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PoE lets a network switch deliver power to devices through the same cable that carries data. An IP camera on the side of a building only needs one cable run – an Ethernet cable to the nearest PoE switch – instead of a separate power cable to the nearest socket.
PoE is defined by three IEEE standards with different power levels:
- PoE (802.3af) – up to 15.4W per port; suitable for IP cameras, wireless access points, basic VoIP phones
- PoE+ (802.3at) – up to 30W per port; supports pan-tilt-zoom cameras, high-power access points
- PoE++ (802.3bt) – up to 90W per port; supports displays, laptops, and high-power devices
- Budget check – the switch has a total PoE power budget; check this before designing a large camera installation
- UPS benefit – all PoE devices share the switch’s backup power, simplifying battery backup for security systems