what do you need to play multiplayer on halo 3 with a system link and how do...

[Louis K]

...you do it?
What type of Ethernet cable do you need

 

[Ben]

you need two 360s, two tvs, and a Ethernet chord.

Connect the 360s to the tvs, then connect the two 360s together using the Ethernet chord, go to the menu and select the system link option.

fyi: I don't think you can play online and do system link at the same time.