I've got to clean up some wiring at work, one being a Frankenstein of a connection which has seen many PBX changes and must have a dozen open circuit wires, etc.
I removed the blue and blue/white from the block and replaced with my own connected to a modem, which didn't work. I also tried with the other pair which is terminated: orange orange/white which didn't work either. There is so many joiners, terminations/crimps throughout the whole system I'm not sure if my understanding of how this block works is wrong, or if I've completely identified the wrong cable.
I've put a square of one pair I tested:
As far as I can tell this isn't a 66 or 110 block, any ideas?