In the IEEE802.3af standard, PSE (Power Sourcing Equipment) can achieve the output power of 15.4W, during power transmission, there is voltage drop problem, PD (powered device) can obtain 12.95W input power averagely. In IEEE802.3at standard, PSE power supply device can maximum output 30W power. In real usage, after the current increases, the power consumption loss increases accordingly, thus IEEE802.3at requires Cat5 Ethernet cable to reduce the power consumption during transmission, PD can also obtain 25.5W input power.
Power over Ethernet is the abbreviation of PoE, it’s new technology to offer 48V DC power through a single Ethernet cable. The standard PoE system contains two main devices, one is Power sourcing equipment (PSE), which is LAN switch or passive power supply, the other one is Powered device (PD), which is the terminal device to receive power from cable and use it.
PoE (Power over Ethernet) is the name of a number of methods that allow for powering network devices through UTP/FTP cables. This way it is possible to power devices such as cameras, phones, switches, access points, etc. In 2003, the IEEE established 802.3af PoE standard, upgraded to 802.3at in 2009. 802.3at distinguishes between the first type (prior 802.3af) and the second type with maximum transmitted power of 30 W, nearly two times higher. The second type is suitable to power cameras with high-power IR illuminators, IP telephones, small network printers etc.
Offering network efficiency and low cost are the advantage of PoE IP camera. The PoE, or Power over Ethernet is the technology has been widely used in network equipment which allows them to transmit power and date through the same Ethernet cable, hence eliminated the requirement of extra power cable connection.