The NBC Chimes Museum
A Celebration Of Old–Time Radio’s Most Famous Signature

the national broadcasting company

The story of the nbc chimes begins in 1926. That year the Radio Corporation of America purchased the Broadcasting Company of America from AT&T, and renamed it the National Broadcasting Company. NBC’s inital broadcast was made on the evening of November 15, 1926; this was the beginning of what came to be known as the Red Network, headed by flagship station WEAF. Six weeks later RCA merged their own network operations (based at station WJZ) with NBC, the RCA network becoming the Blue Network in the process.

The color designations were derived from the colors used to trace the network routes on AT&T system maps. An origin story for this practice was given by AT&T’s C. E. Dean, who wrote in the June, 1928 edition of Radio Broadcast:

Perhaps the reader has wondered how the designation of networks by colors originated. This occurred several years ago when the only network then operating received programs from WEAF in New York. The telephone engineers drew in red pencil, on a map, the circuits regularly connected and drew in blue the extensions which were occasionally added. In this way the regularly operating chain became known as the “Red network.” Later, when a network was organized with WJZ in New York as the key station, the name “Blue network” was, of course, given to this. At the important program control points the designation of the networks by colors is a considerable aid to the transmission supervisor in the necessary switching operations.

In its early months of operation, NBC announcers would read a list of stations carrying each program at the end of that particular program. This was actually a continuation of the original method of identifying affiliate stations on the old AT&T network; however, as the network grew this practice became cumbersome and time-consuming, and the identification responsibility was shifted to the stations themselves. Some signal had to be given to mark the end of the program period, however, because announcers at the stations would now need a cue to give their identifications. Plus, with two networks sometimes split into further regional feeds, NBC had to be able to coördinate switching arrangments between the different network feeds and the affiliate stations.

Most major metropolitan areas would eventually have large, well–known stations devoted solely to Red programming, with smaller stations (that often shared the same broadcasting frequency with other small stations) devoted solely to Blue programming. Smaller cities, towns, and rural areas were generally only served by one NBC affiliate, which, at the sponsor’s discretion, could be broadcasting either a Red program or a Blue one at any given time.

Because of this arrangement, it was necessary to be able to inform engineers from NBC (who maintained the links between the originating studios and the network feeds) and AT&T (who maintained the telephone lines feeding affiliates, and who carried out the actual switching) in a single stroke when the program period had ended, so they could immediately switch over the next period’s feed to the correct affiliates.