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Jun 05 2024, 07:30 AM - 11:30 AM (PDT)
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I need to force an USB port to only work on the same COM port (production line test)

Copper Contributor

Hello! I posted this question on but they redirected me here since it's not a home user issue:


We have to test a (very) large number of devices by connecting them to a PC (Windows 10) with an USB connection and a terminal emulator (Tera Term)

At the moment, every time a new device is connected it creates a new com port. This means that each time we change the device we have to re-configure the serial port, baud rate, ecc. and this is VERY time consuming (also, we actually don't know what will happen when we reach COM256. Will it go back to 1? Will it show some error?).

Since this use case is very specific, is there a way to force a COM port number on a fixed USB port? The PC is only used for that test line, so if forcing a COM number would create issues elsewhere it would not be an issue.

Thank you!

1 Reply
Bing AI says this:

:Yes, there is a way to force a COM port number on a fixed USB port. Here are the steps you can follow:

Open Windows Device Manager.
Right-click on the device and select Properties.
Under the Port Settings tab, click on Advanced.
Change the COM port number to your desired number1.
If the cable is connected to the same USB port, it should get the same COM number1. This way, every time a new device is connected, it won’t create a new COM port, and you won’t have to reconfigure the serial port and baud rate each time2.

As for your concern about reaching COM256, Windows should handle this automatically and assign available COM ports as needed2. However, it’s always a good practice to monitor this to ensure there are no issues.

Please note that these changes should not create issues elsewhere if the PC is only used for that test line2. I hope this helps! Let me know if you have any other questions.

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