{{Short description|Component of analog telephones}} [[File:Wolfsonian-FIU Museum - IMG 8151.JPG|thumb|upright|An early telephone manufactured in 1909, known as "Strowger". The black earpiece is seen resting on the hook.]]
A '''telephone hook''' or '''switchhook''' is an electrical switch which indicates when the phone is hung up, often with a lever or magnetic button inside the cradle or base where a [[telephone]] handset resides. It takes its name from old wooden wall telephones and [[candlestick telephone]]s, where the mouthpiece was mounted on the telephone box and, due to [[sidetone]] considerations, the [[Transceiver|receiver]] was separate, on a cable. When the telephone was not in use, the receiver was hung on a spring-loaded hook; its weight would cause the hook to swing down and open an electrical contact, disconnecting the talking circuit from the line.<ref name="Cyclo"/> When the handset is on the cradle, the telephone is said to be "[[on-hook]]", or ready for a call. When the handset is off the cradle, the telephone is said to be "[[off-hook]]", or unable to receive any (further) calls.
Pushing the switchhook briefly is termed a "[[hook flash]]".
==Purpose== Telephone switchhook separates talking and signaling circuits of the telephone so that only one is active at a time. Before the invention of the switchhook the user had to manually turn the switch. Some users forgot to turn the switch, leaving the telephone off-hook after the end of the call.<ref name="Cyclo">{{Cite book |url=https://www.gutenberg.org/files/15617/15617-h/15617-h.htm |title=Cyclopedia of Telephony & Telegraphy |publisher=American School of Correspondence |year=1919 |location=Chicago |page=132}}</ref>
==Invention== Several people claimed to be the first inventors of the switchhook (such as [[Thomas A. Watson]]<ref>[https://patentimages.storage.googleapis.com/37/f2/ae/ea79e2a7dae07b/US209592.pdf US Patent № 209,592. T.A.Watson. Automatic Switch or Cut-Out for Telephones. Patented Nov 5, 1878.]</ref><ref name="Watson">{{Cite book|author=Watson, Thomas A.|title=Exploring Life: The Autobiography of Thomas A. Watson|year=1926|location=New York|publisher=D Appleton and company|page=132}}</ref><ref>{{Cite web|lang=|url=https://telhistory.ru/telephone_history/inostrannye-izobretateli/priklyucheniya-tomasa-vatsona/|title=Приключения Томаса Ватсона|author=Иванов Александр|website=telhistory.ru|date=|publisher=Музей Истории Телефона}}</ref>), but [[Hilborne Roosevelt]] managed to get recognition and royalties for his invention.<ref>[https://patentimages.storage.googleapis.com/4a/d4/a5/444cbe66469188/US215837.pdf US Patent № 215,837. H.L. Roosevelt. Telephone Switch. Patented May 27, 1879.]</ref><ref name="Watson"/> The son of [[Edwin Holmes (inventor)|Edwin Holmes]] claimed to use that device long before their patents.<ref>{{Cite book|author=Holmes, Edwin Thomas|title=A Wonderful Fifty Years|year=2017|publisher=Andersite Press|page=72|isbn=9-781376-317312}}</ref><ref>{{Cite web|url=https://telhistory.ru/telephone_history/inostrannye-izobretateli/edvin-kholms-edwin-holmes-/|title=Эдвин Холмс (Edwin Holmes)|author=Иванов Александр|website=telhistory.ru|publisher=Музей Истории Телефона}}</ref>
==See also== * ''[[Off the Hook (radio program)|Off the Hook]]'' – A radio show * [[Permanent signal]]
==References== {{Reflist}}
[[Category:Telephony equipment]] [[Category:Telephony signals]]