Power over Ethernet (PoE) transfers power and data simultaneously over a single Ethernet cable. This is achieved through a clever trick: using unused wires within the Ethernet cable to carry electrical current.
Here's how it works:
- Standard Ethernet cables: Typically have eight wires, four pairs.
- PoE: Uses two of these pairs for data transmission and the other two for power delivery.
- PoE injectors: Devices that convert standard AC power into DC power and inject it into the unused wire pairs of the Ethernet cable.
- PoE-powered devices (PDs): Equipped with circuitry that can extract power from the cable and use it to operate.
There are two main types of PoE:
- Passive PoE: Simplest and least expensive, uses a fixed voltage (typically 48V) and relies on the PD to regulate power consumption.
- Active PoE: More complex and offers better power management, allowing for different voltage levels and power negotiation between the injector and the PD.
Examples of PoE applications:
- IP cameras: PoE simplifies installation and reduces wiring costs.
- Wireless access points: PoE enables flexible placement without needing nearby power outlets.
- VoIP phones: PoE provides power and data connectivity in one cable.
Benefits of PoE:
- Simplified installation: Reduces the need for separate power cables.
- Cost-effective: Eliminates the need for dedicated power outlets and wiring.
- Flexible deployment: Allows devices to be placed in locations without power outlets.
- Centralized power management: Enables remote power control and monitoring.
