Four LEDs indicate IEEE802. 3af or 802. 3at/bt standard Dual 7-digit LEDs indicate power source either End Span (1/2, 3/6) or Mid Span (4/5, 7/8) or across all four pairs Determines standard PoE or non-standard passive PoE yellow LEDs indicate reversed polarity for power type When used inline, the display alternates between Voltage, Current and Power with a step button for selecting specific data to display