Grim, but not impossible
http://www.modem-help.co.uk/chips/motsm56.html#drivers
The SM56 though, was probably the most performance draining of all software modems, with reports that it can hurt performance even while just listening in auto-answer for fax or voicemail.
The Intel "HaM" chipset based modems (and the later "536") seem to be about the best replacement.
But if you want to try the drivers:
First link is a page on the site - 84.32
The Mercury/Kobian one is not responding at the moment
(
http://www.kobian.com/download_produ...&product_id=93 ) corrected link, 84.32
The PURETEK 3027 drivers are updated to 84.41 now