EXHIBIT
10.48
 
 REAFFIRMATION
OF GUARANTY
 
 
 REAFFIRMATION
dated January 11, 2010 (this “Reaffirmation”) by Gerald J.
Burnettand byGerald
J. Burnett and Marjorie J. Burnett as Trustee for The Gerald J. Burnett and
Marjorie J. Burnett Revocable Trust (collectively, the “Guarantor”) in
favor of JPMorgan Chase Bank, N.A., formerly known as JPMorgan Chase Bank (the
“Bank”).
 
 WHEREAS, Avistar Communications
Corporation, a Delaware corporation (the “Obligor”), has executed and
delivered to the Bank that certain Second Amended and Restated Revolving
Promissory Note (Libor/Prime) dated as of December 22, 2009 by the Grantor
in favor of the Bank in the maximum principal amount of $11,250,000 (as amended,
restated or otherwise modified from time to time, “Note”);
 
 WHEREAS,
the Obligor and the Bank are parties to that certain Third Amended and Restated
Security Agreement dated as of December 22, 2009, which secures, among other
things, the Obligor’s obligations to the Bank under the Note (as amended,
restated or otherwise modified from time to time, the “Original Security
Agreement”);
 
 WHEREAS,
the Obligor has executed and delivered to the Bank that certain Fourth Amended
and Restated Security Agreement dated as of January ___, 2010, which would
secure, among other things, the Obligor’s obligations to the Bank under the Note
(as amended, restated or otherwise modified from time to time, the “New Security
Agreement”);
 
 WHEREAS,
the Guarantor has executed and delivered to the Bank that certain Second Amended
and Restated Guaranty dated December 22, 2009 by which the Guarantor
guaranteed, among other things, the Obligor’s obligations to the Bank under the
Note and the Original Security Agreement (the “Guaranty”);
 
 WHEREAS, the Guarantor desires the Bank
to accept delivery of the New Security Agreement and to acknowledge and agree
that the New Security Agreement supersedes and replaces the Original Security
Agreement in its entirety;
 
 NOW THEREFORE, FOR VALUE RECEIVED, and
as an inducement to the Bank to accept delivery of the New Security Agreement,
and acknowledge and agree that the New Security Agreement supersedes and
replaces the Original Security Agreement in its entirety, Guarantor, without in
any respect limiting the scope of the Guaranty, hereby confirms, acknowledges
and agrees that (i) from and after the date hereof the guaranty provided
for in the Guaranty shall extend to, cover and guarantee (in addition to any
other obligations guaranteed thereby, including, without limitation, the
Borrower’s obligations under the Note) all obligations of the Borrower arising
under the New Security Agreement and (ii) the Guaranty is (and, following
the Bank’s acceptance of the New Security Agreement, will be) in full force and
effect.
 
 This Reaffirmation shall be governed by
and construed in accordance with the law of the State of New York applicable to
agreements made and to be performed wholly within the State of New
York.
 
 IN WITNESS WHEREOF, the undersigned has
executed this Reaffirmation as of the date first set forth above.
 
 
 /s/ Gerald
J.
Burnett
 Gerald
J. Burnett
 
 
 Gerald
J. Burnett and Marjorie J. Burnett, as Trustee for
 The
Gerald J. Burnett and Marjorie J. Burnett Revocable Trust
 
 
 By:          /s/ Gerald
J.
Burnett
 Gerald J. Burnett
 
 By:          /s/ Marjorie
J.
Burnett
 Marjorie J. Burnett
 
 
 
 
 State
      of _________
              )
 ) ss.:
 County
      of ________
              )
 
 On the ____ day of January in the year
2010, before me, the undersigned, personally appeared Gerald J. Burnett,
personally known to me or proved to me on the basis of satisfactory evidence to
be the individual whose name is subscribed to the within instrument and
acknowledged to me that he/she executed the same in his/her capacity, and that
by his/her signature on the instrument, the individual, or the person upon
behalf of which the individual acted, executed the instrument.
 
 ____________________________________
 Notary Public
 State
      of _________
              )
 ) ss.:
 County
      of ________
              )
 
 On the ____ day of January in the year
2010, before me, the undersigned, personally appeared Marjorie J. Burnett,
personally known to me or proved to me on the basis of satisfactory evidence to
be the individual whose name is subscribed to the within instrument and
acknowledged to me that he/she executed the same in his/her capacity, and that
by his/her signature on the instrument, the individual, or the person upon
behalf of which the individual acted, executed the instrument.
 
 ____________________________________
 Notary
Public