[asterisk-users] Ring back when free?

[Tony Mountifield]

Has anyone here implemented "Ring back when free" in Asterisk?

The way it works in the UK is as follows:

1. A calls B. B is engaged (busy).
2. A hears "The number you called is busy. To use ringback, press 5"
3. A presses 5, and hears "Your ringback request has been accepted".
4. A hangs up.
5. Later, B hangs up. The system then calls A (if A is now busy, it
   waits until A is clear again).
6. If/when A answers, the system calls B on A's behalf and A hears ringing.

Any implementation has to cater for the fact that when B is busy, he
could be either the calling or the called party on his current call.
If he is the calling party, he will execute 'h' when he clears, but
if he is the called party, he won't be in the dialplan to execute 'h',
so we need some other way to invoke the ringback (step 5).

Thoughts?

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org