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                                                                 EXHIBIT 10.11.4

                                SECOND AMENDMENT
                                       TO
                           LOAN AND SECURITY AGREEMENT

This Second Amendment to the Loan and Security Agreement (the "Amendment") is
entered into as of March 10, 2003, by and between COMERICA BANK - CALIFORNIA
("Bank") and AVISTAR COMMUNICATIONS CORPORATION ("Borrower").

                                    RECITALS

         Borrower and Bank are parties to that certain Loan and Security
Agreement dated as of February 27, 2002, (as amended from time to time,
including without limitation that certain First Amendment to Loan and Security
Agreement dated December 16, 2002, together with any related agreements, the
"Agreement"). Hereinafter, all indebtedness owing by Borrower to Bank shall be
referred to as the "Indebtedness." The parties desire to amend the Agreement in
accordance with the terms of this Amendment.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

                                    AGREEMENT

I.       INCORPORATION BY REFERENCE. The Recitals and the documents referred to
         therein are incorporated herein by this reference. Except as otherwise
         noted, the terms not defined herein shall have the meaning set forth in
         the Agreement.

II.      AMENDMENT TO THE AGREEMENT. Subject to the satisfaction of the
         conditions precedent as set forth in Article IV hereof, the Agreement
         is hereby amended as set forth below.

         A.       The definition of "Eligible Accounts" in Section 1.1 of the
                  Agreement is hereby amended and restated in its entirety to
                  read as follows:

                  ""Eligible Accounts" means trade receivables, determined in
                  accordance with GAAP."

         B.       The definition of "Revolving Maturity Date" in Section 1.1 of
                  the Agreement is hereby amended and restated in its entirety
                  to read as follows:

                  ""Revolving Maturity Date" means February 27, 2004."

         C.       The first sentence of Section 6.8 of the Agreement is hereby
                  amended and restated in its entirety to read as follows:

                  "Borrower shall maintain, measured as of the last day of each
                  calendar month, on a consolidated basis, a ratio of Adjusted
                  Quick Assets to Current Liabilities plus, to the extent not
                  already included therein, all Indebtedness (including without
                  limitation any Contingent Obligations) owing from Borrower to
                  Bank, less deferred maintenance contract revenue, of at least
                  1.00 to 1.00 for the quarters ending March 31, 2003 and June
                  30, 2003 and 0.75 to 1.00 for the quarters ending September
                  30, 2003, December 31, 2003, and February 27, 2004."

III.     LEGAL EFFECT.

         A.       The Agreement is hereby amended wherever necessary to reflect
                  the changes described above.

AMENDMENT
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         B.       Borrower agrees that it has no defenses against the
                  obligations to pay any amounts under the Indebtedness.

         C.       Borrower understands and agrees that in modifying the existing
                  Indebtedness, Bank is relying upon Borrower's representations,
                  warranties, and agreements, as set forth in the Agreement.
                  Except as expressly modified pursuant to this Amendment, the
                  terms of the Agreement remain unchanged, and in full force and
                  effect. Bank's agreement to modifications to the existing
                  Indebtedness pursuant to this Amendment in no way shall
                  obligate Bank to make any future modifications to the
                  Indebtedness. Nothing in this Amendment shall constitute a
                  satisfaction of the Indebtedness. It is the intention of Bank
                  and Borrower to retain as liable parties, all makers and
                  endorsers of Agreement, unless the party is expressly released
                  by Bank in writing. No maker, endorser, or guarantor will be
                  released by virtue of this Amendment. The terms of this
                  paragraph apply not only to this Amendment, but also to all
                  subsequent loan modification requests.

         D.       This Amendment may be executed in two or more counterparts,
                  each of which shall be deemed an original, but all of which
                  together shall constitute one instrument.

         E.       This is an integrated Amendment and supersedes all prior
                  negotiations and agreements regarding the subject matter
                  hereof. All modifications hereto must be in writing and signed
                  by the parties.

IV.      CONDITIONS PRECEDENT. Except as specifically set forth in this
         Amendment, all of the terms and conditions of the Agreement remain in
         full force and effect. The effectiveness of this Agreement is
         conditioned upon receipt by Bank of this Amendment, and any other
         documents which Bank may require to carry out the terms hereof,
         including but not limited to the following:

         A.       This Amendment, duly executed by Borrower;

         B.       A legal fee from the Borrower in the amount of $250; and

         C.       Such other documents, and completion of such other matters, as
                  Bank may reasonably deem necessary or appropriate.

IN WITNESS WHEREOF, the undersigned have executed this Amendment as of the first
date above written.

                                           AVISTAR COMMUNICATIONS
                                           CORPORATION

                                           By: /s/ Robert J. Habig
                                               ---------------------------------

                                           Title: Chief Financial Officer

                                           COMERICA BANK - CALIFORNIA

                                           By: /s/ Robert Fernandez
                                               ---------------------------------

                                           Title: Vice President

AMENDMENT
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