Photo Diode is the same technology used on early consoles. It requires a CRT display to work correctly, and works best when the guns are 90 degrees from the screen.
IR requires the user to setup sensors around the screen. They work on both CRT and LCD displays.
|House of the Dead||Photodiode|
|House of the Dead 2||Sega Type II IR||Requires Old Type Naomi motherboard|
|Point Blank 2||Photodiode|