[asterisk-users] Echo cancellation and DTMF from the Asterisk console?

[Nikhil Nair]

Hi,

I'd like to try using a good quality microphone and a set of PC speakers 
(in the first instance) to create a powerful speakerphone; if I get that 
working, I'll probably try more elaborate audio equipment.

For this to work, I'll need software acoustic echo cancellation, or the 
caller at the other end will constantly hear his/her voice echoing back.

I gather Asterisk can do very good software echo cancellation, but I can 
see no reference to using it with chan_console (using the Alsa driver). 
Am I overlooking something obvious, or is that really not implemented?

If not, I guess I'll have to try Linphone, as I hear it does pretty good 
acoustic echo cancellation (it uses the code from the Speex library, I 
believe).  that's not an ideal solution, though, as the two would be 
running on the same machine (I'd have to recompile Linphone to use a 
different port for SIP, or else tell Asterisk to do so).

In addition, I've tried using 'dial' from the Asterisk console while a 
call from the console is already established, hoping that this would send 
DTMF signals.  So far those signals haven't been received at the other 
end, while I've had no trouble sending DTMF from a Windows softphone via 
the same Asterisk box.

If all this isn't promising, is there a better way to combine a line out 
socket, a mic in socket and either software or hardware acoustic echo 
cancellation?  I'm not very familiar with the hardware options around for 
Asterisk, but it strikes me that this would be a fairly obvious thing to 
do....  I haven't come across a hardware speakerphone which allows you to 
replace its own speaker and mic with line out and mic in sockets, but if 
there is such a thing, I suppose that connecting it to an FXS socket might 
be a sensible way forward.

Any help much appreciated!

Best wishes,

Nikhil.