At Last!!! After weeks of searching this modem worked for me on a Sportster 33600 Winmodem shown as a US Robotics x 2 Winmodem Voice by Win98.
As a bonus it even speeds it up to 56k. Extract to a floppy, delete modems in control panel. Restart and when system searches for a driver select manual search and point to A drive. Windows will say incorrect driver but proceed anyway. Good luck.