Why does my serial to USB adapter not work in Windows 10?

This article details a driver issue you may experience with your R829 serial to USB adapter in Windows 10.

Product applicability

The following products are discussed in this article:

  • Legacy: R829 and R829C

For legacy Carmanah school zone beacon systems you have the ability to connect via serial (RS-232) or a serial to USB adapter when programming with the R829 School Zone Calendar software.

Some older adapter chips are unsupported in Windows 10 running newer drivers. You may experience this with the following error/warning shown in Device Manager within Windows:


The following Prolific chips are not supported in Windows 10 and have gone end of life (EOL):

  • PL-2303HXA and PL-2303X

Prolific recommends using one of the following:

  • PL-2302HXD or PL2302TA

The adapter you have may also be flagged with a counterfeit chip. For more information Prolific please see this article.


Carmanah recommends replacing the serial to USB adapter from a reputable manufacturer and supplier. A temporary workaround involves downgrading the adapter's driver. Please see the instructions below:

These instructions will require Administrative privileges. Please contact your IT department as required.

  1. Download these legacy Prolific drivers here.
  2. Unzip and run the installation file.
  3. Restart your computer if required by Windows.
  4. Navigate to Device Manager within Windows.
    1. Start --> Run --> devmgmt.msc
  5. Double click on the Ports section to expose all available ports.
  6. Right click on the PL2303HXA device and click on Update Driver.
  7. Click on "Browse my computer for drivers."
  8. Click on "Let me pick...."
  9. Choose the driver from 2008 and click Next.
  10. The driver should now show as successfully installed and the error message should now be gone.

Windows may automatically update the driver and render the adapter unusable again the next time you plug it into the PC/laptop. Carmanah does not recommend manually downgrading the driver as a long term solution.

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