The TP-DCDC-1248G-HP DC to DC converters offered by Tycon Power Systems are a low cost and high reliability solution for those requiring 48VDC Power Over Ethernet voltage from a +/-12V battery system.  The PoE inserters are Passive.  They accept data-in to a shielded RJ45 Jack and provide data-out and PoE power on the shielded RJ45 output jack. They work by supplying power on the Ethernet pins 4,5(V+) and 7,8(V-). They have various protections for surge, short circuit and overload. The units have power output of 50W.