Dial plan autoselect free line

Hi, we have this situation:

1 isdn (2 channel)
3 voip provider (SIP)

we’d like asterisk to use for outgoing calls isdn and if 2 channels of isdn are busy to use automatically one of the 3 sip provider (if the 1st is also busy, use the 2nd)

is it possible?


just have a dialplan that defines both routes and steps over on congestion to the voip.


Ok, any example?


There are a lot of exmples in the forums if you search for failover here is one simple example you could build on or there are more complex ways to do it.

forums.digium.com/viewtopic.php? … t=failover