Introduction to the working principle of poe power supply

PoE (Power over Ethernet) is powered by spare pairs (4, 5 and 7, 8) in the Ethernet cable. There are two types of devices (powered devices and sourcing devices) and three power supplies. Mode (Alternate A, Alternate B, 4 pairs), there are three IEEE standards (802.3af, 802.3at, 802.3bt), providing multiple power levels. The advantages of PoE include simplified installation, flexible deployment, reliable power supply, and cost-effectiveness.

PoE power supply working principle

What is PoE?

PoE (Power over Ethernet) is a technology that allows powering devices through standard Ethernet cables.

How does PoE work?

PoE transmits power over the spare pairs (4, 5 and 7, 8) in the Ethernet cable. These pairs are generally not used for data transmission.

PoE Powered Device Type

There are two types of PoE devices:

• Powered Device (PD): Devices that require power, such as IP phones, webcams, and access points.
• Power Supply Equipment (PSE): The device that provides power to the PD, usually a network switch or router.

PoE power supply mode

There are three PoE power supply modes:

• Alternate A:Through the line For 4,5 and 7,8.
• Alternate B: Through pairs 7,8 and 4,5.
• 4 Pairs: Pass all 8 pairs.

PoE Standards

PoE has the following standards:

• IEEE 802.3af: Provides 15.4 watts of power.
• IEEE 802.3at (PoE): Provides 30 watts of power.
• IEEE 802.3bt (PoE): Provides up to 90 watts of power.

Advantages of PoE

• Simplified installation: No need for a separate power cord.
• Flexible deployment: The device can be installed in places where wiring is inconvenient.
• Reliable power supply: PoE power supply is not affected by power outages.
• Cost Effectiveness: Eliminates the need for additional power supplies.

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