Operation and reuse of AL-D4W-DP lightning protector

Operation and reuse of AL-D4W-DP lightning protector I have a phone lightning protector I purchased and have some questions about installation and how it works. I will have only one phone pair going to this, a normal phone/DSL line. So the pair will initially come in on the D1 punch-down on the left and go to the house from the right, although direction doesn't matter. Why are they marked +/- ? What do the chips D1,D2,D3,D4 with the ~ and +- on them do? I'm guessing they are diodes that short to ground? I can't see how the etching under the chips runs, so it's not clear to me what the - terminal is connected to. They are mounted with the + pin to ground; do these somehow deal with both positive and negative lightning? What is the purpose of the J::H17 S3J chips (D5,D6)? They appear to connect the etchings for the ground connection on the top, where the D1,D2,D3,D4 chips are, to the actual ground on the bottom. Why is an active component used for that instead of just a solder connection? What does the unmarked chip at D7 do, and why is it only on the top 2 pairs? Is there a way to test if each of the chips are still good after a strike -- can they be continuity tested like regular diodes? Finally, if nothing is connected to the D2, D3, and D4 lines and a strike occurs, can the phone be moved from the D1 terminals to another set? Or would a strike likely damage all the protective components?