Understanding How Inline Power Works - Cisco WS-C2950SX-48-SI Configuration Manual

Chapter 28 Power Management

Understanding How Inline Power Works

The Catalyst 4006 switch and the Catalyst 4500 series switches can sense if a powered device is
connected to an inline power module. The Catalyst 4006 switch and the Catalyst 4500 series switches
can supply inline power to the powered device if there is no power on the circuit. The powered device
can also be connected to an AC power source and supply its own power to the voice circuit. If there is
power on the circuit, the switch does not supply it.
Note A powered device is any device that is connected to the switch that requires external power or can utilize
inline power. An access point or IP phone is an example of this device type.
Table 28-3
Table 28-3 Switch Components Supporting Inline Power
Switch Chassis
Catalyst 4006
Catalyst 4503
Catalyst 4506
You can configure the switch to stop supplying power to the powered device and to disable the detection
mechanism. If your switch has a module that can provide inline power to end stations, you can set each
port on the module to detect and apply inline power automatically if the end station requires power.
For information on powering powered devices that are connected to other Catalyst switching modules,
Note
refer to the Catalyst Family Inline-Power Patch Panel Installation Note.
You can power only one device for each port; you must connect the phone directly to the switch port. If
you daisy chain a second phone off the phone that is connected to the switch port, the switch cannot
power the second phone.
The WS-X4148-RJ45V switching modules can supply a maximum of 6.3 W per port and is 100 percent
efficient.
To determine the power requirements for your configuration, you need to estimate the following:
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•
•
•
78-15486-01
If the bridge priority of the Catalyst 4006 switch has been lowered administratively and you use the
same configuration in the new Catalyst 4500 series switch, then the switch remains the root switch
and the spanning tree topology does not change.
lists the switch components that support inline power.
Modules
WS-X4148-RJ45V
WS-X4148-RJ45V
Power requirements for all powered devices for the entire switch and for each module.
Maximum power that is available per port for each module.
Total available inline power that is available for the switch (see
PEM documentation).
When using variable power supplies, consider the required system power (see
page 28-9).
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
Understanding How Inline Power Works
Power Supplies
Catalyst 4000 Series Power Entry Module
(PEM)
1300 W AC
2800 W AC
1400 W DC
Table 28-1 on page 28-4
Table 28-2 on
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Release 8.1
and the
28-11