PoE+ (Power over Ethernet)
Power over Ethernet — deliver both power and data over a single network cable. "PoE+" (802.3at) gives ~25 W, the original PoE (802.3af) ~13 W, and PoE++ (802.3bt) up to ~90 W. Powers cameras, access points, IP phones, and more without a separate power outlet.
Mechanic: a switch or "injector" feeds DC power on the same pairs as data; a PD (powered device) receives it. Negotiation ensures only PoE devices get power (protecting non-PoE gear). Power classes: af (13 W), at/PoE+ (25 W), bt/PoE++ (60-90 W, powers e.g. videoconferencing, thin clients, some laptops). Win: install a camera/AP where there's no power outlet, central UPS backup via the switch. Trade-off: cable length + power limit; higher power → more heat. Standard in modern building networks. PoE++ extends to ever more power-hungry devices.