[Asterisk-Users] DID and Callback - Questions!!!

[U. Abdullah Sheikh]

Hi,

I need some information on DID and Callback. Please read-on:


Question on DID (User1 Calling User2 via normal Telephone line and sending
its CLI:
Connectivity is as below:
User1 ==PSTN==> DigiumE1/Asterisk1 ==INTERNET==> DigiumE1/Asterisk2
==PSTN==> User2

1. Can User1 make a single stage call to User2 via Asterisk1?
  Currently User1 is able call User2 on Two Stage basis (Asterisk answers,
and then user1 hears a message, and then he is allowed to call)


Question on CALLBACK.
Connectivity diagram is as below:
User1 ==PSTN==> DigiumE1/Asterisk1

2. Is callback supported on Asterisk? How to implement this? ANI/CLI based? 
Web Based? SMS based? Any experiences, please share!!!

Thanks & regards
Shek