The game port is a device port that was found on IBM PC compatible and other computer systems throughout the 1980s and 1990s. It was the traditional connector for joystick input, and occasionally MIDI devices, until made obsolete by USB in the late 1990s. Originally located on a dedicated Game Control Adapter expansion card, the game port was later integrated with PC sound cards, and still later on the PC's motherboard. During the transition to USB, many input devices used the game port and a USB adapter dongle was included for systems without a game port. At the time IBM was developing its game port, there was no industry standard for controller ports, although the Atari joystick port was close. It was introduced in 1977 with the Atari Video Computer System, and was later used on the VIC-20 (1980), Commodore 64 (1982), and Amstrad's PC1512 (1986). In contrast with the IBM design, the Atari port was primarily designed for digital inputs (including a pair of two-axis/four-contact digital joysticks, each with a single pushbutton trigger). Its only analog connections were intended for paddles -- although, as there were two analog inputs per port, each port could theoretically support a two-axis analog joystick, touchpad, trackball, or mouse (some of these being eventually developed for Atari systems). The Apple II, BBC Micro, Tandy Color Computer, and other popular 8-bit machines all used different, incompatible, joysticks and ports. In most respects, the IBM design was similar to, or more advanced than, existing designs. The IBM PC game port first appeared during the initial launch of the original IBM PC in 1981, in the form of an optional US$55 expansion card known as the Game Control Adapter. The design allowed for four analog axes and four buttons on one port, allowing two joysticks or four paddles to be connected via a special "Y-splitter" cable. Originally available only as add-on that took up an entire slot, game ports remained relatively rare in the early days of the IBM PC, and most games used the keyboard as an input.
Jean-Michel Sallese, Chiara Rossi