Right-click the desktop My Computer chart → left-click the drop-down menu Manage → left-click the drop-down menu Device Manager → the device manager window appears. Expand the ports (com and LPT), and you can see the com port and port number.

For example, an industrial computer plugs two expansion cards (PCI- 1602 is RS485 expansion card and Moxa-C 104 is RS232 expansion card) and * * 8 COM ports, among which COM 1 and COM2 are native, COM3 and COM4 are RS485 expansion ports, and COM 5 ~ COM 8 are RS232 extensions of multi-serial card extensions.

Counting from the back of the industrial computer, the local computers are COM 1 and COM2, the serial ports are COM 5 ~ COM 8 in turn, and the remaining two are COM3 and COM 2.

COM4