OmniSwitch 7700/7800 Hardware Users Guide
April 2005
page 3-1
3 Installing and Managing
Power over Ethernet (PoE)
Power over Ethernet (PoE) is supported on OmniSwitch 7700 and 7800 switches and provides inline
power directly from the switch’s Ethernet ports. Powered Devices (PDs) such as IP phones, wireless LAN
stations, Ethernet hubs, and other access points can be plugged directly into the Ethernet ports. From these
RJ-45 ports—provided on Alcatel’s OS7-ENI-P24 modules—the devices receive both electrical power
and
data flow.
Because the feature reduces devices’ dependence on conventional power sources, PoE eliminates many
restrictions that traditional electrical considerations have imposed on networks.
In a PoE configuration, power source equipment (PSE) detects the presence of a PD and provides an elec-
trical current that is conducted along the data cable. The PD operates using the power received via the
Ethernet data cable; no connection to an additional power source (e.g., an AC wall socket) is required.
Note on Terminology.
There are several general terms used to describe this feature. The terms
Power
over Ethernet (PoE)
,
Power over LAN (PoL), Power on LAN (PoL)
, and
Inline Power
are synonymous
terms used to describe the powering of attached devices via Ethernet ports. For consistency, this chapter
and the
OmniSwitch CLI Reference Guide
refer to the feature as
Power over Ethernet (PoE)
.
Additional terms, such as
Powered Device (PD)
and
Power Source Equipment (PSE)
are terms that are not
synonymous with PoE, but are directly related to the feature:
•
PD
refers to any attached device that uses a PoE data cable as its only source of power. Examples
include access points such as IP telephones, Ethernet hubs, wireless LAN stations, etc.
•
PSE
refers to the actual hardware source of the electrical current for PoE. In the case of OS7700 and
OS7800 switches, the PSE is the peripheral power shelf unit, which contains up to four 52V hot-
swappable power supplies.
