Interval signal

An interval signal, or tuning signal, is a characteristic sound or musical phrase used in international broadcasting 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 practice 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 USA, where jingles were used as identification.

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.

Frost, Jens Mathiesen (1974). World Radio-TV Handbook 1974. London: Billboard Publications. p. 408. ISBN . 

Sennitt, Andrew G.; David Bobbitt (December 2005). World Radio and Television Handbook 2006. Billboard Books. p. 608. ISBN . 

Sennitt, Andrew G. World Radio and Television Handbook 1997. Billboard Books. p. 560. ISBN . 

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