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Comfort Noise local to phone - avayax - 04-17-2018 10:32 PM

The feature comfort noice generation that can be enabled on the phone, is that local to the phone or something that is sent to the PBX server?


RE: Comfort Noise local to phone - Evan_Yealink - 04-18-2018 08:10 AM

Dear Customer,

This is Evan from Yealink Support Team, I'm glad to answer this question for you!

For example, A is talking with B.
A: Enables the CNG, CNG=1
If A mutes the call, A will send CN packets to B. When B receiving CN packets, it will
generate comfortable noise.

For more information about CNG:
Comfort Noise Generation (CNG) is used to generate 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 silence occur and inserts artificial noise until voice activity resumes. The insertion of artificial noise gives the illusion of a constant transmission stream, so that background sound is consistent throughout the call and the listener does not think the line has released. The purpose of VAD and CNG is to maintain an acceptable perceived QoS while simultaneously keeping transmission costs and bandwidth usage as low as possible.

Best Regards,
Evan You


RE: Comfort Noise local to phone - avayax - 04-18-2018 09:26 AM

So if phone A send comfort noise packets, then the server must support it.
And if it doesn't, like Asterisk, I should better turn off that feature.


RE: Comfort Noise local to phone - Evan_Yealink - 04-18-2018 09:43 AM

(04-18-2018 09:26 AM)avayax Wrote:  So if phone A send comfort noise packets, then the server must support it.
And if it doesn't, like Asterisk, I should better turn off that feature.

Hello Dear Customer,

The server is only responsible for forwarding these packets and signalling. It doesn't matter whether the server supports this feature or not.

Best Regards,
Evan You