[Asterisk-Users] Looking for advice on cell carrier's default "Un avaliable" message

[Andrew Kohlsmith]

On Monday 05 December 2005 13:39, Colin Anderson wrote:
> That appears to work *perfectly* but I don't get it. With the 'r' option
> on, how can Asterisk determine that the user has answered the phone as
> opposed to the carrier? Is it a signal that the carrier is sending?
> Anyway, thanks. Works like a hot damn.

With the carrier voicemail turned off (not subscribed to) the carrier does not 
answer the line to say "this person is out of the service area or has their 
phone off" -- it's the same trick (early audio) used with digital lines to 
inform the caller of a problem without charging them for the privilege.

-A.