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.

Thanks,
Alex

I think for building a line-out cable you need to connect the pin 11 (Serial GND) to ground. See this link for reference to the pins
http://pinouts.ru/Devices/ipod_pinout.shtml

With this pin connected to GND you will get the not compatible message.

Originally Posted by feltumonis

I think for building a line-out cable you need to connect the pin 11 (Serial GND) to ground. See this link for reference to the pins
http://pinouts.ru/Devices/ipod_pinout.shtml

With this pin connected to GND you will get the not compatible message.

obviously it is not serial ground but the accessory pin which is grounded with a resistor.

There are lot's of confusing and wrong pinouts available in the internet...

In this description NUMBERING is INVERSED: pin 1 is pin 30 and pin 30 is pin 2, so, don't look at numbers on connector.

While in the past they only used different static values for accessory identification, it looks like they use an "accessory bus protocol" or at least some pulses on this pin.

Hmm, even with the accessory pin connected directly to ground I still do not get any message on the iphone. Does power have to be applied as well? Does it matter if the line out is not actually hooked up to anything (I doubt it)?

To get the "not compatible" message, the cable needs to make the same connections that ipod accessories make. Someone must know wht this is, right?

Hey, did you try what I said? That was how i got the not compatible acessory message. You have to connect the resistor between the acessory pin and the GND pin (i think it is pin 30, look the link again) AND connect the serial gnd pin to the GND pin.

I'm looking forward to doing the same thing. I've managed to build an ipod line out connector but it doesn't work with the iphone.. Hasn't anyone tried to open the iphone dock to check the pinout?