The
somewhat-
famous NBC chime tune (three
notes) comes directly from that
network's ownership by
General Electric.
If you take GE's full name, General Electric Corporation, and reduce it to an acronym, you get GEC. Those three letters happen to also be musical notes, forming a C Major chord. If you play those three notes in succession -- start with G, then the E above it, and finally the C between them -- well, that's that's the three-note tune you hear on NBC.