Can Asterisk sieze a line?

I’ve had an idea about a system that combines POTS and VoIP lines. I thought it might be a plan to connect the Asterisk server and the POTS phones on a splitter so that if the Asterisk server was down, the POTS phones could still make and receive calls. But I’d like to send long distance over VoIP. I was wondering if I could do a scenario like this.

  1. User picks up POTS handset.
  2. User dials 1- or 011-
  3. Asterisk server goes “Holy cow! This must be a long distance call!”
  4. Asterisk disconnects the POTS line, switches the user’s phone to VoIP, and completes the call.

If anyone has any other ideas that would be similar, that would be appreciated as well.


This would work if you plugged the POTS telephone into the system in one of the following ways:

  1. Use something like a Digium TDM400 with one FXO and one FXS interface. The FXO interface is connected to the telephone line and the FXS interface is connected to the telephone handset. Asterisk handles the routing of the calls eithe across the analogue telephone line or via VoIP.

  2. Use something like a Linksys SPA-3002. This can support one analogue telephone and one analogue phone line. Again this can be setup so that long distance calls are routed to the Asterisk box and set out over VoIP and local calls go out through the analogue line. In this case the SPA-3002 can make the routing decisions for the phone cased on the numbers that you dial (it has it’s own mini dialplan). Also the SPA-3002 has the advantage that it’s lifeline facility means that if the power is off or the Asterisk server is down all calls get routed out through the analogue line.

This sounds like just what I need - thanks.