Fixing USB to Serial Device Driver Issues (Windows)


Do NOT attempt to download or install any device drivers for the USB to Serial cable from the internet. Windows must use the device driver it selects and installs on its own.

If you have an older USB to Serial adapter (the short translucent blue and silver cable) which was purchased before March of 2016, then to work with recent versions of Windows, you will need to purchase a new USB to Serial adapter from FarmTek or a computer store. To purchase from FarmTek, contact us at 972-429-0947.

To determine if you already have the compatible USB to Serial adapter, look for the LED in the blue connector while the cable is connected to a powered on computer as shown here. If you see an illuminated LED, the cable is is compatible with recent versions of Windows. Otherwise, a new USB to Serial adapter must be purchased.

Installing the USB to Serial Cable
  1. Make sure you have a working internet connection. An internet connection is required only during the first installation of the cable during which time Windows downloads and installs the proper device driver.
  2. Connect the USB cable to a convenient USB jack on your computer. You'll want to plug into the same jack each time the cable is used in the future.
  3. Windows will automatically install the proper device driver for the cable. This may take a while, so be patient and let the process finish. Under Windows XP, you will be asked to confirm that Windows can connect to the Internet to find the driver, choose either of the "yes" options, and at the next prompt, select the "Automatically install driver software" option.
  4. Installation creates a COM port number that you will select or specify in the record keeping software you are using. To find the assigned COM port number, look for the "Prolific to USB Serial Adapter" entry under the "Ports (COM & LPT)" category in the Windows Device Manager.

To access the Windows Device Manager under Windows 10 and Windows 8.x, press and hold the Windows key (bottom left corner of keyboard) and type an "X". A menu will pop up near the bottom left of the screen. Left-click on "Device Manager."