Can Asterisk detect if an outgoing call is answered?

Good evening, all.

This is a problem I had a couple of years ago and never did solve it with the hardware I had.

Somebody calls in and presses 1 for Jack. Jack’s internal extension rings three or four times, then Asterisk says “Jack’s AWOL; let me transfer you to his cell” and it makes an outbound call to Jack’s cell phone.

All of this works fine.

However, if Jack doesn’t answer his cell phone, I want Asterisk to pick the call back up and redirect it to Jack’s internal voicemail.

I never did get that to work with the Digium TDM400 card because that card is incapable of detecting when a call to the outside is answered.

When I ran into this problem in the past, some of you here told me that there is some kind of signal that the telco can provide (I think it has to do with reversing the voltage polarity on the POTS line) that signals that a call has been answered. The TDM400 cannot make any use of this, but I was told by someone on this forum that the Sangoma A200 card can.

I’ve been going back and forth with Sangoma tech support, had a bit of difficulty making him understand exactly what it was I wanted, and he said the A200 cannot do that.

So, I’m back to square one. Is there any hardware out there that will support this capability? If I find some, then what do I need to say to the telco to enable whatever service it is that provides this capability?

Thanks…