Exhibit 4.1


FIRST  SUPPLEMENTAL INDENTURE


FIRST
SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of
April 2, 2007, by and among Integrated Alarm Services Group, Inc. (the “Company”),  the guarantors identified on the signature
pages hereto and Wells Fargo Bank, N.A., as trustee (the “Indenture Trustee”).  All capitalized terms used herein without
definition herein shall have the meanings ascribed thereto in the Indenture (as
defined).


W I T N E S S E T H:


WHEREAS, the Company issued and sold those certain 12% Senior
Secured  Notes due 2011 (the “Notes”),
which Notes are guaranteed by the
Subsidiary Guarantors named therein, pursuant to that certain indenture (the “Indenture”),
dated as of November 16, 2004, by and among the Company, the Subsidiary
Guarantors and the Indenture Trustee;


WHEREAS,
Section 9.02 of the Indenture authorizes the Company, the Subsidiary
Guarantors and the Indenture Trustee, with the consent of the holders of at
least a majority in aggregate principal amount of the Notes then outstanding,
to amend the Indenture, and any past default or compliance with any provisions
of the Indenture may also be waived;


WHEREAS,
in connection with the consent solicitation conducted by the Company for
consents to amend and waive certain provisions of the Indenture, holders of
approximately 92% of the aggregate principal amount of the Notes (the “Consenting
Holders”), in accordance with Section 9.02 of the Indenture, have consented
to certain amendments and waivers to the terms of the Indenture as set forth in
this Supplemental Indenture; and


WHEREAS,
the Company, by appropriate corporate action, has determined to amend the
provisions of the Indenture in the manner described herein and has taken all
acts and proceedings required by law, by the Indenture, and by its governing
documents necessary to duly authorize, execute and deliver this Supplemental
Indenture and to constitute this Supplemental Indenture a legal, valid and
binding agreement of the Company enforceable against the Company in accordance
with the terms herein.


NOW,
THEREFORE, the parties hereto agree as follows:


Section 1.1.            Amendment of Section 4.03.  Section 4.03 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.2.            Amendment of Section 4.07.  Section 4.07 of the Indenture is hereby
amended by deleting the existing section in its entirety.













Section 1.3.            Amendment of Section 4.08.  Section 4.08 of the Indenture is
hereby amended by deleting the existing section in its entirety.


Section 1.4.            Amendment of Section 4.09.  Section 4.09 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.5.            Amendment of Section 4.10.  Section 4.10 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.6.            Amendment of Section 4.11.  Section 4.11 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.7.            Amendment of Section 4.12.  Section 4.12 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.8.            Amendment of Section 4.13.  Section 4.13 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.9.            Amendment of Section 4.14.  Section 4.14 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.10.          Amendment of Section 4.15.  Section 4.15 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.11.          Amendment of Section 4.16.  Section 4.16 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.12.          Amendment of Section 4.17.  Section 4.17 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.13.          Amendment of Section 4.18.  Section 4.18 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.14.          Amendment of Section 4.19.  Section 4.19 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section 1.15.          Amendment of Section 5.01.  Section 5.01 of the Indenture is hereby
amended by deleting the existing section in its entirety.


Section
1.16.          Amendment of
Section 6.01.  Section 6.01
of the Indenture is hereby amended by deleting subsections (iii), (iv), (v),
(vi), (vii), (viii) and (ix) of the existing section in their entirety.













Section 2.               Deletion of Certain
Definitions.  The Indenture is hereby
amended to delete all definitions and defined terms from the Indenture where
all references to such definitions or defined terms would be eliminated as a
result of the amendments set forth herein.


Section
3.               Waiver of Existing
Defaults.  To the fullest extent
permitted under Sections 6.04 and 9.02 of the Indenture, the Consenting Holders
have irrevocably waived any and all Defaults or Events of Defaults arising or
existing under the Indenture prior to the effectiveness of this Supplemental
Indenture.


Section
4.               Instruments to be Read
Together.  This Supplemental
Indenture is an indenture supplemental to the Indenture; and, as such, the
Indenture and this Supplemental Indenture shall henceforth be read
together.  To the extent that the Notes
conflict with or are inconsistent with the terms of the Indenture as amended by
this Supplemental Indenture, the terms of the Indenture as amended by this
Supplemental Indenture shall govern.


Section
5.               Trustee Disclaimer. The Indenture Trustee has accepted the
amendment of the Indenture effected by this Supplemental Indenture and agrees
to execute the trust created by the Indenture as hereby amended, but only upon
the terms and conditions set forth in the Indenture, including the terms and
provisions defining and limiting the liabilities and responsibilities of the
Indenture Trustee, and, without limiting the generality of the foregoing, the
Indenture Trustee shall not be responsible in any manner whatsoever for or with
respect to any of the recitals or statements contained herein, all of which
recitals or statements are made solely by the Company, or for or with respect
to (a) the validity or sufficiency of this Supplemental Indenture or any of the
terms or provisions hereof, (b) the proper authorization hereof by the Company
by corporate action or otherwise, (c) the due execution hereof by the Company,
(d) the consequences (direct or indirect and whether deliberate or inadvertent)
of any amendment herein provided for, and the Indenture Trustee makes no
representation with respect to any such matters, and (e) the validity or
sufficiency of the consent solicitation materials or procedure in connection
with the solicitation of consents to the amendments and waivers provided for
herein.


Section
6.               Trust Indenture Act
Controls.  If any provision of this
Supplemental Indenture limits, qualifies or conflicts with another provision
that is required to be included in this Supplemental Indenture or the Indenture
by the TIA, the required provision shall control.


Section 7.               Governing Law.  The internal law of the State of New York
shall govern and be used to construe this Supplemental Indenture without giving
effect to applicable principles of conflicts of law (other than Section 5-1401
of the New York General Obligations Law) to the extent that the application of
the laws of another jurisdiction would be required thereby.


Section 8.               Counterparts.  This Supplemental Indenture may be signed in
any number of counterparts, each of which shall be an original, with the same
effect as if the signatures thereto and hereto were upon the same instrument.













Section 9.               Severability.  In case any provision in this Supplemental
Indenture shall be invalid, illegal or unenforceable, the validity, legality
and enforceability of the remaining provisions shall not in any way be affected
or impaired thereby.


Section 10.             Ratification.  Except as expressly amended hereby, each
provision of  the Indenture shall remain
in full force and effect and, as amended hereby, the Indenture is in all
respects agreed to, ratified and confirmed by each of the Company, the
Subsidiary Guarantors and the Indenture Trustee.


*     *     *    
*     *













IN WITNESS WHEREOF, the
parties hereto have caused this Supplemental Indenture to be duly executed as
of the date first above written.


	
  

  	
  INTEGRATED ALARM 

  SERVICES GROUP, INC.

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  CRITICOM
  INTERNATIONAL

  CORPORATION

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  MONITAL SIGNAL CORPORATION

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  INTEGRATED ALARM SERVICES,

  INC.

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  AMERICAN
  HOME SECURITY, INC.

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  NATIONAL
  ALARM COMPUTER

  CENTER INC.

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
						



 













 


	
  

  	
  EVEREST VIDEO SYSTEMS, L.L.C.

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  /s/ J. Eric Griffin

  
	
   

  	
  Name: J. Eric
  Griffin

  	
   

  
	
   

  	
  Title: Vice
  President & Secretary

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  WELLS
  FARGO BANK, N.A., as Trustee

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  By: 

  	
  /s/ Joseph P. O’Donnell

  	
   

  	
   

  
	
  Name: Joseph P.
  O’Donnell

  	
   

  	
   

  
	
  Title: Vice
  President