Exhibit
      10.40

    

      THIS
        NOTE
        HAS
        NOT
        BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES
        ACT”), OR ANY APPLICABLE STATE SECURITIES LAWS AND MAY NOT BE SOLD OR OTHERWISE
        TRANSFERRED OR PLEDGED BY ANY PERSON, UNLESS (1) EITHER (A) A REGISTRATION
        WITH
        RESPECT THERETO SHALL BE EFFECTIVE UNDER THE SECURITIES ACT, OR (B) THE COMPANY
        SHALL HAVE RECEIVED AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT
        AN
        EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT IS AVAILABLE, AND (2)
        THERE
        SHALL HAVE BEEN COMPLIANCE WITH ALL APPLICABLE STATE SECURITIES OR “BLUE SKY”
LAWS.

    

    


    
      	
              DATAMETRICS
                CORPORATION

            
	 	 	
              December
                18, 2007

            
	 	 	 
	 	 	
              $535,000

            
	
               

              Demand

              Secured
                Promissory Note

            


    

    


    DATAMETRICS
      CORPORATION, a Delaware corporation (“Borrower”),
      for
      value received, hereby promises to pay on demand to the order of THE PHILIP
      S.
      SASSOWER 1996 CHARITABLE REMAINDER ANNUITY TRUST and JAG MULTI INVESTMENTS,
      LLC,
      a Delaware limited liability company (the “Payees”),
      the
      principal sum, which shall be an amount equal to the amount drawn upon under
      those certain letters of credit (the “Letters”) dated of even date hereof by JAG
      Multi Investments, LLC and Philip S. Sassower in favor of Comerica Bank
      (“Comerica”), up to a maximum of Five Hundred Thirty Five Thousand Dollars
      ($535,000)
      (the
“Principal
      Amount”),
      together with interest on the unpaid Principal Amount from the date that the
      Principal Amount becomes payable, which such date shall be the date of the
      drawdown by Comerica pursuant to the Letters (the “Accrual Date”), at a per
      annum rate equal to ten percent (10%), in lawful money of the United
      States.

    


    1.  Payment
      Terms.

     

    A.  Mandatory.
      The
      Principal Amount of this Note shall be payable on demand or upon the occurrence
      of an Event of Default hereunder, and any and all interest accrued and unpaid
      thereon shall be immediately payable on demand or upon the occurrence of an
      Event of Default hereunder. Accrued and unpaid interest shall commence on the
      Accrual Date and be payable on demand. All payments by Borrower hereunder shall
      be applied first to pay any interest that is due, but unpaid, and then to reduce
      the Principal Amount.

     

    B.  Optional.
      This
      Note can be prepaid, in whole or in part, with the prior written consent of
      Payees.

     

    
      
        
        

      

      
         

        
          

        

      

      
        
        

      

    

     

    C.  No
      Right to Set-Off or Counterclaim.
      Each
      payment by Borrower pursuant to this Note shall be made without set-off or
      counterclaim and shall be made in lawful currency of the United States of
      America and in immediately available funds.

     

    D.  Waiver
      of Presentment/Payment of Legal Fees.
      Borrower (i) waives presentment, demand, protest or notice of any kind in
      connection with this Note and (ii) agrees to pay to the holder hereof, on
      demand, all costs and expenses (including reasonable legal fees and expenses)
      incurred in connection with the preparation, enforcement and collection of
      this
      Note.

     

    2.  Interest.

     

    A.  Interest.
      The
      Principal Amount shall accrue interest at a rate equal to ten percent (10 %)
      per
      annum.

     

    B.  Calculation
      and Payment.
      Interest on the Principal Amount shall be calculated on the basis of a three
      hundred sixty-five (365) day year for the actual number of days
      elapsed.

     

    C.  Default
      Rate of Interest.
      At the
      election of Payee, after the occurrence of an Event of Default and for so long
      as it continues, the Principal Amount shall bear interest as set forth in
      Section 2.A above, plus 8% per annum.

     

    D.  Excess
      Interest.
      Notwithstanding anything to the contrary set forth herein, the aggregate
      interest, fees and other amounts required to be paid by Borrower to Payees
      are
      hereby expressly limited so that in no contingency or event whatsoever, whether
      by reason of acceleration of maturity of the Principal Amount or otherwise,
      shall the amount paid or agreed to be paid to Payees hereunder exceed the
      maximum permissible under applicable law. If under or from any circumstances
      whatsoever, fulfillment of any provision hereunder at the time of performance
      of
      such provision shall be due, shall involve exceeding the limit permitted by
      applicable law, then the Principal Amount shall automatically be reduced to
      the
      limit permitted, and if under or from circumstances whatsoever Payees should
      ever receive as interest any amount which would exceed the highest lawful rate,
      the amount of such interest that is excessive shall be applied to the reduction
      of the Principal Amount and not to the payment of interest. In the event of
      a
      conflict, this provision shall control every other provision
      hereunder.

     

    3.  Representations
      of Borrower.
      Borrower hereby represents to Payees that: 

     

    A.  Borrower
      is a corporation duly organized, validly existing and in good standing under
      the
      laws of the State of Delaware and has full power and authority to conduct its
      business as presently conducted and as proposed to be conducted by
      it.

     

    B.  Borrower
      has the corporate power and capacity to enter into this Note, and to do all
      acts
      and things as are required or contemplated hereunder to be done, observed and
      performed by it. Borrower has taken all necessary corporate action to authorize
      the execution, delivery and performance of each of this Note.

     

    C.  The
      execution and delivery of this Note and the performance by Borrower of its
      obligations hereunder (i) does not and will not contravene, breach or result
      in
      any default under (A) the articles, memorandum of association, by-laws,
      corporate documents or other organizational documents of Borrower, or (B) under
      any mortgage, lease, agreement or other legally binding instrument, license,
      permit or applicable law to which Borrower is a party or by which Borrower
      or
      any of its properties or assets may be bound, (ii) will not oblige Borrower
      to
      grant any encumbrance to any person other than to Payees, and (iii) will not
      result in or permit the acceleration of the maturity of any indebtedness,
      liability or obligation of Borrower under any mortgage, lease, agreement or
      other legally binding instrument of or affecting Borrower.

     

    
      
        
        

      

      
        2

        
          

        

      

      
        
        

      

    

     

    4.  Events
      of Default.
      Upon
      the occurrence of any of the following events (each an “Event of Default”), the
      entire unpaid principal of this Note, together with all accrued interest hereon,
      shall become immediately due and payable, and Payees shall be entitled to pursue
      all remedies that Payees may have, at law or in equity, for the enforcement
      and
      collection hereof:

     

    A.  The
      failure of Borrower to make (i) any payment of all interest due on this Note
      or
      (ii) full payment of all interest and principal due on this Note immediately
      upon demand; or

     

    B.  Borrower
      shall make an assignment for the benefit of creditors, file a petition in
      bankruptcy, consent to entry of an order for relief against it in an involuntary
      case, be adjudicated insolvent or bankrupt, petition or apply to any tribunal
      for the appointment of any receiver, trustee or similar official for it or
      a
      substantial part of its assets, or commence any proceedings under any
      bankruptcy, reorganization, arrangement, readjustment of debt, dissolution
      or
      liquidation law or statute of any jurisdiction, whether now or hereafter in
      effect; there shall occur the appointment of a receiver, trustee, assignee,
      liquidator, custodian or similar official of it or a substantial part of
      Borrower’s assets; or there shall have been filed any such petition or
      application or any such proceeding shall have been commenced against Borrower,
      which remains undismissed for a period of sixty (60) days or more; Borrower
      by
      any act or omission shall indicate its respective consent to, approval of or
      acquiescence in any such petition, application or proceeding or the appointment
      of any trustee for it or any substantial part of any of its respective
      properties; or

     

    C.  A
      court
      of competent jurisdiction shall enter an order or decree under any bankruptcy
      law that is for relief against Borrower in an involuntary case, appoints a
      receiver, trustee, assignee, liquidator or similar official of Borrower, or
      for
      any substantial part of Borrower’s property, or orders the liquidation of
      Borrower; and the order or decree remains unstayed and in effect for thirty
      (30)
      days.

     

    D.  The
      occurrence of a default in any covenant or agreement or breach of any
      representation or warranty under any present or future document, instrument
      or
      agreement between Borrower and Payees which, with respect to a default of a
      covenant or agreement, is not cured within the grace period applicable thereto,
      if any, or if no grace period is designated and such default is capable of
      cure,
      remains uncured for more than thirty (30) days following its
      occurrence.

     

    E.  
      A court
      of competent jurisdiction shall enter into a judgment, order or decree against
      Borrower for an amount of $25,000 or more.

     

    
      
        
        

      

      
        3

        
          

        

      

      
        
        

      

    

     

    5.  Acceleration.
      Upon
      the occurrence of an Event of Default, the unpaid Principal Amount and accrued
      interest thereon shall automatically become immediately due and payable, without
      presentment, demand, protest, notice of intent to accelerate, notice of
      acceleration or other requirements of any kind, all of which are hereby
      expressly waived by Borrower.

     

    6.  Amendments
      and Waivers.

     

    A.  The
      provisions of this Note may from time to time be amended, modified or waived,
      if
      such amendment, modification or waiver is in writing and consented to by
      Borrower and Payees.

     

    B.  No
      failure or delay on the part of Payees in exercising any power or right under
      this Note shall operate as a waiver thereof, nor shall any single or partial
      exercise of any such power or right preclude any other or further exercise
      thereof or the exercise of any other power or right. No notice to or demand
      on
      Borrower in any case shall entitle it to any notice or demand in similar or
      other circumstances. No waiver or approval by Payees shall, except as may be
      otherwise stated in such waiver or approval, be applicable to subsequent
      transactions. No waiver or approval hereunder shall require any similar or
      dissimilar waiver or approval thereafter to be granted hereunder.

     

    C.  To
      the
      extent that Borrower makes a payment or payments to Payees, and such payment
      or
      payments or any part thereof are subsequently for any reason invalidated, set
      aside and/or required to be repaid to a trustee, receiver or any other party
      under any bankruptcy law, state or federal law, common law or equitable cause,
      then to the extent of such recovery, the obligation or part thereof originally
      intended to be satisfied, and all rights and remedies therefor, shall be revived
      and continued in full force and effect as if such payment had not been made
      or
      such enforcement or setoff had not occurred.

     

    7.  Miscellaneous.

     

    A.  Governing
      Law.
      This
      Note shall be governed by and construed in accordance with the laws of the
      State
      of New York, without regard to its principles of conflicts of law. Sections
      5-1401 and 5-1402 of the General Obligations Law of the State of New York shall
      apply to this Note and Borrower hereby waives any right to stay or dismiss
      on
      the basis of forum non conveniens any action or proceeding brought before the
      courts of the State of New York sitting in New York County or of the United
      States of America for the Southern District of New York and hereby submits
      to
      the jurisdiction of such courts.

     

    B.  Notices.
      Unless
      otherwise provided, all notices required or permitted under this Note shall
      be
      in writing and shall be deemed effectively given (i) on the day delivered or
      transmitted to the party to be notified in the case of notices delivered by
      hand
      or by facsimile, (in the event confirmation is received) (ii) upon confirmed
      delivery by Federal Express or other nationally recognized courier service
      providing next-business-day delivery, or (iii) three business days after deposit
      with the United States Postal Service, by registered or certified mail, postage
      prepaid and addressed to the party to be notified, in each case at the address
      set forth below, or at such other address as such party may designate by written
      notice to the other party (provided that notice of change of address shall
      be
      effective upon receipt by the party to whom such notice is
      addressed).

     

    
      
        
        

      

      
        4

        
          

        

      

      
        
        

      

    

     

    
      	
              If
                sent to Payees, notices shall be sent to the following
                address:

            
	 
	
              The
                Philip S. Sassower 1996 Charitable Remainder Annuity Trust

              110 East 59th Street,
                Suite 1901 

              New York,
                New York 10022 

              Attention:
                Mr. Philip Sassower

              Fax:
                (212) 202-7565

            
	 
	
              JAG
                Multi Investments, LLC

              112 East 52nd
                Street, 29th
                Floor 

              New York,
                New York 10022 

              Attention:
                Mr. Alex Goren

              Fax:
                (212) 759-0572

            
	
               

              With
                a copy to:

            
	 
	
              Thelen
                Reid Brown Raysman & Steiner LLP

              875
                Third Avenue

              New
                York, New York 10022

              Attn:
                Joel H. Handel, Esq.

              Fax:
                (212) 603-2001

            
	
               

            
	
              If
                sent to Borrower, notice shall be sent to the following
                address:

            
	
               

            
	
              Datametrics
                Corporation

              1717
                Diplomacy Row

              Orlando,
                FL 32809

              Attention:
                John Marceca, President

              Fax:
                (407) 251-4588

            
	
               

            
	
              With
                a copy to:

            
	
               

            
	
              McLaughlin
                & Stern LLP

              260
                Madison Avenue

              New
                York, New York 10016

              Attn:
                Steven Schuster, Esq.

              Fax:
                (212) 448-0066

            


    

    


    C.  Waiver
      of Jury Trial.
      PAYEES
      AND BORROWER HEREBY KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVE ANY RIGHTS
      THEY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION BASED HEREON,
      OR
      ARISING OUT OF, UNDER, OR IN CONNECTION WITH, THIS NOTE OR ANY OTHER DOCUMENT
      OR
      INSTRUMENT EXECUTED AND DELIVERED IN CONNECTION HEREWITH, OR ANY COURSE OF
      CONDUCT, COURSE OF DEALING, STATEMENTS (WHETHER VERBAL OR WRITTEN), OR ACTIONS
      OF PAYEES OR BORROWER. THIS PROVISION IS A MATERIAL INDUCEMENT FOR PAYEES'
      PURCHASING THIS NOTE.

     

    
      
        
        

      

      
        5

        
          

        

      

      
        
        

      

    

     

    8.  Security.
      

     

    A.  Creation
      of Security Interest.
      In
      order to secure the payment of the principal and interest and all other
      obligations of the Borrower now or hereafter owed by the Borrower to the Payees
      (the “Secured Obligations”), the Borrower hereby grants to the Payees (or their
      designees) (the “Secured Parties”) a security interest in all of the personal
      property of the Borrower, including without limitation the personal property
      described below (the “Collateral”):

     

    (i)  all
      equipment in all of its forms, wherever located, now or hereafter existing,
      all
      parts thereof
      and
      all accessions thereto;

     

    (ii)  all
      inventory in all of its forms, wherever located, now or hereafter existing,
      including, but not limited to, (A)
      all raw
      materials and work in process therefor, finished
      goods thereof, and materials used or consumed in the manufacture or production
      thereof; (B)
      goods in
      which the Borrower has an interest in mass or a joint or other interest or
      right
      of any kind (including, without limitation, goods in which the Borrower has
      an
      interest or right as consignee); and (C)
      goods
      that are returned
      to or
      repossessed by the Borrower and all accessions thereto and products thereof
      and documents therefor;

     

    (iii)  all
      accounts, accounts receivable, contract rights, chattel paper, documents,
      instruments, deposit accounts, general intangibles, tax refunds and other
      obligations of any kind owing to the Borrower, now or hereafter existing,
      whether or not arising out of or in connection with the sale or lease of goods
      or the rendering of services, and all rights now or hereafter existing in and
      to
      all security agreements, leases, subleases, and other contracts securing or
      otherwise relating to any such accounts, contract rights, chattel paper,
      documents, instruments, deposit accounts, general
      intangibles, or obligations;

     

    (iv)  all
      intellectual property of any kind or nature whatsoever, including without
      limitation patents, patent applications, copyrights, copyright applications,
      trademarks and service marks and applications therefore, mask works, net lists
      and trade secrets;

     

    (v)  all
      other
      general intangibles, whether now existing or hereafter arising and wherever
      arising, including, but not limited to, all (A) partnership, corporate, and
      other interests in and to any person or entity; (B) letters of authorization,
      permits, licenses, consents, contract rights, franchises, documents,
      certificates,
      records, customer lists, customer and supplier contracts, easements, variances,
      certifications
      and approvals of tribunals, bills of lading (negotiable and non-negotiable),
      warehouse receipts, any claim of the Borrower against any lender, liquidated
      or
      unliquidated, and other rights, privileges and goodwill obtained or used in
      connection with any property of the Borrower; (C) rights of the Borrower under
      any equipment leases; and (D)
      tax
      refunds and other refunds or rights to receive payment from U.S.
      federal,
      state or local governments or foreign governments or other
      tribunals;

     

    
      
        
        

      

      
        6

        
          

        

      

      
        
        

      

    

     

    (vi)  all
      bank
      accounts, deposit accounts, and margin accounts, maintained by the Borrower
      with
      financial
      institutions, brokers, dealers, and all other persons or entities relating
      to
      commodities and/or securities, including all funds
      held
      therein and all certificates
      and
      instruments, if any, from time to time representing or evidencing such accounts;
      

     

    (vii)  all
      investment property (as defined
      in
      Section 9-115 of the New York Uniform Commercial Code);

     

    (viii)  to
      the
      extent it is possible to create a security interest or perfect a security
      interest in such Collateral by filing a UCC-1
      financing statement centrally, or in the case of dual filing states, centrally
      and at the county level, as applicable, all of the Borrower's
      fixtures now existing or hereafter acquired, all substitutes and replacements
      therefor, all accessions and attachments thereto, and all tools, parts, and
      equipment now or hereafter
      added
      to or used in connection with the fixtures on or above all real property now
      owned
      or
      hereafter acquired by the Borrower;

     

    (ix)  all
      records and documents relating to any and all of the foregoing, including,
      without limitation, records of account, whether in the form of writing,
      microfilm, microfiche, tape, or electronic media; and

     

    (x)  all
      substitutes and replacements for, accessions, attachments, and other additions
      to tools, parts, and equipment used in connection with, and all proceeds,
      products, and increases of, any and all of the foregoing Collateral, in whatever
      form, whether cash or noncash; interest, premium, and principal payments,
      redemption proceeds and subscription rights, and shares or other proceeds of
      conversions or splits of any securities in Collateral, and returned
      or
      repossessed Collateral; and, to the extent not otherwise included, all (A)
      payments under insurance, or any indemnity, warranty or guaranty, payable by
      reason of loss or damage to or otherwise with respect to any of the foregoing
      Collateral, (B)
      cash and
(C)
      security
      for the payment of any of the Collateral, and all goods which gave or will
      give
      rise to any of the Collateral or are evidenced, identified, or represented
      therein or thereby.

     

    B.  Sale
      or Removal of Collateral Prohibited.
      Except
      for the sale of inventory in the ordinary course of the Borrower's business
      and
      except for the security interest granted to SG DMTI Capital, LLC pursuant to
      that certain Secured Promissory Note dated December 30, 2005, as it may be
      amended from time to time, the Borrower shall not sell, lease, encumber, pledge,
      mortgage, assign, grant a security interest in, or otherwise transfer the
      Collateral without the written consent of the Payees, which consent shall not
      be
      unreasonably withheld. 

     

    C.  Uniform
      Commercial Code Security Agreement.
      This
      Section is intended to be a security agreement pursuant to the Uniform
      Commercial Code for any of the items specified above as part of the Collateral
      that, under applicable law, may be subject to a security interest pursuant
      to
      the Uniform Commercial Code, and the Borrower hereby grants the Payees a
      security interest in said items. The Borrower agrees that the Payees may file
      any appropriate document in the appropriate index as a financing statement
      for
      any of the items specified above as part of the Collateral. In addition, the
      Borrower agrees to execute and deliver to the Payees, upon the Payees’ request,
      any financing statements, as well as extensions, renewals and amendments
      thereof, and reproductions of this Note in such form as the Payees may
      reasonably require to perfect a security interest with respect to said items.
      The Borrower shall pay all costs of filing such financing statements and any
      extensions, renewals, amendments, and releases thereof, and shall pay all
      reasonable costs and expenses of any record searches for financing statements
      the Payees may reasonably require. Without the prior written consent of the
      Payees, the Borrower shall not create or suffer to be created pursuant to the
      Uniform Commercial Code any other security interest in the Collateral, other
      than the Security Interests of Secured Parties and existing secured creditors.
      Upon the occurrence of an Event of Default, the Secured Parties shall have
      the
      remedies of a holder under the Uniform Commercial Code and, at Secured Parties’
option, may also invoke the other remedies provided in this Note as to such
      items. In exercising any of said remedies, the Secured Parties may proceed
      against the items of real property and any items of personal property specified
      above as part of the Collateral separately or together and in any order
      whatsoever, without in any way affecting the availability of the Secured
      Parties’ remedies under the Uniform Commercial Code or of the other remedies
      provided in this Note.

     

    
      
        
        

      

      
        7

        
          

        

      

      
        
        

      

    

     

    D.  Rights
      of Secured Party.
      

     

    (i)  Upon
      an
      Event of Default, the Secured Parties may require the Borrower to assemble
      the
      Collateral and make it available to the Secured Parties at the place to be
      designated by the Secured Parties that is reasonably convenient to the parties.
      The Secured Parties may sell all or any part of the Collateral as a whole or
      in
      parcels either by public auction, private sale, or other method of disposition.
      The Secured Parties may bid at any public sale on all or any portion of the
      Collateral. Unless the Collateral is perishable or threatens to decline speedily
      in value or is of the type customarily sold on a recognized market, the Secured
      Parties shall give the Borrower reasonable notice of the time and place of
      any
      public sale or of the time after which any private sale or other disposition
      of
      the Collateral is to be made, and notice given at least 10 days before the
      time
      of the sale or other disposition shall be conclusively presumed to be
      reasonable.

     

    (ii)  Notwithstanding
      any provision of this Agreement, the Secured Parties shall be under no
      obligation to offer to sell the Collateral. In the event the Secured Parties
      offer to sell the Collateral, the Secured Parties will be under no obligation
      to
      consummate a sale of the Collateral if, in their reasonable business judgment,
      none of the offers received by them reasonably approximates the fair value
      of
      the Collateral.

     

    (iii)  In
      the
      event the Secured Parties elect not to sell the Collateral, the Secured Parties
      may elect to follow the procedures set forth in the Uniform Commercial Code
      for
      retaining the Collateral in satisfaction of the Borrower's obligation, subject
      to the Borrower's rights under such procedures.

     

    (iv)  In
      addition to the rights under this Agreement, in the Event of Default by the
      Borrower, the Secured Parties shall be entitled to the appointment of a receiver
      for the Collateral as a matter of right whether or not the apparent value of
      the
      Collateral exceeds the outstanding principal amount of the Notes and any
      receiver appointed may serve without bond. Employment by the Secured Parties
      shall not disqualify a person from serving as receiver.

     

    
      
        
        

      

      
        8

        
          

        

      

      
        
        

      

    

     

    IN
      WITNESS WHEREOF, Borrower has caused this Note to be signed in its name by
      its
      duly authorized officer.

     

    
      	 	 	 
	 	
              DATAMETRICS
                CORPORATION

            
	 
 	 
 	 
 
	
            	By:  	/s/
              John
              Marceca   
	 	
              

              Name:
                John Marceca

            
	 	
              Title:
                President

            




    
      
        
        

      

      
        9