Denwa Communications DW-820, User Manual

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incoming call is automatically answered.
8.7 Phone->Audio
Sections Description
Echo Canceller Echo Canceller: To remove acoustic echo from a voice
communication in order to improve the voice quality .

VAD (Voice Activity Detection): Allow IP phone to
detect the presence or absence of human speech during
a call. When detecting period of “silence”, VAD
replaces that silence efficiently with special packets
that indicate silence is occurring. It can facilitate
speech processing, and deactivate some processes
during non-speech section of an audio session. It can
avoid unnecessary coding or transmission of silence
packets in VoIP applications, saving on computation
and network bandwidth.

CNG (Comfort Noise Generation): Allow IP phone to
generate comfortable background noise for voice
communications during periods of silence in a
conversation. It is a part of the silence suppression or
VAD handling for VoIP technology. CNG, in conjunction
with VAD algorithms, quickly responds when periods of