What Are Serial Ports ?

Serial ports are a type of communication interface that transfers data sequentially, one bit at a time. Unlike parallel ports, which transfer multiple bits simultaneously, serial ports have been used throughout the history of personal computers to transfer data to devices such as modems, terminals, peripherals, and even directly between computers.

While Ethernet, FireWire, and USB also use serial streams to transfer data, the term “serial port” typically refers to hardware that is compliant with RS-232 or related standards like RS-485 or RS-422.

Today, most consumer PCs have replaced serial ports with faster standards like USB. However, serial ports remain popular in applications that require simple, low-speed interfaces, such as scientific instruments, point of sale systems, and industrial automation.

Serial ports are also commonly used as control consoles for diagnostics in server computers, while serial console ports are used for configuration, diagnostics, and emergency maintenance access in networking hardware like routers and switches. USB-to-serial converters can be used to quickly and easily add a serial port to modern PCs for interfacing with these devices and others.