Know what you're working with!
Scenario: It worked before but doesn't now.
Layout: 568B jack in wall labeled '1' connected
to 568B jack in panel labeled '1'
568B jack in same panel labeled '47' conected to 568B in remote panel labeled '86'.
IT guy said he had to use cossover whenever he connected equipment to to each end of '1', ie computer at one end, router at other end. So he fixed wiring error in patch panel.
Now jumpering '1' to '47', has to use crossover at wall jack '1' or remote panel '86'
Siemons tester says ?? on pairs 1 and 3.(White/Orange & White/Green)
Finally read fine print on patch panel labels.
568A of course! Only 1 panel, everything else is 568B
Wire incorrectly and it all works! Why did it used to work? 2 wrongs DO make a right. Straight patch cord between panel jacks '1' and '47' turned over the turnover.

KNOW WHAT YOU'RE WORKING WITH!!!!!!!!!!!!!
John C.

ARE WE HAVING FUN YET?

When I was young, I was Liberal. As I aged and wised up, I became Conservative. Now that I'm old, I have settled on Curmudgeon.