Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 591)

Power over Ethernet Introduction
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 22.7
1000BASE-T
Endpoint Mode
An amendment to the IEEE 802.3at (2008) standard defines PoE cable connections for data
transmission at 1 GHz. Although data is carried over all four cable pairs, the same cable
pinning is used for PoE. i.e. alternative A applies power to the cable using pins 1-2 and 3-6,
and alternative B applies the power to the cable using pins 4-5 and 7-8.
Cable Types
Although the IEEE standards 802.3af and 802.3at indicate minimum cable types for each
standard version; using cables of a higher rating will reduce the cable resistance, allowing
more power to be provided from the PSE to the PD. Also the power negotiation process
that takes place between the PD and the PSE takes no account of the cable type that
connects them, therefore the cabling used should be rated to meet the highest power
that your PSE is able to supply
A further factor is that network operation at 1 Gbps places higher demands on the cabling
type used. These demands are increased when power is also carried over these cables.
For more information on twisted-pair cable selection for PoE, see the switch’s Installation
Guide.
Static and Automatic Power Allocation
When configuring PoE on your switch, you can either allow each port to auto-negotiate its
power requirement, based on the power class of its connected PD, or you can statically
allocate fixed power levels to each port.
Where dynamic PoE power assignment is used, the total power drawn from your switch’s
power supply will be the total of the individual power requirements of each port. See
“power-inline max” on page 23.8