Following the recent announcement of its new family of Communications Servers, ESI, an industry leader in digital and IP-based business phone systems, today announced a National Accounts Program ...

The U.S. Patent and Trademark Office has awarded ESI, a leading manufacturer of digital and IP-based business telephone systems, a patent for Quality of Service (QoS) in a Voice-over-Internet ...

The ESI 250 Smartphone is a high-performance enterprise-grade IP desktop phone that harnesses the power, communications productivity, and flexible ease-of-use of the Android OS.