Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

use the same PRI for Voice and fax


i have the following scenario, i have right fax server , callManager 5.0 and a voice gateway 3845 with one PRI with DID number 2795XXX, My questions is how i can configure my gateway so that PRI channels can be used for both voice and fax call ( i used MGCP between CCM and gateway and SIP between rightfax and the gateway) , another question how can i use the same DID number for both the fax and the voice incoming call, for example there is an employee have a number 2975123 so when he recieve a voice call it will go to CCM, while when we have recieve a fax it will go the right fax server like a traditional Fax machine.



Re: use the same PRI for Voice and fax

I do not think that is possible. Generally, you have two separate numbers for that purpose. So in my opinion, I would order another block of DID's for FAXing. Use a H323 Gateway for T.38 Faxing. Create a Translation pattern for your DID's and send them to the correct destination. Here is an example of the configuration:

voice service voip

fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback cisco


bind control source-interface Loopback0

bind media source-interface Loopback0

fax send transmitting-subscriber $s$

fax send left-header Fax for $d$ containing $p$ pages

fax send right-header Sent $a$ $t$

voice translation-rule 1

rule 2 /^60\(98..\)/ /\1/ <----USER DID

rule 3 /^74\(81[5-9].\)/ /\1/ <---FAX DID

dial-peer voice 999020 voip

translation-profile outgoing changeNum

destination-pattern 6098..

voice-class codec 10

session protocol sipv2

session target ipv4:

session transport udp

no vad

Hope this helps.

Re: use the same PRI for Voice and fax

im intrigued now. I know it is possible, because I have seen it before, but I have never configured it for CCM or voice gateways. It seems if the gateway was h323, it could see it was fax transmission and route accordingly and same for voice. Im going to dig around and see if Cisco does in fact do this. (instead of having seperate DIDs)

Traditional way is a seperate block for voice and one for fax.

But think about the home user. 1mb with the little gadget that sends faxes to the fax machine and voice to the phones. You would think in a big $10k router, it could do the same function.....

Re: use the same PRI for Voice and fax

If you know of way, I'm interested in finding it. Typically some of the fax machine have the ability to determine if it is a voice call or a fax call and that how it would work before.

New Member

Re: use the same PRI for Voice and fax

thanks all:

i think there must be an identifer on the incoming call so that can determine if the call is fax or voice, if the gateway able to do that the problem will be solve. beacuse i dont thing every customer able to buy another DID number, in addition it IS a good facility to have one number for both fAX AND VOICE


Re: use the same PRI for Voice and fax

anyone want to comment on this? From searching everyone with "one number" and "one" I changed my search to "single" and I got some other results. This is theory seems like it would work.

New Member

Re: use the same PRI for Voice and fax

We have almost the same setup...

call manager 4.13 right fax hooked into a 3845 which has an incoming pri line.

the right fax server is plugged into the 3845 via a pri cross over cable so to be clear the 3845 has an incoming pri from the telco and the fax server hooked into it as another pri... at least as far as right fax thinks.

We then use a route pattern to route the did we want to the pri of the right fax server .. works great! and yes it can use any did number of our did pool.

I too wanted incoming fax and phone number to be the same but thought about how to preanswer or determine the call and thought it would be a pain .. also i think it comes down to the type of pri line you have what it supports for options.. i forget the exact option or terminology....

Hope this helps.. will read the link above to see what it is about


CreatePlease login to create content