Off line since last Sunday night. It coincided with some big ATT goat dink that collapsed DSL and some cell service in Reno and all over N. Nevada. But then neighbors were getting back on, and I couldn't. Many conversations with the nice (really) ATT techs, and decided it was the DSL modem.
Called the ATT store: "Do you have any modems in stock?" "Yes, but bring the modem and the power supply when you come in." ATT store person tested modem with new wall wart: Ah ha! $10 fix instead of $100!
There is a lesson here, but I forgot what it was.