Power over Ethernet

Circuit Protection of Ethernet -- Power over Ethernet (PoE) Ports

Protection Application:: There are two basic ways of providing DC Power over an Ethernet Port. Shown in the top figure is a method known as "phantom power" that puts a common-mode voltage on the Tx and Rx pairs. The lower figure shows the use of the spare pairs fround in the RJ45 connector to provide power.
Solution Description:: The Tx and Rx pairs should be protected using the appropriate Ethernet protection scheme. The DC power port should be protected using the DC Input protection scheme.
Companion Solutions:: None.
Regulatory Issues:: IEEE standard 802.3af, UL 60950 or EN 60950, Telcordia GR-1089 may apply.
Unique Features:: None.
Application Warnings:: None.