PC Hardware in a Nutshell, 3rd Edition

USB Keyboard Interface

Some keyboards can be connected to a USB port. Most USB-capable keyboards also provide a standard PS/2 connector, via either a split cable with both USB and PS/2 connectors or a separate adapter that converts the USB connector to PS/2. To use a USB keyboard, the PC BIOS must support USB keyboards, and you must run an operating system, such as Windows 9X/2000/XP or Linux, that supports USB. BIOS support is needed so that the keyboard can be used before the operating system loads to do such things as changing Setup parameters or choosing options from a boot menu. Operating system support is required for the keyboard to be accessible after the system boots.

Tip

In previous editions, we concluded that USB-only keyboards were not ready for prime time. We experienced numerous lockups and other weirdities, including situations in which the PC continued to run normally but the keyboard was no longer recognized. Although such problems still occur with older hardware, and although we still prefer to use PS/2 keyboards for Linux systems, current USB keyboards are generally quite reliable with recent Windows systems.