OK, now I'm starting to understand, especially finding out that the data is transmitted to the unit via serial bus. However, a couple of questions remain: does the serial bus plug into the fuse block also? and is all the hardware already on the car for the various information that EVIC and/or OTIS displays?
Mileage/fuel consumption/speed, etc, I'm guessing comes thru the bus from the car's computer. But what about outside temp? compass sensor (or is it in the EVIC/OTIS?)? etc. I don't know much about factory wiring, but I'm surprised that everything's there already except for the display.
(I'm a DIYer, but I do learn as I go, not having any prior experience with factory wiring, installations, etc.)