Busy tone in called number, jump to next FXO channel

Hello everyone, I have a little problem that I want to share and see if someone can give me a hand on this. Here it goes.
I have a system with 4 FXO lines, and couple of IP phones connected to the server, the company that provides us with the analog lines for the FXO ports is a low quality company and most of the time when a call is made in one of the ports a busy tone is heard and then you have to keep trying until the call gets through. What is needed to do is to fix the dialplan that if it sense a busy tone in the called line to jump to the next FXO channel. How can I accomplish this.

Thanks in advance.

Are you getting a busy or a reorder (fast busy). Do you have the same problem when you plug a regular phone into the POTS line and dial?

Finally, since you’re using POTS lines as trunks, you’ll probably have to set a delay after the box seizes the line and when it is ready to accept DTMF tones. You do this in trunk settings in the “Dialed Number Manupilation Rules” in the Prepend area. You’ll have to put one or more “W” before any other entries in the box. Start with one and keep adding until it dials reliably and then add 1more.


Let me rephrase this, the problem is that the ZAP channels are getting a busy tone when the call is made from the provider, what I think it is needed is to check for this busy tone and if it is receive in the ZAP channel making the call then pass the call to another ZAP channel. Thank you for taking the time.

Ok…you’re talking about incoming calls. You need to have your telco lines set up as a hunt group…

See: http://en.wikipedia.org/wiki/Line_hunting


No no, actually everything here is outgoing call.

If you can call on all of those pairs of wire (your FXO interfaces) with a regular analog phone reliably, then proceed to FreePBX, if not, have your provider fix their service first.

Using a regular phone I get the same problem, actually the problem is more related to international calls.

Then it is carrier related, have them fix it.