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New Member

problem with Converencing a PSTN caller

We have a configuration with a central Call Manager and one remote locations. We have hardware conferencing via a 6608 at the head end.Regions are set up and we are using g.711 within each region, G.729 between regions. We can conference fine between locations from IP phones. However, if a person at the remote location calls someone on the PSTN(out their local PRI/gateway) and transfers that person into an active conference the PSTN person gets dropped.

Both locations use the same Media resouce group/list since it is the same hardware (central 6608). Transcoders, MTPs and confrencing are configured in this MRG.

Any thoughts?


Re: problem with Converencing a PSTN caller

This can be because to the RTP timer used by the dsp, can you check out by increasing the DSP timer by the command

dspfarm rtp timeout 172800 (48 hours), check with following links for further troubleshooting

New Member

Re: problem with Converencing a PSTN caller

We had a similar issue. We were using H323 with T1 PRI in 2651 routers. We added the folowing commands and everything worked.

network-clock-participate wic 0

network-clock-select 1 T1 0/0

on all dial peers ( voip ) insert

dial-peer voice xxxx voip

preference 1

destination-pattern ...

progress_ind setup enable 3

session target

codec g711ulaw

no vad

If we used different codecs for internal and external calls the Conferencing would react exactly as you stae above. We are runnig CM3.3(3) all the latest patches.

hope this helps

New Member

Re: problem with Converencing a PSTN caller

But, I have to use g729 between location because of less bandwidth consumption. I just can't use g711 between central and remote location... What then? How to make conference between central and remote users?