IEEE advances PoE Plus spec

An IEEE task force has reached a milestone in its quest to increase the power that can be delivered to devices using the Power over Ethernet standard.

The IEEE 802.3at task force created Draft 3.0 of its specification, also known as PoE Plus, and the Ethernet Alliance issued a statement last week saying that the task force submitted it to the 802.3 working group ballot for technical review.

The alliance added that the task force expects the standard to be ratified by next year.

The main function of PoE Plus is to increase the amount of power that can be supplied from Ethernet switches to the devices attached to them, via the same Category-5 unshielded twisted pair wiring that delivers the Ethernet signal.

The current standard for PoE is 802.3af, which provides for about 15.4 watts of power on each port. That standard was ratified five years ago. The new specification attempts to bring the power supplied up to 24 watts by using four pairs of wires in the cable instead of just two.

The PoE Plus work has been going on for some time. The original working group was created in late 2004, and turned into a task force in mid-2005.

PoE is often used for IP phones and for WLAN access points. One of the most often cited reasons to raise the power level is to support surveillance video cameras - the kind you could pan, tilt and zoom remotely. Those functions require more power.

The technology has been available for quite a while. Nearly two years ago I wrote about PowerDsine offering a pre-standard version. At the time, the company said future versions of its technology would be made compatible with the standard once it was completed.

Jeff Caruso is site editor at Network World.