frog:
Thanks - I didn't explain myself well - I'm getting 5v across pin 6 (5v) and pin 2 (0v). Is there a maximum length of cable for this eye? The total cable length is 10m - 5m of B&O cable and 5m of cat5.
Technically Graham is correct that B&O defines the maxmium length to be 5 metres, however I have had cable lengths up to 15 metres work without problems.
You problem may have more to do with using CAT5 cable depending how you wired it. CAT5 cable uses 4 sets of twisted pairs which if you send a differental signal down the wire pair cancels out any noise, however, depending on how you used the extra 5 metres of CAT 5 you may find it has killed the small signals because you are not using a differential signal.
I suggest you extend the cable with non twisted pair cable.