Available in this download is the latestWindows 95/98/NT 4.0 driver for USRobotics Voice 33.6k and 56k modems bought between January 1996 to present. Copy this file onto a blank floppy disk. Remove all Sportster modems in Control Panel/Modems. Shutdown and restart your computer. When prompted select "Change" or "Have Disk" and point it to the floppy drive. Select the appropriate model and then follow the prompts to finish modem installation. NOTE: You will need to download the 3COMWAVE.INF to complete the modem's installation.
Here's other similar drivers that are different versions or releases for different operating systems: