While slightly off-topic, it is still of interest
NBC Chime Machine:
In the early days of NBC, the announcer on a particular program would read off the callsigns of the stations carrying the program. This got too cumbersome, so it was decided to create a sound effect to alert the stations as to when to ID themselves. Several employees of NBC came up with the idea of using a set of dinner chimes to serve as a coordinating signal. Originally the chimes were rung manually by the announcer, who would do this after saying "This program has reached you from the New York studios of the National Broadcasting Company". The chime sequence was originally 7 notes, but after awhile it was reduced to the soon-to-be-familiar 3 notes G-E-C(the story that GEC referred to General Electric is an urban legend I believe). The manual ringing of the chimes became inadequate after a few years though, and NBC asked a Captain Ranger, the inventor of the electric organ, to develop an electromechanical device that would play the chimes in a consistant manner. The device was developed and installed at all of NBC's facilities in NY, Chicago and the coast. I understand that the original chime machine is on display at the NBC studio tours at 30 Rock.
NBC Chime Machine