AMENDED AND RESTATED REVOLVING CREDIT PROMISSORY NOTE

$10,000,000 Dated as of December 22, 2008

For value received, Avistar Communications Corporation , a Delaware corporation (the “ Borrower ”) hereby promises to pay to the order of JPMorgan Chase Bank, N.A. (the “ Bank ”) at its office at 345 Park Avenue, New York, New York 10154-1002  for the account of the lending office of the Bank, the principal amount of each loan made by the Bank to the Borrower (the “ Loans ”), up to an aggregate principal amount equal to the Maximum Facility Amount, on the first anniversary of the date hereof (the “ Final Maturity Date ”).

The Revolving Credit Promissory Note (Libor/Prime) dated as of December 23, 2006, as amended, by the Borrower to the order of the Bank (the “ Original Note ”) is amended and restated in its entirety by this Note.

The Borrower promises to pay interest on each Interest Payment Date on the unpaid balance of the principal amount of each such Loan from and including the date of such Loan to but excluding the date of its repayment at either (i) a floating rate per annum equal to the Prime Rate applicable to such Loan plus 1.25% (such Loan a “ Prime Loan ”), or (ii) a fixed rate per annum equal to the Adjusted Libor Rate applicable to such Loan plus 1.25% (such Loan a “ Libor Loan ”).  After the occurrence and during the continuance of an Event of Default, principal shall bear interest from and including the date of such Event of Default until paid in full at a rate per annum equal to the Default Rate, such interest to be payable on demand.  Interest shall be payable on the relevant Interest Payment Date and for Libor Loans shall be calculated on the basis of a year of 360 days for the actual number of days elapsed and for Prime Loans shall be calculated on the basis of a year of 365 or 366 days, as the case may be, and actual days elapsed.  Prior to the Final Maturity Date, provided that no Event of Default has occurred and is continuing, and subject to the terms of this Note, the Borrower may borrow, repay and reborrow under this Note, up to the aggregate principal amount equal to the Maximum Facility Amount (the “ Commitment ”).

All payments hereunder shall be made in lawful money of the United States and in immediately available funds.  Any extension of time for the payment of the principal of this Note resulting from the due date falling on a non-Banking Day shall be included in the computation of interest.  The date, amount, type and Interest Period of, and the interest rate with respect to, each Loan evidenced hereby and all payments of principal thereof shall be recorded by the Bank on its books and, at the discretion of the Bank prior to any transfer of this Note at any other time, may be endorsed by the Bank on a schedule.  Any such endorsement shall be conclusive absent manifest error. The Bank may (but shall not be obligated to) debit the amount of any payment under this Note that is not made when due to any deposit account of the Borrower with the Bank.  The Borrower waives presentment, notice of dishonor, protest and any other notice or formality with respect to this Note.

1.             Definitions.   The terms listed below shall be defined as follows:

“ Adjusted Libor Rate ” shall mean the Libor Rate for such Loan divided by one minus the Reserve Requirement.

“ Banking Day ” shall mean any day on which commercial banks are not authorized or required to close in New York City and whenever such day relates to a Libor Loan or notice with respect to any Libor Loan, a day on which dealings in U.S. dollar deposits are also carried out in the London interbank market.

“ Borrowing Notice ” shall mean a request for a borrowing substantially in the forma of Exhibit A hereto.

“ Collateral Agreement ” means the Amended and Restated Collateral Agreement dated as of December 22, 2008 by the Guarantor in favor of the Bank securing, among other things, the Guarantor’s obligations to the Bank under the Guaranty, as amended, restated or otherwise modified from time to time.

“ Convertible Notes ” means the “Notes” (as defined in, and issued pursuant to, the Convertible Note Purchase Agreement).

“ Convertible Note Purchase Agreement ” means the Convertible Note Purchase Agreement dated January 4, 2008 by the Borrower and the purchasers parties thereto with respect to the Borrower’s sale of its 4.5% convertible subordinated secured promissory notes.

“ Default Rate ” shall mean a rate per annum equal to: (a) if a Prime Loan, a floating rate of 2% above the rate of interest thereon (including any margin); (b) if a Libor Loan, a fixed rate of 2% above the rate of interest in effect thereon (including any margin) at the time of the applicable Event of Default until the last day of the Interest Period thereof and, thereafter, a floating rate of 2% above the rate of interest for a Prime Loan (including any margin).

“ Event of Default ” shall mean an event described in Section 7.

“ Facility Documents ” shall mean this Note and any other documents, instruments, or agreements delivered as security or collateral for, or a guaranty of, the Loans, or in connection with, or as support for, any of the foregoing, whether by the Borrower or a Third Party, and any updates or renewals thereof (including, without limitation, the Collateral Agreement, the Guaranty and the Security Agreement).

“ Guarantor ” means (i) Gerald J. Burnett and (ii) Gerald J. Burnett and Marjorie J. Burnett as Trustees for The Gerald J. Burnett and Marjorie J. Burnett Revocable Trust.

“ Guaranty ” means the Amended and Restated Guaranty dated as of December 22, 2008 by the Guarantor in favor of the Banks guarantying, among other things, the Borrower’s obligations to the Bank under this Note hereto, as amended, restated or otherwise modified from time to time.

“ Interest Payment Date ” shall mean (i) the last Banking Day of each calendar month for Prime Loans commencing January 31, 2007; (ii) the last Banking Day of each calendar month and on the last day of the Interest Period with respect to Libor Loans (and for any Libor Loan with an Interest Period longer than three months, every three months); and (iii) on any payment of principal.

“ Interest Period ” shall mean (i) with respect to a Prime Loan, the period commencing on the date such Prime Loan is made and ending on the earlier of the Final Maturity Date or the date recorded by the Bank on its books or if such day is not a Banking Day, then on the immediately succeeding Banking Day, and (ii) with respect to a Libor Loan, the period commencing on the date such Libor Loan is made and ending on the numerically corresponding day  One, Three or Six calendar months thereafter, as recorded by the Bank on its books, or if such day is not a Banking Day, then on the immediately succeeding Banking Day; provided that if such Banking Day would fall in the next calendar month, such Interest Period shall end on the immediately preceding Banking Day; and provided, further, that each such Interest Period which commences on the last Banking Day of a calendar month (or on any day for which there is no numerically corresponding day in the appropriate subsequent calendar month) shall end on the last Banking Day of the appropriate calendar month.  No Interest Period may extend beyond the Final Maturity Date.

“ Libor Rate ” shall mean the rate per annum (rounded upwards, if necessary, to the nearest 1/16 of 1%) quoted by the Bank at approximately 11:00 a.m. London time (or as soon thereafter as practicable) two Banking Days prior to the first day of such Loan for the offering by the Bank to leading banks in the London interbank market of U.S. dollar deposits having a term comparable to such Loan and in an amount comparable to the principal amount of such Loan.

“ Main Office ” shall mean the main office of the Bank, currently located at 1111 Polaris Parkway, Columbus, Ohio 43240.

“ Maximum Facility Amount ” shall mean the lesser of (i) Ten Million Dollars ($10,00,000) and (ii) the value assigned by the Bank from time to time, in its sole reasonable discretion, to the collateral, if any, pledged and collaterally assigned to the Bank, and in which the Bank has a first-priority security interest and against which the Bank has a right of setoff, as security for the Borrower’s payment of its obligations under this Note.

“ Prime Rate ” shall mean the rate of interest per annum announced from time to time by the Bank as its prime rate.  Each change in the Prime Rate shall be effective from and including the date the change is announced as being effective.  The Prime Rate is a reference rate and may not be the Bank’s lowest rate.

“ Regulation D ” shall mean Regulation D of the Board of Governors of the Federal Reserve System.

“ Regulatory Change ” shall mean any change after the date of this Note in United States federal, state or municipal laws or any foreign laws or regulations (including Regulation D) or the adoption or making after such date of any interpretations, directives or requests applying to a class of banks, including the Bank, of or under any United States federal, state or municipal laws or any foreign laws or regulations (whether or not having the force of law) by any court or governmental or monetary authority charged with the interpretation or administration thereof.

“ Reserve Requirement ” shall mean, for any Libor Loan, the average maximum rate at which reserves (including any marginal, supplemental or emergency reserves) are required to be maintained during the term of such Loan under Regulation D by member banks of the Federal Reserve System in New York City with deposits exceeding one billion U.S. dollars, or as otherwise established by the Board of Governors of the Federal Reserve System and any other banking authority to which the Bank is subject, against “Eurocurrency liabilities” (as such term is used in Regulation D).  Without limiting the effect of the foregoing, the Reserve Requirement shall reflect any other reserves required to be maintained by such member banks by reason of any Regulatory Change against (x) any category of liabilities which includes deposits by reference to which the Libor Rate is to be determined or (y) any category of extensions of credit or other assets which include Libor Loans.  The Reserve Requirement shall be adjusted automatically on and as of the effective date of any change in any reserve percentage.

“ SEC ” means the Securities and Exchange Commission.

“ Security Agreement ” shall mean the Second Amended and Restated Security Agreement dated as of December 22, 2008 by the Borrower in favor of the Bank securing, among other things, the Borrower’s obligations to the Bank under this Note, as amended, restated or otherwise modified from time to time.

“ Third Party ” shall mean any party liable with respect to, or otherwise granting support for, this Note, whether by guaranty, subordination, grant of security or otherwise.

2.  Borrowings, Conversions, Renewals and Prepayments.   (a) The Borrower shall deliver a Borrowing Notice to the Bank, which shall be irrevocable,  by 12:00 noon New York City time three (3) Banking Days prior to each requested borrowing of a Libor Loan and by 12:00 noon New York City time on the date of each requested borrowing of a Prime Loan; provided that no Libor Loan shall be in a minimum amount less than $500,000; provided, further, that no Prime Loan shall be in an amount less than $30,000; and provided, further, that the aggregate outstanding principal amount of all Loans shall not exceed the Maximum Facility Amount.  Subject to the provisions of this Note, the Borrower shall have the right to (i) convert one type of Loan into another type of Loan on the last day of the Interest Period with respect to a Libor Loan or at any time for a Prime Loan, or (ii) renew any Libor Loan as a Libor Loan on the last day of the Interest Period with respect to such Libor Loan; provided that the Borrower shall give the Bank irrevocable notice by 12:00 noon New York City time three Banking Days prior to conversion into or renewal as a Libor Loan, and by 12:00 noon New York City time on or before the date of conversion into a Prime Loan.  If the Borrower shall fail to give notice to the Bank of the renewal of any Libor Loan as provided herein, such Libor Loan shall automatically become a Prime Loan on the last day of the Interest Period thereof; provided that the Bank may renew such Loan as a Libor Loan for an Interest Period equal to that then ending, provided that no such renewal shall be made if the number of months in the renewal period is greater than six.

(b)           The Borrower shall have the right to make prepayments of principal at any time or from time to time, provided that:  (i) the Borrower shall give the Bank irrevocable notice of each prepayment by 12:00 noon New York City time three Banking Days prior to prepayment of a Libor Loan, and by 12:00 noon New York City time on the date of prepayment of a Prime Loan; (ii) Libor Loans may be prepaid prior to the last day of their Interest Period only if accompanied by payment of the additional compensation calculated in accordance with paragraph 5 below, if applicable; (iii) all prepayments of Libor Loans shall be in a minimum amount equal to the lesser of $100,000 or the unpaid principal amount of this Note; and (iv) all prepayments of Prime Rate Loans shall be in a minimum amount equal to the lesser of $30,000 or the unpaid principal amount of this Note.

3.             Additional Costs.   (a) If as a result of any Regulatory Change which (i) changes the basis of taxation of any amounts payable to the Bank under the Note (other than taxes imposed on the overall net income of the Bank or the lending office by the jurisdictions in which the Main Office of the Bank or the lending office are located) or (ii) imposes or modifies any reserve, special deposit, deposit insurance or assessments, minimum capital, capital ratios or similar requirements relating to any extension of credit or other assets of, or any deposits with or other liabilities of the Bank, or (iii) imposes any other condition affecting this Note, the Bank determines (which determination shall be conclusive absent manifest error) that the cost to it of making or maintaining a Libor Loan is increased or any amount received or receivable by the Bank under this Note is reduced, then the Borrower will pay to the Bank on demand an additional amount that the Bank determines will compensate it for the increased cost or reduction in amount.

(b)           Without limiting the effect of the foregoing provisions of this Section 3 (but without duplication), the Borrower shall pay to the Bank from time to time on request such amounts as the Bank may determine to be necessary to compensate the Bank for any costs which it determines are attributable to the maintenance by it or any of its affiliates pursuant to any law or regulation of any jurisdiction or any interpretation, directive or request (whether or not having the force of law and whether in effect on the date of this Note or thereafter) of any court or governmental or monetary authority of capital in respect of the Loans hereu