O'Reilly logo

Power Over Ethernet Interoperability Guide by Sanjaya Maniktala

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Introduction
In Power over Ethernet (PoE), power and data are sent together down a standard Ethernet cable. The first formal PoE standard, IEEE 802.3af, was ratified in 2003, applicable to devices requiring up to 13 W. IEEE 802.3at followed in 2009, bringing into its fold higher-power devices, up to 25.5 W. The IEEE 802.3at standard actually contains two clear application categories. The first 13 W is as measured at the end of a 100-m cable, called Type-1, or “low-power.” This was the same as in IEEE 802.3af. But it also introduced a new category for 25.5 W at the end of 100 m and called it Type-2 or “medium power.” So, the “AT standard,” as it is often colloquially called, is supposed to be just an “enhancement” of the previous AF standard, ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required