Power over Ethernet (POE) is a technology that allows network cables carry electrical power.
Instead of using an adapter or outlet to power your device, Power over Ethernet (PoE) devices can receive electrical current directly from an Ethernet cable that is connected to a LAN. For example, wireless access points, IP cameras, network routers andVoIP phones. An Ethernet injector pushes the electricity into the cable from a switch on the LAN, which is picked up by the device at the other end and routed toward the device's power supply.
There are several common techniques for transmitting power over Ethernet cabling. Three of them have been standardized by IEEE 802.3 since 2003. These standards are known as Alternative A, Alternative B, and 4PPoE.
Devices that do not have PoE only receive data from an Ethernet cable.PoE devices can be mixed in a network with non-PoE devices, but non-PoE devices cannot provide power for Powered Devices (PDs) or be powered by Power Sourcing Equipment (PSEs)
5 big ones:
Eliminates the need for AC/DC power supplies and outlets to give power to PD equipment. That lowers the costs of adding or installing compatible PD equipment.
There are fewer points of failure.By connecting the PoE switch or PoE injector to an uninterruptible power supply (UPS), the PoE powered devices offer a constant power delivery.
The ability to remotely restart connected PoE devices: this can be done either manually, automatically or based on a schedule