Tech Solutions Library > What is Power over Ethernet?
Use Case

What is Power Over Ethernet (PoE) & How Does it Work?

What is a Power over Ethernet (PoE) device, how does it work, and is it right for your network?

Before you can decide if Power over Ethernet (PoE) is the right decision for your network, it is essential to answer the question, "How does PoE work?" To put it simply, PoE allows both data and power to be transmitted simultaneously with a single cable. In this post, we’ll cover everything you need to know about how Power over Ethernet works, its benefits, and how you can incorporate it into your business.

How Does PoE Work?

An easy way to explain the primary function of PoE is to use a security camera as an example. Under normal circumstances, a digital security camera needs both power and network connections using two different cables. In a PoE-enabled device, the camera receives both power and network connections via a single cable.

This is a major breakthrough in terms of network design. Whereas previously it was necessary to include both a network connection and power connection to all devices on the network, PoE makes it possible to cut those connections in half by consolidating the two.

Devices like phones, cameras, routers and more can now leverage PoE to both power the devices and transfer important data.

Benefits of Power over Ethernet

Once you learn the foundation of how Power over Ethernet works, imagine the number of PoE-enabled devices that can be used on your network and eliminate the need for additional power cords. A few other perks for choosing Power over Ethernet are:

  • Reduced Costs. Using PoE-enabled devices means you cut the time and expense of electrical cabling for your network as devices are powered by the network cables.
  • Flexible Design. Since there is no need for devices to be connected to outlets, they can be positioned as needed without the requirement of an electrical outlet. PoE is especially applicable to wireless access points and digital security cameras.
  • Enhanced Safety. PoE power delivery is designed to protect equipment connected to the network from overload, power drain and installation fails. Since the power is centrally provided by a system compatible source, it can be easily backed up by an uninterruptible power supply (UPS) and controlled. It also grows with your network—since the power you need for any new PoE-enabled devices is already at the ready, your network becomes plug-and-play as you add devices.

Where is PoE Used Most?

You can find many PoE devices on networks, but one of the big applications is VoIP phone systems, which mean the phones on the network only need a single connection and can be powered down remotely if needed. IP cameras used for surveillance and security are often PoE-enabled, so they do not require tethering to a power cable and can be positioned anywhere. Wireless and Bluetooth IPs are also usually PoE-compatible and allow for the setup where you want them instead of where there is an AC outlet.

How does a PoE injector work?

A PoE injector is also called a midspan. Using a PoE injector allows you to upgrade all your existing LAN installations and make them PoE-capable. This solution works especially well when fewer PoE ports are required by devices on the network.

Power Over Ethernet Standards

Here’s a quick look at power over ethernet standards. As you can see, the latest PoE devices can deliver power greater than 60 watts to connected devices. 

IEEE Extension


802.3at / PoE+

802.3bt / UPoE



Type 1

Type 2

Type 3

Type 4


15.4 W

30.8 W

60 W

90-95 W

Myths About PoE

PoE is a recently-developed technology, and many people put off adopting it due to conflicting or out-of-date information. Here are the most common misconceptions:

PoE is Rife with Compatibility Issues

Because of the standard IEEE 802.3af has been adopted universally, the popularity of PoE devices has increased substantially as compatibility with modern devices is assured.

Electrical Knowledge is Required

In the early days of networking, ad-hoc user setups required careful design. Since IEEE 802.3af PoE is designed to work with the industry standard configuration and ensures operation, you can rely on it without worrying about electrical needs. The user can set up their network as they wish and PoE takes care of the power delivery.

Special Wiring is Needed

Another myth busted. PoE works over the same standard cabling: Cat 5e, Cat 6, etc., as well as "RJ45"-style connectors used in regular networks.

PoE Overloads Devices

An early misconception is PoE forced unlimited power into devices. It is important to remember the power scales quoted by device manufacturers are usually the upper limits and not finite. For example, if a 5-watt device is plugged into a 15-watt PoE injector, it does not mean that 10-watts of extra power is pushed through the device, nor that 10-watts is lost. The device merely pulls what it needs from the network. 

What Equipment Do You Need?

Not all devices support PoE. If you were to attempt to connect a PoE cable to an unsupported device directly, it could damage the device. Even though the relatively low electrical output may be safe to humans, sensitive equipment could be damaged. The good news is that there are devices available to help you use PoE with your existing systems, so you do not need to completely replace your infrastructure. If you want to upgrade your systems to use power over ethernet, PoE injectors and PoE switches are some of the most important pieces of equipment to consider:

What is a PoE Injector?

A PoE injector is also called a midspan. Using a PoE injector allows you to upgrade all your existing LAN installations and make them PoE-capable. This solution works especially well when fewer PoE ports are required by devices on the network.

What is a PoE Switch?

In cases where your current network switch does not support PoE or is not providing enough power to your devices, an injector can allow you to connect PoE devices to the switch safely. The other option is to replace your non-PoE switch with a PoE switch. This is simply a network switch that has PoE capability built-in for easy use to connect PoE capable devices. With a PoE switch, a PoE injector is not necessary, as it already supports PoE.

Configure Your Business for PoE

As you can see, boosting your network with Power over Ethernet-enabled devices, PoE injectors and switches is a move in the right direction for overall network stability and productivity for users. Talk to one of our experts today to put together the correct configuration for your business or organization and make the switch to the power of PoE.

Find the right Power over Ethernet devices for your business.

You May Also Like

Use Case
What is Network Virtualization?

What is network virtualization, and how can it improve your business operations?

White Paper
Organizations Put Digital Innovation into Action

Valuable use cases show IT leaders how they may benefit from IoT.

Digital Transformation for the Enterprise

Today’s businesses are connected. They rely on real-time data to adapt to changing conditions and make instant decisions.