What is Poe?

Poe refers to the transmission of data signals to a Poe based on IP terminals (such as IP telephones, wireless LAN access point APS, network cameras, etc.) while the existing Ethernet CAT.5 cabling infrastructure is not changed Ethernet It can also provide DC-powered technology for such equipment. Poe is also known as a LAN based power supply (PoL) or active Ethernet, sometimes referred to as Ethernet power, which is the latest standard specification for transmitting data and power while using existing standard Ethernet transmission cables, and maintains compatibility with existing Ethernet systems and users.

Characteristics

Poe technology can ensure the existing structure wiring security while ensuring the normal operation of the existing network, to minimize costs. The IEEE 802.3AF standard is the new standard for Poe based on the Ethernet power supply system, which, based on IEEE 802.3, adds the relevant standards for direct power through the network cable, is an extension of existing Ethernet standards and is the first international standard on power distribution.

Poe has no standard for early application and uses idle power.

IEEE 802.3AF

IEEE 802.3AF (15.4W) has become the first Poe power supply standard, which prescribes the Ethernet power supply standard, which is now the mainstream implementation standard of Poe application.

IEEE began setting up the standard in 1999, with the earliest participants being 3Com, Intel, Powerdsine, Nortel, Mitel and National Semiconductor. However, the shortcomings of the standard have been restricting the expansion of the market. Until June 2003, IEEE approved the 802. 3AF Standard

It clearly stipulates power detection and control matters in remote systems, and provides for the way routers, switches, and hubs are powered by Ethernet cables to IP telephony, security systems, and wireless LAN access points. The development of the IEEE 802.3AF encompasses the efforts of many corporate experts, which makes it possible to test the standards in all respects.

A typical Ethernet power supply system. In the wiring cabinet to retain the Ethernet switch equipment, with a power supply hub (Midspan hub) to the local area network of twisted pair cable power supply. At the end of the twisted pair, the power supply is used to drive telephones, wireless access points, cameras, and other devices. To avoid power outages, you can choose a UPS.

IEEE 802.3at

Ieee802.3at (25.5W) should be born in the demand of high power terminals, on the basis of compatible 802.3AF, provide more power demand and meet new demand.

To comply with the IEEE 802.3AF specification, Poe Power on the device (PD) is limited to 12.95W, which is sufficient for traditional IP phones and webcams, but with the advent of high power applications such as dual-band access, video telephony, PTZ video surveillance systems, 13W The power supply is obviously not enough to meet the demand, which limits the application range of Ethernet cable power supply. To overcome the limitation of Poe's power budget and push it to new applications, IEEE has set up a new task force to explore ways to improve the power limits of the international power supply standard. In order to assess the technical and economic possibilities for IEEE802.3AT implementation, the IEEE802.3 Working group founded the Poeplus Research group in November 2004. The plan to establish an IEEE 802.3at commission of Inquiry was subsequently approved in July 2005. The new standard, called Power-over-ethernet Plus (poep) IEEE 802.3at, defines a device with a power requirement higher than 12.95W as Class 4 (the level is described in IEEE 802.3AF but is reserved for future use), Power levels can be extended to 25W or higher.