PoE Splitter – This Splits the data from the power and is used to connect a non PoE end device to PoE source. The legacy switch cannot provide the power so the injector does. PoE Injector – These are used to connect a PoE end device to a non PoE device like a legacy switch. Typical devices are cameras and Wireless access points. PDs must work in both Alternative A and Alternative B modes. Powered Devices ( PD) – These consume power provided by PSEs. You should notice in the screen shot that it clearly states that it supports PoE.
Power Source equipment ( PSE) supplies power to end devices. 802.3at -(Type2 – known as PoE+) Up to 30W.There are 4 standards designed to support 4 device types. The difference in the standards is the amount of power that can be provided to end devices. PoE as defined in IEEE 802.3 standard supplies power at 47V – 57 Volts DC. In both cases only two pairs are being used for carrying DC power.Īs the requirement for more DC power for end devices increased a third mode was defined called 4PPoE which uses all 4 pairs to carry DC power. So to supply DC power you needed to supply power over pairs that were also being used for carrying data.īecause it is DC power this is relatively easy to do.Īlternative A mode was defined which sent power over the same cable pairs as used in !0Base T to carry data. In the IEEE 802.3 standard this is known as Alternative B mode.Īs Ethernet speeds increased (1000Base T and above) then it became necessary to utilise all 4 pairs to carry data. These two spare pairs can be used for carrying DC power. On early Ethernet networks operating using 10base T and 100base TX only 2 pairs were used for carrying data and the other two were spare. It is used for connecting remote devices that don’t have a convenient local power source like IP cameras, VOIP phones etc.Įthernet cable (CAT 5,6 &7) uses 4 twisted pairs. Power over Ethernet allows an Ethernet cable to carry DC power as well as data signals to attached devices.
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