ANS:B - universal asynchronous receiver/ transmitter

Definition:

The UART (Universal Asynchronous Receiver/Transmitter), is a large scale integrated circuit (IC) which contains all the software programming necessary to fully control the serial port of a PC.

A UART chip is an electronic circuit that transmits and receives data through the serial port. It converts bytes into serial bits for transmission, and vice versa. It also generates and strips the start and stop bits appended to each character.

Once a connection is established, the UART then reconstructs a byte of data based on the receiving line. If parity is in use, the UART will also check the parity for the correctness and strip the parity bit off the byte being passed to the computer.

SingleByte FlFO Buffers:

The UART speed in most PCs, until recently, used 8250 or 16450 UARTS. These are singlebyte FlFO (FirstIn, FirstOut) buffers.