All calls with a 2-wire analog piece have echo. You cannot perceive the echo because it happens so fast on non-VoIP connections. On VoIP calls you have significant extra latency while causes you you to perceive the echo. Echo must be removed before the call is converted to VoIP -- in your case the Media Gateway is the device that must remove echo.
Olivier wrote: > Hi, > > I'm using the following setup : > Alice ---- IPPhone ------<LAN>----- Media gateway ----<PSTN> ------- Phone > ---- Bob > > For certain calls, users complains about echo : they can ear their own voice > in their handset, though media gateway echo cancel is turned on. > > I'm wondering how this echo cancelation engine is supposed to work. > My understanding of echo is that most probably, when users complains about > earing their own voice, that means that distant phone or nearby equipment is > "leaking" : Bob's phone is sending Alice's voice signal back to Alice. > > So, to properly cancel, I would say Media gateway should substract from > incoming signal the signal that left the media gateway few ms before. > > Discussing here and there, some say that Media Gateway never work this way : > it would only filters out locally generated echo. > Do you agree with that ? > If positive, then what can you do, if Bob's phone generate much echo ? > > Regards > > > > ------------------------------------------------------------------------ > > _______________________________________________ > -- 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 > -- Consulting for Asterisk, Polycom, Sangoma, Digium, Cisco, LAN, WAN, QoS, T-1, PRI, Frame Relay, Linux, and network design. Based near Birmingham, AL. Now accepting clients worldwide. http://www.fnords.org/skillslist.html _______________________________________________ -- 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
