PSE devices send power and data over the Ethernet cable to a connected PD. PSE devices are classified as either “midspan” or “endspan.” PoE Power Sourcing Equipment (PSE) controllers support multiple power levels of power over Ethernet: IEEE PoE (13W, 802.3af), IEEE PoE+ (25.5W, 802.3at), IEEE PoE++ (71.3W, 802.3bt), and ADI LTPoE++ (90W) standard. PSE controllers are responsible for detecting and classifying powered devices (PDs), as well as sourcing the right amount of power to PDs over Ethernet cables.