Universal Asynchronous Receiver / Transmitter. The UART is the hardware component that performs the main serial communications tasks:
- converting characters into a serial bit stream
- adding start / stop / parity bits, and checking for parity errors on the receiver side
- all tasks related to timing, baud rates and synchronization
Common UARTs are compatible with the 16550A UART. They include a 16 byte buffer for incoming data (RX FiFo), and a 16 byte buffer for outgoing data (TX FiFo). Usually these buffers can be disabled/enabled using the Windows Device Manager and opening the property page for the appropriate COM port (e.g. COM1).