Power over Ethernet HAT (B) for Raspberry Pi 3B+/4B and 802.3af PoE network

Jargon buster

Plain-language definitions for the technical terms used above.

DC

DC means direct current, where electricity flows in one constant direction, as supplied by batteries, USB ports and many plug-pack power supplies. When a product specifies DC, it runs from a DC supply rather than mains AC, so you need to provide the correct voltage and polarity.

GPIO

General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.

I2C

I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.

OLED

OLED stands for organic light-emitting diode, a display type where each pixel produces its own light. It matters because OLED screens are thin, high-contrast and easy to read for small status displays, but they can be more sensitive to image burn-in than some other display types.

PoE

Power over Ethernet lets one Ethernet cable carry both network data and electrical power. This is useful when installing a device where running a separate power adaptor would be difficult.