I just upgraded to the latest FreeSWITCH (version 1.6.8-15 from files.freeswitch.org/repo/deb/freeswitch-1.6/), so I'm starting to work on FA
X again.
So far success with:
FAX machine -> Grandstream HT502 -> LAN -> FS -> Flowroute -> PSTN -> POTS line -> FAX modem (TRENDnet brand) -> HylaFAX.

Then I tried:
FAX machine -> Grandstream HT502 -> LAN -> FS -> Flowroute -> FS -> application="rxfax"

This failed when I set fax_enable_t38_request=true and fax_enable_t38=true, but worked when I removed those lines. So what's going on here? When I remove those lines is T.38 not being used at all? I was under the impression that without T.38, FAX machines would fail because of latency present in VoIP. Is that not true? What about when the FAX machine is sending from the PSTN instead of the ATA?

-- 
Steve