« Trashed iPhone Docking Station | Main | Hmmmm...blogging from iPhone »

August 17, 2007

iPhone Dock Extender Cable (with USB data sync)

Buy a Dock Extender Cable for iPod or iPhone at CableJive

It was only a matter of time. Since I picked up the iPhone I've had a nagging thought about about making the dock extender cable I hacked together iPhone-compatible.

So after a few long nights of poking around at it I've put together the iPhone/iPod Dock Extender Plus, or a cable that is compatible with the iPod and iPhone that does everything that the original hack did but also includes USB data connectivity and a workaround for a special trick Apple seems to have thrown into the iPhone dock.

How? Well, everything is almost the same, except the pins that you have to connect.

Using the original iPod dock extender cable with the iPhone only worked on Firewire-powered devices (ie the Bose SoundDock), and not so great because the iPhone doesn't recognize the device so you're constantly warned about it. It does charge, play music, and provide iPhone control.

Using the original iPod dock extender cable on the iPhone dock was a complete failure. The phone wouldn't charge (even though the pins for USB power are connected).

My first ideas was to add in USB data connectivity (pins 25 & 27). Still doesn't work connecting to the dock, but I discovered that if I connect the iPhone to the extender cable, and connect the extender cable directly to the Apple-provided iPhone sync cable, bypassing the docking station, that the iPhone charges and syncs as expected. Hmmm. A bit of a mystery.

Curiosity got the best of me and I ended up ripping the iPhone docking station apart to see what was going on inside. I discovered (although the ripping apart wasn't strictly necessary for this) that pin 7, an undocumented pin previously unused is accepted on the connector where the iPhone sits. It is not passed through to the USB cable on the back of the dock...but perhaps that is the mystery.

Sure enough, if you connect pin 7 (along with 25 & 27 for USB data and 16 & 18 for USB power) the iPhone works perfectly through the extender cable connected to the dock (I had to buy a second one since I trashed the first one trying to get it open).

So there you have it. An iPhone Dock Extender Cable, or better yet a iPhone/iPod Dock Extender Plus, which does everything that the original cable does plus it adds in USB data connectivity.

I've had a lot of requests for putting together a cable that has USB connectivity...mostly for automobiles that use the USB data connection to get playlists etc.

Now you have it.

For reference, the pinouts diagrams and site to get the connectors.

Posted by mike at August 17, 2007 8:00 AM