Traditionally, on a wireless access point you would have two wires running to it, one for network connectivity, and one to provide power to the wireless access point. With Power over Ethernet (PoE), you can just have one Ethernet cable that supplies both the network connectivity and the electricity needed to power the device. PoE doesn’t just apply to wireless access points, it can also be applied to phones, cameras, and other devices. It’s best used in areas where it may be difficult to supply power.
Switch
The power from PoE is provided at the switch with a single run between the switch and PoE device. This scenario with the switch having built in power to supply to PoE devices, is called “Endspans.”
Switches that do support PoE will be commonly marked as PoE on the switch itself or on its interfaces.
Injectors
If your switch is not able to supply power to power your PoE devices, you may need to install an injector. An injector adds power to an Ethernet connection so that you can then power the PoE device. An injector would be placed in line between the switch and the PoE device.
