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

[Alan Lord]

Nikhil Nair wrote:
> 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.
> 

Interesting... After playing with - and being very impressed by the 
OSLEC Echo canceller - my business partner and I had an idea about using 
it as a module that could be plugged into ALSA (The Linux Sound 
Architecture) so it could be used with various audio devices. It is just 
a pipe dream at this moment however.

The biggest issue I can see is the delays. OSLEC and the other echo 
cancellers in Zaptel are Line Echo Cancellers and as such deal with with 
very short delays. Acoustic echo Cancellation needs to handle far longer 
delays potentially...

I use the Polycom Communicator C100s desktop speaker/mic on Linux, and 
despite the fact that Polycom integrate "most" of their EC software in 
the Windows Driver, it works very well with the OSLEC canceller on the 
line side.

Take a look at the OSLEC package 
(http://www.rowetel.com/ucasterisk/oslec.html) and maybe try and get in 
touch with David Rowe - he is very approachable and very knowledgeable 
on this subject.

HTH

Alan


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