PoE (Power over Ethernet)

PoE (Power over Ethernet) carries data and electrical power over the same Ethernet cable to compatible devices such as access points, phones, sensors or cameras. The equipment supplying power is the PSE and the receiver is the PD. IEEE standards define negotiation and power classes; matching connectors are not enough. Design should verify standard, device demand, total switch budget, distance and cable quality. An injector can add PoE but also needs compatibility. Loss and temperature reduce margin, and a system may fail when many devices draw maximum power together. Validation should measure link, consumption and behaviour during restart or peak load, not merely confirm that a device powers on. Redundant data paths also need suitable power resilience.