PoE : Computer Hardware Buyers’ Glossary

PoE (Power over Ethernet) lets you deliver power to devices on an Ethernet LAN (Local Area Network). It can deliver DC power over long distances typically to a camera. The original IEEE (Institute of Electrical & Electronics Engineers) 802.3af-2003 PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA) to each device. Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable. The updated IEEE 802.3at-2009 PoE standard also known as PoE+ or PoE plus, provides up to 25.5 W of power. The 2009 standard prohibits a powered device from using all four pairs for power.