•2 min read•Samaneh Pardaz Soroush
PoE (Power over Ethernet) delivers the power a device needs over the same network cable. That way a CCTV camera, access point or VoIP phone no longer needs its own socket and adapter.
PoE standards
- 802.3af (PoE): up to about 15 watts per port; enough for most fixed cameras and phones.
- 802.3at (PoE+): up to about 30 watts; for cameras with heaters or strong infrared, and for access points.
- 802.3bt (PoE++): up to 60 or 90 watts; for pan-tilt-zoom (PTZ) cameras and power-hungry equipment.
Work out your power budget
Every PoE switch has a total power limit. The combined consumption of the connected devices (at their peak, for example when infrared switches on at night) must not exceed it. It is best to keep a safety margin of about 20 percent.
Benefits
Simpler, cheaper installation, the ability to reset a device remotely by switching its port off and on, and centralized backup power with a single UPS for the switch are among the key benefits of PoE in video surveillance projects.
