> I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the > office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On > the office side, they hear an echo of _their_ speech, not mine. > > The office uses sip-providers generally without any echo problem. > > Where do I start to figure this out? How do I narrow it down? Can I > figure out if it is an iaxagent problem? Could using jitterbuffer cause > this?
One thing you must consider, is that this echo they're hearing may be entirely an acoustic one, within (or around) the Droid itself. It's very possible for the microphone in a handset to pick up sound being emitted by the handset's speaker. This acoustic feedback can occur within the handset itself (sound from the speaker "leaks" through the chassis of the handset and reaches the microphone from behind), via mechanical coupling through the handset body, or by the mic picking up the sound from the outside (after it has come out of the speaker into the air). The best way to determine whether this is the case, is probably to shut down the speaker and isolate the mic... plug in an earphone which has a separate mic on its cord, and see if the callers still report the echo. If they do, it's due to electronic or digital goofs somewhere, but if they do not, it's due to acoustic feedback at the handset. There are (in principle) three ways to reduce or eliminate the echo: - Damp it out physically - block the acoustic feedback pathways. In a small USB phone handset I have, I found it necessary to "stuff" the open spaces inside the handset with cotton and foam, to block the back-wave from the speaker before it reached the microphone. - Use software which has some sort of VOX (voice-operated switch) detection or squelching... so that when the sound level at the microphone is less than you'd get by speaking into the mic, the handset "cuts off" the mic audio pathway entirely, and sends only silence (or sends nothing at all, although Asterisk doesn't always deal gracefully with this). - Use a better handset. -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users