The IEEE recently ratified 802.3at, a new Power over Ethernet Plus standard. The IEEE 802.3at-2009 Power over Ethernet (PoE) Plus standard defines the technology for powering a wide range of powered devices at up to 25W over existing CAT5e and above cables.
Mike McCormack, Chair of the IEEE P802.3at Task Force said
, "IEEE 802.3at uses the Link Layer Discover Protocol (LLPD) from IEEE Std 802.1AB, which allows dynamic power allocation and negotiation down to 1/10th of a Watt, and associated technology including Type, Length, Values (TLVs) from IEEE 802.3bc, which was also recently approved. This will allow equipment manufactures to manage their power supply costs and efficiencies at levels not possible with previous standards, and to cut their costs in the process."
I contacted Daniel Feldman, Director of Marketing, Telecom, Microsemi and he responded to Mike's quote by saying, "This is a mis-interpretation of what can be actually done. All LLDP allows is for more devices to be powered with a given power supply, it does not increase the power supply efficiency in any way."
Mike McCormack also stated, "In addition, we have increased available power up to 25W.