Power over Ethernet

Power over Ethernet commonly abbreviated as PoE is a new technology to transmit electrical power over Cat 5 cable in a standard Ethernet Network. This technology is designed for connecting low powered devices such as webcams, IP telephones and WiFi Wireless Access Points, without the need to run additional power cables.

PoE technology was standardized in IEEE 802.3 and requires two pairs of cable connected, with 48 volts DC provided between the two pairs. Polarity between the two pairs is unspecified in the standard, and a bridge rectifier must therefore be employed.

It is major source of frustration that for years Broadband over Powerline technology has struggled to overcome signal leakage issues from joining Power and Data lines, whereas the new PoE technology causes no ill effects.

See Also: Powerline Networking — described as Ethernet over Powerline, a system for connecting two or more computers for data transfer and file sharing using power cabling.