What is PoE?

PoE (Power Over Ethernet) refers to the existing Ethernet Cat. 5 In the absence of any changes to the cabling infrastructure, it is also possible to provide a PoE with power to transmit data signals to IP-based terminals such as IP phones, wireless LAN access points APs, and network cameras. Provides DC powered technology. PoE is also known as PoL (Power over LAN) or Active Ethernet, sometimes also referred to as Power over Ethernet. This is the use of existing standard Ethernet transmission cables for simultaneous data transmission and The latest standard specification of electrical power, and maintain compatibility with existing Ethernet systems and users.

PoE

Features PoE technology can ensure the normal operation of existing networks while ensuring the security of existing structured cabling, minimizing costs. The IEEE 802.3af standard is a new standard based on Power over Ethernet (PoE). It adds the relevant standards for direct power supply via the Network Cable based on the IEEE 802.3 standard. It is an extension of the existing Ethernet standard and is the first international power distribution system. standard.

There is no standard for early application of PoE, and idle power supply is used.

IEEE 802.3af

IEEE 802.3af (15.4W) became the first PoE power supply standard, which stipulated the power-over-Ethernet standard. It is now the mainstream implementation standard for PoE applications.

The IEEE began to develop this standard in 1999. The earliest vendors involved were 3Com, Intel, PowerDsine, Nortel, Mitel, and National Semiconductor. However, the shortcomings of the standard have always restricted the expansion of the market. Until June of 2003, the IEEE approved the 802.3af standard, which clearly stipulates power detection and control in remote systems, and provides routers, switches, and hubs with Ethernet cables to IP phones, security systems, and wireless LAN access points. The method of power supply for such equipment is stipulated. The development of IEEE 802.3af includes the efforts of many company experts, which also makes the standard can be tested in various aspects.

A typical Power over Ethernet system. Keep the Ethernet switch device in the wiring closet, and use a power supply hub (Midspan HUB) to provide power to the LAN's twisted pair cable. At the end of the twisted pair, this power is used to drive phones, wireless access points, cameras, and other devices. To avoid power outages, use a UPS.

IEEE 802.3at

IEEE802.3at (25.5W) was born in response to the needs of high-power terminals. Based on 802.3af compatibility, it provides greater power supply requirements and meets new demands.

To comply with the IEEE 802.3af specification, PoE power consumption on powered devices (PDs) is limited to 12.95W, which is sufficient for traditional IP phones and webcams, but with dual-band access, video telephony, With the advent of high-power applications such as PTZ video surveillance systems, the 13 W power supply clearly cannot meet the demand, which limits the application range of the Ethernet cable power supply. In order to overcome the PoE's limitations on power budgets and push them to new applications, the IEEE established a new task force to explore ways to increase the power limits of the international power standard. In order to evaluate the possibility of IEEE802.3at implementation technically and economically, the IEEE 802.3 Working Group created the PoEPlus research team in November 2004. Later, in July 2005, the plan to establish the IEEE 802.3at investigation committee was approved. The new standard is called Power-over-Ethernet Plus (PoEP) IEEE 802.3at, which defines a device with a power requirement higher than 12.95W as Class 4 (this level is described in IEEE 802.3af but reserved for future use). Extend the power level to 25W or higher.