Denso QK20-R User Manual page 17

(3) Check that the USB device (scanner) to be connected is not
plugged in the computer, and then click OK.
Note: When installing the serial port driver for the 2nd or
the following USB devices on the same computer, check that
none of those USB devices is plugged in the computer, and
then click OK.
If the conventional USB-COM device driver version 1.x has
been installed, the message asking for uninstallation of the
conventional driver appears. Click OK.
If the message shown at left appears, the conventional driver
is running on the computer. Terminate the application using
the COM port of the driver, remove the corresponding USB
device, and then click OK.
Uninstalling drivers is in progress, showing the uninstalling
message given at left. Upon completion of uninstallation,
select Finish and reboot the computer.
After the computer reboots, go back to step (1) above again.
(4) Wait for installation of the driver files to proceed.
Note: When installation is in progress, the DOS prompt
window appears as shown at left. Do not close the window
since it is not abnormal. Wait for the window to
automatically close.
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