Understanding Power over Ethernet (PoE) and How It Works

What’s up guys, welcome back! In today’s episode, we’re answering two important questions: What is PoE, and how does it work?

So first—what is PoE? PoE stands for Power over Ethernet. In the simplest terms, it means you’re running power and data through the same cable.

Now let’s dive into the power standards for PoE connections:

• IEEE 802.3af (2003): 15.4 watts of DC power per port
• IEEE 802.3at (2009): Upgraded to 25.5 watts (PoE+)
• IEEE 802.3bt (2018): Type 3 delivers 51W; Type 4 delivers up to 71.3W

In simple terms, the more power a PoE connection can deliver, the more types of devices it can support.

So, how does PoE work? First, you need a device that supports a PoE connection—like a security camera or video doorbell. Then, connect it using an Ethernet cable (Cat5e or Cat6). The other end connects to either a PoE switch or PoE injector.

PoE Switch: Has power built-in. You simply plug in the cable, and it powers the device.

PoE Injector: Great if you don’t have a PoE switch. It typically has three ports—power input, data input, and a combined power/data output. Just connect your Ethernet cable from a non-PoE switch to the injector, plug it in, and connect the cable to your PoE device.

Pro Tip: If your PoE device has issues like freezing or not connecting, unplug the power to the injector for 30 seconds and plug it back in. This usually fixes it.

Can all devices use PoE? No. The device must support PoE. If it doesn’t, it won’t work. And to power things like TVs or laptops, you’ll need high-wattage PoE—those setups are expensive.

Common low-watt PoE devices include:

• VoIP and video phones
• IP cameras
• Wireless access points
• Audio devices
• Video doorbells
• Remote computer terminals

Benefits of PoE switches:

• They provide both power and data
• Require only one cable per device—great for tight spaces
• Plug-and-play setup—no electrician needed

Limitations? Yes. PoE switches have limited power. They’re ideal for smaller devices. If you want to power a TV, you’ll need a high-watt switch—which is costly and often not worth it.

When should you use each?

• 1–2 PoE devices: Use a PoE injector
• 3+ PoE devices: Use a PoE switch

PoE switches usually have 16, 24, or 48 ports—great for scaling. They also include both powered and non-powered ports, so they work in general networks too.

So now, you should have a solid understanding of PoE, how it works, compatible devices, and the difference between injectors and switches.

If you have any questions, drop them in the comments—I answer them all. And if you like this content, hit like, share, and subscribe. Thanks again for watching!