Power Sourcing Equipment and Powered Devices
As explained in Chap. 1, Ethernet has evolved into a star topology, in which a number of end-point devices are connected to a switch or hub. Looking at things from the perspective of data (just Ethernet), on one side of a given cable we have the switch/hub, and on the other side we have the data terminal equipment (DTE). Looking at this arrangement from the perspective of power (Power over Ethernet), we have Power Sourcing Equipment (PSE) on one side of the cable, and on the other side a Powered Device (PD). See Fig. 2.1.
FIGURE 2.1 Typical (simplified) PSE and PD.
In general, the DTE could ...