What is UART?

UART stands for universal asynchronous receiver / transmitter and defines a protocol, or set of rules, for exchanging serial data between two devices. Asynchronous means no shared clock, so for UART to work, the same bit or baud rate must be configured on both sides of the connection.

UART is very simple and only uses two wires between transmitter and receiver to transmit and receive in both directions. Both ends also have a ground connection.