POE (Power Over Ethernet) refers to the technology that supports Ethernet powered switches, while transmitting data signals to some IP based terminals (such as IP phones, wireless local area network access points, network cameras, etc.) without any modifications to the existing Ethernet Cat.5 cabling infrastructure.

The POE switch port supports an output power of 15.4W or 30W, complying with the IEEE802.3af/802.3at standard. It supplies power to standard POE terminal devices through Ethernet cables, eliminating the need for additional power wiring. Compliant with IEEE802.3atPOE switch, the port output power can reach 30W, and the power that the powered device can obtain is 25.4W Simply put, a POE switch is a switch that supports network cable power supply. It can not only achieve the data transmission function of a regular switch, but also provide power to network terminals at the same time.

POE technology can ensure the security of existing structured cabling while ensuring the normal operation of existing networks, minimizing costs.

POE, also known as Power over LAN or Active Ethernet, is the latest standard specification that utilizes existing standard Ethernet transmission cables to simultaneously transmit data and electrical power, while maintaining compatibility with existing Ethernet systems and users. The IEEE 802.3af standard is a new standard based on Ethernet power supply system POE. It adds relevant standards for direct power supply through Ethernet cables on the basis of IEEE 802.3. It is an extension of existing Ethernet standards and the first international standard on power distribution.

IEEE began developing this standard in 1999, with the earliest participating vendors being 3Com, Intel, PowerDsine, Nortel, Mitel, and National Semiconductor. However, the shortcomings of this standard have always constrained the expansion of the market. Until June 2003, IEEE approved 802 The 3af standard specifies power detection and control matters in remote systems, and specifies the way routers, switches, and hubs power IP phones, security systems, and wireless LAN access points through Ethernet cables. The development of IEEE 802.3af has included the efforts of many company experts, which has also enabled the standard to be tested in various aspects.

The IEEE 802.3at standard was developed in 2005 and promulgated in 2009. The output power of the 802.3at standard can reach 30W, and the available power at the receiving end is 25.5W

In late 2012, the IEEE 802.3 working group and various manufacturer alliances launched the POH-POWER Over HDBASET in the industry

By utilizing the current 4-Pair four wire technology and achieving a dual power supply of 60-100W, it can be achieved using Category 5 or 6 wires. Applied in high-definition video streaming to power 42 "LED TVs, according to the new regulations in the United States in 2010, 42" LED TVs require less than 70W of power consumption.

When arranging POE switches in a network, the working process of POE switches is as follows:

Detection: At the beginning, the POE switch outputs a very small voltage on the port until it detects that the cable terminal is connected to a powered end device that supports the IEEE802.3af standard.

PD end device classification: After detecting the PD of the receiving end device, the POE switch may classify the PD device and evaluate the power loss required by this PD device.

Start power supply: within a configurable time (usually less than 15) μ s) During the startup period, the POE switch starts supplying power to the PD device from low voltage until it provides 48V DC power.

Power supply: Provide stable and reliable 48V DC power for PD equipment, meeting the power consumption of PD equipment not exceeding 15.4W.

Power outage: If the PD device is disconnected from the network, the POE switch will quickly (usually within 300-400ms) stop supplying power to the PD device and repeat the detection process to check if the cable terminal is connected to the PD device.

A complete POE system consists of two parts: power sourcing equipment (PSE) and power receiving equipment (PD). A POE switch is a type of PSE device. PSE devices are devices that power Ethernet client devices and are also managers of the entire POE Ethernet power supply process. The PD device is the client of the POE system, which receives power from the PSE load.