Is it possible to configure Call Forward Bus in voice gw FXO lines?

[dgonzalez1]

Hello, we have a Cisco ISR 4300 voice router with six FXO lines. For some reason the service privider can not configure a header line for them, so when one of these ports is busy a new call to it is rejected.

Is there some way to configure a sort of Call Forward Busy to these ports so that when they are busy a new call can be diverted to some of the other lines?

Thank you.

[Les Pruden]

Inbound POTS hunting (linear hunting or a hunt group) is only controlled by your provider. If you have DID numbers somewhere else in your environment, you might be able to remote call forward (RCF) the main number of that POTS group to a DID. 

[lpersing]

We use the trunk group command to aggregate all of the FXO interfaces and then set an order on the interfaces. You can also select a hunt scheme on the trunk group. Sample config:

trunk group PSTN

description ### for FXO ports for calls ###
hunt-scheme sequential

voice-port 0/1/0
trunk-group PSTN 1
description ### XXX-XXX-XXXX line 1 ###
caller-id enable
!
voice-port 0/1/1
trunk-group PSTN 2
description ### XXX-XXX-XXXX line 2 ###
caller-id enable
!
voice-port 0/1/2
trunk-group PSTN 3
description ### XXX-XXX-XXXX line 3 ###
caller-id enable
!
voice-port 0/1/3
trunk-group PSTN 4
description ### XXX-XXX-XXXX line 4 ###
caller-id enable

Under the trunk group command:

hunt-scheme ?
least-idle The interface with timeslot, that has been idle least, is selected
least-used The interface with maximum free timeslots is selected
longest-idle The interface with timeslot, that has been idle longest, is selected
random The timeslot is selected randomly
round-robin The next interface with free timeslots is selected
sequential The interface with highest preference is selected

[dgonzalez1]

Ok, thanks, but I assume this only works for outgoing calls, right? Maybe I was not very clear but I was talking about incoming calls to these fxo ports.

Thank you.

[Les Pruden]

The design Ipersing describes is for outgoing calls. 

I understood you to say that your service provider cannot route an inbound call to a second (or more) POTS line if the first is busy. If that is correct, then there isn't anything you can do in the UC environment. The second call does not reach your system.