It's like a shrunken version of the Arduino Leonardo as it features the same ATmega32U4 microcontroller, micro-USB port, and pinouts. It also operates at 5V and requires an external supply of 7 to ...

However, the USB port doubles as a power port. To use it as such, you need a USB cable and a 5V power source. In the case of the Arduino Nano, a mini-B USB cable is required.

On board is a Mini-PCIe slot, 100Mb Ethernet port, Micro SD slot, RS-232, and USB host and client ports. Here’s the datasheet for the Galileo with all the applicable information.