TP-DCDC-1248GD-HP is the  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 802.3af/at compatible. 
They have an integrated Gigabit PoE+ injector to apply the regulated 56VDC to 
the CAT5 Ethernet cable. The input voltage must be between 10VDC and 15VDC. 
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 35W.