I was looking through the Becket web site and found the Monza series radio and it looks exactly the same as the Crossfire's radio. They have several models so I don't know exactly which one it is but they have .pdf files of the radio that are very informative that show the connecttions on the back and lots of other good stuff.

http://www.becker.de/beckerCC21/www_...sp?language=En

Go to the "Car HiFi" link, then to "Monza", then to "Product Service" for the .pdf files.