For more information about USB on Macintosh computers, you should refer to Apple Computer's Mac OS USB DDK API Reference. Information is also available on the World Wide Web, at
http://developer.apple.com/documentation/Hardware/DeviceManagers/usb/usb.html
USB game controllers are supported by the InputSprocket component of the Apple Games Sprockets software architecture. InputSprocket software and information about the InputSprocket APIs can be found at
http://developer.apple.com/games/
For full specifications of the Universal Serial Bus, you should refer to the USB Implementation Forum on the World Wide Web, at:
http://www.usb.org/developers/index.html