Allied Telesis 8100S Series - Manual (Page 35)

Stack Installation Guide for 8100S Series Switches
35
Power Over Ethernet
The AT-8100S/24POE Switch features Power over Ethernet (PoE) on the
10/100Base-TX 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-8100S/24POE Switch acts as a
PSE unit 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-8100S/24POE Switch supports 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 9 on
page 36. The classes are based on the amount of power the devices
require. The AT-8100S/24POE Switch supports all five classes.