I still haven't installed mine so I thought I might as well help with this. Here goes:

1 - permanent power input
2 - amp. remote
3 - tuner
4 - tuner
5 - tuner
6 - tuner
7 - tuner
8 - serial pin 2 (RD)
9 - serial pin 3 (TD)
10 - headlights sense input / serial pin 8 (CTS)
11 - tel. mute input / serial pin 1 (CD)
12 - microhone sleeve
13 - earth
14 - ignition sense input
15 - rear output right
16 - rear output ground
17 - rear output left
18 - front output right
19 - front output ground
20 - front output left
21 - aux input right
22 - aux input ground
23 - aux input left
24 - microphone tip

The wiring of the serial port confuses me, can anybody verify this?

Best,
Borislav