Thanks to friendly support by MVS, Germany, I got a Telelink IMS 08 modem
for testing and was able to adapt mgetty accordingly.
The modems factory defaults are very good, so it’s sufficient for
mgetty operations to set init-chat (in mgetty.config)
to ATQ0V1E0 OK AT&F2S0=0&D3X6&K3 OK, and switchbd to
19200 (yep, it switches baud rate. Stupid, but true). After that,
receiving fax + data calls works fine.
Fax sending is not that trivial. Basically, it works after setting
modem-handshake to AT&K3. FAX_SEND_FLOW (in
policy.h) can be anything that the host machine supports (because
the modem does both Xon/Xoff and RTS/CTS handshake simultaneously).
Unfortunately, a few problems remain:
– faxing multi-page faxes to ZyXELs with ROM release 6.11a doesn’t work (fails on the receiving end with +FHNG:100 and on the sending side with +FHNG:50).
– faxing to some paper fax machines fails completely, for others, “only”
complex graphics (like the Ghostscript-“tiger.ps”) fail. This one can be
partially cured by adding lots of padding zeroes into the fax data
(g3cat -p 24) - but that’s unelegant, not complying to class 2
specs, and not supported (besides, it still doesn’t work all the
time). Maybe later versions of sendfax will do the padding
automatically.
I recommend against using this modem with sendfax. In addition to the technical problems, their customer support (at least, that of the german distributor MVS) is basically non-existant. (I wrote them four times describing my problems with the modem, and never got an answer).