POE (Power over Ethernet) is a method that passes electricity along with data on a pair of twisted cables. Devices like VOIPs (conference phones), Wireless Access Points (wireless routers) and IP security cameras all use single pair of cables to achieve data and power transmission in a network security environment. These twisted pair cables are CAT5e or CAT6 cables.
Ethernet cables, CAT5e and CAT6, have a data transmission range of 100M or 328ft before exhibiting data degradation on the receiver end. Both CAT5e and CAT6 can carry data a transmission range of 1000Gbits. POE injector devices work by injecting electric power over an Ethernet cable, while simultaneously returning the data back to switch. Many switches have a POE function built-in and use IEEE 802 standardized in 2003. In May 2011, IEEE consortium started using different types or classes for POE devices. Each POE device now comes with a different power rating and, before purchasing POE injector, one must first verify the power requirement for their devices. IEEE 803af (known simply as POE) has a maximum power delivery of 15.4W. IEEE 803at (POE+) has maximum power delivery of 30W. IEEE 803b (POE++) has total maximum delivery of 41W and 71W. Type 4 with the range of delivery of 60W is more common than the two listed previously. IEEE 803bt is also the least commonly used type. Type 4 POE is the only one that can provide the necessary power required to run IP PTZ (pan-tilt-zoom) cameras. Since PTZ cameras are usually installed in the middle of parking lots or remote areas, many network installers usually power the IP based PTZ camera at the source, making this type of POE the least favorite.
A POE Extender helps the installers overcome the transmission limitations Ethernet cables. A POE extender is also a POE injector. In theory, one would need one or two pairs of extenders for every 100M. If the switch is not POE, then the network installer would need two pairs, one at the switch and another at the network device. Many POE switches, like the 2M New 8000 NVR security sysetems, have a POE extender built into each POE port and can extend the transmission of both data and electric power for up to 200M or 656FT. This is true for POE or POE+ devices because for any distance greater than 656 feet, a CAT5e and CAT6 would not be able to handle wattage load because the pair of twisted cables are only 22 gauge.