Why won't my son's Nintendo DS read any games?

Dual-slot mode is a method of communication between a Nintendo DS game card and a Game Boy Advance game cartridge by

Durable Original DS Game System; Includes slots for both Game Boy Advance Games & Nintendo DS Games Product Details Is Discontinued By Manufacturer: No

ds lite gba slot My goal is to reverse engineer the protocol, but I have no idea where to even start Specifically: How does the DS game know which GBA game is

ds with gameboy slot I recommend it for those who mainly want to play PSP, Nintendo DS and Game Boy Advance, since its widescreen screen is ideal for this Good: - Price