[Asterisk-Dev] Uncommon callback

[Tamas J]

Hello!

I got an interesting task to make with asterisk:

pstn--- * ---sip--- * pstn
This sounds common till now. What I have to make is:

1.the call is routed through PSTN to asterisk1 (#1) which has ISDN PRI
interface(s) - leg1
2.#1 doesn't pick up the call, neither rejects, it just place into state
CALL PROGRESS (?) [maybe gives back alerting tone? probably not]
3.#1 notifies that there is a call to number B from number A to system
asterisk2 (#2) - through non-voip protocol [xml-rpc, anything else,
doesn't matter here]
4.#2 dials number B through PSTN - leg2
5.#2 dials #1 (on number #1 sent in notification) through SIP - leg3
6.#2 interconnects leg2 and leg3 without ISDN CONNECT
7.#1 interconnects leg1 and leg2 without ISDN CONNECT
8.when B picks up the phone, channels are getting CONNECT message

I know that my explanation can be a bit mess, but I wasn't able to write
it down better.
I was thinking about putting the incoming call on #1 into meetme, but
meetme looks to establish the call, so it is charged from the 1st second
- that's not good in this case. In #2 I thought, .call feature can
initiate the call out to number B (leg2) which will dial to #1 using SIP.

What would be the goal is to 'connect' A with B through the callback but
without answering call legs. So finally party A can hear the ringback
tone from the remote side and if B picks up the phone, the whole call is
answered [established].

I have many black holes right now.

Any help appreciated!

Kind regards,
	Tamas