Talkswitch CT.TS005.002606 - Manual (Page 23)

2 2 V O I P N E T W O R K C O N F I G U R A T I O N G U I D E
The Codec Options window allows you to select the codecs that your system can
use, specify the preferred codec, and clear the unsupported codecs. You can
specify the codecs for the TalkSwitch profile, and for each service provider profile.
External IP extensions will use the preferred codec specified in the
TalkSwitch profile.
1. Select the VoIP Configuration page.
2. Click Codec Options. The Codec Options window appears.
3. Select the codecs that your system can use, and clear the unsupported codecs.
The following codecs are supported:
• G.729 — This codec provides good quality. It requires the least bandwidth
and accommodates the highest number of concurrent calls.
• G.726 — This codec provides better quality. It requires more bandwidth
and accommodates fewer concurrent calls.
• G.711µ — This codec provides high quality and supports Fax over IP. It
requires the most bandwidth and accommodates the fewest number of
concurrent calls. G.711µ is used in North America and Japan.
• G.711A — This codec provides high quality and supports Fax over IP. It
requires the most bandwidth and accommodates the fewest number of
concurrent calls. G.711A is used worldwide except for North America
and Japan.
4. Select the Preferred codec. G.729 is the default codec, which uses the least
bandwidth and accommodates the highest number of concurrent calls.
5. Set Voice activity detection (VAD). Enabling VAD reduces voice bandwidth
when no speech is detected, and reduces transmission of background noise.
We recommend disabling VAD to keep bandwidth available for speech.