First, I am a new member who has very limited knowledge about cell phones. I just bought a 2005 Ford F250. It has a 6 disc cd player. On the back of the cd / radio is a plug that is not used. Is it for connecting an auxiliary device like a cell phone car kit like the cark-91? I took the car kit out of my last vehicle and saw that only 2 wires were connected to the vehicle (probally + and - for power). There are additional wires that may be used to mute the radio? or some other function? I would like to have this feature if it is avaliable and also maybe some sort of external ring in case I am not in the truck, but the phone is. I have the Nokia 6340i. Is there a wiring diagram for the cark-91 connection? I know, a lot of questions, but as I said, I have limited knowledge. Thanks in advance. John.