This number just called my landline, caller ID read "A T T". I let the answering machine pick up, and a chirpy female robo-call voice started speaking over my outgoing message, then hung up. Could not make out what was being said, but it sounded like a telemarketing call to me. May or may not be a call from AT&T.
(We are not AT&T customers, and are regularly harassed by their door-to-door salespeople in spite of a prominently posted "NO SOLICITING" sign and frequent requests that they NOT knock on our door.)
If this number calls again, I'll be blocking it.