Echo

[jmessina]

Currently when we place a call out to the pstn the users on the digital or analog phones at the other end are claiming they experience periodic echo. What would be some possible ways of troubleshooting and resolving this echo .

[jraarons]

It seems odd the high number of echo issues with CallManager (compared to a digital PBX). While several will post the CCO Url on echo, I am beginning to wonder if the Cisco solution needs better echo correction (above 32ms), or if the loads/phones need some echo correction as well. This is a common posting on NPC.

[tony.nguyen]

As you may already aware, set maximum echo coverage on gateway to 32ms.

Try to use the latest phone load version P0030301ESP3 for 7960 and P0040301ESP3 for 7910.

These phone loads can be requested from Cisco, you need to log a case for this. They are bundled with latest version of 3.1.3a CallMgr update.

We have tried this out and all our echo related issue has gone now !

Good luck !

[jaiello2000]

Hopefully they have increased the aggressiveness of the acoustic echo cancellation, however, there still may be echo for PSTN callers.

Two common problems are; Volume too high on the IP Phone and Headset volume too high.

Also, the echo cancellation on the Cisco gateways cancels echo reflections from the PSTN. So, when the IP Phone user speaks, the echo reflected from the PSTN users phone is canceled by the gateway. The gateway does not cancel a PSTN callers echo generated at the IP Phone.