Calls sometimes only have outbound sound

[Ruud van Strijp]

We have about 350-400 7961G IP phones in our network and since about a week quite some (I think at least 10 reports/day) calls don't have inbound sound: The external party does hear us, we don't hear them. This problem happens with both inbound and outbound calls.

First we thought it was a firmware issue, since the first time the problem occured (about 1.5 month ago), we figured out that if you put the call on hold and get it back, the inbound sound was working again. We were running 41sccp.8-2-2ES1 back then.

After a period of testing (which seemed to solve the problem), we upgraded to firmware 41sccp.8-3-3ES2. Two days after that the problem got worse, multiplying the number of 'broken' calls by 4 or so.

Because of this, yesterday we went back to firmware 41sccp.8-2-2ES1. But still we get as many troublesome calls as we had before. So this seems to be independant of the firmware version.

Is anyone familiar with these problems?

[Hieu Cao]

Take a look at these docs to troubleshoot one-way voice issue:

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a008009484b.shtml

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080115a52.shtml

hth,

hieu

[Ruud van Strijp]

Thanks for the answer, hieu. I have read a bit through both articles (haven't really read them thoroughly yet), but they seem to cover perminent one way voice problems due to misconfigurations. The problems we are experiencing only occur once every X calls.

The first document also discribes an IOS bug, concerning IOS version 12.2(6). We are running 12.2(40) on core and 12.2(37) on access, so that doesn't seem to be the problem.

[Ruud van Strijp]

We just heared what's causing the problem: Our telephony provider seems to have these issues for 2 weeks now, and they were too &%#&%^@% to tell their customers. So it wasn't an internal issue, it were just the ISDN-lines that were causing all the problems.

Thanks for the help anyway :)