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

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