TP-DCDC-1248GD is the DC to DC converters offered by Tycon Power Systems are a 
low cost and high reliability solution for those requiring 48VDC 802.3af Power 
Over Ethernet voltage from a 12 or 24V battery system. 
They have an integrated Gigabit 802.3af PoE injector to apply the regulated 
48VDC to the CAT5 Ethernet cable. The input voltage must be between 9VDC and 
36VDC. 
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 
unused 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 17W.