[Asterisk-Users] VAD/DTX implementation through zaptel cards

Steve Kann stevek at stevek.com
Tue Apr 12 07:11:27 MST 2005


Eric Wieling wrote:

> parijat at varaha.com wrote:
>
>> Hi,
>> How can i implement VAD/DTX using zaptel with asterisk towards PSTN. 
>
>
> TDM (PSTN/telcos) do not support VAD. The entire idea of VAD is not 
> even a valid idea.

Doing VAD on audio coming _from_ the TDM world certainly is something 
you might want to do, to dramatically reduce the bandwidth you consume 
when sending the audio via VoIP channels.

This kind of thing is not presently implemented in *, though, but it 
could be. (note: doing it well will require a bunch of CPU, though. I 
wonder if it could be done in the same DSP that is doing 
echo-cancellation on the new TE4xxP boards?

-SteveK




More information about the asterisk-users mailing list