Hi All,  The complete (I think) history of the NBC Chimes, as well
as RealAudio recordings of the three- and four-note chimes, can be
read and heard at:

    http://www.old-time.com/chimes.html

Some interesting reading, photos, and sounds here.

Gabe Della Fave
http://www.mindspring.com/~gabedellafave/player.htm