Steve Underwood has posted his updates on progress with T.38 support for Asteris:

Hi,

I have T.38 over UDPTL with SIP signalling kind of working-ish within Asterisk. I hope to be passing code around for some serious testing by other people in a couple of weeks, or so. Certainly within a month. Once I have it stabilised with UDPTL and SIP I will get it working with IAX. Then I aim to get it working over RTP. I have no plans for T.38 over TCP right now, as it doesn't seem to be in common use. I have no persoanl interest in H.323. If someone wants to extend it to work with H.323 that's fine by me. I am making a PSTN gateway, and extended app_rxfax and app_txfax programs which can transfer via T.38.

The bigegst holdup has really been the poor state of T.38 support in current equipment. Few ATAs do it. Fewer do it right.

Regards,
Steve