Serial port is a communications port. Such devices as modem, mouse or serial printer can be connected to it. The serial type of information exchange used provides for serial transmission of information (bitwise).Usually data can be transmitted in both directions (duplex mode).

Serial port is widely used when plugging in standard external devices (such as printer, scanner, mouse etc.), using the external computer interface and interconnecting computers.

Main advantages of using serial port when compared to parallel port are the ability of much longer distance transmission and much simpler connection cable. At he same time it is more difficult to work with it (in comparison with parralel port).

Today most PC serial ports comply with RS-232-C standard or RS-422 standard.