[Asterisk-Users] Speaking of echo canceling...

[Andrew Kohlsmith]

On Sunday 30 October 2005 16:45, Dave Grey wrote:
> Is there any echo cancelation that I can enable or add for pure
> IP<>IP calls?

No.  There is no need because IP<-->IP calls are what is known as "four wire 
circuits" -- there is no mixing of the received audio and the send audio, and 
thus zero need for an echo canceller.  You only need echo cancellation when 
you go from a 4-wire circuit to a two-wire circuit.

> I frequently get bad echo on IAX2/ulaw connections between my CVS
> HEAD and a friend's 1.2 Beta, using analog phones connected through
> IAXys on both ends. Neither PBX has a zap interface. We understand

You want echo cancellation on the IAXys then, and they do have some limited 
echo cancellation.

> that this is primarily a problem with the acoustic/electric
> properties of the telephones we are using, exacerbated in conditions
> of higher latency, but is there a software canceler that I can apply
> to the problem?  Replacing the devices is not really an option.

Unfortunately I don't know of anything at this point.  You may be able to hack 
an echo canceller into chan_iax2 but I don' t know of any already-done 
solution.

-A.