The composition of POE system:

A complete POE system consists of a power supply end device (PSE, Sourcing equipment) and an electrical terminal device (PD, Powered Device) in two parts. PSE equipment is a power supply for Ethernet Terminal devices and is also the manager of the entire POE Ethernet power supply process. And the PD device is the PSE load that receive the power supply, that is, the POE system's terminal devices, such as IP telephone, network security cameras, AP and PDA (PDA) or mobile phone chargers, and many other Ethernet devices (in fact, any power not exceeding 13W devices can obtain the corresponding power from the RJ45 socket). The two are based on the IEEE 802.3af. standard establishes information on connections to PD devices, device types, power levels, and so on, and uses this as the basis for PSE to supply PD via Ethernet.