To interface with these and other devices, USB-to-serial converters can quickly and easily add a serial port to a modern PC.

Server computers may use a serial port as a control console for diagnostics, while networking hardware (such as routers and switches) commonly use serial console ports for configuration, diagnostics, and emergency maintenance access. However, serial ports are still frequently used in applications demanding simple, low-speed interfaces, such as industrial automation systems, scientific instruments, point of sale systems and some industrial and consumer products. Modern consumer personal computers (PCs) have largely replaced serial ports with higher-speed standards, primarily USB. While interfaces such as Ethernet, FireWire, and USB also send data as a serial stream, the term serial port usually denotes hardware compliant with RS-232 or a related standard, such as RS-485 or RS-422. Throughout most of the history of personal computers, data has been transferred through serial ports to devices such as modems, terminals, various peripherals, and directly between computers. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time.

A male D-subminiature connector used for a serial port on an IBM PC compatible computer along with the serial port symbol

Serial communication pdf