We're working on a new deployment that we're putting in production in less than 2 weeks and we've hit a bump. We are running 6921's, 7940's, 7942's, 7962's and 7937's. Call quality on the 7940's are phenominal while the 7942/7962's are horrible. There is a tunnel sound w/ a clicking sound going on. We've updated the firmware and then downgraded trying to get through this.
If we put a 7940 in its place, the call quality issues goes away. Any ideas?
What is the exact call manager and phone firmware version you are running now?
Does the issue go away if you are on speakerphone or is it both with the speaker and handset ?
It is puerly a firmware issue and we can check the best compatible phone load WRT your call manager version
Call Manager System version: 220.127.116.1100-11
7942/7962 Firmware: 8-5-2. We were running 8-5-3 but quality was worse.
Speakerphone sounds better than using the handset for these devices but both are poor. Both have a hollow tunnel sound. If you have any ideas I would love to hear them.
There is a setting that is applied to newer phones like the 7962 and not
older phones like the 7940. I would try disabling this;
"Advertise G.722 Codec"
This can be done on the individual IP Phone for testing and then
in Enterprise Parameters if successful.