A network (Internet or LAN) must be available for the use of POE power.
Two methods of power supply of POE:
The POE standard defines two methods for transmitting direct current to a POE-compliant device using an Ethernet transmission cable:
Intermediate Bridging method
A kind of mid-span, known as the Tease Intermediate bridging method, uses an independent Poe power supply device that spans the switch and a POE-capable terminal, typically using an idle line that is not used in an Ethernet cable to transmit DC power. Midspan PSE is a dedicated power management device that is usually put together with switches. It corresponds to two RJ45 jacks per port, one with a short line to the switch (here refers to the traditional no POE function switch), and the other to the remote device.
End Bridging method
Another method is the end-bridging method (End-span), which is to integrate the power supply equipment in the switch signal in the export end, such an integrated connection generally provides the idle line pair and data line to amuse the dual power supply function. The data line uses the signal isolating transformer, and uses the center tap to realize the DC power supply. It can be foreseen that End-span will be quickly promoted, this is due to the use of Ethernet data and transmission of common lines, thus eliminating the need to set up independent transmission line, which is only 8-core cable and matching standard RJ-45 socket is particularly significant.