Apple 30-pin dock connector was used on iPhone (original to 4S), iPad 1-3, and iPod from 2003 to 2012. Carried USB, FireWire 400, analog stereo audio output, composite video, S-Video, and serial data.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | GND | Ground | GND |
| 2 | Audio GND | Audio signal ground | GND |
| 3 | Right Audio Out | Right stereo audio output | ADC |
| 4 | Left Audio Out | Left stereo audio output | ADC |
| 5 | Right Audio In | Right audio input (line in) | ADC |
| 6 | Left Audio In | Left audio input | ADC |
| 7 | GND | FireWire ground | GND |
| 8 | TV Out | TV-out video select | I/O |
| 9 | (reserved) | Reserved | I/O |
| 10 | (reserved) | Reserved | I/O |
| 11 | GND | Composite video ground | GND |
| 12 | TX- | FireWire TX negative | BUS |
| 13 | TX+ | FireWire TX positive | BUS |
| 14 | GND | FireWire power ground | GND |
| 15 | GND | FireWire ground | GND |
| 16 | RX- | FireWire RX negative | BUS |
| 17 | RX+ | FireWire RX positive | BUS |
| 18 | +12V | FireWire power 12V | PWR |
| 19 | +12V | FireWire power 12V | PWR |
| 20 | (accessory) | Accessory indicator | I/O |
| 21 | USB GND | USB ground | GND |
| 22 | (reserved) | Reserved | I/O |
| 23 | USB Data- | USB D- | BUS |
| 24 | USB Data+ | USB D+ | BUS |
| 25 | USB PWR | USB +5V | PWR |
| 26 | USB PWR | USB +5V | PWR |
| 27 | (reserved) | Reserved | I/O |
| 28 | (reserved) | Reserved | I/O |
| 29 | +3.3V | 3.3V device power | PWR |
| 30 | +5V | 5V power | PWR |