What is Power over Ethernet?

Power over Ethernet (PoE) technology describes a system that passes electrical power safely along with data through Ethernet cabling.

PoE enables remote network devices such as access points, IP phones and surveillance cameras to be installed in locations far away from AC sources. It also eliminates the bulky AC adapter for each device. In addition, PoE can be used as an electrical source for the most efficient LED lighting.

PoE sends electrical power over unused wires in eight-wire cables and over signal wires in four-wire cables. PoE networks are created with a PoE-based Ethernet switch, but PoE can also be added to a non-PoE switch. In addition, regular Ethernet devices can be used in a PoE network.

The IEEE standard for PoE requires category 5 cable or higher for high power levels, but can operate with category 3 cable if less power is required. Power is supplied in common mode over two or more of the differential pairs of wires found in the Ethernet cables and comes from a power supply within a PoE-enabled networking device such as an Ethernet switch or can be injected into a cable run with a midspan power supply.