Poor call quality reported when using Cisco 7975 Speakerphone

[martinward1234]

Hi all,

We seem to be experiencing poor quality calls when making external calls using the speakerphone on Cisco 7975 handsets. For example the call participant at the other end of the line will complain that we are cutting out, breaking up or there being lots of noise on the line.

The phones are connected to a Cisco Unified Call Manager Cluster (version 7.1.5) and the phones themselves run SCCP75.8-5-2SR1S image and G7.11 Codec. External calls go out via a Cisco 3925 router gateway which runs IOS 15.1(1)T.

When you look at the call statistics during the call the MOS value is usually very high 4.4+.

We have tried swapping handsets out but to no avail - the problem persits.

Any thoughts or suggestions to help get to the bottom of this would be greatly appreciated.

Regards,

Martin

[clileikis]

Hi Martin,

Sounds like you could be hitting the following bug:  http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCsz68389

Try updating the firmware on the phone and see if the problem persists.

HTH,

Chris

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[martinward1234]

Hi Chris,

I have reviewed the bug notes and compared it against the release notes of the phone image that we are running and apparently this bug was fixed in the image that we are currently running on our IP Phones. However that said I guess there would be no harm in trying a newer version.

Martin

[Tommer Catlin]

Postive its G711?  I see alot of CUCM clusters that left the default Enterprise configuration to advertise G722, which causes some phones to sound like crap.

[martinward1234]

Hi Tommer,

I have checked the enterprise cluster configuration and you are correct that the Advertise G.722 codec option has been enabled, however the same feature is diabled at the device level, which I have confirmed by checking call stats during a call which shows the codec in use as G.711.

Regards,

Martin