reply to nunya
Re: [Asterisk] What about Flowroute for faxing? They used to be much more "YMMV" with T.38 termination, but within the last year or so they've stuck their neck out as officially supporting T.38: »twitter.com/flowroute/status/135···17888512 -- I also posted about my experience with Flowroute here: »puck.nether.net/pipermail/voiceo···986.html
To sum up, my experience has been that whenever I run into a particular destination that I have issues negotiating T.38 with, I open a ticket with Flowroute (on their on-line ticketing system, "T.38 Negotiation" is even a specific problem category now) and they either identify the upstream provider that is causing the issue and open a ticket with them, and/or they simply re-route around that provider for that particular destination and have you re-test. So unfortunately it isn't completely "100% worry-free, works-every-time", but if you are willing to take the time to work with their support guys (who are very, very good) when you do run into problems, they will provide you with a solution.
Note that this only speaks to their termination services. I generally do not use Flowroute to get my DIDs, but I do have 1 DID with them and T.38 origination works flawlessly on it. I believe they have said (although I can't find it right now) that they support T.38 on the majority (if not all) of their DIDs, but again I can't really speak to that given how limited my experience is with their origination product. But the one I do have works great.
Hope this helps,