What is a PoE Switch and How Does It Work

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Brief Introduction:

Industrial communication devices need long cables to transmit power. With the increasing number of devices, the need for cables is also increasing, resulting in complexity in the network. In such cases, Power over Ethernet (PoE) technology comes to the rescue. PoE provides higher transmission of power using lesser cables than other cabling technologies.


PoE technology is administered through different devices like PoE Switches. Since its introduction to the telecommunication industry, PoE Switches have made it possible to transmit power supply and data through a single Ethernet cable. With IoT technology in huge demand, PoE technology has a huge scope for growth. This article explains what PoE Switches are and how they work.


What is PoE Technology?

Structured cabling allows you to transmit electric power along with data using Power over Ethernet technology. Power over Ethernet is beneficial for various devices, including IP security cameras and wireless network repeaters. Using PoE technology for these devices means that the transmission of data, voice, and power can be done using only a single Ethernet cable.


Using PoE not just simplifies the network installation but also reduces the installation cost as fewer cables are required. You don’t have to use extra cables and add power sockets for providing power to the network. It also uses a lesser amount of power than the mains voltage, making it a safer and reliable option. However, devices may get damaged if they aren’t equipped with PoE technology. So, during network installation, networking technicians need to use PoE technology carefully.


PoE is an advanced networking functionality that allows Ethernet cables to carry data and power to connected devices simultaneously. Although both signals are transmitted through the same cable, they use different sets of wires. This functionality administers operations of various networking equipment, ensuring the interoperability between various devices connected within the same network. Devices equipped with PoE technology consist of power sourcing equipment (PSE) and powered devices. The PoE switch is a power sourcing equipment that transmits power whereas, the devices that receive the power from PSE are called powered devices.


PoE Switch Side

What is a PoE Switch?

A switch is used to allow various devices in a network to communicate with each other. A PoE switch is a switch with a built-in Power over Ethernet functionality. This means that the network devices can be powered through Ethernet cables. PoE switch provides the power required to operate the devices through Ethernet cable. These switches are also powered by PoE, and the power is passed to connected devices like phones, cameras, network repeaters, etc.


How PoE Switch Works?

The inner workings of a PoE switch are quite simple and easy to understand because of its simple configuration. The PoE switch comprises several ports to connect different devices. These switches can operate in two different configurations:

  • Mode A configuration: In mode A configuration, the PoE switch provides power as well as data transmission through the same wire.
  • Mode B configuration: In this configuration, the switch uses different wires to transmit data and power.

Industrial PoE switches usually have five or eight Ethernet ports, whereas a non-industrial PoE switch may have 8-24 Ethernet ports. Non-industrial PoE switches are of two types: managed and unmanaged PoE switches.


PoE Switch side over the top

What devices use PoE Switches?

Several devices can be connected with PoE switches. Here are some of the devices, classified according to power requirements, that can be connected with PoE switches:

Low Watt Devices:

  • IP cameras
  • Video and VoIP phones
  • Audio devices
  • Wireless Access points
  • Remote Computer Terminals


High Watt Devices:

  • Computers
  • Laptops
  • Monitors
  • TV


Benefits of Using PoE

PoE offers several benefits over the traditional cabling standards. Here are three major benefits of Power over Ethernet standard:


  • Reduced Installation Cost

The installation cost of PoE is lesser than the cost of the installation of traditional wiring. One twisted pair cable can transmit power and data to devices. PoE splitters and injectors allow networking technicians to connect legacy devices with more advanced networking components that support PoE. PoE allows organizations to install advanced devices, such as IP cameras and VoIP phones, without requiring a separate electrical infrastructure. PoE splitters and injectors can carry power signals to and from the PoE switch.


  • PoE installation is Safer

The voltage required for PoE is usually less than 60 Volts for type-3 devices and less than 90 Volts for type-4 devices. Hence, metal cladding and conduits are not required. With lesser voltage requirements, the PoE switch and cabling are safer than the traditional standards.


  • Deployment of PoE Switches is responsive

Devices connected to a PoE switch are adaptable to the environment. They can be easily removed and reconnected to another switch and can be integrated easily into varying network configurations. As PoE devices are as simple as plug-and-play, you don’t have to disturb the whole network to add or remove a single device.



Limitations of PoE Switches

There are some limitations to PoE switches:


  • Transmission distance

PoE switches can transmit data signals and power to a distance of 100 meters. It is not the limitation of the power but the limitation of the Ethernet cabling standard. However, a PoE extender can cover a maximum distance of 4000 feet to transmit the signal for large distance applications.


  • Power

If high power is required over the PoE network, the network installation technician needs to make sure the power capacity of the PoE switch meets device needs as there is a limitation of power in the PoE standards.


  • Device Compatibility

Some devices are not PoE compliant and are known as legacy devices. These devices would need splitters and injectors to be connected with a PoE switch.


When to Use PoE Switch?

If there are only one or two devices to be connected, an injector can be used to power these devices.  These PoE devices are plugged into the power source and are installed between the device to be powered and the PoE switch.


When there are multiple PoE devices, using injectors for each device makes the networking complicated. Normal switches usually don’t support PoE, so injectors cannot provide power to the switch. However, for such instances, most PoE switches offer powered as well as non-powered ports so that devices not compatible with PoE can also be connected with ease.


After understanding what PoE switch is and how it works, you can use it efficiently in your network application to connect devices compatible with PoE functionality.