Editing Telegraph key (section)

===Straight keys===
A ''straight key'' is the common telegraph key as seen in various movies. It is a simple bar with a knob on top and an electrical contact underneath. When the bar is pressed down against spring tension, it makes a closed electric circuit.<ref name="elements">{{cite book |title=Elements of Telegraph Operating |publisher=International Correspondence Schools |location=Google Books |page=9 |url=https://books.google.com/books?id=luQOAAAAYAAJ&pg=PA9&dq=%22Telegraph+key%22+-wikipedia&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwjf__TMy6qKAxVFqZUCHSQEKtcQ6AF6BAgJEAI#v=onepage&q=%22Telegraph%20key%22%20-wikipedia&f=false |access-date=15 December 2024}}</ref> Traditionally, American telegraph keys had flat topped knobs and narrow bars (frequently curved), while European telegraph keys had ball shaped knobs and thick bars. This appears to be purely a matter of culture and training, but the users of each are tremendously partisan.{{efn|
The longer shape of the ball-headed knobs is intended to encourage the operator to incline the hand and grasp the key more lightly, to put less strain on the arm. The design is intended to reduce [[repetitive strain injury]] once common among telegraphers, which telegraphers called "[[glass arm]]", and medical literature referred to as ''telegraphers’ paralysis''. However it is possible to injure one's arm by improperly holding the key, or striking with too much force (called "pounding brass") with either type of up-and-down key.
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Straight keys have been made in numerous variations for over 150&nbsp;years and in numerous countries. They are the subject of an avid community of key collectors. The straight keys also had a ''shorting bar'' that closed the electrical circuit through the station when the operator was not actively sending messages. The shorting switch for an unused key was needed in telegraph systems wired in the style of North American railroads, in which the signal power was supplied from batteries only in telegraph offices at one or both ends of a line, rather than each station having its own bank of batteries, which was often used in Europe. The shorting bar completed the electrical path to the next station and all following stations, so that their sounders could respond to signals coming down the line, allowing the operator in the next town to receive a message from the central office. Although occasionally included in later keys for reasons of tradition, the shorting bar is unnecessary for radio telegraphy, except as a convenience to produce a steady signal for tuning the transmitter.

The straight key is simple and reliable, but the rapid pumping action needed to send a string of dots (or ''dits'' as most operators call them) poses some medically significant drawbacks.
 
Transmission speeds vary from 5&nbsp;words (25&nbsp;characters) per minute, by novice operators, up to about 30&nbsp;words (150&nbsp;characters) per minute by skilled operators. In the early days of telegraphy, a number of professional telegraphers developed a [[repetitive stress injury]] known as ''[[glass arm]]'' or ''telegraphers’ paralysis''.<ref>{{cite book |last1=Cocconcelli, Marco and Fonte, Cosimo |title=Explorations in the History and Heritage of Machines and Mechanisms: Dynamic Analysis of a Semiautomatic Telegraph Key |publisher=Springer Nature |location=Google Books |isbn=978-3-030-98498-4 |page=383 |edition=7th |url=https://books.google.com/books?id=FrVoEAAAQBAJ&pg=PA382&dq=%22Telegraph+key%22+-wikipedia&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwi_zNeGzqqKAxXfMlkFHQ8TGYM4FBDoAXoECAwQAg#v=onepage&q=%22Telegraph%20key%22%20-wikipedia&f=false |access-date=15 December 2024}}</ref> "Glass arm" may be reduced or eliminated by increasing the side play of the straight key, by loosening the adjustable [[trunnion]] screws. Such problems can be avoided either by using good manual technique, or by only using side-to-side key types.<ref>{{youTube|ncOcgarGJHI|How to operate a straight key}}</ref><ref>{{youTube|nVkLr0GyJPI|Technique of hand sending (1944)}}</ref><ref>{{youTube|x6ggckXtZjs|Straight key hand sending technique approved by professionals}}</ref>