External fax modem fails to initialise after XP SP2 installed

[Earl Chew]

I have an external fax modem connected on COM1 working ok prior to SP2
being installed.

In particular, I was able to leave the modem powered off most of the
time, and could power on the modem just prior to sending or receiving
a fax.

If I powered the modem on after XP started, I would see the lights
blink and TR would light and remain lit.

With SP2 installed, powering the modem on after XP starts results in a
blank display. TR lights for a short time, then extinguishes.

If I reboot the PC, and leave the modem powered on, XP notices and
initialises the modem soon after I log in, and the TR light remains
lit.

Can anyone offer any suggestions?

How might I debug this problem?

Earl

 

[Earl Chew]

Some browsing of this newsgroup and some experimentation show that the
problem might lie with the revised XP SP2 fax service.

With the modem turned on, stopping then restarting the fax service
(net stop fax; net start fax) successfully re-initialises the modem.

Leaving the fax service running, and cycling the power on the modem
doesn't cause the modem to be reinitialised.

I suspect that the fax service no longer senses the modem control
lines on the serial port properly (probably DTR or one of its ilk)
and thus cannot detect that the modem is unavailable then available
again.

Are there debug or logging settings on the fax service I can use
to figure out if this is so?

Meanwhile, a workaround is to create a restartfax.bat file containing:

net stop fax
net start fax

and to execute it after powering up the modem :-(

Earl