>> Next question: does anybody know how to handle extremely long tail >> echo that a VPM module cannot? > > How long is 'long' in this case? The VPMs and HPEC (and OSLEC) can > handle 128ms echo tails, which is pretty darn long. It's rare to see an > echo tail longer than that except on very high latency connections, or > when the echo is actually acoustically generated by the far end and not > by network effects.
I haven't done any real measurement on it, but I believe it's actually longer than 128ms. As I go higher and higher with echocancel values, the echo does get better, but is never totally eliminated. At echocancel=1024, there is still rather pronounced echo on calls in the "local" exchanges. The calls are also more or less half-duplex at that point because the vpm is filtering out so much of the signal as echo. I may just tell the client to look at a partial PRI. All this echo chasing is getting costly for them. Thanks! Noah _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- AstriCon 2009 - October 13 - 15 Phoenix, Arizona Register Now: http://www.astricon.net asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
