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Installing the USB driver for SQM-LU

Your SQM-LU needs a driver to allow your computer to communicate with it. This information is detailed by operating system here. Windows 10 users will usually find that Windows Updates locates and installs the correct driver once the SQM-LU is plugged into a USB port on your computer.

Installation on older versions of Windows

You can also read below this author's experience with installing drivers on Windows 7 (US English.) The information given below is accurate as of August 2013.


  1. Plug your SQM-LU into a USB port using the cable provided with the meter. Windows should notify you that a new device has been detected. Windows Update may notify you that a driver is available and you should allow Windows Update to install it. The driver name is FTDI - Other hardware - USB Serial converter.

  2. You will need to download an updated driver from You want the latest VCP driver for your version of Windows. The driver supports many devices made by this company, including the FT232R device used in the SQM-LU. The file that is delivered to you at the time of this writing is 'CDM 2.08.30 WHQL'.

    Save the updated driver to your hard drive and unzip it to a folder of your choosing - note the folder into which you unzipped the driver.

  3. Open the Windows Device Manager and scroll to the Ports (COM & LPT) item. Expand it to see 'USB Serial Port' item with a yellow caution icon overlaid. This indicates that the SQM-LU device has been detected but the driver needs updating. Right click the 'USB Serial Port' item and choose Update Driver Software.

  4. The Update Driver Software dialog opens. Choose Browse my computer for driver software. Navigate to the folder into which you unzipped the driver in step 2, and click Next. The driver should be updated; close the dialog.

  5. Returning to the Device Manager, note the 'USB Serial Port' item. The yellow icon should be gone, indicating that the driver for the device is working. Also note that a COM port number has been assigned, for example 'USB Serial Port (COM4)'. This is the COM port that you should assign for this connection in SQM Reader or SQM Reader Pro.