One of the ports is for the modem
Went to salvation army store today and found a game cube for 4 bucks. With both av ports regular and the composite 001 model. No cords but works great. I already had one so I was able to test. Works great. I don't have that expensive rgb cable with chip inside so no way to test but rest works great.
Except the ports on both. Port 1 works fine and port 2 maybe with a 2 player game I can see. But how to test all 4 ports. Do I need a 4 player game or is there another way to test all 4 ports are good shape. Every thing else is good. Turns on and loads a game. And my Gameboy player works also so serial is good also.
And also what are the other 2 serial ports on the bottom of the thing under where the Gameboy player goes. There are 2 doors labeled serial also.