VOIP Fax Dial Peers

jgorman1977 · ‎06-11-2010

Our VOIP system allows us to receive faxes on our direct

numbers. The question I have is how to create a separate fax dial-peer that would interfere with our

normal VOIP dial-peers.

Here are our current dial-peers:

dial-peer voice 200 voip
translation-profile outgoing inbound
destination-pattern 123....
session protocol sipv2
session target ipv4:10.173.0.2
dtmf-relay sip-notify
codec g711ulaw
no vad
!
dial-peer voice 924 pots
destination-pattern 1230394
port 0/1/0
!
dial-peer voice 201 voip
translation-profile outgoing inbound
destination-pattern 12340..
session protocol sipv2
session target ipv4:10.173.0.2
dtmf-relay sip-notify
codec g711ulaw
no vad

Jonathan Schulenberg · ‎06-15-2010

I can't figure out what you mean "by create a separate fax dial-peer that would interfere with our normal VOIP dial-peers." Can you clarify please?

Also, are you using a single DID for both voice and fax; or, two separate DIDs per user: one for fax and the other for voice?

jgorman1977 · ‎06-15-2010

Our system allows for all DID's to receive faxes. So, would it be possible to do add the following to my current dial-peers to allow both faxing and voice?

fax protocol t38

Jonathan Schulenberg · ‎06-17-2010

It doesn't work this way with Cisco products. The router must use a TCL script that answers the call and listens for the specific tones while playing ringback to see if this is a voice or fax call. This adds a delay to all calls because this ringback is fake; the user's phone does not actually ring until the TCL script timeout occurs defaulting to a voice call. Based on what the TCL script decides it chooses different called number and dial-peers.

I have done this in real life and let me tell you, it isn't worth it. It's more trouble than it is worth and your time would be better spent buying the extra DIDs to give people a dedicated fax number.