Since this circuit is also used in all the other versions of the interface I will give a detailed description of its operation. This one is intended for use with 4QD NCC or Pro-120 series controllers which use a 9v internal supply, so the circuit is powered from this. However the supply voltage is not critical.
http://www.4qdtec.com/jsi.html
If you have watched an adventure movie featuring aircraft you have probably encountered someone yelling, Pull up Pull up You are gonna crash A huge explosion in which one of the good guys dies in a ball of flames usually occurs a few moments later.
http://www.circuitcellar.com/library/print/0305/Bachiochi176/index.htm
Bernard shows us how to use an use an accelerometer as a mouse. This project uses a MEMS X/Y accelerometer, a PIC microcontroller and a old mouse. He also describes a trick for powering the new mouse with the unused RS232 serial control lines.
http://www.uchobby.com/index.php/2007/10/27/accelerometer-based-mouse/
The joystick port is a quick and dirty analog to digital converter that can be used for many more things than just joysticks and gamepads.
http://kc0wys.homeunix.com/projects/electronics/03/index.html