Editing AM broadcasting (section)

====United States====
In the U.S., the [[AT&T|American Telephone and Telegraph Company]] (AT&T) was the first organization to create a radio network, and also to promote commercial advertising, which it called "toll" broadcasting. Its flagship station, [[WFAN (AM)|WEAF]] (now WFAN) in New York City, sold blocks of airtime to commercial sponsors that developed entertainment shows containing [[radio commercial|commercial messages]]. AT&T held a monopoly on quality telephone lines, and by 1924 had linked 12 stations in Eastern cities into a "chain". The [[RCA|Radio Corporation of America]] (RCA), [[General Electric]], and [[Westinghouse Electric Corporation|Westinghouse]] organized a competing network around its own flagship station, RCA's [[WABC (AM)|WJZ]] (now WABC) in New York City, but were hampered by AT&T's refusal to lease connecting lines or allow them to sell airtime. In 1926 AT&T sold its radio operations to RCA, which used them to form the nucleus of the new [[National Broadcasting Company|NBC]] network.<ref>[https://news.google.com/newspapers?id=iI8tAAAAIBAJ&sjid=yZwFAAAAIBAJ&pg=5492%2C2424619 "Announcing the National Broadcasting Company, Inc."] (advertisement), ''Reading (Pennsylvania) Eagle'', September 13, 1926, p. 10.</ref> By the 1930s, most of the major radio stations in the country were affiliated with networks owned by two companies, NBC and [[Columbia Broadcasting System|CBS]]. In 1934, a third national network, the [[Mutual Radio Network]], was formed as a cooperative owned by its stations.