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

[Eric "ManxPower" Wieling]

Tzafrir Cohen wrote:
> 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?

It will if the call is going out the PRI. 8-)