This is really strange, and really bad: my phones can't get a dial tone, but my DSL service is working. Earlier in the morning, I lost dial tone and DSL at the same time.
I called Verizon on my cel phone, and they told me the problem was on my end, that their diagnostics were showing I had a 'phone off the hook'. Nope, I didn't. So they're sending a repair person tomorrow.
I expected to be without phone or internet access for the next 24 hours, but unexpectedly, DSL came back up. God only knows how long it will stay up for.
And I suspect this means that whatever the the problem is, it's not on my end, it's somewhere in the Verizon net, if DSL signals are getting switched correctly, but POTS isn't.