When my house was originally wired(1950's), I had a 4 post box on the exterior of my house. From that I had added 2 additional home runs. I have tested the lines with a simple Telephone Line Tester (Radio Shack cat No. 43-104) and always got a "Correct Wiring" light on the tester. Its a simple 4 wire setup, Red, Green, Yellow and Black. It was simple to match the colors (OK, the newest line I added 4 yrs ago is Cat5e). My phones have worked without fail for years. Recently my DSL has some issues. During the Verizon strike 2 managers showed up to troubleshoot the issue. They replaced the 4 post box with a "Network Interface" and isolated my DSL to its own home run (Turned out to be the modem). Everything is working, but I happen to plug in my tester, and all the line now show that the polarity is reversed. Is this Normal? Is this something I need to be concerned about?
Thanks in advance for any information you can provide on this.

Looks like they turned the line over when they installed the NID. No big deal, polarity is not the issue it was years ago, won't affect anything.

Thank you for the extremely quick reply. You put my mine at ease.

Which goes to show why the CO> needs people that know what their doing.

Steve, 1 note. If you ever get an old TT phone, it may not dial, the first TT phones were/are polarity sensitive. The fix, of course, is to swap the red and green wires, either at the NID, or at the jack you will be using the phone in. Best would be to swap all cables at the NID, and make it right/correct throughout the house.