The mUPS is a PoE injector with battery backup capability with a 12 V battery connector. It works just like a Gigabit PoE injector, but when power is lost, it switches over to the 12 V battery. Even if your power source is 28 V, the connected RouterBOARD will not reboot when the power source is lost, it will switch over to the 12 V battery transparently. The LEDs indicate DC line or battery usage, the charging of battery and low battery level (<50%).
Simply plug DC power supply or PoE powered ethernet cable into PoE in on the mUPS and connect any single 12V battery (AGM, Gel, Lead Acid, regular car batteries, deep cycle marine batteries, etc.).
Operating Temperature : -35C to +70C
Input Voltage : 12-28V (DC Jack & PoE In)
Output Voltage : 12-28V PoE & 12v DC Battery Charger