We have been having issues with T.38 negotiate failing between our CUCM 8.6 and a RightFax server. Anyone have any documentation on the setup for RightFax? Are configuration is PSTN--(SIP)--CUCM--(SIP)--RightFax server.
We have the SIP trunk and route pattern configured. If the RightFax server is configured for T.38 the CCM does not responde to the T.38 invite. I am guessing we have something not configured on the SIP trunk or SIP profile, unfortnately I do not have access to the RightFax server and the only documention I have been given is for CCM 7.0 and earlier, was looking for the correct setting for the SIP trunk and SIP profile.
Have you found the resolution to this? I am currently experiencing the exact same issue and working with RightFax/OpenText hasn't gotten me anywhere...
UPDATE: Not sure if your using just a PSTN PRI, but I am attempting to use PSTN SIP, after working some more with the provider I have found that the PSTN Sip circuit does not support T.38, I'll update your thread if I get a work around from OpenText.