Allied Telesis AT-S62 - Manual (Page 344)

Chapter 19: Power Over Ethernet
344 Section II: Advanced Operations
Power Over Ethernet Overview
The twisted pair ports on the AT-8524POE switch offer the same features
as the twisted pair ports on the other switches in the series. As such, they
can operate at 10 or 100 Mbps, feature Auto-Negotiation and Auto-MDI/
MDI-X, and so forth.
These ports, however, also offer Power over Ethernet (PoE). PoE is a
mechanism for supplying power to network devices over the same twisted
pair cables used to carry network traffic. This can simplify network
installation and maintenance by allowing you to use the switch as a central
power source to other network devices.
A device that receives its power over an Ethernet cable is called a
powered device. Examples can be wireless access points, IP telephones,
webcams, and even other Ethernet switches, such as the unmanaged AT-
FS705PD Ethernet switch from Allied Telesyn. A powered device
connected to a port on the switch receives both network traffic and power
over the same twisted pair cable.
There are several advantages that the PoE feature of the AT-8524POE
switch adds to the installation and maintenance of your network. Since the
switch acts as the central power source for your powered devices, adding
a redundant power supply (RPS) or uninterruptible power source (UPS) to
the switch increases the protection not just to the switch from possible
power source problems but also to all of the powered devices connected
to it. This can increase the reliability of your network by minimizing the
impact to network operations from a power failure.
PoE can also simplify the installation of your 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. With
PoE, you can install PoE-compatible devices wherever they are needed
without having to worry about whether there are power sources nearby.
This feature requires little configuration or management. The switch
automatically determines whether a device connected to a port is a
powered device or not.
A port on the switch connected to a powered device can supply up to 15.4
watts of power to the device, while at the same time furnishing standard
10/100 Mbps Ethernet functionality. A port connected to a network node
that is not a powered device (that is, a device that receives its power from
another power source) functions as a regular Ethernet port, without PoE.
The PoE feature remains activated on the port but no power is delivered to
the device.