Switch User Manual
33 
APPENDIX A 
A.1 MDI Settings 
The Medium-Dependant Interface (MDI or RJ-45) serves as the data/power interface between Ethernet elements. As such, 
it has two optional connection methods, to carry the power. named Alternative A & B. Table 1 details the two power feeding 
alternatives. 
Pin  Alternative A  Alternative B 
1  Vport Negative   
2  Vport Negative   
3  Vport Positive   
4   Vport Positive 
5   Vport Positive 
6  Vport Positive   
7   Vport Negative 
8   Vport Negative 
 Table -1 Alternative Table 
Delivering power through an RJ-45 connector’s center tap (“Phantom Feeding”) guarantees that bi-directional data flow is 
maintained, regardless of a module’s power status. 
A.2 Power Device Classification values 
Class  PD Current – Classification Period
 [mA] 
PD Power – Operation Period 
[W] 
Note 
0  0 – 4  0.44 – 12.95  Default 
1  9 – 12  0.44 – 3.84  Optional 
2  17 -20  3.84 – 6.49  Optional 
3  26 – 30  6.49 – 12.95  Optional 
4  36 - 44  Future use  Future use 










