[Asterisk-Dev] Answer Supervision for incoming calls in Asterisk

[Peter Svensson]

On Mon, 21 Mar 2005, Kevin P. Fleming wrote:

> Early audio like this has a very short time window; I'd be surprised if 
> very many telcos let you send early audio for more than 15-20 seconds 
> before dropping the call if you don't answer it.

It is limited to the amount of time they (the shorter inteval of the 
originating and the terminating telco) allow a call to remain in the 
Alerting or Proceeding states. Time limits of one minute are 
more common.

Early audio is sometimes prohibited across national borders. This is done
so to prevent confusing audio progress tones between countries with 
diffrerent tone cadenses.

Peter