Mac OS 8.x no longer includes Apple Telecom as part of the Mac OS Installer. You will have to reinstall the Apple Telecom software before your GeoPort modem or Express modem will work.
Mac OS 8.0 and 8.1 CDs have Apple Telecom in the CD Extras folder on the CD. Apple plans to make Apple Telecom Software available online. Apple recommends that you use the latest version of the Apple Telecom software with your computer on Mac OS 8.5. Versions of Apple Telecom prior to 3.1 are not recommended.
To find the most recent version of this software, refer to the Apple Software Updates Library at
http://www.apple.com/swupdates.