What Is PoE and How Does It Work?
Power over Ethernet (PoE) lets network cables carry electrical power to any device on a network without an outlet or an adapter. It allows one cable to provide power as well as connect a device to your network.
The way it works is simple. Ethernet cable that meets CAT5e (or better) standards consists of four twisted pairs of cable, and PoE sends power over these pairs to PoE-enabled devices. In one method, two wire pairs are used to transmit data, and the remaining two pairs are used for power. In the other method, power and data are sent over the same pair.
When the same pair is used for both power and data, the power and data transmissions don’t interfere with each other. This is known as "phantom power." Phantom power is accomplished by power being transmitted on the data conductors by applying a common voltage to each pair. Data transmission is not affected since twisted-pair Ethernet uses differential signaling. The center tap of the standard Ethernet pulse transformer is then used to extract the common-mode voltage.
Security cameras, digital signage, video conferencing systems and wireless access points are examples of PoE-compatible devices.
To get the best PoE performance, you need to effectively dissipate heat and keep a cool, stable temperature in your cables. As the temperature of a cable rises, the electrical performance can be degraded. Higher heat dissipation is crucial to increase physical performance and longevity.