English COM (serial port)

COM: serial communication port cluster communication port

It's a serial port. Nowadays, PC computers generally have two serial ports, COM 1 and COM 2. Serial port is different from parallel port in that its data and control information are transmitted bit by bit. Although the speed will be slower, but the transmission distance is longer than the parallel port, so long-distance communication should use serial port. COM 1 usually uses 9-pin D-connector, also known as RS-232 interface, while COM 2 uses old-fashioned DB25-pin connector, also known as RS-422 interface, but it is rarely used at present.

Serial interface, COM interface for short, is an extended interface using serial communication protocol. The serial port appears around 1980, and the data transmission rate is115 kbps to 230 kbps. Serial port is generally used to connect mouse and external modem, old camera and tablet. At present, some new motherboards have begun to cancel this interface.