I have a long Ethernet run (about 280 ft/85 m) that goes through a conduit between two buildings. On each end, I have an APC Ethernet surge protector that is grounded to the main ground for each building. While I had some trouble getting it to work at first, once I stumbled across Zyxel's very fine 24-port switches, it has worked really, really well.
Then, a storm hit and the link quit working. As far as I can tell the switches were fine and I've tried replacing both APC surge protectors. It appeared the cable in the conduit — which has a water leak in it — was damaged. However, I tried new, better insulated cable and it didn't work (either through the conduit or running on the ground). On the other hand, I had three spare 100ft (30m) pre-terminated cables that I coupled together and that worked just fine running across the ground. I can't imagine why three unshielded cables patched together would work while nicely terminated, shielded direct burial grade Cat5e cable would not.
There is one difference I just observed after putting everything away for the evening: I've been using the TIA 568A wire pattern to the RJ45 connectors and the pre-terminated cable used the TIA 568B pattern.
Could that make the difference in signal loss? Can you think of anything else that would cause 3 patched together cables to work but one solid run not to work?
Best Answer
The only practical difference between A and B in this case is termination order.
The only way to know for sure what the problem is would be to get a professional cable installer to come out with a cable certifier and test your cable.
However, for the cost of having someone come out and do that and implement whatever repairs or mitigations are needed you could easily buy fiber and transceivers or media converters. Do that instead and save yourself a bunch of hassle and money in the long term.