https://www.analog.com/jp/resources/technical-articles/ieee-802-3af-compliant-single-port-power-sourcing-equipment-application.html
IEEE 802.3af-Compliant Single-Port, Power-Sourcing-Equipment Application | Analog Devices
Power-over-Ethernet (PoE) technology enables switch/router and midspan systems, collectively named Power Sourcing Equipment (
ieee 802 3afpower sourcing equipment