Allied Telesis AT-x510-28GTX User Manual

Page of 90
x510 Series Installation Guide for Stand-alone Switches
25
Power Over Ethernet
The AT-x510-28GPX and AT-x510-52GPX Switches feature Power over 
Ethernet (PoE) on the 10/100/1000Base-T ports. PoE is used to supply 
power to network devices over the same twisted pair cables that carry the 
network traffic.
The main advantage of PoE is that it can make it easier to install a 
network. The selection of a location for a network device is often limited by 
whether there is a power source nearby. This often limits equipment 
placement or requires the added time and cost of having additional 
electrical sources installed. But with PoE, you can install PoE-compatible 
devices wherever they are needed without having to worry about whether 
there are power sources nearby.
A device that provides PoE to other network devices is referred to as 
power sourcing equipment (PSE). The AT-x510-28GPX and AT-x510-
52GPX Switches act as PSE units by adding DC power to the network 
cable, thus functioning as a central power source for other network 
devices.
Devices that receive their power from a PSE are called powered devices 
(PD). Examples include wireless access points, IP telephones, webcams, 
and even other Ethernet switches.
The switch automatically determines whether or not a device connected to 
a port is a powered device. Ports that are connected to network nodes that 
are not powered devices (that is, devices that receive their power from 
another power source) function as regular Ethernet ports, without PoE. 
The PoE feature remains activated on the ports but no power is delivered 
to the devices.
PoE Standards
The AT-x510-28GPX and AT-x510-52GPX Switches support these PoE 
standards:
PoE (IEEE 802.3af): This standard provides up to 15.4 watts at the 
switch port to support powered devices that require up to 12.95 
watts.
PoE+ (IEEE 802.3at): This standard provides up to 30.0 watts at 
the switch port to support powered devices that require up to 25.5 
watts.
Powered Device
Classes
Powered devices are grouped into the five classes listed in Table 2 on 
page 26. 
The classes are based on the amount of power the devices 
require. The switches support all five classes.