1 Right output + 2 Right output - 3 Left output + 4 Left output - 5 GND 6 ? 7 ACC 8 (no connection) 9 Clock 10 BATT +B 11 Data 12 (no connection) 13 ?
If you can use a soldering iron and are willing to void your CD changer warranty, it's possible to use certain Panasonic CD changers in certain Audi's with certain factory head units, without paying for an adapter. This is known to work on a 98.5 A4 having a 13-pin DIN connector in the trunk, with a Panasonic CX-DP610. It will probably also work with a CX-DP601 and Audi's at least up to 2001. In all cases, use this information at your own risk.
To allow the changer to interface with the head unit, it's necessary to bridge pins 8 and 11 of the changer. An easy place to do this is on the circuit board. Remove the bottom panel and look for the area where the external connector attaches to the circuit board. This is shown in the following picture, which has pins 8 and 11 labeled. With a continuity tester, verify these pins on your own. Once confirmed, place a bead of solder across the two pins, as shown.
Note: the RAND function will not operate.
The last step is to be courteous to future owners of your CD changer, and stick a mailing label on the unit which explains the modification you made. This way someone won't try to use it in another make of car and start a fire.