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Strange Problem: Fixed line calls ok, mobile calls keep ringing

CCM 3.3(3):

I have 2 CCM connected to 2x Cisco3745 gateways with 6 x ISDN lines for voice.

When I dial into call manager using a fixed line phone, everything works ok.

But when I use a mobile line to call into call manager, I can hear a secondary dial tone on my mobile, but the call is already put thru on the IP Phone (IP Phone user can hear the mobile user talking, but mobile user hears a secondary dial tone). Also to note is that this problem does not occur all the time, Sometimes, mobile calls work ok, but other times, they dont function properly.

I need help to know where to start troubleshooting, and is there a difference in how CCM handle fixed line call and mobile calls?

3 REPLIES
Silver

Re: Strange Problem: Fixed line calls ok, mobile calls keep ring

It could be the mobile network is passing or processing ISDN progress messages differently to the fixed network. Can you post the output for debug isdn q931 for a fixed call and a a mobile call so we can see the difference.

New Member

Re: Strange Problem: Fixed line calls ok, mobile calls keep ring

Attached are the debug on my 2 gateways.

One thing I cannot understand is that sometimes mobile calls work, and sometimes they don't. I suspect it could be some timing issues, but I need some pointers to what timers are these.

Silver

Re: Strange Problem: Fixed line calls ok, mobile calls keep ring

One of the calls has a progress indicator in it, the other does not. Try adding the following command under the VOIP dial peer/s that point to the call manager -

progress_ind setup enable 3

This command forces the gateway/router to treat the inbound ISDN Setup message as if it came in with a PI = 3 and to generate an in-band ringback tone towards the calling party if the H225 Alert message does not contain a PI of 1, 2 or 8.

Also add the global config command -

voice rtp send-recv

this cuts through the audio path in both direction before a connect message has been received.

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