Cisco 2811 outbound VOIP not faxing

[bkelly1676]

Hello all, i am looking for any solution that you may have for my outbound faxes not working. currently the setup is as follows
inbound comes across a pri to a nortel option 61 phone system and is routed to the propper extension so all inbound is working fine (no VOIP involved)

outbound calls are routed over an outbound pri if local or over a VOIP circuit if LD. We cannot fax outbound at all to any ld numbers.

what would be the best step to fix this problem

 

[kwing112000]

Are you sure the VOIP provider can handle faxes. Sounds like it could be them. Does the system dial and connect or never even dial.

 

[bkelly1676]

it seem to dial but wont connect, sorry but i am actually the phone tech for the nortel so this cisco router is new to me. i have been reading about T.38 protocol for faxing but it doesnt look like the 2811 supports it. i am currently trying to get ahold of the VOIP circuit vendor at this time.

 

[kwing112000]

Thats funny i am an tech that works on Avaya and was just reading thru the cisco stuff. i dont know any cisco

 

[whykap]

2811 routers support t38 fax protocol. However you have to configure the router to do that. Does you PBX support t38?
I seriously doubt that.
Can you post your routers config?

 

[bkelly1676]

if im not mistaken the pbx wont need to support it, the pbx hands it off to the router for delivery over the internet, so the 2811 is the last point for the call to passthrough before leaving. as far as the pbx goes it doesnt change anything, it just passes all outbound LD over another circuit that simulates a PRI so no changes were ever made to it. so the 2811 does support t.38, is it a simple setting or is there hardware needed to get this working?

 

[ADB100]

Codecs is the 1st thing that springs to mind - do you know what Codec's you are using over VoIP? I know there are issues using anything other than G.711 for faxes.


Andy

 

[bkelly1676]

no, it is defaulted to 729, what effects would changing have on the bandwidth overall, is there a way that i could recognize just the fax and have it sent as g.711

 

[whykap]

No hardware needed but you do need to run the latest IOS. I highly recommend 12.4 for t38.

 

[bkelly1676]

thanks, we will work on this, as for now changing to g.711 has helped the problem, not sure about how well but we were able to fax several times without a problem.

thanks

 

[bkelly1676]

we are running 12.4, do you have the config for t38, it was working fine for a while but no longer works