Although a Dock Connector can refer to many things, Apple has established the small, rectangular, 30 terminal connector used to connect a full sized iPod to a personal computer or power adapter as "the Dock Connector" This device is often called a "30-Pin Connector".
The pins of the connector on most iPods are as follows:
| Pin | Signal | Description |
|---|---|---|
| 1 | GND | Ground (-) |
| 2 | GND | Audio & Video ground (-) |
| 3 | Right | Line Out — R (+) |
| 4 | Left | Line Out — L (+) |
| 5 | Right In | Line In — R (+) |
| 6 | Left In | Line In — L (+) |
| 7 | ||
| 8 | Video Out | |
| 9 | C | S-Video Chrominance |
| 10 | Y | S-Video Luminance |
| 11 | GND | Serial GND |
| 12 | Tx | iPod sending line, Serial TxD |
| 13 | Rx | iPod receiving line, Serial RxD |
| 14 | ||
| 15 | GND | Ground (-) |
| 16 | GND | USB GND (-) |
| 17 | ||
| 18 | 3.3V | 3.3V Power (+) |
| 19, 20 | +12V | FireWire Power 12 VDC (+) |
| 21 | Serial enable | Connects to ground via a 1 MΩ, 1 % resistor in Belkin Amp/Charger. When this pin is grounded it appears to close a switch making the iPod shut off in case of a power loss. Dock has the same resistor. Some sources suggest connecting this pin to pin 11 through a 500 kΩ resistor to enable serial communications. |
| 22 | TPA (-) | FireWire Data TPA (-) |
| 23 | 5 VDC (+) | USB Power 5 VDC (+) |
| 24 | TPA (+) | FireWire Data TPA (+) |
| 25 | Data (-) | USB Data (-) |
| 26 | TPB (-) | FireWire Data TPB (-) |
| 27 | Data (+) | USB Data (+) |
| 28 | TPB (+) | FireWire Data TPB (+) |
| 29, 30 | GND | FireWire Ground (-) |
The S-Video output has been replaced by a component (YUV) output at the iPod Touch and iPhone models, outputting 480i signals.
