ISDN MSG Call not end to end

Unanswered Question

I am trying to make a call from my Germany office to a fax machine in Colorado. However I keep receiving this ISDN msg everytime... and the call just hangs and you can't hear anything.


CM 4.2.3

000764: Jun 23 14:39:33.723 CEST: ISDN Se0/0/0:15 Q931: TX -> SETUP pd = 8 callref = 0x0024

Sending Complete

Bearer Capability i = 0x8090A3

Standard = CCITT

Transfer Capability = Speech

Transfer Mode = Circuit

Transfer Rate = 64 kbit/s

Channel ID i = 0xA9839F

Exclusive, Channel 31

Calling Party Number i = 0x0081, '7379051'

Plan:Unknown, Type:Unknown

Called Party Number i = 0x80, '0013037543995'

Plan:Unknown, Type:Unknown

000765: Jun 23 14:39:33.823 CEST: ISDN Se0/0/0:15 Q931: RX <- CALL_PROC pd = 8 callref = 0x8024

Channel ID i = 0xA9839F

Exclusive, Channel 31

000766: Jun 23 14:39:34.971 CEST: ISDN Se0/0/0:15 Q931: RX <- PROGRESS pd = 8 callref = 0x8024

Progress Ind i = 0x8481 - Call not end-to-end ISDN, may have in-band info

000767: Jun 23 14:39:40.123 CEST: ISDN Se0/0/0:15 Q931: TX -> DISCONNECT pd = 8 callref = 0x0024

Cause i = 0x8090 - Normal call clearing

000768: Jun 23 14:39:40.371 CEST: ISDN Se0/0/0:15 Q931: RX <- RELEASE pd = 8 callref = 0x8024

000769: Jun 23 14:39:40.491 CEST: ISDN Se0/0/0:15 Q931: TX -> RELEASE_COMP pd = 8 callref = 0x0024

I have this problem too.
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Nicholas Matthews Tue, 06/23/2009 - 04:52

Hi Dan,

This is a normal message. This means that the PSTN is trying to send some type of information, and that the audio path should be cut through. This is something you would see for an international ringtone. The router obviously doesn't know the ringtone for the country, so the remote end plays it and the provider has to tell the router to 'open up' for the ringtone.

This can all be for service messages that the provider wants to play.

If you're not hearing anything, it could be 1-way audio, media could be failing to establish, or we could just be getting blank audio from the other end of this ISDN circuit.


Kenneth Mohammed Tue, 06/23/2009 - 06:23


You may want to check with your telco, and confirm the TON settings on your PRI as far as international calls are concerned. Right now it is unknown/unkown. Your telco may want ISDN/International or unknown/international for international calls.

Are you able to make international voice calls to the US successfully? You may also want to do a show controller t1 to see if you have any slips on your PRI as this can affect faxing as well.

Hope that helped, if so please rate.

Nicholas Matthews Tue, 06/23/2009 - 17:14

Hi Daniel,

This can be tricky to confirm. I would start with the telco to see if they can bring out a butt sett or an equivalent for the T1 to make sure they're getting tones.

Otherwise, you would need a TAC case so that you can do a PCM capture.

Most of these cases are provider issues, but you could still have media negotiation issues.

What protocol are you using? H323, SIP, MGCP..

If MGCP, which IOS version and codec is in use?



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