What is the com port?

COM port (cluster communication port) is the serial communication port, referred to as serial port. The serial port on the microcomputer is usually 9-pin, and there are also 25-pin interfaces with a maximum rate of 115200 bps. Usually used to connect the mouse (serial port) and communication equipment (such as connecting an external modem for data communication or some factory CNC machine interfaces), etc.

Generally, there is only one serial port outside the motherboard. The nine-hole output port (trapezoid) on the back of the chassis together with the parallel port is the COM1 port. The COM2 port generally requires pins from the motherboard. lead out. The parallel port is the longest trapezoidal port.

But the current mainstream motherboards generally only have one serial port, or even none, and it will gradually be replaced by USB.

The interface standard specification and bus standard specification of the serial port are RS-232, sometimes also called RS-232 port.

9-pin serial port pin diagram

9-pin serial port pin function:

Pin function

1 Carrier detection (CD)

2 Receive data (RXD)

3 Send data (TXD)

4 Data terminal ready (DTR)

5 Signal ground Line(SG)

6 Data ready(DSR)

7 Request to send(RTS)

8 Clear to send(CTS)

9 Ring Instructions(RI)

The above is the detailed content of What is the com port?. For more information, please follow other related articles on the PHP Chinese website!