Just got a Volvo 10 disk CD changer, when I wanted to install it into the trunk, I found power cable (blue color) is already there. It also is fit to the CD changer. But the signal cable I could not found it in the trunk. If Volvo also preinstalled these cables in the trunk, at least I know Audi does. But I can see there is a big square style plugs in the trunk. I guess it could be the signal cable. But in my CD changer, the adapter reveiver is round style with 8 holes (8 pins). Is there anyone who knows about it. If the suqare one is right, can I buy a cable changer from square to the 8pin? Thanks.