T38 Fax

[Kenan Muharemagic]

Hi guys,

got a question about t38.

I have a setup with a SIP trunk from an ITSP, a IOS router 2801 as the voice gw and an XMedius Xpress T38 fax server also using SIP.

I have been trying to get this working for about 2 weeks now without any success. I get the call through, inbound and outbound, but when the t38 fax server send a SIP REINVITE with T38 the router forwards the T38 reinvite over the ITSP SIP networkto the legacy fax machine and after a few seconds i get a 488 Not Acceptable Media SIP message.

Has anyone got t38 working with a SIP ITSP trunk terminated at an IOS voice gateway?

i have attached debug output for ccsip messages and voip ccapi inout.

[Jonathan Schulenberg]

Have you confirmed that your ITSP supports T.38 media?

[Kenan Muharemagic]

Yes... a friend of mine works at the ITSP... they also have t38 fax servers running in their network for hosting and internal use...