This was originally posted at your 3-COM site by James Gelhaar. I am merely reposting it on the US Robotics site for better cross reference.
My notes to James follow
This was a great find. Your posting is the only one that was recognized as being correct by windows for model 74691074 56k Voice Win modems. I have 30 of these and would be stuck without a valid driver!!
Internal code USR0033, model 74691074,type US Robotics 56k Voice Win.