Thread: shut down start up help

hi all got a problem you may be abel to help with. about a year ago now
when i was first looking at putting a pc in my car i found a thread a bit like this. http://www.mp3car.com/vbulletin/powe...n-circuit.html
but alot better.
now i get what the guy in that post is doing but the big part i dont rember is
what pins on the serial port i need to use to make the pc turn off and
what volts i need to feed it or remove from it to do so