1. Putty to Proxmox.
  2. Make sure that your USB device (UPS) had been detected by Proxmox by issuing this command:

  3. I tried adding the hostusb 0d9f:0002 to the virtual machine but it won’t start the VM. The command I used was:
    qm set <WMID> -hostusb 0d9f:0002

    After issuing that command above, it will add line to your vm configuration file. It has been tested in Windows 7 and XP, it did not work on both.

  4. But adding this line worked on XP as guest VM. You have to stop and start your VM to recognise your port.

    args: -serial /dev/ttyUSB0

    Adding this line on your guest machine with Windows 7 will not start your VM.

  5. Boot your virtual machine and go to Device Manager. You will see a COM port.
  6. Install your UPSmon and search for UPS to initiate the port.