ISDN Alerting before Connect

Unanswered Question
Feb 19th, 2007


is it possible to send the ISDN Alerting message in front of the ISDN Connect message with a PRI voice-port when a port is used for a two-stage-dialing? I mean some configuration like the "ring number" with FXO voice interfaces.

I have an issue with some PBX that requires to first receive the Alerting and just then the Connect message.

interface Serial2/0:15

no ip address

encapsulation hdlc

isdn switch-type primary-qsig

isdn incoming-voice voice

isdn send-alerting

no cdp enable

voice-port 2/0:15

description E1_abc

bearer-cap Speech

Thank you.

I have this problem too.
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Paolo Bevilacqua Mon, 02/19/2007 - 16:49

(can you post to IP telephony forum ?)

For "isdn send-alerting", the manual states:

isdn send-alerting

To specify that an Alerting message be sent before a Connect message when making ISDN calls, use the isdn send-alerting command in interface configuration mode. To disable the Alerting information element, use the no form of this command.

However, just like you found, I've verified on latest 12.4T that even if send-alerting is configured, no Alerting is sent before connect.

I suggest that you open a case with the TAC so that a bug is raised and/or a valid workarond provided.


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