USBSER.SYS does not handle RTS signal correctly

  • Thread starter Thread starter Stanlazy
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Stanlazy

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Issue with RTS control via usbser.sys

Virtual serial port (USBSER.SYS) is not sending RTS/CTS via SET_CONTROL_LINE_STATE packets.


So yeah this issue is 10 years old now.


Using Wireshark+USBPcap and also logic analyzer directly on the USB line, it shows that usbser.sys does not send SET_CONTROL_LINE_STATE packets when I toggle RTS on software.
[COLOR=rgba(0, 0, 0, 1)]SET_CONTROL_LINE_STATE is only send on any write to DTR, along with the last RTS value set.[/COLOR]​

[COLOR=rgba(0, 0, 0, 1)]
I'm using pyserial but other post shows that using other software still produces the same issue.​
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[COLOR=rgba(0, 0, 0, 1)]
Partial workaround is to set DTR to any value after set RTS. However I sincerely hope this issue is fixed on the driver level.​
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