[Audio line-out] Building a line-out cable
I have seen the long thread about building a video out cable, bu has anyone had any luck building just an audio line-out cable to connect to the dock connector on the iphone?
i have used a dock connector in my car for a while to play my ipod through the car stereo, and I would really like to use the setup with my iphone. Right now, when i plug in the iphone, absolutely nothing happens and the audio still plays through the iphone speaker.
I have tried connecting a 10K resistor and a 1M resistor between pin 10 and ground, and I still get no response when I plug in the iphone. I would be happy to even get the message about the accessory not being iphone compatible. Does anyone know what configuration will trigger this message?
I've opened up the iphone dock and done some testing. the big chip in there is a dual one-shot timer chip, which seems to control a couple transistors which switch pin 10 to ground through one of two transistors (I think one is for audio mode, and one is for serial mode). Anyone have any more information about this? I'm going to keep working with it, but I was wondering if anyone has already figured it out.
I have read about apple's custom ID chip to identify iphone accessories. As far as I can tell this chip is not in the iphone dock, so it should be possible to turn on the line-out signals without it (unless the chip labeled Q1 is the ID chip, but that wouldn't make much sense).
anyway, let me know if you have nay information about this. This is quite a challenge, and I would love to get it working.