USB 3.0 Header is a 20 pin 2mm pitch header using the less common ICC pin numbering. The header has a key slot on the pin 1-10 side if enclosed.
USB 2.0 Header is a 10 pin .1 pitch header using the standard IDC pin numbering. The header has a key slot on the pin 1-9 side if enclosed. (The 10-pin IDC male graphic shown has the keying on the wrong side).
Both headers contain two ports each, and have a missing pin for filled female connectors.
|USB 3.0||USB 2.0|
IDC Pin #
|4||7||GND||Ground for Power||GND||7|
|7||13||DRAIN||Ground for Shield Drain||Shared pin 10|
|8||15||D1-||USB 2.0 data||D1-||3|
|11||20||D2+||USB 2.0 data||2||D2+||6|
|13||16||DRAIN||Ground for Shield Drain||S-GND||10|
|16||10||GND||Ground for Power||GND||8|
|20||2||No Pin||Space of Filled Keying||No Pin||9|
The standard USB 2.0 Header is missing pin 9 (for keying), but logically pin 9 is for port1's Sheild GND. The sheild is left unconnected if a single port cable is plugged in to port 1. Dual Port hear connectors, share port 10 for both sheilds
This is the most common USB 2.0 header (10 pin [2x5], missing pin 9) and it is pin compatable with the rare 8 pin [2x4] version (missing pins 9 and 10) and 10 pin [2x5] (no pins missing). It is not pin compatable with the very rare (10 pin [2x5], missing pins 10 and 2).
A new feature of USB 3.0 is the SuperSpeed bus, which provides a fourth transfer mode at 5.0 Gbit/s, this is simply left out of the 2.0 header.