Elo TouchSystems C-Series User Manual page 47

In usual, even if the operating system reassigns these serial ports, they
are still in order. In this case, you should change it as the following table.
USB Serial Port (COM5)
USB Serial Port (COM6)
Thus, the settings for these USB Serial Ports should begin at COM3 and
end at COM4 in order.
4. To correct it, please follow the instructions below:
Double click the port you need to change. In this case, it is COM5.
C-Series Touchcomputer for Healthcare Applications User Guide 32
Original one Change to
USB Serial Port (COM3)
USB Serial Port (COM4)