The working group session of the standards task force recently approved new power specifications for Power over Ethernet (PoE), which it released in draft 2.1 of the IEEE802.3at. The draft includes a significant change, limiting the maximum current delivered to a powered device to 600 mA (down from 720 mA). The net result is the useable power delivered at the end of a 100-m Ethernet cable will be 24.6 W. The specification continues to forbid four-pair powering, even after heavy lobbying in its favor.
The increased IEEE802.3at power levels will benefit applications including wireless multi-radio access points, Pan Tilt Zoom security cameras, and IP phones with streaming video displays. Other emerging applications, including emergency lighting, security system sensors, biometric sensors, RFID, and medical monitoring will benefit from combining data and centralized backup power.
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