POE power supply (Power Over Ethernet) is a technology that provides power supply to terminal devices while transmitting data through the existing Ethernet wiring infrastructure.The main components of POE power supply include power supply equipment (PSE) and terminal equipment (PD). PSE is usually a switch or injector, while PD can be IP camera, wireless access point (AP), IP phone and other devices.
Working principle
POE technology transmits data and power simultaneously through Ethernet cable. The standard Category 5 network cable has four pairs of twisted pairs, but only two pairs are used in 10M BASE-T and 100M BASE-T. The voltage of the POE power supply system is between 44 and 57V, the typical value is 48V, the maximum current is 550mA, the power supply power is between 3.84 and 12.95W, and the maximum does not exceed 13W.
Application scenario
POE power supply is widely used in various devices that need to be powered and networked at the same time, such as IP phones, video surveillance, wireless access points, etc. Its advantage is that it simplifies the equipment installation and wiring process, does not require additional power sockets and cables, improves the deployment flexibility and system reliability of the equipment, and reduces the installation and maintenance costs.
Historical background
The standards for POE technology are defined by IEEE 802.3af and IEEE 802.3at. The IEEE 802.3af standard was approved in 2003 and specifies the way to power devices such as IP phones, security systems, and wireless LAN access points via Ethernet cables. IEEE 802.3at (PoE+) provides greater power while being compatible with 802.3af.
