CUCM 6.1 Conference call not working

Unanswered Question
Aug 1st, 2008


I have a CUCM 6.1 server pointing to an H323 gateway. When I do a conference it seems like the 3rd party is connected but there is no voice either way. When i hit the confrn button again to bring the 3rd party in to the conversation i hear the beep as if they have joined but can't hear anything. Everything seems to be configured correctly and this was working before. The only difference is we have a new ISP but there really is no difference in the type of service.

I have this problem too.
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Chris Deren Fri, 08/01/2008 - 15:48

Are you using software or hardware conference bridge?

If software then are all parties G711?

If hardware please post your router config, and ensure the SCCP is bound to the proper interface.


scottm65 Fri, 08/01/2008 - 15:51

Hello Chris,

I am using a software bridge and i am fairly certain all parties are using G711. Do you know how exactly i can find out for our CUCM server?? Thanks for your help!


Chris Deren Fri, 08/01/2008 - 15:54

The quickest test would be to create 3 party conference between 3 IP Phones and double press "?" button on all IP phones and validate G711 is used codec.

What version of CM are you using?


scottm65 Fri, 08/01/2008 - 15:58

I did confirm that we are using G711. The exact version of CUCM is

Jaime Valencia Fri, 08/01/2008 - 16:07

do you have the routing configured for the GW to reach the SW CFB? in this case routing to/from GW and CUCM server?



if this helps, please rate

scottm65 Fri, 08/01/2008 - 16:11


Yes, I do have the routing configured correctly from the GW to CUCM. The calls work fine for the first two parties but when I join the 3rd person it displays as though it is connected but just no voice between the 3rd party and the first 2. Do you know of a good way to troubleshoot in CUCM, i use the RTMT tool but it is hard to interpret. Thanks for your help!


Adam Frankel Fri, 08/01/2008 - 17:05

Sounds like the call is getting connected. You would need to analyze the Detailed CCM traces as well as simultaneous sniffer captures from the GW and CFB to see whats happening.


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