There are no standard. Just select one of the four pairs.
When looking for various notation for devices from different manufacturers, they may interpret the polarity differently. If one manufacturer uses D+/D- notation, an other manufacturer will have the opposite polarity. Only the official standard A/B notation seems to be OK with all manufacturers, so use it in your documentation (not D+/D-).
You may (or may not) need a signal ground, so you may have to use an other pair for this.
Preferably (because some old cables from pre-gigabit may still be useful) use positions 1,2 or positions 3,6 (the orange/orange-white or the green/green-white pairs).
Lasse Langwadt Christensen wrote in news:eb63850e- snipped-for-privacy@googlegroups.com:
They are pretty smart and would likely not energize the port.
Every POE I saw was a managed port that was energized only through software, but once energized, I suppose one could plug a cable into a "turned on" port. But I think they have load sensing too, and would shut the P part off. Likely shut it of for failing to handshake ENET too.
If you are making your own link, you could use a ten pin wide connector. That would keep anyone from inserting it into an ENET port. That would be RJ-50. Crimpers or the die might be more difficult to find.
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