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.
A standard PoE system mainly contains the following parameters:
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:
some of the advantages with PoE over other technologies may be: