Service Terminal Troubleshooting

My Com Port numbers keep increasing:

Download the following zip file, extract it, and follow the included instructions:

Downloading and Installing FTDI drivers

In most cases, if you’re using Windows 10, the FTDI drivers should install automatically when you plug the device in (you must have an internet connection for this to work).

If this does not work, please download and install the drivers from the FTDI website as follows:

  1. Go to the FTDI website:
  2. Look at the table at the bottom of the page
  3. At the top right corner of the table, click the link “setup executable” to download the driver
  4. Extract the .zip file to get an .exe file
  5. Double click the driver to install the .exe file

FTDI provides detailed instructions on how to install the FTDI drivers, but in most cases they are not necessary. See

A driver is installed, but it’s the wrong driver/doesn’t work/has a yellow exclamation mark next to it

If a driver appears to be installed, but you still get this error, it is possible you have an old or incorrect driver. The first method to fix this is to simply re-install the driver. If this does not work, you should remove all existing drivers first by doing the following:

  1. Open device manager
  2. Plug the service terminal USB cable into the DCU.
  3. A new device will appear (likely under the ‘Com Ports’ or ‘Unknown Devices’ section)
  4. Right click the device, then select Uninstall
  5. In the dialog box that pops up, tick the checkbox labeled “Delete the driver software for this device.”
  6. Click Uninstall
  7. Repeat from step 1. until the device shows up with a yellow triangle exclamation mark symbol

After this is complete, you can re-install the FTDI drivers. (see above section)

Everything seems installed correctly, but the service terminal doesn’t work.

There are a number of issues that could cause this problem.

  1. Check that the DCU is powered on.
  2. Check that the computer makes a ‘USB plug in’ sound when (make sure windows sounds are enabled and your volume is not muted)
  3. Check Window’s Device Manager for any issues with the COM Port. Make sure a device appears when you plug or unplug the USB cable. The device should appear under the “Ports (COM & LPT)” section of Device Manager.
  4. If the service terminal is slow to connect or freezes, check that you do not have any extra serial ports plugged into your computer. Some computers come with built-in serial ports which you cannot remove – it’s suggested you use a different computer or contact EPDM for a workaround.