Change the COM port for USB232A-B on Windows OS

Start by going to the Device Manager. Once there do the following: Expand the Ports ‘(COM& LPT)’

Device Manager Ports COM and LPT section

You should be looking at something like this:

Device Manager Ports COM and LPT section expanded

As you can see Windows has set the port to COM10. However many legacy applications expect the port to be between 1-4. Let’s change that:Right click on the device and click on ‘Properties’.

Device Manager Ports COM and LPT section expanded menu

Click on ‘Port Settings’. Then click on ‘Advanced…’.

Serial Adapter Properties page

Once you’re in ‘Advanced Settings for COM10’ on the bottom you can see the ‘COM Port Number: COM10’. Click on that to change it to the lowest possible number (between 1-4).

Select COM port number from the drop down menu

Then click ‘OK’ on all open Property Windows. Now the device should look like this:

Verify COM Port number in the Device Manager Port COM and LPT section