After a pissed off week of messing around with cables, splitters, jacks, modems, and ranting, I think my phone is working again. About two weeks ago, it developed a loud and dreadful case of static. It came and went, and most notably went away when the DSL was unplugged. Which meant I couldn't test it downstairs at the junction box and thus I couldn't get Verizon to come look into it without charging me piles of money.
I used to have the DSL and my phone connected to a splitter, which connected in turn to a long flat cable that ran along the ceiling of the hallway. This worked fine. Then suddenly it didn't. Now, after many trials, I have the DSL out in the hallway connected to the only phone jack in the apartment, through a splitter, and a DSL line filter right at the splitter, and my phone still at the other end where it used to be. And now it seems to work.
The static was pretty clearly DSL artifacts echoing on the audible portions of the line, however that works. It is my theory that something else in the building is now generating a field that interferes with the long phone cord; after all, a long cord with cheap shielding is basically an antenna. There's some chance that it's actually the distressingly noisy fish tank pump currently living on
eternal_fish's desk, since that happened around the same time, except that unplugging it doesn't do any good, so probably not. It is a corollary to my theory that someone in the building is doing something stupid, possibly with the power illegally boosted on a wireless access point, because they think it's cooler with the power turned all the way up.
Now let's hope it doesn't show up more static tomorrow and I have to go hunting again.
RANT!