How does Power over Ethernet (POE) work?

The primary working principle of Power over Ethernet (POE) is to transmit both power and data signals over network cables to remotely power devices and enable them to communicate over the network. Here are the key steps of how POE operates:

Data Transmission: POE is based on standard Ethernet protocols and utilizes common network cables (typically Cat 5e or Cat 6 Ethernet cables) for transmitting data signals. These data signals allow devices to connect to a local area network (LAN) or the internet for data communication.

Power Signals: POE technology leverages additional wire pairs within the Ethernet cable to carry power signals. Typically, power is transmitted over the spare wire pairs, which are separate from the data wire pairs. Commonly used pairs for power are the 3rd and 6th wire pairs in the Ethernet cable.

POE Power Sourcing Equipment (PSE): POE power is injected into the Ethernet cable by POE power sourcing equipment, which includes network switches, POE injectors, or POE-capable repeaters. These devices inject power signals into the Ethernet cable alongside data signals.

POE Powered Devices (PD): POE powered devices are the equipment that requires power and data connectivity. These devices are equipped with POE receivers, allowing them to extract power from the Ethernet cable.

Separation of Power and Data: Inside POE powered devices, power and data signals are separated. Typically, power signals are converted to the required voltage and current levels for device operation.

Device Powering: POE powered devices receive power through the Ethernet cable without the need for additional power cords or adapters. This enables devices to be powered remotely, reducing cable clutter and maintenance costs.

Device Communication: Once powered, POE powered devices can communicate over the network, sending and receiving data signals. This enables devices to interact with other networked equipment, supporting various applications.

In summary, the main working principle of POE involves the simultaneous transmission of data and power signals over an Ethernet cable, with the separation and utilization of these signals within POE powered devices. This allows devices to be powered and communicate via a single network connection, making it well-suited for simplifying cabling and enabling remote power delivery.

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