I thought it would be a good idea to make note of this while it was
> fresh in my memory. At about 3:45 PM a message went to my voice mail
> where the person said "are you still there?" That was all he said,
> but the voice-driven caller ID (on Vonage voicemail) said the call
> was from 512-220-2013. Then almost immediatly, the same voice called
> again and I saw his number this time on my own caller ID from the
> same 512-220-2013 number. This person did not identify himself, but
> seemed interested in speaking to ...
> I hung up and decided to just write it off as some sort of a sneaky
> prank call when lo-and-behold, the phone line reserved for calls on
> Digest things (602-402-0134) rang again, and it was the same voice,
> but this time the caller ID said the call was from Irvine, CA and
> the number given was 949-296-0549. T
Neither of these numbers are from AT&T, but both are from various resellers/small switch owners. Probably both telemarketing calls where your switch has picked up the originating switch's number, not the valid Caller ID.
Doesn't smell quite like a conspiracy, just a bunch of clueless callers.