宇的宇中聆聽

Power over Ethernet or PoE describes a standardized system to pass electrical power along with data on Ethernet cabling. This allows a single cable to provide both data connection and electrical power to such devices as network hubs or closed-circuit TV cameras. Unlike standards such as Universal Serial Bus which also power devices over the data cables, PoE allows long cable lengths. Extra pairs of wire, not used for data transmission, are used for power. Up to 25 watts is available for a device, depending on the version of the standard in use.

簡單講就是用乙太網路上面可帶電，最大可跑到25w，這樣有甚麼好處?

有! 如果你要接IP Phone就很好用。詳細的資料可上

http://en.wikipedia.org/wiki/Power_over_Ethernet

查閱。