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December 26, 2008

Connect Your Zune to an iPod or iPhone Dock

Update: CableJive is selling a universal dock adapter, which gives you standard USB for charging and audio from an iPod or iPhone dock. With the charging cable that comes with the Zune, the CableJive adapter will give you this same Zune to Ipod connection.

Over the holiday break I've had some extra time, which means breaking out the soldering iron to fiddle with some hardware stuff that's been sitting on my desk for awhile.

The short story, I've put together a hack to dock a Zune on an Apple iPod or iPhone dock connector. This Zune to iPod cable provides USB charging from the iPod dock to the Zune, and audio from the Zune back through the dock for listening.

The longer story . . .

Over the past year or so I've gotten a number of emails from folks who have a Zune, and are looking for a way to help it get along with the myriad of iPod and iPhone accessories (hacks like this and this invite these kinds of questions). Some folks hope it might be as simple as just plugging directly from the Zune to the iPod dock, but with just a little poking around it's quickly obvious that there's a lot more to it than just connectors and wiring.

So I did some digging, reading, and fiddling with the hardware. It seems like there are three levels of sophistication when it comes to connecting the Zune to an iPod or iPhone dock:

  1. Charge Only: Zune owner is happy with audio output but has a readily available iPod dock that would be nice to charge from.
  2. Charge and Listen: Zune owner would like to use the iPod/iPhone dock to get a charge, and take audio from the Zune back to device
  3. Charge, Listen & Control: Zune owner would like Zune to behave fundamentally like an iPod when docked. Not just charge and play music, but provide ability to choose music, control playback, etc.

Charge Only
The charge-only option is fairly straightforward, and doesn't require any kind of hack. You can buy a Charge Converter that connects to an iPod dock or cable and provides USB power through the mini-USB connector on the side. Connect your Zune cable to the mini-USB and you've got charging for the Zune from the iPod dock.

Charge, Listen & Control
Building a cable that offers charge, listen & control is complex. There have been efforts to provide a solution, including an on-the-fly conversion to make iPod commands understandable to the Zune, but seems like there hasn't been any activity lately on this effort.

Charge and Listen
It dawned on me the other day that for most folks, a simpler solution is probably adequate. Being able to listen to the Zune through, and charge it from the iPod connector might be enough.

The iPod connector pinouts are well documented, and the Zune pinout info is readily available. The male Zune connector and female iPod connectors are available from SparkFun or PodGizmo.

First thing was to make sense of the Zune pinouts. The documentation is simple enough, but it wasn't clear which direction they mapped to the physical connector. I plugged the USB end in and ran some tests with the multitester. When looking at the connector from the front, with the pins on the upper side, pin 1 is on the right and pin 24 is on the left.

Then it was to connect the USB power to see if the Zune would indicate charging. At first I connected just the USB power, pins 16 & 23 from the iPod connector to pins 22 and 1 on the Zune. Didn't charge. I tried a combination of the different ground and 5VDC(+) pins but finally figured out that the Zune won't charge unless the proper USB data pins are connected too. After connecting pins 25 & 27 from the iPod to pins 20 & 21 on the Zune, the power source was recognized and the Zune charged. I tested using the Apple wall charger, USB to iPod cable, and the dock.

Getting audio out of the Zune was a bit of a journey. I thought it would be as simple as connecting up the audio-out pins from the dock connector, but apparently the folks at MS require accessory validation before activating the audio output to the dock connector. I dug everywhere looking for an answer and was almost resolved that audio output wasn't going to be possible. Then it dawned on me...while not ideal, audio can be grabbed from the headphone output and routed into the iPod dock connector pins 2 (ground), 3 (right audio) & 4 (left audio). Sure enough, once I had added the 1/8" (3.5mm) stereo jack I was able to listen to music and FM radio through the iPod dock.

So there it is, in very rough form. A few parts, some wires, a soldering iron and a steady hand, and you've got a Zune charging and playing audio through an Apple iPod or iPhone dock. Next step is to grab a length of cable and build a more polished version.

Thoughts, ideas, feedback welcome in the comments. Is there interest in such an adapter?

Posted by mike at December 26, 2008 3:55 PM