# GPIO
GPIO (general-purpose input/output) is a series of digital interfaces that can be used to connect relays, LEDs or sensors.
Using GPIO on a Pi-KVM is a feature designed for advanced users, so make sure you understand exactly what it is.

In the case of Pi-KVM, the general term GPIO refers not only to the [physical interface of the Raspberry Pi](https://www.raspberrypi.org/documentation/usage/gpio),
but also to various plugins (for example, for [USB relays](http://vusb.wikidot.com/project:driver-less-usb-relays-hid-interface))
that can also be used transparently by emulating abstract GPIO API.