USB port #1 (the first from the left) is 24V. The remaining USB ports, 2-4, are all 12V.
Note: Depending on the age of the unit. the USB ports may be all Black (older variants) or a mixture of Red and Teal (newer variants)
Regarding the newer/current variant, Port #1 is Red (signifying 24V) and the remaining 3 ports are all Teal (signifying 12V).
Jul 09, 2019