POE stands for Power over Ethernet. A technology that allows network switches to deliver both data and power to connected devices over a single Ethernet cable.

This eliminates the need for separate power adapters and outlets.Simplifies the installation process, and reduces the cost of network deployment.

POE network switches are widely used in various scenarios. Such as surveillance, conference call, Wi-Fi coverage, and smart building lighting. In this article, we will explain how POE network switches work and what benefits they offer.

How POE Network Switches Work

POE network switches work by using a combination of power sources, power injectors, and power splitters.

A power source is a device that provides electrical power to the switch. Such as a power supply unit or a wall outlet.

A power injector is a device that injects power into the Ethernet cable along with the data signal. A power splitter is a device that splits the power and data signals at the end of the cable, and delivers them to the connected device.

There are two methods of injecting power into the Ethernet cable: endspan and midspan. Endspan means that the power injector is integrated into the switch itself, so the switch can directly provide power to the connected devices.

Midspan means that the power injector is a separate device that is placed between the switch and the connected devices, so the switch only provides data and the injector provides power.

There are also two standards of POE: IEEE 802.3af and IEEE 802.3at.

The IEEE 802.3af standard, also known as POE, can provide up to 15.4 watts of power per port.

The IEEE 802.3at standard, also known as POE+, can provide up to 30 watts of power per port.

Some devices may require more than 30 watts of power, such as high-definition IP cameras or wireless access points. In this case, a new standard called IEEE 802.3bt, also known as POE++, can provide up to 60 or 90 watts of power per port.

To ensure compatibility and safety, POE network switches use a negotiation process to determine the power requirements and capabilities of the connected devices.

This process involves four steps: detection, classification, startup, and operation.

Detection means that the switch sends a low voltage signal to the device to check if it supports POE.

Classification means that the switch determines the power class of the device based on its response.

Startup means that the switch starts to deliver power to the device after confirming its class.

Operation means that the switch monitors the power consumption and status of the device during normal operation.

What Benefits POE Network Switches Offer

POE network switches offer many benefits for network deployment and management. Some of these benefits are:

  • Simplicity: POE network switches are easy to install and configure, as they do not require additional wiring or configuration for power delivery. Most POE network switches are plug-and-play devices, which means they can automatically detect and provide power to compatible devices.
  • Cost-efficiency: POE network switches can reduce the cost of network deployment by eliminating the need for separate power adapters, outlets, and cables. They can also save energy by using intelligent features such as port prioritization and isolation, which can optimize the power usage and performance of connected devices.
  • Flexibility: POE network switches can enable more placement options for connected devices, as they do not depend on the availability of power outlets. They can also extend the transmission distance up to 250 meters by using extend mode, which is useful for deploying devices in large or complex environments.
  • Reliability: POE network switches can enhance the reliability and security of connected devices by providing protection against power surges, overloads, short circuits, and other electrical issues. They can also support uninterruptible power supply (UPS) systems, which can ensure continuous operation in case of power outages.


POE network switches are powerful devices that can deliver both data and power to connected devices over a single Ethernet cable. They can simplify the installation process, reduce the cost of network deployment, enable more placement options, and enhance the reliability and security of connected devices.

POE network switches are suitable for various applications, such as surveillance, conference call, Wi-Fi coverage, and smart building lighting.