Gigabit PoE (802.3af)

http://en.wikipedia.org/wiki/Power_over_Ethernet#Power_capacity_limits

http://forum.mikrotik.com/download/file.php?id=10417&sid=6fc2e8eb2c2daca423ee4b91e19a1405

http://www.dipolnet.cz/poe_-_iee_802_3af_and_iee_802_3at_bib746.htm

C = 100nF (ceramic, stacked tin foil,…)

L = 300uH

Ferrite material 43 or 61 (toroid FT-37-61)

https://www.youtube.com/watch?v=t8mB6xz2NPI

Experiments

I've decoupled all of 8 gigabit ethernet conductors using 100nF ceramic capacitors and the link was still OK.

I've shorted + and - of 3 meters 100M ethernet pair through FT-50-61 toroid choke. For 4 and more windings it did not affected the link. When removing the winds the link quality was getting gradually worse.

I've put FT-50-61 toroid choke on + of the same pair and from 9-10 winds and up it prevented the ethernet from linking. When trying less winds the link quality was gradually better.

It's not good idea to use wire with 0.2mm diameter for more than 3A (too much voltage drop, too much heat). So probably 2A should be maximum.