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No ringback tone on incoming calls

Hi all,

I'm experiencing a strange problem with ringback tones and incoming PSTN calls toward IP Phones which are busy.

The scenario is: a 2821 with IOS 12.4.9T2 and CCM 4.1.3sr3b.

When I try to call the IP Phones using a mobile phone or a digital line which sends all the digits togheter (en-block) the call goes fine.

If I try to call from a phone connected to an home analog line, which sends the digits with the overlap sending, I see in the isdn Q931 debug that the VG sends the call_proceed command (after correctly collected all the digits) to the CCM but nothing happen until the telecom operator close the connection after exactly 30 secs with the "recovery on timer expiry" cause. In the analog phone I hear silence and the reorder tone after 30 secs.

Could anyone help me?

Thanks

Daniele

8 REPLIES
Bronze
New Member

Re: No ringback tone on incoming calls

Thanks Ken for your links, however it's not my problem because I know this issue and the prog_ind is just setted on the voice dial-peer but it works only for certain type of inbound calls but not for others therefore this is my strange issue.

Daniele

New Member

Re: No ringback tone on incoming calls

Daniele,

Did you ever get this problem resolved? I am having the same issue with a gateway in Germany.

Thanks,

Diarmuid.

New Member

Re: No ringback tone on incoming calls

Diarmuid,

unfortunately the problem is not yet resolved.

We decided to open a TAC case yesterday and I hope to resolve the issue soon.

Daniele

New Member

Re: No ringback tone on incoming calls

Hi Daniele,

how is your outbound dial-peer to the CCM matched? Are you using en-block (123T)?

I would suspect that not all digits are send to the CCM. You could check with the "debug voip ccapi inout".

Gunnar

New Member

Re: No ringback tone on incoming calls

All digits aren't being sent to ccm only 6 of the required 8 are ever seen in the debug ISDN q931. I am using an MGCP gateway...tried adding isdn overlap-recveing to the config. Configured Call Manager for overlap-receiving etc. I have a case open with TAC. One of the engineers had me add ##BC=3.1kHz## in the description field and reset the gateway on Call Manager - none of these changes worked. I just sent some CCM traces however they don't contain any real data outside of CDR data for the call. All I know is any call from any legacy devices such as my analog phone at home to any DDI on our PRI E1 in Cologne consistently fails since it is using overlap instead of en-bloc. I thought this was a bug but supposedly I am in the clear with CCM 4.1(3)sr3b. Are you running MGCP or H323? What ver of Call Manager? There is a bug affecting CCM 4.1.3sr1 relating to isdn overlap-receiving.

Diarmuid.

New Member

Re: No ringback tone on incoming calls

Hi Gunnar,

yes, the outbound dial-peer is like 0T.

However I have this problem only inbound and only with callers which use old analog phone (i.e. they are calling from their home line).

The Italian telecom provider uses to send incoming digits in en-block if the callers are "digital" (i.e. ISDN or mobile) and with overlap if the callers are "analog" and I have the problems only when "analogs" users call inbound and the IP Phone is busy.

Yesterday we opened a case and the TAC asked us to perform some debugs including the one you suggested.

Thanks

Daniele

New Member

Re: No ringback tone on incoming calls

Daniele,

Did you make any progress on this issue? At this stage I am inclined to think I am running into CSCsb62669 even though it is supposed to be resolved in 4.1(3)sr3.

We are both having the same issue in Germany running Call Manager 4.1(3)sr3b. That is just too much of coincidence for me. I presume you are running MGCP?

Thanks,

Diarmuid.

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