Some special software, due to the simplification of programming, only provides COM 1-COM4 port number for selection, which has no influence on desktop computers with their own serial ports, because the two serial ports on the motherboard of desktop computers are fixed COM 1 and COM2. USB to serial port is a big problem, because the simulated port number is very large, you can't choose the correct COM port in the software, and no matter how you change the USB interface, you can't change it to COM 1-COM4.

In fact, this problem can be solved by setting up the system. First, right-click the desktop "My Computer" and select "Properties" to open the window shown below. Then find the hardware bar above and click "Device Manager" below.

Then click the+sign in front of "Ports (COM and LPT)" in Device Manager. In this way, you can see the simulated COM port number of your patch cord, and then click "right-click" on this item and select "Properties".

Then find the "Port Settings" column in the properties window that appears, and click the "Advanced" option. See the COM port number? Just change it here, click on it, there are many port numbers. Then select the port number you want to set. Then keep clicking "OK".

Then go back to the device manager, right-click the "port" item, and select "Scan to detect hardware changes". After scanning, if the change is successful, it will be displayed as the port number of the COM port you just changed.