Serial port

In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals or modems. Mice, keyboards, and other peripheral devices also connected in this way.

While such interfaces as Ethernet, FireWire, and USB all send data as a serial stream, the term "serial port" usually identifies hardware more or less compliant to the RS-232 standard, intended to interface with a modem or with a similar communication device.

For many computer peripheral devices the USB interface has replaced the serial port — as of 2007, most modern computers are connected to devices through a USB connection, and often don't even have a serial port. The serial port is omitted for cost savings, and is considered to be a legacy port. However serial ports can still be found in industrial automation systems and some industrial and consumer products. Network equipment (such as routers and switches) often have serial ports for configuration. Serial ports are still used in these areas as they are simple, cheap and allow interoperability between devices. The disadvantage is that setting up serial connections may require expert knowledge and complex commands if poorly implemented.