John, that's what I did initially to discover that I had a problem and on all the jacks. The problem is fixed now.
Arthur, I was the one who made him switch the wires twice at the NID because I thought he made a mistake the first time. I watched him do it a second time and still got reversed polarity. Here is a summary:
1. All jacks showing reversed polarity. Must be a Ma Bell problem.
2. Installer switches wires at NID for 1st time. All jacks still showing reversed polarity, CO line correct polarity.
3. I think installer must have accidentally not switched them, so I ordered him to switch them again while I watched him do it. All jacks still showing reversed polarity.
4. Wires switched in basement. All jacks OK.
Bottom line: this seems impossible and why I posted this to the forum.
