Comfort Noise Generation; Jitter Buffer - Matrix Sparsh VP110 User Manual

To configure VAD via web user interface:
• Click on Settings->Voice.
• Select the desired value from the VAD list.
• Click Confirm to save the change.

Comfort Noise Generation

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
Local
To configure CNG via web user interface:
• Click on Settings->Voice.
• Select the desired value from the CNG list.
• Click Confirm to save the change.

Jitter Buffer

Jitter buffer is a shared data area where voice packets can be collected, stored, and sent to the voice processor in
even intervals. Jitter is a term indicating variations in packet arrival time, which can occur because of network
congestion, timing drift or route changes. The jitter buffer, located at the receiving end of the voice connection,
intentionally delays the arriving packets so that the end user experiences a clear connection with very little sound
distortion. IP phones support two types of jitter buffers: fixed and adaptive. A fixed jitter buffer adds the fixed delay
to voice packets. You can configure the delay time for the static jitter buffer on IP phones. A adaptive jitter buffer is
292
<MAC>.cfg
Web User Interface
Configure CNG.
For more information, refer
"Appendix D ‐ Configuration
Parameters".
Configure CNG.
Navigate to:
http://<phoneIPAddress>/
servlet?p=settings‐voice&q=load
Matrix SPARSH VP110 User Guide