Apple Mac Performa 5300CD - Manual (Page 15)

Connecting the mouse and keyboard
1 Plug the mouse cable into the recessed port on the back of the keyboard.
The plug and the port are marked with the ◊ icon (symbol). The positions of
the port and icon on your keyboard may be different from those pictured.
By the way: A port marked with the ◊ icon is called an Apple Desktop Bus
(ADB) port.
This cable plugs into the Apple Desktop Bus (ADB) port,
marked with the
◊ icon, on the back of the computer.
Plug the mouse into the recessed port on
the keyboard. The flat part of the plug should
be pointing down, as shown here.
5 Getting Started