[Asterisk-Users] Leaving messages on answering machines (no its not spam)

[Clayton Smith]

Hey there

I'm trying to get asterisk to leave messages on answering machines
So i have a pretty cool php notifying script (it notifys, it doesn't 
spam!!) to phones and cellphones

Now all is fine if a human picks up, but if an answering machine picks 
up, well the script plays, but only the ending is recorded

So really, the tricky part is knowing WHEN to leave a message

Now to the best of my knowledge, there is no way to tell when an 
answering machine picks it (be it the "sprint cellphone operator", or  a 
home owned cellphone), but i was thinking...

I could play my script using an EAGI script
So i get extensions to run an EAGI script, that then manages everything, 
So when the call is picked up, relay the message, but if a high pitched 
beep is detected (via the EAGI script), repeat the message from scratch

Now I'm no expert on asterisk, and i can see that this method could be a 
little buggy, so I'm wondering if there are any suggestions or if there 
is a better way to leaving messages on answering machines

Any help or suggestions will be greatly appreciated
Thanks