[asterisk-users] bridging isdn calls to free up channels

[James Harper]

I was incorrect in a previous email... The situation in question is
this:

Asterisk <---BRI---> PBX <---BRI---> PSTN

There are Samsung extensions on the PBX and SIP extensions on Asterisk.
I want to be able to use TAPI to initiate dialling, and the PBX has no
such feature so Asterisk must initiate it.

For an Asterisk initiated call from a PBX extension to a PSTN number,
this works as follows:
1. TAPI (eg Outlook) sends the instruction to Asterisk
2. Asterisk calls the extension.
3. The extension answers
4. Asterisk dials the PSTN number
5. Asterisk joins the ends together

This works great except it ties up two BRI channels between asterisk and
the PBX for the duration of the call. Is there a trick I can do to tell
the PBX to join the channels together internally? A transfer or
something?

I'm using mISDN at the moment, but I guess I could use CAPI if the
required features were missing from mISDN...

Thanks

James