A COM port, short for communication port, is a physical interface used to connect a computer to external devices, such as modems, printers, and other peripherals. COM ports have been a common feature on personal computers since the early days of computing, but their use has declined in recent years as other interface standards, such as USB, have become more popular.
Despite their declining popularity, COM ports are still used in a variety of applications, including industrial automation, medical devices, and point-of-sale systems. In these applications, COM ports offer several advantages over other interface standards, including their reliability, low cost, and wide availability.