Microsemi recently published a white paper: Using Power over Ethernet to Reduce Network Energy Consumption. As you can tell from the title of the technical paper, the article is about how companies can reduce costs by using energy-efficient Power over Ethernet (PoE) midspan technology. These systems implement four-pair powering and built-in power-management capabilities while minimizing idle power consumption through the use of smaller internal power supplies.
PoE White Paper Overview
Power over Ethernet technology has become an increasingly important tool for simplifying network deployment while improving overall energy efficiency. The latest advances have presented new opportunities to further reduce power consumption and associated energy costs. PoE enables data and power to be carried over a single Ethernet cable. The technology delivers up to 60 watts (W) of safe, uninterrupted power over the existing LAN infrastructure to powered devices (PDs), at voltages from 50 to 57 volt (V) levels, in support of the latest high-power IEEE802.3at-2009 standard. The IEEE802.3at-2009 standard is backwards compatible with and supersedes the earlier IEEE802.3af-2003 specifications.
PoE enables network administrators to deploy VoIP phones, WLAN access points (APs), IP security cameras, access control system and other PDs anywhere throughout the facility without having to install AC outlets or send electricians to pull cables, modify building plans or get safety approvals. By eliminating the need for separate electrical wiring and power outlets, PoE technology can deliver savings of up to 50 percent as compared to traditional network powering infrastructures.