PRI Signalling question

Answered Question
Dec 12th, 2007

When DTMF is transmitted across a PRI, is it sent inband across the B channel as part of the voice call, or is it sent out of band across the D channel?

I have this problem too.
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Correct Answer by dgahm about 8 years 12 months ago

John,

Only call setup information goes across the D channel. After the call is connected, DTMF would be carried in band on the B channel.

You can do a debug isdn q931 on a PRI gateway router to verify this.

Please rate helpful posts.

Dave

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Correct Answer
dgahm Wed, 12/12/2007 - 12:26

John,

Only call setup information goes across the D channel. After the call is connected, DTMF would be carried in band on the B channel.

You can do a debug isdn q931 on a PRI gateway router to verify this.

Please rate helpful posts.

Dave

jcmartin Wed, 12/12/2007 - 12:29

Thanks Dave. Don't tell the Cisco guys this, but it isn't plugged into a Cisco gateway, which is limiting my troubleshooting capabilities, but it's the customer requirement. But, this will certainly help point to where they need to make corrections.

yxsjwsb Fri, 12/14/2007 - 19:22

I hope this is helpful, you can download a graphical PRI debugger that parses q931 debugs at pippinsoftware.com It's demo, just 10 channels, since they are still in beta testing. Could be useful for general debugging.

yxsjwsb Thu, 01/03/2008 - 10:23

The full version of this is out now and it's very inexpensive.

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