what is POE
POE is what?PoE (Power Over Ethernet) refers to the existing Ethernet Cat. 5 cabling infrastructure do not make any changes, are for a PoE Power supply based on IP terminal (e.g., IP telephone, wireless LAN access point AP, webcams, etc.) to transmit data signals at the same time, also can provide such equipment with technology of dc Power supply.PoE is also known as the Power supply system based on LAN (PoL, Power over LAN) or Active Ethernet (Active Ethernet), and is sometimes referred to as "for the Ethernet Power supply, this is to use the existing standard Ethernet transmission cables transmit data at the same time the latest standards and electric Power, and keep the compatibility with existing Ethernet system and user.
POE technology can ensure the safety of the existing structured cabling in guarantee the normal operation of the existing network at the same time, minimizing cost.IEEE 802.3 af standard is the new standard of PoE power supply system based on Ethernet, it based on the IEEE 802.3 increased by direct power supply cable's standards, is an extension of the existing Ethernet standards, is also the first international standards on the distribution of power.Early
POE application there is no standard, adopt the way of spare power supply.
ieee 802.3 af af
IEEE 802.3 (15.4 W) became the first PoE power supply standard, rules on the Ethernet standard power supply, is now the mainstream of PoE application implementation standards.
ieee began to set the standard in 1999, involved in the earliest manufacturer 3 com, Intel, PowerDsine, Nortel, Mitel and National Semiconductor.However, the shortcomings of the standard is always restricts the market to expand.Until June 2003, the IEEE approved 802. 3 af standard
it defined the electric power monitoring and control of the remote system, and the routers, switches, and hubs through Ethernet cable to the IP phone, security systems, and wireless LAN access points and other equipment power supply in a way that the rules.The development of IEEE 802.3 af containing the efforts of many experts, it also makes the standard can be tested in various aspects.
a typical Ethernet power supply system.Keep Ethernet switch equipment, wiring compartment with a power supply HUB (Midspan HUB) for LAN twisted-pair cable to provide power supply.At the end of the twisted pair, the power used to drive the telephone, wireless access points, cameras and other equipment.To avoid power outages, can choose a UPS.
ieee 802.3 at
IEEE802. 3 the at (25.5 W) should be born power terminal demand, on the basis of compatible with 802.3 af, provide greater demand, meet the new requirements.
in order to follow the IEEE 802.3 af specification, the electrical equipment (PD) on PoE are restricted to 12.95 W power consumption, this for traditional IP phone and web camera is enough to meet demand, but as the dual band access, video phone, PTZ video monitoring system of high power application, 13 W power is obviously cannot meet the demand, this limits the application range of the Ethernet cable power supply.In order to overcome the PoE power budget constraints, and applies it to the new, IEEE has set up a new task group, aims to explore to improve the international standard for power supply power limit of the method.IEEE802.3 working group to IEEE802.3 on technology and economy to evaluate at the possibility of implementation, in November 2004, the research team created PoEPlus.In July 2005 after approved the plans for the IEEE 802.3 an investigation committee.New standards is called Power - over - Ethernet Plus (PoEP) at the IEEE 802.3, it defines the Power requirements are higher than 12.95 W equipment for Class 4 (the level in the IEEE 802.3 af has described, but reserved for future use), can be expanded to 25 W Power level or higher.Related:
192.168.1.1 router set
wireless router how to set up the lei families wireless router set