"800notes.com" has a listing for 480-467-3283.  That number is too close to this one, 480-467-3276, to be a coincidence.  I have taken the suggestion of another contributor to "800notes.com", and I downloaded and recorded a fax tone, picked up the call on speakerphone, and played the fax tone.  I received a short series of clicks, and then the line went dead.

If the other contributor is correct, the robo-caller will not want to waste time placing calls to a fax machine.  They should take the number off of their list.

I'm keeping a record of numbers I responded to with the fax tone, and if the fax-tone strategy works, I will report that to the discussion thread for this number, 480-467-3276.