User’s Manual of GS-4210-16T2S_24T2S_16P2S_24P2S_48T4S
428
pair on pins 7 and 8 connected and forming the negative supply. (In fact, a late change to the spec allows either polarity to be
used).
Figure 8-1:
Power Supplied over the Spare Pins
The data pairs are used. Since Ethernet pairs are transformer coupled at each end, it is possible to apply DC power to the
center tap of the isolation transformer without upsetting the data transfer. In this mode of operation the pair on pins 3 and 6 and
the pair on pins 1 and 2 can be of either polarity.
Figure 8-2:
Power Supplied over the Data Pins
