As I was explained not long ago, the OEM CD-changers can be used with the factory DSP systems, some of which use a coaxial cable RG-174 for getting the audio signal from the CD changer into the DSP unit. This "aerial" is actually audio output from the changer to the digital DSP. Some of the DSP units do not utilize this "aerial" for the audio input and use instead standard 6-pin connector.
So, you may end up (like my own set-up) with a CD changer that has a mini coax plug and a DSP (if you have one) that has a same plug but they are not connected to each other. In this case, you should consider yourself "lucky", since the statements about "not compatible/not applicable to vehicles with DSP", that you see sometimes on the vendors' pages, do not apply to your audio set up, so you can buy the products that will work in your set up...
check this post
http://www.xoutpost.com/bsws-mobile-e...gital-dsp.html