Wiring Implementation - Allied Telesis AT-x510-28GTX Installation Manual

x510 Series Installation Guide for Virtual Chassis Stacks
You can use port prioritization on dual power supply PoE switches to
protect your important networking devices from loss of power should one
of the power supplies fail or lose power. If you limit the power requirements
of the critical devices connected to a switch to less than 185 watts, the
PoE power provided by a single power supply, a switch will have sufficient
power to support the critical devices even if it has only one functional
power supply.
Wiring
The IEEE 802.3af standard defines two methods for the delivery of DC
power over twisted pair cable by a PSE, such as the switch, to PDs. These
Implementation
methods, known as modes A and B, identify the wires within the cable that
carry the DC power from the PSE to a PD.
Twisted pair cabling typically consists of eight wires. With 10Base-T and
100Base-TX devices, the wires connected to pins 1, 2, 3, and 6 on the RJ-
45 connectors carry the network traffic while the wires connected to pins 4,
5, 7, and 8 are unused. With 1000Base-T devices, all eight wires are used
to carry network data.
It takes four wires to deliver DC power to a PD. With Mode A, the power is
delivered on pins 1, 2, 3, and 6. These are the same pins in 10Base-T and
100Base-TX devices that carry the network data. With mode B, the power
is provided over the spare wires.
The ports on the AT-x510-28GPX, AT-x510L-28GP, AT-x510-52GPX, and
AT-x510L-52GP Switches deliver the power using pins 1, 2, 3, and 6,
which corresponds to mode A in the IEEE 802.3af standard. Powered
devices that comply with the IEEE 802.3af standard are required to
support both power delivery methods. Legacy devices that do not comply
with the standard will work with the switch if they are powered on pins 1, 2,
3, and 6.
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