Power Over Ethernet
13.1 POE Overview
Power Over Ethernet (POE) is probably the most under-valued technology in buildings. It provides both power and communications through one cable; and it can centrally monitor the devices. The devices can be telephones, wireless access points, cameras, paging speakers, card readers, lighting, and clocks.
Several major IT manufacturers have developed software to manage power to the devices, either turning the devices off and on, or dimming the power to the device, much like a lighting control systems. The POE management software essentially enables and disables POE ports on a network switch. The result is a reduction in peak energy demand for IT networks and the flexibility for network managers to set different power consumption for different IT devices at different times. The POE management software is typically a module in a larger suite of network management tools, with capabilities to scale from one network to an enterprise. Since the devices that are monitored and managed are already on an IT network, the monitoring of the devices is done with SNMP tools to monitor any device defined by a Management Information Base (MIB).
POE truly reduces the cost of building construction and operation. One cable can provide power and connectivity, thus eliminating the
Figure 13.1 ©Matt Buchanan, licensed under CC BY-SA 2.0
cost of materials and labor for one additional cable installation. Here's an overview of POE, its uses in products, devices, and systems that are installed in buildings, and the reasons why it needs to part of specifications for building technology systems.