HANSUN A typical PoE system consists of a Power Sourcing Equipment (PSE) and a Powered Device (PD) or several PDs. According to the IEEE 802.3af specification, PSE is responsible for inserting power onto an Ethernet cable. The PSE may either be an Endspan (PoE switch) or a Midspan (PoE injector). And the PD is a device that draws power from the PSE, which could be an IP phone, a WLAN access point or any other IP device requires power.
