Exhibit
      10.41


    Datametrics
      Corporation

    1717
      Diplomacy Row

    Orlando,
      Florida 32809


    


    December
      18, 2007


    


    JAG
      Multi
      Investments, LLC

    150
      East
      52nd
      Street

    29th
      Floor

    New
      York,
      NY 10022

    


    The
      Philip S. Sassower 1996 Charitable Remainder Annuity Trust

    110
      East
      59th
      Street

    Suite
      1901

    New
      York,
      NY 10022

    


    Philip
      S.
      Sassower

    110
      East
      59th
      Street

    Suite
      1901

    New
      York,
      NY 10022

    


    Re: Datametrics
      Corporation


    


    To
      Whom
      It May Concern: 

    


    This
      letter memorializes the agreement by and among Datametrics Corporation, a
      Delaware corporation (“Datametrics”),
      Philip S. Sassower (“Sassower”)
      and
      JAG Multi Investments, LLC, a Delaware limited liability company (“JAG”,
      together with Sassower, the “Issuers”),
      regarding the letters of credit, dated December 18, 2007, issued by each of
      Philip S. Sassower and JAG to Comerica Bank (“Comerica”) on behalf of
      Datametrics (the “Letters”).

    


    In
      the
      event that Datametrics should default under the Master Revolving Note issued
      by
      Datametrics to Comerica , dated December 18, 2007 (the “Master
      Note”),
      and
      Comerica Bank enforces any of its rights by drawing funds against the Letters,
      then the Secured Promissory Note issued by Datametrics to The Philip S. Sassower
      1996 Charitable Remainder Annuity Trust and JAG, as yet undated (the
“Note”),
      will
      be in full force and effect to the extent of any amounts drawn against the
      Letters by Comerica. In the event that Datametrics does not default under the
      Master Note, the Note shall have no force and effect. 

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    


    In
      connection with the performance of the Issuers in providing the Letters to
      Comerica Bank, Datametrics hereby agrees to compensate the Issuers in the amount
      of $25,000 (the “Fee”).
      The
      Fee shall be paid by increasing the principal amount due under the Secured
      Promissory Note issued by Datametrics to SG DMTI Capital, LLC, a Delaware
      limited liability company, dated December 30, 2005 (the “Original
      Note”),
      pursuant to the Seventh Allonge to the Original Note, dated December 18,
      2007.

     

    
      	 	 	 
	 	
              Very
                Truly Yours,

            
	 	 
	 	
              Datametrics
                Corporation

            
	 
 	 
 	 
 
	
            	By:  	/s/
              John
              Marceca 
	 	
              

              John
                Marceca, President 

            


    

     

    
      	
              Agreed
                and Accepted:

            	 	 	 
	 	 	 	 
	JAG Multi Investments
              LLC	 	 	 
	 	 	 	 
	

              By: /s/
                Alexander M. Goren

            	 	 	
            
	
              
                
Name:
                Alexander M. Goren
Title:
                Manager


            	 	 	
            


    

    


    
      	 	 	 	 
	
              The
                Philip S. Sassower 1996 Charitable Remainder Annuity
                Trust

            	 	 	 
	 	 	 	 
	

              By: /s/
                Philip S. Sassower

            	 	 	
            
	
              
                

              

              Name:
                Philip S. Sassower

              Title:
                Trustee

            	 	 	
            


    

     

    
      	 	 	 	 
	
              
                Philip
                  S. Sassower

              

            	 	 	 
	 	 	 	 
	

              Philip
                S. Sassower