We’re sure there’s still a lot of folks using their original Xbox either for gaming or as an XBMC device. If you ever owned one yourself you’ll remember that you can’t turn it on with a remote control. If you have to get up and push a button on the front of the black box, as least this hack will take care of tuning the television to the correct channel. That is, if you are using a SCART adapter to connect it to your TV.
[Karl-Henrik] figured out that mapping a voltage to pin 8 of a SCART port tells a TV that the port is active, and allows it to select the proper aspect ratio. Check out the Wikipedia SCART page to see that pushing 5-8V is the signal for a 16:9 aspect ratio, and 9.5-12V translates to 4:3. So he added an audio jack to the back of his Xbox and a matching one on the plastic case of the adapter. Now just tap into the wires on the power connector for the hard drive inside, connecting them to the newly installed jack. There’s a 12V and a 5V line, just choose the one based on the aspect ratio you prefer. He uses a jumper wire with the appropriate plugs on each end to make the connection. Now the TV will automatically tune to the correct AV input when the Xbox powers up.