PoE - Power over Ethernet

PoE – Power over Ethernet

Posted on by FS.COM

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PoE(Power over Ethernet), sometimes called Active Ethernet, refers to a technology which provides data and the DC(Direct Current) power for wide range of network products, such as IP telephones, wireless device, IP cameras etc. over the Ethernet cable. IEEE 802.3af (15.4W) is the first standard of PoE which defines the PoE standard, such as the electric power detection and control items of the remote system as well as the power supplying pattern of switch and device vendors. Now, it is the mainstream standard for PoE applications. Recently, a new standard(IEEE802.3at(25.5W)) was born as the highly demands of larger power which is compatible on the basis of 802.3af and can provide greater power supply to meet the new requirements. In general, there are two methods of PoE. One is Mid-span, and the other is End-Span. PoE is becoming an innovative technology that provides a new, more cost-effective method for powering network devices and widely used in many network solutions.

Parameters of PoE

A standard PoE system mainly contains the following parameters:

  • The voltage is between 44~57V, typically 48V
  • The allowable maximum current is 550mA while the maximum starting current is 500mA
  • The typical operating current is 10~350mA while the overload detection current is 350~500mA
  • In the no-load condition, the maximum current is 5mA
  • To provide three levels of power from 3.84 to 12.95W for save device, the maximum is less than 13W.

Types of Devices Powered by PoE

Nowadays, PoE is more and more widely used in many device. The following examples are some common types of devices powered by PoE in our daily life:

  • Network routers & switches
  • IP cameras
  • IP telephone
  • Wireless divice
  • Industrial devices (sensors, controllers, meters etc.)


some of the advantages with PoE over other technologies may be:

  • Inexpensive cabling carries both data and power
  • Power to equipment can be remotely cycled
  • Fast data rate
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