standard for extended power over Ethernet: 802.3at, or POE
Plus. POE Plus has the following features:
Increased electrical power - POE Plus nearly doubles the
amount of electrical power available to powered devices,
to 25.5 watts.
Compatible with 802.3af POE - POE Plus switches and injectors
will recognise 802.3af powered devices and enable POE to
them as normal. POE Plus powered devices can also be connected
to 802.3af POE switches or injectors, and are supposed to
restrict how much power they use accordingly.
Smart power budgeting - 802.3at includes scope for power
sources and powered devices to communicate with each other
to negotiate an allowance of electrical power.
POE Plus means that a more complete range of network equipment
can now be POE-powered, including IP cameras with heater/blowers,
and multichannel wireless access points.
802.3at exists alongside the 802.3af standard; it does not
replace it. 802.3af will still be employed by the majority
of Power over Ethernet devices for the foreseeable future.