Neil,
How right you are ... It's bit a long time since i had to configure this kind of connection, though I'm trying again after a long hiatus in trying PMFax Pro again.
I also have a US Robotics External 54K Voice FaxModem Pro, connected by the USB cable and to a landline. While PMFax is (I believe) installed properly, I can't get a dial-in recognized by it. (I first used Suntan Special for installation but got an Error that "Product not enabled." I then copied an old directory, and used the Registry Editor to change the directory reference.)
USBCOM.SYS is referenced in <config.sys>. Since FMD1 as the Port didn't work, I tried COM1 but No Joy there either.
Looking in <system.ini> for COM1, the PORTDRIVER key is "Serial". Since the modem now has a USB connection, is this the problem? (I also have a Serial cable for it and might be able to use an adapter to connect it to my ThinkCentre M93p, but would prefer to avoid this if this extra work would be in vain.)
Any ideas?