Apple iPod dock interface

Back side of dock connector;
 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29

Pins 1,2 connected on motherboard.
Pins 15,16 connected on motherboard.
Pins 19,20 connected on motherboard.
Pins 29,30 connected on motherboard.

If you disassemble the original apple-ipod-dock-connector-cable and look at the connector itself, on the back side, where it is soldered, you can see the number 1 and 30 (e.g. pin 1 and 30). 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.

The remote control, iTalk and other serial devices use Apple Accessory Protocol for communication with iPOD. This protocol was introduced with the 3rd generation iPods, and is also compatible with the 4th generation iPods and mini iPods. The connections uses a standard 8N1 (one startbit 8 data bits 1 Stopbit) serial protocol, 19200 baud (higher rates up to 57600 also possible, but speed faster than 38400 may cause problems with large amounts of data), delay of 12 microseconds inserted between end of the stopbit and the beginning of the next startbit (also working without this delay).
Electrical: high +3,3V low 0V
default line state: high. Codes used for communication with peripherals are here

This device may be connected to the firewire computer port by straight cable (TPB+/-, TPA +/- shoulde be twisted pairs in cable)