Interval signal
An interval signal, or tuning signal, is a characteristic sound or musical phrase used in international broadcasting, numbers stations, and by some domestic broadcasters, played before commencement or during breaks in transmission, but most commonly between programmes in different languages. It serves several purposes: The practise began in Europe in the 1920s and 1930s and was carried over into shortwave broadcasts. The use of interval signals has declined with the advent of digital tuning systems, but has not vanished. Interval signals were not required on commercial channels in the United States, where jingles were used as identification. List  of interval signals by station. Formerly used. Classical radio station WQXR-FM in New York City, during its ownership by The New York Times Company, played different variations of a classical infused gong with the ID read at the same time as "The Classical Station of the New York Times, WQXR, New York (And WQXR.com 2000–2009) Numbers station interval signals. Numbers stations are often named after their interval signals, such as The Lincolnshire Poacher or Magnetic Fields after "Magnetic Fields Part 1" by Jean-Michel Jarre.