[olug] RJ45s

[Luke -Jr]

Reading up on 802.3af (PoE), it appears to be intentionally designed to be 
compatible with MDI-X.
In particular, Wikipedia says:
	The polarity of the DC supply is unspecified; the powered device must operate
	 with either polarity on pair 45+78 or 12+36 with the use of a bridge
	 rectifier.

Pairs 45+78 are the same in both T568a and T568b. Pairs 12+36 are flipped in a 
MDI-X arrangement. Thus, if the PoE provider used pairs 12+36, the polarity 
would be reversed and a 802.3af compliant device must tolerate it. If it uses 
pairs 45+78, it looks the same as a regular MDI cable.