AV output from iPhone 3G dock

Q: I bought the iPhone 3G dock in the U.S. about two weeks ago, as they were not available for sale in Denmark at that time. Now that I’m back in Denmark for a couple of months I want to use it to direct the output sound from the iPhone’s iPod application to my AV system. So back in Denmark I purchased the Apple Composite AV Cable. However, I am not getting any sound from the iPhone when using these cables via the Dock. The iPhone does charge in the dock, but there is no sound.

However, when I connect the AV cables directly to the Dock Connector on the bottom of the iPhone, everything works as it should.

So to get sound from a Dock MUST I use the mini-jack out on the back? Can I not transfer sound through the Dock Connector? Could this be an issue with my 3G Dock being purchased in the U.S. and the Apple AV cables being purchased in Denmark?  Any advice is appreciated.

– Kenneth

A: Unfortunately, this appears to be a limitation of the iPhone 3G dock itself, and has nothing to do with where the Dock or AV cables were purchased (there are no international differences between iPhone 3G Docks, and the only difference with the AV cable between countries is the power adapter it is bundled with).

The iPhone 3G Dock simply does not output audio or video via the Dock Connector at all, nor does it pass-through the AV Cable’s video authentication. As a result, the only way to get audio from the iPhone 3G Dock is to connect directly to the audio out mini-plug on the Dock itself.

Note that the audio quality from this plug should be equivalent to what you will get via the Apple AV cable anyway, and you can still charge your iPhone either with the AV cable or with the original USB cable and power adapter which came with the iPhone.

For playing back video you will need to either connect the Apple AV cables directly to the bottom of the iPhone, or look at a different dock, as the iPhone 3G Dock has no video output capabilities and does not recognize the Apple AV cables.

The 2007 Apple Universal Dock is compatible with the Apple AV Cables and will pass audio and video output through the Apple AV cables. The AV cables are required for video output, however, as this Dock has an audio-only line-out but does not have any video outputs of its own.

On the other hand, the older 2005 Apple Universal Dock will provide audio and video output via its own S-Video and Line-out port (which can also be used as a video port with a three-lead mini-to-RCA cable). However, the 2005 Universal Dock does not work with the Apple AV cables as the audio and video output is directed to the Dock’s own ports rather than the Dock Connector.