Having just realised I have screwed up my board by stupidly swapping pins 4 & 5 on the magjack output, I have realised I don't properly understand the PoE power pins on the magjack. I wonder if someone could help explain before I do anything else stupid.
I am using the
Kycon G8X-188S7-BP jack with integrated magnetics, the schematics below labels pins 9 & 10 as the VC+/VC- but confusingly leaves pins 4 & 5 unlabelled.
What is the purpose of combining pins 4+9 and 5+10? Why do pins 9 & 10 feed via the transformer?
These are my current, hopefully now correct schematics:
[EDIT] This is for a PoE PD expecting a 24v passive mode B supply.