This is an ISA Sportster modem 0481 56K.
Unzip it and replace each 'USR002C' to 'USR0014' in Winmodem.inf file. The modem came with PackardBell Mutimedia601. It has paper sticker "21x769420712 38269700" on the phone cable outlet.
The link to the NT version of this file was submitted by a "Vlad" whose comments I've coppied. He may contact me if he wishes firstname.lastname@example.org