What is an RS232 serial port?

Answer: "It is an asynchronous transmission standard interface formulated by the Electronic Industries Association (EIA). The electrical characteristics of the serial port: 1) The maximum distance of RS-232 serial communication is 50 feet; 2) RS232 can achieve bidirectional transmission, full Duplex communication; the 9-pin interface behind the desktop computer is the com port (serial port), which is widely used in industrial control data acquisition;"