[asterisk-users] Echo cancellation and DTMF from the Asterisk console?
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. ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Echo cancellation and DTMF from the Asterisk console?
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 ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Echo cancellation and DTMF from the Asterisk console?
Nikhil Nair wrote: 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 see, dial is part of using chan_console, I didn't realize ;) Moj ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Echo cancellation and DTMF from the Asterisk console?
In my other response to this topic I mentioned chan_mobile, I could have meant chan_bluetooth. ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Echo cancellation and DTMF from the Asterisk console?
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 -- The way out is open! http://www.theopensourcerer.com ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Echo cancellation and DTMF from the Asterisk console?
Hi Alan, Thanks for these helpful comments. I had a look at David Rowe's site, and found it very interesting - I'm blind myself, and the Louder router project he's working on sounds like a wonderful idea. It looks like I got my wires crossed, to some extent - I hadn't realised that all the echo cancellation within Asterisk is line rather than acoustic. While I'm new to all this, I believe it's acoustic echo cancellation I need, so it looks like I'll need to take a look at the Speex AEC implementation, and maybe get hold of version 1.2beta2 (which has significant improvements, apparently). Maybe Linphone running on the same box as Asterisk will be the solution, after all. That is, if Linphonec will consent to run for me without giving all sorts of errors and segfaulting... and I thought this release of Debian was supposed to be stable! ;) Ah well. Cheers, Nikhil. On Tue, 4 Dec 2007, Alan Lord wrote: 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 -- The way out is open! http://www.theopensourcerer.com ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users ___ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
