THE
      OBLIGATIONS EVIDENCED HEREBY ARE SUBORDINATE IN THE MANNER AND TO THE EXTENT
      SET
      FORTH IN THAT CERTAIN SUBORDINATION AGREEMENT (THE “SUBORDINATION AGREEMENT”)
      DATED AS OF SEPTEMBER 30, 2008, BY AND BETWEEN ARGYLE SECURITY, INC., AND
      LASALLE BANK NATIONAL ASSOCIATION, A NATIONAL BANKING ASSOCIATION (“SENIOR
      LENDER”) TO THE OBLIGATIONS (INCLUDING INTEREST) OWED BY ISI SECURITY GROUP,
      INC. (THE “OBLIGOR”) TO THE HOLDERS OF ALL OF THE NOTES ISSUED PURSUANT TO THAT
      CERTAIN AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT DATED AS OF JANUARY
      23,
      2008, BETWEEN OBLIGOR AND SENIOR LENDER, AS SUCH AGREEMENT MAY BE SUPPLEMENTED,
      MODIFIED, RESTATED OR AMENDED FROM TIME TO TIME; AND EACH HOLDER HEREOF, BY
      ITS
      ACCEPTANCE HEREOF, SHALL BE BOUND BY THE PROVISIONS OF THE SUBORDINATION
      AGREEMENT.

     

    PROMISSORY
      NOTE


    

      
        	
                $2,000,000.00

              	
                September
                  30, 2008

              


      

    

    


    FOR
      VALUE
      RECEIVED, ISI
      SECURITY GROUP, INC.
      a
      Delaware corporation, (hereinafter called "Maker"), promises to pay to
ARGYLE
      SECURITY, INC.
      (hereinafter called "Lender"), the principal sum of Two Million Dollars
      ($2,000,000) with interest thereon at the rates and on the dates specified
      in
      subsections 1.2 and 1.4 of the Loan Agreement between Maker and Lender dated
      September 30, 2008 (the “Loan Agreement”).

    


    Upon
      the
      happening of any default under the Loan Agreement, Lender may declare that
      all
      liabilities of the Maker to the Lender under shall be accelerated and become
      immediately due and payable; provided, that upon the occurrence of any default
      specified in Sections 2(c) or (d) of the Loan Agreement, all liabilities of
      the
      Maker to Lender shall become immediately due and payable without declaration,
      notice or demand by Lender 

    


    Maker
      shall pay all reasonable and documented costs and expenses incurred by or on
      behalf of Lender in connection with Lender’s exercise of any or all of its
      rights and remedies under this Note, including, without limitation, reasonable
      attorneys’ fees and expenses. 

     

    Any
      demand upon or notice to Maker shall be sufficiently served for all purposes
      if
      personally delivered or placed in the mail addressed to the address shown above
      or such other address as may be shown on Lender's records.

    


    There
      will be no pre-payment penalty on this Note.

    


    If
      any
      provision in this Note is held invalid or unenforceable by any court of
      competent jurisdiction, the other provisions of this Note will remain in full
      force and effect. Any provision of this Note held invalid or unenforceable
      only
      in part or degree will remain in full force and effect to the extent not held
      invalid or unenforceable.

    


    This
      Note
      will be governed by and construed under the laws of the State of Texas without
      regard to conflicts-of-laws principles that would require the application of
      any
      other law. Any dispute arising out of or in connection with this Note shall
      be
      submitted to the exclusive jurisdiction of the courts of Bexar County in the
      State of Texas.

    


    To
      the
      fullest extent permitted by applicable law, Maker waives: (a) presentment,
      demand and protest, and notice of presentment, dishonor, intent to accelerate,
      acceleration, protest, default, nonpayment, maturity, release, compromise,
      settlement, extension or renewal of the Loan Agreement or this Note; (b) all
      rights to notice and a hearing prior to allowing Lender to exercise any of
      its
      remedies; and (c) the benefit of all valuation, appraisal and exemption
      laws.

    


    IN
      WITNESS WHEREOF, Maker has executed and delivered this Note as of the date
      first
      stated above.

     

    
      	 	
              ISI
                SECURITY GROUP, INC.

            
	 	 
	 	
              By:
                /s/
                Sam
                Youngblood                          

            
	 	
              Name:
                Sam Youngblood

            
	 	
              Title:  
                President