audio issues with CCM 4.1 when calling between 7905 and 7920/7921

Unanswered Question
Apr 26th, 2008


We seem to have an ongoing issue when making calls between 7905 and 7920/21 phones. Often you get one-way audio or no audio at all. Its specific to calls between these model types, calls to/from other phone models or the PSTN are fine. This is across multiple sites, some using AP's and others using 877W's.

We are using the latest software for the 7905 (8.0.3), the 7920 (4.0-03-02) and the 7921 (1.1.01).

Has anyone experienced this issue?



I have this problem too.
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Jaime Valencia Sat, 04/26/2008 - 14:22

one way audio and no way audio is mostly related to routing issues in which the RTP cannot reach the destination even if it's addressed to the right IP.

i'd say you need to check there is the proper routing and that there are no loops in there or anything blocking the RTP stream to be 2ways



if this helps, please rate

ccpagel Sun, 04/27/2008 - 04:06

The 7905 and the AP, or the Cisco 877W, are connected to the same Ethernet switch on the same subnet. Its only 7905 to 7920/21, the customer also has 7940's and 7941's which do not experiance the same issue. Therefore I'm ruling out any issue with anything on the LAN blocking the RTP traffic.

Thanks for your response anyway.


spiecomcisco Sun, 05/04/2008 - 09:33

Hello, i 've the same problem between 7920G phones. I can't communicate (audio) between 2 7920 phones : the comuunication is established but i have no sound. I can communicate with a 7920 and others ip phones. My phones and my ccm6 are on the same subnet and the same vlan. Any idea?



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