For those who have older Audi with AMI (Audi Music Interface) unit installed, we tend to get stuck with a 30-pin iPod and iPhone original AMI cables. There are many part numbers for each type and year of the car, but by playing and modifying AMI cables, I found out that they’re basically the same, the only thing different is the resistors detection. All 3G cables have detection resistor (pin21 & pin22) ~18.7k and 2G ~ 1.87k. When the resistor detection is less than 900 ohm – 0 ohm, the AMI changes to Auxiliary mode which will turn off the USB power and play whatever on pins 1,2 with ground 3. By design, the resistor detection will go to Auxiliary mode with value of 1k ohms for all version. .
To make an external USB drive connector.
We need to get a female USB connector and wired it to the AMI connector with correct pins and designation: pin 28 (orange) = 5V, pin 25 (black) = Ground, pin 17 (green) = USB data +, pin 18 (yellow) = USB data -.
To make an Auxiliary Female Connector.
We need a female 3.5 mm jack connector: pin 1 (light brown) to left, pin 2 (purple) to right, and pin 3 (dark brown) to ground. It doesn’t really matter which pin 1 or 2 is left or right, as long as pin 3 is to ground.
To make a USB female power cable for USB dongle and relay (auxiliary mode) power when plugged in.
Get a female to male USB extension or a bulk female, but it’s better to get the extension an try to splice out the 5V and Ground line for the relay.
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Thanks Louis for your fast response.
You also tried this? great! Yesterday night I thought a bit on this because such AMI-RCA cable exists and someone demonstrated successfully: https://www.youtube.com/watch?v=rDOproECwDU, he claims it works on MMI 2g/3g but I am not so sure..
2ndly, I also think about the detection resistor on 21-22 , you said it should be 1.87K for 2G, but someone says 1K, I don’t if this cable for all VAG cars the same. BTW: I tried 10K still not detected.
3rdly, as you have shown on the Android box, does the resolution also play a role here, because MMI-2G high screen would only accept 480p? i.e. any video input should be 480×240?
If all above fails …
So, instead to buy a new Interface Unit with FBAS green connector (need to remove “component lock”) or as you do add manually the missing pieces on to the IC board. I may jump a little further to directly go to the display interface, which is the -22b- plug to J685(the screen). Do you have any research on this port? is it a SCART like or LVDS? comparing with the 3G LVDS which has only 4 pins, this 2G one has 22pins, really strange. On this other side, since it can display navigation motion pictures, so the head unit(infact interface box J523) should be capable to handle the video even w/o the add-on of “SAF7113H”? which is a video A-D convertor, if somewhat the video can be directly digital/LVDS(22b?) then it would be perfect but what kind of 22b header it is?
Thanks for discussion.
Cheers