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Cisco Voice Gateway - force extension to use specific port for outgoing calls

Steve Bantz
Steve Bantz used Ask the Experts™
I have a Cisco Voice Gateway 4331 that handles all of our calls in conjunction with Cisco Call Manager.  The voice gateway has a PRI circuit connected to a port and three POTS lines using the remaining three ports.  In this example, I want to have the internal extension 3337 use the specific port of a POTS line on port 0/2/2.  This is for a fax machine (attached to CUCM via an ATA 190) that only sends and I am having trouble with it being reliable over the PRI.  I was hoping to tie it to a POTS line to avoid trouble.

I tried the following and it did not seem to work correctly.  I feel like I am missing an important component:

dial-peer voice 3199 pots
desc ***** Send faxes over pots lines for mailroom *****
preference 1
answer-address 3337
port 0/2/2
forward-digits all

In the above, I am attempting to identify the internal extension of the fax machine (3337) so that it can be directed to use the POTS line on port 0/2/2.  Is there another set of commands that I might be missing?
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Sr. Systems Engineer
Top Expert 2008
What type of gateway is it in cucm? If mgcp, you can create a new css, partition and route group that only includes that port. The ata gets assigned the css with the corresponding route pattern using only the one port.
I don't think you can do source-based call routing on the gateway without using translation patterns in a very creative way.
Or you could create a dial peer using a different destination number pattern, maybe a leading 7 instead of 9, and match those on the out the port through a dial peer. Then on the cucm be sure to create a route pattern. Then when sending external fax just prefix the number with 7 intead of 9..
Distinguished Expert 2017
In pots line setup, you have outgoing dial plans where you can set the extension to always use the specific FXO port

If you are running into issues with sending faxes through the PRI, the issue can be fixed by advising your provider to properly encode the DID as a fax, then you can configure your 3337 to napped to the same DID
Steve BantzIT Manager


This seems to have worked:  the x's mask the real phone number.  :)

dial-peer voice 8888 pots
 description ****Fax machine to POTs line***
 preference 1
 answer-address xxxxxxx3337
 port 0/2/1
 forward-digits all