Right, I've just spent some time on ICQ with Tony, and he had some good advice. Unfortunately, it looks like the wallplates are bogus.

I just plugged a (known-good) piece of CAT5 into the front, and then used a multimeter to check the connections (one probe on loose end of CAT5, other on the blades on the back of the plate).

My findings are these:

1. Orange and white doesn't appear to be connected at all.
2. Green, Blue and Blue/White appear to be common.

These findings apply to both plates. Either it's a bad batch, or these aren't actually meant for Ethernet. Do these pin assignments make any sense for any other cabling standard anyone knows? (I'm guessing Rob Schofield will be able to think of some arcane mil-spec standard from the 70's )

I'm going to crack one of them open and see if there's a solder bridge or anything in there...