The Unite 50 is powered over the USB cable and has been tested and does work with our 10m and 30m Fiber USB 3.0 cables as long as those are getting sufficient power.
The Unite 150 and 200 cameras will work on USB 2.0 but the video quality will be reduced as USB 2.0 only has about 10% of the bandwidth of USB 3.0 With our testing the best video quality we saw with USB 2.0 was 720P30, but you may see lower quality ...