A Polycom 550 and a IAX client (Mozphone and ZoIPer were used) are having a conversation. Call quality is reported as good except for an echo with a 3 second delay. Most of my searches are saying echo happens only on the PSTN piece, but there isn't one here. Can someone point me in the right direction? Asterisk 1.4.21.2 Under 40 users Quad-Core AMD Opteron(tm) Processor 2352 and 4G RAM (Hey, that's what they wanted to use!)
I'm not sure about the 3 second delay, but I've seen plenty of echo issues on Polycom phones when the gain has been changed on the handset. Check the voice.gain.tx and voice.gain.rx settings in your sip.cfg to make sure they're not too high. You also may want to make sure there aren't any system resource constraints such as high CPU usage or memory usage... :-) Tim Nelson Systems/Network Support Rockbochs Inc. (218)727-4332 x105 ----- "c james" <cjames at callone.net> wrote:> A Polycom 550 and a IAX client (Mozphone and ZoIPer were used) are > having a conversation. Call quality is reported as good except for > an > echo with a 3 second delay. > > Most of my searches are saying echo happens only on the PSTN piece, > but > there isn't one here. > > Can someone point me in the right direction? > > Asterisk 1.4.21.2 > Under 40 users > Quad-Core AMD Opteron(tm) Processor 2352 and 4G RAM (Hey, that's what > they wanted to use!) > > > _______________________________________________ > -- 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
c james wrote:> A Polycom 550 and a IAX client (Mozphone and ZoIPer were used) are > having a conversation. Call quality is reported as good except for an > echo with a 3 second delay. > > Most of my searches are saying echo happens only on the PSTN piece, but > there isn't one here. > >Which end hears the echo? If it is the Polycom end, try a better quality headset with the softphone. Echo comes from analogue portions of the "circuit" and is usually caused at the end that doesn't hear it. regards, Drew -- Drew Gibson Systems Administrator OANDA Corporation www.oanda.com
c james <cjames at callone.net> writes:> A Polycom 550 and a IAX client (Mozphone and ZoIPer were used) are > having a conversation. Call quality is reported as good except for an > echo with a 3 second delay.Feedback from speaker to microphone. The problem is always at the end which doesn't hear it. /Benny
> Coming from outside the network, setting up for a couple rounds of > NATting isn't going to work well. They are not seeing it between > phones. Others, using the polycom phones have reported echo between two > SIP on a 4ms ping trip.Could this be due to a purely acoustic echo within the Polycom handsets? I encountered a nasty echo / hollow sound when using a cheap USB "telephone" to connect to my Asterisk system (via KPhoneSI). The echoing was due to acoustic feedback - the handset body acted as a very nice channel for sound waves from the back side of the speaker down to the microphone cartridge. I opened up the handset, added some damping materials (panel- vibration-damping and soft-foam sheeting, left over from a car stereo speaker installation I did), closed it back up, and the echoing was gone. You might not notice in some calls, if the Polycom phones have silence-detection turned on for those calls and if the amount of feedback falls below the phones' silence threshold. If the phone silence-detection algorithm were turned off on other calls, the echo would then be audible.