Power-over-Ethernet - Why you should use PoE!

Power-over-Ethernet combines data transmission and power supply in a single cable and is thus an extension of Ethernet technology. Especially for smaller network devices, PoE is used as a cost-effective, secure and flexible solution for businesses and private individuals. But why should you choose PoE? What other advantages does PoE offer? 

What is Ethernet? What is PoE? 

Ethernet and PoE are two closely related technologies with different applications.

Ethernet is a wired data network in which the devices connected in a local area network (LAN) communicate via the standard Ethernet protocol (IEEE 802.3). Ethernet technology refers specifically to the transmission of data between network devices using a LAN or Ethernet cable. Regularly, the Ethernet cable contains four pairs of wires, each pair being responsible for data transmission. Common end devices connected with the Ethernet cable are, for example, computers, printers, routers or also servers.

PoE means Power-over-Ethernet and is an extension of the Ethernet technology. Here, a device can not only transmit data by a single power cable, but also supply the device with power at the same time. This eliminates the need for at least two cables for power supply and data transmission. PoE can be used to connect devices to the network that require power, such as surveillance cameras.

But how does PoE work? 

In order to be able to use PoE and thus transmit power and data via a single Ethernet cable, special PoE devices are necessary. These include the PSE devices (Power Sourcing Equipment) and PD devices (Powered Devices).

PSE devices are network devices, such as PoE switches or PoE injectors, which detect a connected PoE-capable device and supply it with the required amount of power. The PSE device receives the information about the required power from the PD device (e.g. IP telephones or network cameras), which in turn demands the necessary power from the PSE device.

An Ethernet cable is also required to connect a PD unit and a PSE unit. The ethernet cable usually consists of copper and 4 twisted pairs of cables that are used to transmit power and data. The exchange takes place on different frequencies. For example, power is always supplied at a frequency below 10 million Hz, while data is transmitted at a frequency well above 10 million Hz. In this way, interference and mutual damage can be avoided. The PD unit is able to perform its functions smoothly. In addition, a stable power supply is guaranteed.

poe graphic of how it works

And where does PoE apply?

PoE is suitable for private individuals as well as companies. PoE is often used with smaller network devices. This is because Ethernet cables are designed more for data transmission. Devices with higher voltages and greater power can cause problems because such a network cable cannot guarantee sufficient power supply. Whereas the power supply for network devices with lower to medium powers can be ensured with PoE on the other hand.

The use of PoE is also worthwhile for smaller network devices due to the increased flexibility in the choice of location. Network devices would normally have to be connected to a power source in order to be operated. With PoE, the power supply is ensured by an Ethernet cable. The placement of the devices can therefore be independent of the location of the power socket. This is particularly advantageous for mounting surveillance systems or network cameras, for example, as these are often installed on high walls without proximity to a power source. 

PoE is also used for the following small network devices:

  1. VoIP telephones
  2. surveillance cameras
  3. small hubs, switches and media servers
  4. small NAS servers
  5. time recording systems 
  6. WLAN access points 
  7. Smart home devices
  8. Industrial environment: sensors & measuring devices

But what other advantages does PoE offer?

1. Cost savings

PoE can be used to save costs. Starting with the savings in material costs, as no classic power cable is required for companies and private households due to the reduced cabling. With PoE, an Ethernet cable takes over data transmission and power supply. 

In addition, PoE is also a cost-effective variant for installing or expanding a network in places where there is no power supply( e.g. no socket). A small number of sockets is therefore no obstacle for PoE-capable devices, as the Ethernet cables are usually several metres long. There is also no need to lay new power lines and thus no costs for an installer.

Furthermore, electricity costs are reduced because the use of PoE results in efficient power transmission. For each device, only the required power is provided at any one time, so that electricity costs and energy consumption are reduced. Conventional power sources continue to consume unnecessary power even when not in use.

2. Increased safety and reliability  

PoE also provides a stable power supply, as PoE devices generally use lower voltages than conventional power sources. This especially reduces the risk of power surges or short circuits that could cause downtime

Reliability is also increased by using PSE devices that only provide power to PD devices. PSE devices monitor, control and, if necessary, limit the power of PD devices. To ensure a constant power supply in case of power failures, a PSE unit should be connected to an uninterruptible power supply (UPS). This way, the functionality of the connected units is still guaranteed during a power failure. 

Should further disturbances such as short circuits, malfunctions or overloads take place, an automatic physical disconnection and electrical shutdown of the PD terminal takes place to prevent damage and increase safety.

3. Simple installation and higher flexibility 

Since PoE-capable devices can be mounted in locations that are rather unsuitable for power distribution (e.g. false ceilings) and that do not have a power source nearby, PoE technology is particularly popular. 

The high flexibility in the choice of location is given by connecting the PD device to an Ethernet cable, so that proximity to a power outlet is no longer necessary. By connecting new devices to the existing Ethernet cable, the network can also be expanded quickly and easily. Even relocating the devices is no obstacle due to the simple networking.  

In addition, the use of PoE is particularly space-saving. Since data and power are transmitted via a mains cable, cables can be saved. Sorting in network cabinets or even in angled areas of the building is thus simplified.


PoE offers several advantages for businesses, especially when using small network devices. In addition to cost savings, private households and businesses benefit from the high flexibility of location. 

Have we aroused your interest? 

Then take a look at our online shop. Here you will find a large selection of refurbished, used and new PoE-capable devices from renowned manufacturers. Do you need support? No problem! Our sales team is at your side as a professional partner for problems, questions or requests.