ExpressCard/34 is a 34mm wide laptop expansion slot providing PCIe x1 and USB 2.0 interfaces. Used for adding eSATA, FireWire 800, TV tuners, and other expansion to laptops from 2006 to 2012.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | GND | Ground | GND |
| 2 | USB D- | USB 2.0 data negative | BUS |
| 3 | USB D+ | USB 2.0 data positive | BUS |
| 4 | 1.5V | 1.5V supply | PWR |
| 5 | 3.3V | 3.3V supply | PWR |
| 6 | REFCLK+ | PCIe reference clock positive | BUS |
| 7 | REFCLK- | PCIe reference clock negative | BUS |
| 8 | PERXP | PCIe RX positive | BUS |
| 9 | PERXP | PCIe RX negative | BUS |
| 18 | PETXP | PCIe TX positive | BUS |
| 19 | PETXN | PCIe TX negative | BUS |
| 26 | GND | Ground | GND |