T.37 Fax question

[spectre03]

I am trying to set up T.37 fax but can't find any documentation on how to get it working in a slightly different configuration. I have a 2811 with a VWIC-2-MFT terminating a PRI and Data T-1 with the PRI being terminated by MGCP. I would prefer to hairpin the call back to the router and terminate the fax call there from a VoIP dial peer. Has anyone done this? Is it supported? If I had to use a Pots dial peer could I use one VWIC-2-MFT port in loopback and route it straight back into the router that way? I know I could set up a 2-MFT and cross-over between the two ports, but that is a waste for the utility of the feature. Another router is even more of a waste but I refuse to go strictly H.323 on the incoming router. Any suggestions would be great.

[Markus Schneider]

I may be misunderstanding what you're doing...you have to terminate the T37 call inbound on the POTS side. It can't come in via a VoIP dial-peer. Or are you hairpinning the call from the T1/PSTN side inbound back out to the Pots side and then back into another Pots interface and terminate it there? If so, I think that might work, but I haven't done any testing with such a configuration.

[spectre03]

Well, I had hoped I could terminate from a VoIP dial-peer, but what I did end up with was this:

Bring PSTN PRI in via vwic-2MFT configured with MGCP.

Hiarpin call from Call Manager to h323 gateway configured on the same router prefixed with a 9.

Send call out pots interface on second vwic-2mft looped to the second port on the same interface.

call terminates to pots dial-peer which terminates to the onramp.

It actually works, just doubles the dsp usage, but makes configuration and management so much easier than terminating it via h323 initially since it's easily distinguishable for the dial-peer configs the only thing that routes to that gateway via h323 is fax.