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.
The following files are found inside the driver download file.
|Winmodem.inf||47.4 KB||8 Sep 1998|
|Wmldr.vx_||3.4 KB||8 Sep 1998|
|Wmexe.ex_||25.2 KB||8 Sep 1998|
|Winmodem.vx_||329.8 KB||8 Sep 1998|
|Wmdll.dl_||18.8 KB||8 Sep 1998|