And the loser is...

[mdlbear]

... the DSL modem. In spite of the fact that all the lights are on and doing the right thing, it apparently died in some subtle way during the last power glitch. Plugged the line into the other DSL modem, and it came right up.

That, of course, was something I should have thought of yesterday morning. As in, before I went to Fry's.

Dumb bear.

The Alcatel modem is really old and almost certainly won't handle the new 6MB/Sec line, so I'd have to get a new one even if I didn't still need both lines. But...