[asterisk-dev] Adding Octastic Soft-Echo to external SIP adapters

[Matthew Fredrickson]

On May 4, 2007, at 1:00 PM, syd wonder wrote:

> Hi all.  I'm trying to hook into a chan_zap.c function that enables 
> echo cancellation.  I think I've identified the spots to hook into but 
> am wondering if someone can answer a few questions or provide some 
> guidance.
>
> 1 - I'm using an external device (Sipura SPA3000 FXS/FXO) configured 
> as a SIP trunk.  I'm hoping  that along with the Chan_Sip.C file, that 
> the Chan_Zap.c file is used to setup some of the functionality, namely 
> - whether echo cancellation should be enabled
> 2 - With item 1 being true, the reason why echo cancelling is not 
> being enabled is because the external device is being recognized as a 
> digital channel.
>
> Anyone have a suggestion as to whether these assumptions are true?  If 
> not, any suggestions how I can add the echo cancellation functions to 
> non-zap devices.  This is something a bit more interesting now that 
> Octastic has released their SoftEcho software.   Thanks.. Syd

Chan_zap does not have anything to do with enabling echo cancellation 
on SIP devices.  The only thing that chan_zap (and zaptel) echo 
cancelers do is cancel echo received from the TDM interface to which 
they are attached.  They don't do anything with SIP devices, or the 
audio data received from SIP devices.

Matthew Fredrickson