After finding my USB cables for connecting the Drone microUSB to a desktop USB have been mislaid, do the USB cables have to be DJI specific only?
As I have tried other USB-MicroUSB cables but they do not work to help calibrate the Vision Sensors.
I have to Calibrate the Vision Sensors with DJI Assistant but I can not carry out that procedure because of incorrect USB cables?

Any links or advice much appreciated.

Any good quality cable should work. Thing to watch out for on some of the cheaper cables is that they are designed for charging only, so there may be no physical data path, or at best it might not be certified to work properly.

An ordinary USB cable with a mini plug at one end is fine.
If the program DJI Assistant 2 can see your Phantom when you turn it on, your USB cable is ok.
If you can not calibrate your Vision Sensors, either your monitor is not suitable for calibration or your Vision Sensors are defective.

Regards Leif.

If you're using a desktop computer, is there another monitor you could try calibration with ?
Or try changing refresh rate on monitor, this has been suggested in other posts as a fix.

I would recommend you to use the original USB cable. Please contact your local dealer or seller for assistance if applicable. Also, below is one tutorial video of VPS calibration for reference:

I started getting an error message on my P4 Pro saying downward vision sensor needed calibrating. I did this twice successfully in DJI assistant 2 but am still getting the error....any clues why it should pass the calibration test OK and still give this error message. Thanks