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[FAQ] Changing the comfort noise on a Polycom VVX Business Media Phone

Polycom Employee & Community Manager

[FAQ] Changing the comfort noise on a Polycom VVX Business Media Phone

In certain situations or scenarios it may be preferable to change the factory default of comfort noise utilizing a Microsoft Lync or Skype for Business Server.

 

UC Software 5.4.2 or later added the below.

 

Parameter Recommendation

Parameter Range

Default Value

Result

 

voice.cn.hs.enable="1"                

0 or 1

0

Enables the in-band comfort noise fill

 

voice.cn.hs.attn="35"               

90 to -90

0

Sets the in-band comfort noise attenuation (lower numbers are louder, we suggest no lower / louder than 35)

 

voice.vadEnable="0"                     

0 or 1

0

Disables VAD Tx – VAD Rx CNG packets will still be properly received to synthesize local comfort noise

 

voice.vadRxGain="10"         

20 to -20

0

Boosts the VAD CNG synthesis level by 10 dB – subjectively matches the customer site RTP capture

 

voice.vadTxGain="-10"                 

20 to -20

0

Reduces the VAD CNG packet payload value by 10 dB – effectively prevents the synthesis boost in voice.vadRxGain from changing the level in a VVX to VVX call

 

voice.vadRxGain == -voice.vadTxGain

 

Restores default behavior

 

G.722 calls, vadTxGain and vadRxGain have no effect (expected)

 

 

voice.plcCnEnable="1"

0 or 1

0

Enables local comfort noise generation when far end stops sending RTP and no CN packet is sent

 

voice.plcCnGain="0"

20 to -20

0

Changes the loudness of local comfort noise generation when voice.plcCnEnable is set to 1

 

 

 

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Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's