Maybe people just assume that digital is echo free. I think this would be a good feature request, as more people could experience this, with Asterisk itself adding significant processing latency.
Technically, Asterisk has the source of the voice, it also has the resultant voice, so there is something it can do with them. <<<
I totally agree. Actually I have the problem with strong echo on a local
mobile phone <-> GSM<-> GSM-SIP gateway <-> asterisk -<->SIP <-> Xlite
All devices are in the same room, just a test installation, so the only real transmission delay is from my mobile phone to mobile SP and back to my GSM-gateway. But very loud echo. So echo cancellation on the SIP-channel within asterisk should be a big advantage.
And with the availability of new OpenSource echo cancellation code, this might be worthwile the implementation.
Especially, to be honest, asterisk is implemented mainly in low-cost environments. So it makes more sense, to do echo cancellation centrally, even with the drawback to buy a faster CPU, instead of recommending “buy better headsets” etc.
To buy many good headsets probably is much more expensive compared to buying a faster CPU for asterisk, assuming, that the phone lines are not active alltogether simultaneously.