The LinkSprinter’s PoE test capability is limited to the 802.3af standard. It cannot test for non-standard PoE voltages.
When connected to PoE, the batteries are not used, as the unit operates as an IEEE 802.3af Powered Device (PD). The LinkSprinter operates as a Class 0 PD and draws about .4 watts. The LinkSprinter powers up automatically when connected to PoE and remains on until you remove the cable.