Actually, you can see the CD changer connections in the photo above

6p black = CD changer audio
3p black = CD changer power, gnd and ibus

So from the cabling you can ascertain that the car was wired for a phone and CD changer

What radio or screen do you have fitted in the front of the car?
Best to post a photo ...

Again, what market was the vehicle build for?
UK, or Japan?