Please Note: This article previously appeared on my other general purpose blog which I have since shut down. I thought the topic was techie enough that routine TechTraction readers might find it helpful so I decided to republish it here. Enjoy.

I’ve been dying for an affordable way to connect my iPod to my car stereo that doesn’t involve the low-fi audio option of an FM transmitter. For the family’s Volkswagon Eurovan a standard “rip-n-replace” was the most affordable option. Fortunately, that approach wasn’t necessary for the family’s second car because all I needed was an inexpensive adapter for my Pioneer DEH-P3500 to achieve the desired results.

Pioneer CD-RB10 gave the second car a standard RCS composite AUX port

My second car is a Mercedes Benz 190E 2.6. The factory radio thankfully died about 4 years ago. At the time I didn’t have an iPod so I wasn’t worried about the lack of an easily accessible AUX port on the face plate. And, unfortunately the DEH-P3500 doesn’t come with typical RCA composite AUX input jacks in the back of the unit (something you find on most home stereo units); however, the unit does have what Pioneer calls an IP-BUS-RCA Interconnector. I believe this port is normally used to connect an external multi CD changer, but can also be used for other device connections with one of two specialized Pioneer adapters: the CD-RB20 or the CD-RB10. If you search for either of those names, you should find a variety of places that sell them online. I found the CD-RB10 (used) at Amazon for approximately $7.00 US.

Connecting the CD-RB10 adapter to the back of the Pioneer DEH-P3500

The IP-BUS-RCA Interconnector is on the back of the Pioneer DEH-P3500 which meant I had to pull the unit out of the dash to make the connection. I used the removal tools I got from Crutchfield when I purchased the JVC KD-AR480 for the Eurovan. In less than a minute the unit popped out and I was able to plug in the CD-RB10 adapter. Now, I was faced with a new problem: how to feed the newly created RCA composite jacks to an accessible location.

I looked around the dash for a convenient and nondestructive place to feed a composite RCA extension cable. Finally, I decided to rip out half of the factory installed cassette tape holder.

The cassette holder is held in place with some serious adhesive tape but after much pushing and pulling, and little extra persuasion in the form of a screw driver, I managed to finally pop out the holder. After all of that I connected the composite RCA extension cable, feed it through the newly created opening in the dash, and slid the stereo unit back into place.

One last trick to enable the Pioneer DEH-P3500 AUX port

To access the device plugged into your AUX port, press the SOURCE button repeatedly to cycle through options until AUX appears. This approach works only if your AUX port was previously turned on.

I believe the AUX is off by default, but you can easily turn it on with the following steps:

1. Press and hold the SOURCE button until the unit turns off.
2. Press and hold the FUNCTION button until the clock appears
3. Press the FUNCTION button repeatedly to cycle through the adjustable settings (e.g. clock, warn, aux, dimmr, R-SP, tel).
4. Once you have the AUX option selected, press the up and down arrow keys to turn the AUX port from OFF to ON.
5. Press the BAND button to save settings and return to normal operation.

Once everything was turned on, I connected my iPod, switched to the AUX source, pressed play on my iPod, and finally my car was filled with sound from my iPod without the use of a low quality FM transmitter — and the peasants rejoiced.

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Filed under: How-To & Tech Tips