Q: I have an iPhone 3G; my car has an auxiliary input on the dash. I would like a solution where I can connect my iPhone via dock adapter to charge and output music from one device – its a pain to connect a dock-connector car charger and a 3.5mm output jack from the top to output music.
A: At this point, only one of the major accessory manufacturers has released a “Works with iPhone” certified car charger with AUX output. The Kensington LiquidAUX for iPhone and iPod provides a car charger with a non-detachable shielded AUX output cable and a wireless remote with a steering wheel mounting bracket.
Note also that Griffin Technology and Belkin both offer Works With iPhone certified chargers with FM transmitters, both of which work with the iPhone 3G.
From our testing thus far, accessories that were Works With iPhone-certified for the original iPhone will still function normally with the iPhone 3G, however you may receive the nag (“This accessory is not made to work with iPhone”) message whenever you connect one of these accessories, suggesting that you turn on Airplane mode to avoid interference from the cellular radio.
Airplane Mode should not be necessary with a Works With iPhone product, and the display of this message for a certified accessory is a bug that Apple should fix.
Whether or not you will actually hear this interference depends on the individual accessory, but most car charger AUX outputs do not exhibit this problem anyway unless the iPhone itself is left in close proximity to the car speakers.
In fact, despite the lack of official Works With iPhone certification, Griffin’s AutoPilot for the iPod (iLounge rating: B) will work fine with the iPhone, subject to the restrictions and considerations mentioned above: You will get the Airplane Mode prompt (which you can safely select NO to), and there may be a risk of audio interference if the phone is placed too close to your car speakers or head unit.