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

[Tzafrir Cohen]

On Mon, May 07, 2007 at 02:45:48AM -0500, Eric ManxPower Wieling wrote:
> 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
> 
> Generally, once the audio is converted to VoIP audio latency is far too 
> high for echo canceling to work.  Echo needs to be canceled BEFORE the 
> call is converted to VoIP.

So a PRI card with echo cancelling won't help local SIP phones, right?

-- 
               Tzafrir Cohen       
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