A small network switch, providing a small number of Ethernet ports from one uplink cable. Such a switch may, in turn, pass PoE to downstream devices (termed PoE pass-through). 3 refers to Power Sourcing Equipment (PSE), which provides power on the Ethernet. In this configuration, an Ethernet connection includes Power over Ethernet (PoE) (gray cable looping below), and a PoE splitter provides a separate data cable (gray, looping above) and power cable (black, also looping above) for a wireless access point. While PoE doesn't add Ethernet data capabilities, it does offer expanded options for how and where Ethernet end devices can be. Power Over Ethernet (POE) is a technique used for building wired Ethernet local area networks (LANs) which use Ethernet data cables instead of normal electrical power cords and wiring to carry the electrical current required to operate each device.
