When used with specially designed Nintendo GameCube and Game Boy Advance games, the Nintendo GameCube Game Boy Advance Link Cable provides a connection between the two systems. doing so may allow the two systems to exchange data, enable two-player cooperative play, or provide other special features.
Reading: How to connect gba to gamecube
general configuration help:
To connect the Nintendo GameCube Game Boy Advance Link Cable, plug the wider triangle-shaped end of the cable into the external port on the Game Boy Advance system. Insert the smaller end into an available controller port on the Nintendo GameCube. the port that the cable is inserted into varies from game to game. Please refer to the instruction manual for the game you are playing to determine which port to use and how to access the connectivity feature.
how to identify games using nintendo gamecube game boy advance link cable:
The Nintendo GameCube and Game Boy Advance Software Package will indicate if this connectivity feature is available. Please note that Game Boy Advance does not work with the Nintendo GameCube unless the game developer has specifically integrated this feature into their game.