Why would someone cut off 4, 5 and 7 on a 568A Ethernet termination?

Question

I recently ran into a network that was having some very peculiar problems. I ended up having to re-terminate the connections, which seems to have resolved the intermittent problem, but what I found when I went in was surprising:

I found that each of the network ends terminated on the RJ-45 connectors of each side were terminated with the 4, 5 and 7 wires entirely cut off (some bent back and some entirely removed cleanly) by the previous installer about 15 years ago. They had had problems for a very, very long time and were using wireless, which in itself was having some stability problems, but they wanted their wired network to work properly for the sake of stability and possibly moving to gigabit.

What would be the logic in removing these from the termination points? It seems to me that while such a scenario CAN work with regards to the specification, it still would be most undesirable to actually terminate them this way on multiple levels.

Any thoughts or reasoning?

Answer 1

My guess would be; if it was perceived they weren't needed (couldn't predict 1Gbps ethernet) it was simply quicker than stripping them and terminating them properly.

In my current place of work, when the building was originally flood wired ~25 years ago, the (IMO short-sighted) decision was made to have dual ethernet sockets with a single cable going back to the patch panel and each socket using 2 pairs of wires.

This limited us to 100Mbps ethernet and I suspect caused us cross-talk related problems due to untwisting the pairs somewhat in order for the wires to reach each socket.

Only this year have we replaced most of the original cabling with fibre back-bones and replaced the copper that was left with properly terminated Cat 5e.