Do you have a car stereo
that can control a CD changer? Would you like to make use of this input
as a way to connect your MP3 player, portable CD player, mini disc or other
device to your system? If so read on...
A simple idea
In 1997 I bought a new Mazda Protege, and it came with a standard AM/FM
Radio/Cassette deck, and it has controls for a external CD jukebox. At
the time, the price for these players was more than I wanted to spend.
I already had a portable 'discman' player, and I wanted to find a way to
connect the discman to my car stereo. Sure I'm aware of the cassette adapters
and the FM modulators, but I wanted to make a direct connection
to the 'head unit'. I removed the head unit and took a peek at the connector,
only to find that it is totally un-labeled and has 16 contacts! I purchased
the Mazda service manual for the car, and looked up the wiring for this
connector. The manual shows only the speaker and power connectors, but
gives no indication of the wiring for this mysterious connector. I searched
everywhere, but I could find no helpful information. One car stereo installer
I spoke with suggested that the connections to external CD players is purposely
made in such a way as to prevent you from using another manufacturer's
CD changer (or discman) - forcing you to buy one of their units instead
of the competitors. I gave up on my search and used one of those annoying
cassette adapters.
My second attempt
Several years later got a portable MP3 player which sparked a second attempt
to find information on this connector. I opened up the head unit, and found
some stenciling on the bottom of the circuit board. With that information,
I had a place to start. The stenciling indicated the Left and Right
audio inputs and Signal Ground. But this still doesn't solve the problem.
The head unit has to know that there is a CD player attached - or it refuses
to accept the audio inputs. When you press the AUX button on the front
panel the display flashes "no CD".
I assumed that there must be some sort of jumper needed that would fool
the head unit into thinking that there was a CD changer attached. Using
some the information that I got from the stenciling -- and some trial and
error -- I found a solution!
It wasn't exactly what I expected. As I said, I was hoping to fool the
head unit into thinking that there was a CD player attached. I never achieved
that, but I stumbled in on a hidden feature - which I'll call the LINE-INPUT
mode. When I jumpered two pins on the connector, the display showed
the word 'LINE' and I could hear my MP3 player through the car speakers!
Doing it yourself
Ok - if you've read this far - you probably want to know how to do this
yourself. But first a few notes. If there was one standard interface
to CD changers - then this would work for everyone - unfortunately chaos
reigns even with units made by the same manufacturer. This means that my
wiring info most likely won't work if your head unit is different
than mine. But you may be able to learn from this example and apply it
to your situation. Of course the standard disclaimer applies. If you attempt
this and fry your equipment - I can't be held responsible.
Click here to see if this will it work for you