Hi Geoff, Neither really, I'm not sure an i-Bus activated 12v is needed. I'm just taking 12v from the white (pin 8) and blue (pin 7) monitor connectors. It's a 12v Terminal 30 supply, so its on all the time. My screen replacement is simply mimicking the factory unit only in a higher resolution. I wanted it plug and play to keep it as stock as possible, apart from loosing the cassette player. As well as power, all my video feeds are taken from the connector board. An RGsB converter is used to convert the video signals to VGA for my new screen. I've spent countless hours reverse engineering and developing my knowledge base of these old systems, so I haven't had time to finish it yet, but I know it will work in the car fine. That and life getting in the way