Power over Ethernet
Power over Ethernet (PoE) is tech created for wired LAN (using Ethernet cables) that allows for the proper electric current to be carried by the data cables instead of separate power cords.
By using the technology, LANs have easier maintenance, better installation flexibility and significantly lowered costs.
In order for PoE to work, the current must be kept separated from the data signal, leaving no interference.
For this to happen, the current must start at the power-supply and end at the device, not vice versa.
An "injector" is used to make sure the current enters the cable and the device on the other end will require a "picker" if it is not PoE-compatible to start.