How commonplace PoE technology is, and the answer reveals while we think of the popularity of wireless access points(WAPs), IP security cameras, voice-over-IP (VoIP) phones, and building automation and control systems. It seems to penetrate deeply into our work and living.
In other words, PoE is actually a kind of new product generated by the information technology era as people demand of more power and better network to be transmitted via cabling in order to satisfy their high power consumption PoE network devices.
PoE, also known as Power over Ethernet, is designed to make power signal and Ehernet network do not interfere each other so that allows power and data to be transmitted over single Ehernet cable to PoE devices. Simply, more power is able to transmit to PoE network devices from Ehernet cable, because it converts main power supply into low voltage supply, but power dissipation is inevitable.
Besides, PoE is a technology for wired Ethernet local area networks (LANs) that carrys the needed electrical current for operation of devices by data cable instead of power cord, which means the number of wires that must be strung for the installation of network cabling will be minimized.
Two technical teminologies you need to know in figuring out PoE, one is Power sourcing equipment (PSE), commonly called an endspan (switch) or mid-span (injector) provides power source to the Ethernet cable, the other is powered device (PD), any device powered by PoE, such as wireless access points, VoIP phones, and IP cameras.
PoE was originally developed in 2003 to support devices like Wi-Fi access points (APs), which enable to simplify its installation at some locations where hard to find AC outlets, such as ceiling. The Institute of Electrical and Electronics Engineers (IEEE) defined PoE with standards, which combines with other vendors to attemp to solve power supply issue. And PoE technology has been through decades of development so far. From 2003, the PoE technology had a litmitation for supplying devices with power consumption less than 12.9W, then by 2009, its supplying power was increased to up to 25.5W, while in last year, 2018, the PoE is able to deliver at a maximum of 71W to PoE-enabled devices, meeting the various needs for high power supply.
The development of PoE technology is still keep moving forward as the IoT(Internet of Things) has become the trend around the world. Most of eletronic devices used at work or home will be connected to the internet, and more and more IoT devices require high power so that to work，such as LED lighting system. Therefore, PoE+ or PoE++ that provides more power is going to be the key project for experts to study and essential technology for modern society to adopt.
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