WSL2 not able to access physical com port (Not USB!)

[dat422]

Windows-Version: Microsoft Windows 11 Pro Version 24H2 (OS Build 26100.4351)
WSL Version: 2.4.13.0
Kernel Version: 5.15.167.4-1

I am trying to access a physical RS-422 serial port (D-Sub 9) from WSL2 on Windows 11 Pro Version 23H2 using Python. This is not a USB serial device — it is a real COM port. The industrial PC has four dedicated physical COM ports.

What I see:

• The device works fine when connecting from native Windows using COM1.
• In WSL2, /dev/ttyS0 through /dev/ttyS3 are visible.
• I tried connecting via all of them, but none of them work.
• I have checked the Windows registry for the serial device map and it looks fine.
• I know about usbipd for USB devices

[github-actions]

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How to collect WSL logs

Download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
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.\collect-wsl-logs.ps1

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[dat422]

/question

[github-actions]

Diagnostic information

Found '/question', adding tag 'question'