The reason why you need power over Ethernet switches will be obvious when comparing PoE switch vs non-PoE switch. As the most basic switch, the non-PoE switch refers to the switch that is not PoE enabled to supply power for end-users over Ethernet, but can only send data to network devices. To acquire PoE, users have to deploy a midspan power sourcing equipment (PSE) like the PoE injector between the switch and PDs.
This injector or other midspan PSEs can add electrical power while receiving data signals from the cable connected with the non-PoE switch, and then deliver both data and power to PDs. In this application, the injector or other midspan PSEs will also need a wire for power. However, for a gigabit PoE switch application, things will become easier. For a PoE switch, only one power cable for the switch and one network cable to connect PDs are required. Then the PD can be directly plugged into the PoE gigabit switch port for both data transmission and power supply. With PoE switches and devices, you can build a convenient wireless network.