122
configure modbus
(disable|enable)
This command disables / enables the Modbus on the
switch.
6.10.3.
Web Configuration
Parameter
Description
State
Select this option to enable / disable the Modbus on the Switch.
Apply
Click Apply to save your changes to the Switch.
Refresh
Click Refresh to begin configuring this screen afresh.
6.11.
PoE (Power over Ethernet)
6.11.1.
PoE
6.11.1.1.
Introduction
Power over Ethernet
or
PoE
technology describes a system to pass electrical power safely,
along with data, on Ethernet cabling. PoE requires category 5 cable or higher for high power
levels, but can operate with category 3 cable for low power levels. Power can come from a power
supply within a PoE-enabled networking device such as an Ethernet switch or can be injected
into a cable run with a midspan power supply.
The original
IEEE 802.3af-2003
PoE standard provides up to 15.4 W of DC power (minimum
44 V DC and 350 mA) to each device. Only 12.95 W is assured to be available at the powered
device as some power is dissipated in the cable.
The updated
IEEE 802.3at-2009
PoE standard also known as
PoE+
or
PoE plus
, provides up to
25.5 W of power. Some vendors have announced products that claim to comply with the 802.3at
standard and offer up to 51 W of power over a single cable by utilizing all four pairs in the Cat.5
cable. Numerous non-standard schemes had been used prior to PoE standardization to provide
power over Ethernet cabling. Some are still in active use.
PSE
: Power sourcing equipment (PSE) is a device such as a switch that provides ("sources")
power on the Ethernet cable.
PD
: A powered device (PD) is a device such as an access point or a switch, that supports PoE
(Power over Ethernet) so that it can receive power from another device through a 10/100 Mbps
