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                               EXCHANGE AGREEMENT


         EXCHANGE AGREEMENT dated as of the 31st day of January, 2001 (this
"Agreement") by and between DATAMETRICS CORPORATION, a Delaware corporation (the
"Corporation"), and DMTR, LLC, a New York limited liability company ("DMTR").

                              W I T N E S S E T H:

         WHEREAS, the Corporation and DMTR are parties to a Loan Agreement dated
the date hereof (the "Loan Agreement") pursuant to which DMTR has agreed to
provide certain financing to the Corporation; and

         WHEREAS, the Corporation is obligated to DMTR in respect of the Bridge
Notes, as such term is defined in the Loan Agreement; and

         WHEREAS, the Corporation and DMTR have agreed to exchange a certain
portion of the Bridge Notes for shares of the Corporation's common stock, par
value $.01 (the "Common Stock");

         NOW, THEREFORE, in consideration of the premises and mutual covenants
set forth herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, DMTR and the Corporation agree as
follows:

         1. Exchange. DMTR hereby exchanges (the "Exchange") $700,000 in
principal amount of the Bridge Notes for the issuance by the Corporation
simultaneously with the execution and delivery of this Agreement of 700,000
shares of the Corporation's Common Stock (after giving effect to a proposed 1
for 20 reverse stock split). The parties acknowledge that effective upon the
Exchange, the outstanding principal amount of the Bridge Notes is $605,000.

         2. Registration Rights Agreement. As a condition to the consummation of
the Exchange, the Corporation and DMTR are executing and delivering the
Registration Rights Agreement in the form of Exhibit 1 hereto.

         3. Representations. The Corporation represents and warrants that the
execution, delivery and performance of this Agreement have been duly authorized
by all required corporate action of the Corporation and that the Shares are duly
authorized, fully paid and non-assessable shares of the Common Stock of the
Corporation.

         4. Miscellaneous Provisions. (a) Neither this Agreement nor any right
or obligation arising hereunder may be assigned by either party without prior
written consent of the other party, and any purported assignment without such
consent shall be null and void. (b) This Agreement shall be binding upon and
inure to the benefit solely of the parties hereto and their respective
successors and permitted assigns. (c) This Agreement, together with its exhibits
and schedules, if any, set forth the entire agreement between the parties hereto
with respect to the subject matter hereof and supersede and cancel any and all
prior or contemporaneous discussions, negotiations, arrangements and agreements
between them, express or implied, oral or written with respect to such subject
matter hereof. The parties acknowledge that no representations or promises have
been made to induce either of them to enter into this Agreement other than as
may be specifically set forth herein. (d) This Agreement may not be amended or
modified except by a writing signed by each of the parties hereto stating that
an amendment is intended. (e) The execution, interpretation and performance of
this Agreement shall be governed by the internal laws of the State of New York,
without regard to that State's conflict-of-laws principles. (f) This Agreement
may be

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signed in counterparts, each of which shall be deemed an original and all of
which shall be deemed one and the same instrument.

         IN WITNESS WHEREOF, the undersigned have executed and delivered this
Agreement as of the date first set forth above.



                                            DATAMETRICS CORPORATION



                                            By:__________________________
                                                 Name:  Vincent J. Cahill
                                                 Title:  President and CEO


                                            DMTR, LLC



                                            By:__________________________
                                                 Name: Bruce Galloway
                                                 Title:  Managing Member