By:
                                      ------------------------------------------
                                   Name:
                                        ----------------------------------------
                                   Title:
                                         ---------------------------------------