Avistar Adds Zultys to Its Growing List of Industry Leading Technology Partners

San Mateo, Calif., March 11, 2009 -- Avistar Communications Corp. (Nasdaq: AVSR), a leader
in unified visual communications solutions, announced today that Zultys, Inc., a leading provider
of all-in-one unified communication solutions, will integrate Avistar’s C3 Media Engine and make
it available to its customers around the world. Through this agreement, Zultys customers will
have the ability to add best-in-class desktop videoconferencing to their unified communications
systems. Zultys plans to launch the integrated solution in the fall of 2009.

Simon Moss, CEO of Avistar, said, “After a thorough and competitive review, Zultys selected
Avistar. Zultys is recognized for its innovative, open standards IP communications and
telephony products. Avistar C3™ will help Zultys open new revenue streams and provide
important new videoconferencing features that will strengthen its positioning in its markets
worldwide.”

“Videoconferencing provides the ROI our customers are looking for as part of their unified
communications solutions, especially in a down economy, where travel is well scrutinized,” said
Steve Morrison, Vice President, Product Marketing, Zultys. “Avistar C3 augments our line of
VoIP and web conferencing products, empowering our customers to collaborate and take
aggressive action to remain competitive.”

Avistar C3 Media Engine
Based on the award-winning Avistar C3 Desktop™ solution, the Avistar C3 Media Engine
provides a business class desktop videoconferencing experience to technology partners who
require a visual communications experience within their applications. Business-class
videoconferencing is recognized as a valuable communications tool that provides corporations
serious cost savings, improved productivity and ROI. According to a recent Wainhouse
Research study, one third of those polled see the use of videoconferencing accelerating given
today’s economy, as it reduces the need and cost for travel plus improves collaboration and
decision-making. At a fraction of the cost of typical videoconferencing solutions, Avistar C3
makes videoconferencing easy and approachable for both advanced and novice business
users.

About Zultys
Zultys, Inc. is showing what's possible for Open Standards IP communications and telephony.
Its Open Standards IP technology is the building block for its award-winning IP PBX systems.
Zultys develops products that enable companies and organizations in more than 110 countries
and 19 languages to deploy integrated communications systems. For more information visit:
www.zultys.com.

About Avistar Communications Corporation
Avistar (Nasdaq: AVSR) is a unified visual communications solutions, providing proven
business-class technology. Avistar's desktop videoconferencing installations include more than
100,000 committed desktop seats worldwide, bringing together business users anytime and
anyplace. Companies such as IBM Corp., Sony Corp., LifeSize Communications, Inc. and
Polycom Inc. use Avistar technology to power their unified communications solutions. Avistar
works with leading-edge technology partners and resellers including CityIS, Beyondis, Datamart
and Fontel in more than 40 countries. For more information, go to www.avistar.com.