Apple PowerBook (2400c) - Manual (Page 63)

Connecting a mouse, keyboard, or other ADB device
You can connect a mouse, keyboard, graphics tablet, or other Apple Desktop
Bus (ADB) device to the ADB port to the left of the power adapter port on
the back panel of the computer. You can connect up to three low-power ADB
devices in a chain.
IMPORTANT You must shut down the computer before connecting an
ADB device.
Connecting other devices
For instructions on connecting a device not discussed in this chapter—for
example, networking hardware—refer to the manuals that came with
the device.
V Apple Desktop Bus
(ADB) port
63 Using PC Cards and Additional Equipment