asterisk users - Apr 2010 - What's are the possible return values of AMI Originate when Async is set to 0?

Hello all,

What are the possible values returned by AMI Originate when it's called 
with Async set to 0?

Is there any way to find out whether the dialed channel was busy, 
invalid, etc. without requiring Async to be 1?


Thanks in advance,

Leo