GameCube controller data

[TheRocker317]

I was recently taking apart a GameCube controller and have a few ideas for making my own. But one of the wires coming from the board to the port cable is marked data. I am trying to figure out what data is being sent through it so i can recreate it on my own board. I want my controller to function as close to an original manufactured controller. So i am currently trying to find some one who can help me understand what needs to be sent through that wire. I thought Dolphin would be a good place to start. If you have any information or suggestions id love to hear them. Thank you for your help