A splitter, or active splitter, enables an existing network to support PoE. It splits the power and data in an Ethernet cable into two separate cables, which can then connect to a device that has no built-in support for PoE. Because the 802.3af standard supplies only 48 volts DC, another function of the splitter is to step down the voltage to the appropriate level for the device, often by 12 or 5 volts.