using iPhone dock connecter to light a LED?

Question

Is there a way to get output through the iPhone's dock connecter. For example: i have a regular LED and i want to make an application that turns this LED on when pressed on a certain button.

Does an API exists, which enables me to transmit something out through some part of the dock connector?

Answer 1

To get the details of the dock connector, you have to sign up for the hardware developers license through http://developer.apple.com/programs/mfi/

Answer 2

Unless you are a corporation enrolled in the MFi program, you might have better luck using the audio jack to get (modulated) control signals out from a stock iPhone.