Publication date:Aug., 2014
Revision A1
62
4-2-7. PoE Configuration
Power Over Ethernet (PoE) technology allows IP telephones, wireless LAN
access points, and other powered devices (PDs) to receive power and transfer data
over existing LAN cabling.
The PoE detect function is follow the table
Stages of Powering up a PoE Link
Stage
Action
Volts specified
[V]
802.3af
802.3at
Detection
PSE detects if the PD has the correct
signature resistance of 19–26.5 kΩ
2.7-10.1
Classification
PSE detects resistor indicating power
range
14.5-20.5
Mark 1
Signals PSE is 802.3at capable. PD
presents a 0.25–4 mA load.
─
7-10
Class 2
PSE outputs classification voltage again
to indicate 802.3at capability
─
14.5-20.5
Mark 2
Signals PSE is 802.3at capable. PD
presents a 0.25–4 mA load.
─
7-10
Startup
Startup voltage
>42
>42
Normal
operation
Supply power to device
37-45
42.5-57
Power levels available
Class
Usage
Power range
[Watt]
Class description
0
Default
15.4
Classification
unimplemented
1
Optional
4
Very Low power
2
Optional
7
Low power
3
Optional
15.4
Mid power
4
Valid for 802.3at (Type 2)
devices, not allowed for
802.3af devices
30
High power