Eli5: How does Ethernet over Power works?

Question

And while we’re at it, how does Power over Ethernet (PoE) works?

Thanks

In: Engineering

Answer 1

Let’s start with PoE. If you have a switch that can provide power, when it connects to something that needs power, it has a low voltage bit of power already being sent down the line (think, like an old phone or a doorbell). This is enough to power the device up enough to make a handshake that it needs power. This causes the switch to send power down the line and actually fully power on the device.

Ethernet over Power, also commonly called powerline, basically uses the power lines in a building to transmit network traffic. Depending on the wiring and what else the lines are being used for, it can work decently, or have all sorts of issues. Basically, in two different plugs, you plug in a device that translates from a regular ethernet connection to what it can transmit over the powerlines, and then the other end does the reverse.