Specifications

Configuring Audio Features
301
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.
Procedure
CNG can be configured using the configuration files or locally.
Configuration File
y000000000037.cfg
Configure CNG.
Parameter:
voice.cng
Local
Web User Interface
Configure CNG.
Navigate to:
http://<phoneIPAddress>/servl
et?p=settings-voice&q=load
Details of the Configuration Parameter:
Parameter
Permitted Values
Default
voice.cng
0 or 1
1
Description:
Enables or disables CNG (Comfortable Noise Generator) feature on the IP phone.
0-Disabled
1-Enabled
Web User Interface:
Settings->Voice->Echo Cancellation->CNG
Phone User Interface:
None
To configure CNG via web user interface:
1. Click on Settings->Voice.