The TP-DCDC-4848GD offered by Tycon Power is a low cost and high efficiency solution for those requiring IEEE802.3af Power over Ethernet from a +48VDC or -48VDC voltage source like a battery system or telecom power source. They have an integrated Gigabit POE injector to apply the power and data output to the CAT5 Ethernet cable. The output voltage is regulated and protected. They have a common (-) and two (+) inputs for connecting 2 power sources, such as a primary with a backup power source. A metal enclosure model is available for industrial applications. They accept gigabit data-in to a shielded RJ45 Jack and provide gigabit data-out and PoE power on the shielded RJ45 output jack. They work by supplying power on the unused Ethernet pins 4,5(V+) and 7,8(V-). They have various protections for surge, short circuit and overload. The units have power outputs up to 17W.