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

[Mojo with Horan & Company, LLC]

Nikhil Nair wrote:
> 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?
>   
IIRC, echo cancellation is fully in zaptel.  If your remote callers will 
be SIP or IAX based, it probably won't be effective.

> 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.
>   
I don't follow this.  My asterisk (1.4.4) does not have a dial command 
at the console, what are you trying?  I'm
suspecting that if you have something called Dial that it's for 
originating NEW calls rather than sending DTMF down
existing channels.
> 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.
>   
It seems there would be fairly directional desk microphones you could 
find that you could direct at the user.
Maybe a little cylinder of paper around the end of the mic would help.  
Or maybe the speakers can be turned
down to the point where they aren't picked up by the mic as strongly,  
especially after reducing the mic's level
as far as you can.  I'm thinking with a little cylinder of paper, you 
could drop the mic level pretty far and it would
still pick up the user's voice.  Another idea I've considered is 
wireless headphones... have you considered
chan_mobile with bluetooth wireless headset?  but that probably goes 
against the grain of a speakerphone ;)
> Any help much appreciated!
>
> Best wishes,
>
> Nikhil.
>   
You might consider the oslec echo canceller.  I have no idea where it 
integrates into the call flow, there's potential there,
but I suspect it's zaptel-related too.

Good luck!

Moj

>
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