Hmmmm. Did I just ask in the wrong forum, or has _nobody_ experienced image corruption using app_rxfax that was NOT due to using the wrong version of libtiff?
Oh, you can get image corruption on any non-ECM fax, and that doesn't have anything to do with anything other than data corruption over-the-wire. Since spandsp doesn't support ECM, you can get immage corruption and not have it be anything's fault except for the nature of non-ECM faxes. During fax Phase C (the part where the TIFF image data is communicated) if some data gets garbled due to whatever reason, then the image data will be messed up.
If that's the case, then my secondary approach is going to have to be: PSTN <-> Asterisk + chan_h323 <-> t38modem + Hylafax
Well, that would be a lovely thought... if only you could get Asterisk to talk T.38 through chan_h323, and Asterisk does not support T.38 in any way, shape, or form right now.
Is there anybody that could help me with either of these solutions?
As far as I'm aware, the only way to get HylaFAX working behind Asterisk is to connect a HylaFAX-controlled hardmodem either into an FXS port or a passthru span. For example:
PSTN - X100P - Asterisk - SPA-2000 - analog modem - HylaFAX
or
T1 - TE405P - Asterisk - TE405P - T1 modem - HylaFAX
The first configuration, which will generally work tolerably well with modern HylaFAX and most fax machines, is subject to a fair risk in data corruption due to the combined analog-to-digital (digital === ulaw) and digital-to-analog conversions. A mere 20ms delay in faxing can make a huge impact. The only reason that this configuration works tolerably well is due to the ECM support in modern HylaFAX and most fax machines. The ECM protocol is able to recover the corrupted data through retransmission attempts. Now, if the sender doesn't support ECM, then you're generally stuck with whatever corruption occurs (maybe none, but probably some).
The second configuration seems to be quite a flawless way to do this as Asterisk is merely forwarding the already-digital signal. The downside is, of course, that it's probably not really an option unless you have a T1, a TE405P, and a T1 modem (either an Eicon Diva Server or a Patton DataFire 2977).
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