So I just recently completed an installation of several VoIP phones at a customers location. One of the existing CAT 5 jacks failed when I tested it. Unfortunately I could not open the patch panel because there were too many patch cords connected and I did not want to take down their entire network for a single phone. I also was unable to open the jack due to its location behind a solid wooden desk that was fulled with paperwork.
Luckily I knew that 2 pairs were making it from the jack to the patch panel.
My test showed 1+2 open (orange) 3+6 reversed (green) 4+5 open (blue) and 7+8 reversed (brown)
What was I to do? Run a new CAT5? Sure that might have been an option, however the wire would need to be surface run, and I might as well take down the whole network to find where the open was instead of moving everything in the next 3 offices that the wire ran thru to get to the data closet.
My alternative solution was to create a custom patch cord at both ends of the run. These custom patch cords would swap the green/white pair to correct the reversal, while it would swap the orange/white pair over to the brown/white pair and repair the reversal on the brown white pair as well.
I used a short piece of CAT 5 wire and 2 jacks on either end of the cord in place of 8p8c connectors, so that if I had miswired anything I could easily fix it at either end with out needing to waste any 8p8c connectors. I also wanted anyone who saw this contraption to not confuse the custom patch cord with a regular patch cord, as it would only work for this jack, or other jacks that had a similar miswire, or improper punch down.
Here is an image that I just created visualizing the cut over cables that I made. One patch cord goes on one end of the run, while the other goes on the other end of the run, it really does not matter what side either one is on, but they must both be used for this to work.