> 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. _______________________________________________ -- 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
