Extension bell

Extension telephone bell used by taxi service in Rovigo.
Extension bell located on the exterior of a lighthouse in Sprogø.

An extension bell or extension ringer[1] is a device that generates a sound to indicate an incoming telephone call, but is not included in a telephone set itself.

Extension bells may be louder than ordinary telephone ringers. As such they may be used by persons with moderate hearing impairment to help them detect incoming telephone calls, especially when they are outside the telephone's room.[2]

The devices were in use by the late 19th century. An early Australian system at Mount Crosby, Queensland featured an extension bell which was connected to an engineer's telephone over a distance of a quarter mile.[3]

Further reading

  • Telephone and Telegraph Engineers' Handbook. BiblioBazaar. 2008. pp. 274–276. ISBN 978-0-559-36662-8.

References

  1. ^ "Telephone extension ringers". Australian government – Job Access. Archived from the original on 8 October 2009. Retrieved 25 October 2009.
  2. ^ "Hearing / ROHIs". City Council of Devon, United Kingdom. Archived from the original on 30 December 2008. Retrieved 4 September 2009.
  3. ^ "Today". The Brisbane Courier. 27 August 1891. p. 5.[permanent dead link] Column 1.

Public Domain This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 22 January 2022.


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