What is Power Over Ethernet(PoE)?
The state of technology is changing with time. Let’s discuss the Power over Ethernet principle. To connect devices like an IP camera to the network, 2 connections (electrical and data) would have been necessary. These two connections are combined via PoE into a single network cable. “Power over Ethernet” enables the transfer of DC power to devices over copper ethernet cabling, without the need of additional wires. PoE technology is based on the Institute of Electrical and Electronics Engineers’ IEEE 802.3af, 802.3at, and 802.3bt standards, which govern how networking equipment should operate to promote device interoperability.
As far as we are aware, an Ethernet cable has eight wires, four of which are used to transmit data pairs (1, 2, 3, and 6), for crossover cables; the other two pairs are left unutilized. These apply to 10 and 100BASE-T connections. PoE treats each unused pair as a single conductor, and can use the two spare pairs to carry electrical current.
Unlike fast ethernet, Gigabit ethernet uses all 4 pairs of wires, leaving no pairs free for power. PoE needs a pair of wires to transmit power to a device. Using phantom power, power is sent over the same wire pairs as data. Power and data transmissions are not interfered with. Electricity and data can travel over the same cable because they operate at opposite ends of the frequency spectrum.
Several PoE standards have emerged over time. There are now four types of PoE: PoE, PoE+, PoE++(Type 3), and PoE++(Type 4). I’ve explained this briefly below.
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