Asterisk VoIP News

Tuesday, September 27, 2005

Press Release: SANGOMA TECHNOLOGIES Registers Patent Application on Echo Detection And Control System

Technology to improve performance of host-based HMP and hardware-based telephony systems

TORONTO - September 27, 2005 – Sangoma Technologies Corporation (TSXV: STC) (, a leading provider of connectivity hardware and software products for VoIP, TDM voice, WANs and Internet infrastructure, today announced that it has filed a patent application for a method to enhance the efficiency of echo cancellation hardware and software. The provisional patent application titled "Echo Canceller Controller" covers the techniques of measuring echo on incoming voice streams and controlling the echo canceller appropriately.

"This technology is a major step forward in improving the performance of echo cancellation, particularly in the Host Media Processor (HMP) environment," says Sangoma Technologies President and CEO David Mandelstam. "The trend for PC-based telephony is away from expensive hardware solutions toward HMP implementations such as NetStructure by Intel or the open source Asterisk telephony system. High quality echo cancellation on HMP systems consumes approximately 30MHz of host CPU overhead per telephone conversation, so there is considerable scope for reduction of CPU load in systems supporting hundreds of simultaneous calls."

Sangoma's EDAC (Echo Detection and Control) is an algorithm that examines each call as it is connected, and within about one second, determines whether the call has echo or not. It then enables or disables the echo canceller as necessary. Because all long distance, cell phone, ISDN and VoIP calls are either already echo cancelled or have no echo, echo cancellation loads on HMP systems can often be reduced by 80 per cent or more. Where echo cancellation is hardware-based, EDAC can reduce the up-front cost of echo cancellation hardware to match the mix of local analog and other calls that are expected on the system.

"EDAC will be implemented as a standard application in our on-board firmware at no cost," adds Mandelstam. "We expect EDAC to become a must- have feature in the delivery of practical HMP and low- cost hybrid HMP/hardware-based VoIP gateways, PBX and IVR systems and other telephony systems."