It is a mac joystick? My gravis phoenix had a DB15 joystick connector and a keyboard connector. 4 axis and 4 buttons were used with the DB15, and all other buttons emulated keystrokes (you had to plug the keyboard connector between PC and keyboard).
There were PC and Mac versions of that joystick. Old macs used ADB ports to connect keyboard and mouse, and I guess that joysticks were plugged here. ADB port should be a 4 pin miniDIN.
There are ADB to USB adapters. You may buy one ot those on this ebay shop (is reliable, but is as spanish as me), but you should contact with them to ensure that it would work with your joystick.
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