Quick serach gives me this.
Output Voltage DC 203W 12V, 16.5 A, 5Vsb 1A
Seems the Xbox360 likes it's DC input voltage in the same flavour as the Wii, just a LOT more of it. 16.5Amps is a lot of 12V current. No wonder the machine makes a lot of noise, must generate a bucket load of heat (I don't have one so I'm guessing)