On Sat, 20 Sep 2008 09:43:29 GMT, PCPaul wrote:

(Aside: if anybody needs one, try this - it's simple but it works well
and costs almost nothing:
http://www.dealextreme.com/details.dx/sku.4439)

It is almost certainly the limitations of such cheap testers that caused
the confusion about this install in the first place. The correct pins are
wired to the correct pins but with the same wiring error at each end. Thus
the signals between the two sockets are not being sent over the twisted
pairs of wires which is essential for the connection to work.

I hope that the "installation engineer" that did this work has learnt
something from his reliance on his cheap tester...

--
Cheers
Dave.