Since the ratification of the first PoE standard in 2003, PoE use has increased dramatically and made headway into new applications. POE provides huge benefits in relation to ease of installation, Saving CAPEX and OPEX costs, and providing a unified and safe power standard for worldwide use.
The main limiting factor affecting PoE use in new applications is the amount of available power. While 15.4W at the power source is sufficient for most IP phones and 802.11a/b/g access points, it is not enough for IP video phones, 802.11n, and pan-tilt-zoom (PTZ) IP cameras. For that reason, the Institute of Electrical and Electronic engineers, or IEEE, released IEEE 802.3at in 2009, specifying 30W at the PoE source.
Today there is a demand for even higher power to support additional devices connected to the Ethernet Network, such as PTZ security cameras, kiosks, POS terminals, thin client, 802.11ac and 802.11ax access points, small cells, and connected LED lighting, all of which can benefit from POE.
The new IEEE 802.3bt standard increases the maximum PoE power available mainly by utilizing all four pairs of the structured wiring. IEEE 802.3bt extends the power classification information exchanged during initial negotiation to allow meaningful power management capability, enabling support of multiple PoE classes, while also being backward compatible. These enhancements solve the challenge of higher power and more efficiant PoE delivery systems.