Editing Bell Labs (section)

===1940s===
[[File:Replica-of-first-transistor.jpg|thumb|A replica of the first [[transistor]], a [[point-contact transistor|point-contact]] [[germanium]] device, invented at Bell Laboratories in 1947]]
In the early 1940s, the [[photovoltaic cell]] was developed by [[Russell Ohl]]. In 1943, Bell developed [[SIGSALY]], the first digital scrambled speech transmission system, used by the [[Allies of World War II|Allies]] in [[World War II]]. The British wartime codebreaker [[Alan Turing]] visited the labs at this time, working on speech encryption and meeting [[Claude Shannon]].<ref>{{cite book |author-link1=Jack Copeland |first1=Jack |last1=Copeland |author-link2=Jonathan Bowen |first2=Jonathan |last2=Bowen |chapter=Chapter 1: Life and work & Chapter 18: Delilah—encrypting speech |title=The Turing Guide |publisher=[[Oxford University Press]] |year=2017 |isbn=978-0198747833 |title-link=The Turing Guide}}</ref>

Bell Labs Quality Assurance Department gave the world and the United States such statisticians as [[Walter A. Shewhart]], [[W. Edwards Deming]], [[Harold F. Dodge]], [[George D. Edwards]], Harry Romig, R. L. Jones, Paul Olmstead, E.G.D. Paterson, and [[Mary N. Torrey]]. During World War II, Emergency Technical Committee – Quality Control, drawn mainly from Bell Labs' statisticians, was instrumental in advancing Army and Navy ammunition acceptance and material sampling procedures.

In 1947, the [[transistor]], arguably the most important invention developed by Bell Laboratories, was invented by [[John Bardeen]], [[Walter Houser Brattain]], and [[William Shockley|William Bradford Shockley]] (who subsequently shared the Nobel Prize in Physics in 1956). In 1947, [[Richard Hamming]] invented [[Hamming code]]s for [[error detection and correction]]. For patent reasons, the result was not published until 1950.

In 1948, "[[A Mathematical Theory of Communication]]", one of the founding works in [[information theory]], was published by [[Claude Shannon]] in the ''[[Bell System Technical Journal]]''. It built in part on earlier work in the field by Bell researchers [[Harry Nyquist]] and [[Ralph Hartley]], but went much further. Bell Labs also introduced a series of increasingly complex calculators through the decade. Shannon was also the founder of [[History of cryptography|modern cryptography]] with his 1949 paper ''[[Communication Theory of Secrecy Systems]]''.

====Calculators====
<ref>{{Cite journal |last=Irvine |first=M. M. |date=July 2001 |title=Early digital computers at Bell Telephone Laboratories |journal=IEEE Annals of the History of Computing |volume=23 |issue=3 |pages=22–42 |doi=10.1109/85.948904 |issn=1058-6180}}</ref><ref name=":0">{{cite book |chapter-url=https://books.google.com/books?id=oyBUDgAAQBAJ&pg=PA32 |title=Birthing the Computer: From Relays to Vacuum Tubes |last1=Kaisler |first1=Stephen H. |date=2016 |publisher=Cambridge Scholars Publishing |isbn=9781443896313 |pages=32–37 |language=en |chapter=Chapter Three: Stibitz's Relay Computers |access-date=January 17, 2019 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017045959/https://books.google.com/books?id=oyBUDgAAQBAJ&pg=PA32#v=onepage&q&f=false |url-status=live }}</ref>
* Model I: A [[complex number calculator]], completed in 1939 and put into operation in 1940, for doing calculations of [[complex number]]s.
* Model II: Relay Computer / Relay Interpolator,<ref>{{cite journal |last1=Cesareo |first1=O. |title=THE RELAY INTERPOLATOR |journal=Bell Laboratories Record |date=December 1946 |volume=XXIV |issue=12 |pages=457–460 |url=https://www.americanradiohistory.com/Bell_Laboratories_Record_Issue_Key.htm |access-date=September 8, 2018 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017050000/https://www.worldradiohistory.com/Bell_Laboratories_Record_Issue_Key.htm |url-status=live }}</ref> September 1943, for interpolating data points of flight profiles (needed for performance testing of a gun director).<ref>{{cite book |last1=Akera |first1=Atsushi |title=Calculating a Natural World: Scientists, Engineers, and Computers During the Rise of U.S. Cold War Research |date=2008 |publisher=MIT Press |isbn=9780262512039 |page=57 |url=https://books.google.com/books?id=KmSYJkh8WxUC&pg=PA57 |language=en |access-date=January 17, 2019 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017050000/https://books.google.com/books?id=KmSYJkh8WxUC&pg=PA57#v=onepage&q&f=false |url-status=live }}</ref> This model introduced error detection (self checking).<ref>{{cite book |last1=Belzer |first1=Jack |last2=Holzman |first2=Albert G. |last3=Kent |first3=Allen |title=Encyclopedia of Computer Science and Technology: Volume 3 – Ballistics Calculations to Box–Jenkins Approach to Time Series Analysis and Forecasting |date=1976 |publisher=CRC Press |isbn=9780824722531 |page=197 |url=https://books.google.com/books?id=8IXArCuNWy4C&pg=PA197 |language=en |access-date=January 17, 2019 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017050001/https://books.google.com/books?id=8IXArCuNWy4C&pg=PA197#v=onepage&q&f=false |url-status=live }}</ref><ref>{{cite book |page=2 |url=https://books.google.com/books?id=sQwE8Gpsj5EC&pg=PA2 |title=Logic Design: A Review Of Theory And Practice |author=Glen G. Jr. Langdon |isbn=9780323160452 |date=December 2, 2012 |publisher=Elsevier |access-date=January 17, 2019 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017050001/https://books.google.com/books?id=sQwE8Gpsj5EC&pg=PA2#v=onepage&q&f=false |url-status=live }}</ref>
* Model III: Ballistic Computer,<ref>{{cite web |title=Model III computer. Frame with covers removed |date=n.d. |publisher=[[Erwin Tomash#The Erwin Tomash Library|The Erwin Tomash Library]] |url=http://www.cbi.umn.edu/hostedpublications/Tomash/Images%20web%20site/Image%20files/A%20Images/pages/Andrews.Review%20of%20Bell%20labs%20digital%20computers.Model%20III.htm |archive-url=https://web.archive.org/web/20120113081839/http://www.cbi.umn.edu/hostedpublications/Tomash/Images%20web%20site/Image%20files/A%20Images/pages/Andrews.Review%20of%20Bell%20labs%20digital%20computers.Model%20III.htm |archive-date=January 13, 2012}}</ref><ref>{{cite journal |last1=Juley |first1=Joseph |title=THE BALLISTIC COMPUTER |journal=Bell Laboratories Record |date=January 1947 |volume=XXV |issue=1 |pages=5–9 |url=https://www.americanradiohistory.com/Bell_Laboratories_Record_Issue_Key.htm |access-date=September 8, 2018 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017050000/https://www.worldradiohistory.com/Bell_Laboratories_Record_Issue_Key.htm |url-status=live }}</ref> June 1944, for calculations of ballistic trajectories.
* Model IV: Error Detector Mark II, March 1945,<ref name=":1">{{cite book |url=https://archive.org/stream/bitsavers_onrASurveyomputers1953_8778395/A_Survey_Of_Automatic_Digital_Computers_1953#page/n68/search/bell |title=A survey of automatic digital computers |last1=Research |first1=United States Office of Naval |date=1953 |publisher=Office of Naval Research, Dept. of the Navy |others=Model V-VI IV |pages=9–10, 63 (in reader: 15–16, 69) |language=en}}</ref> an improved ballistic computer.
* [[Model V]]:<ref>{{cite web |url=http://oplib.ru/random/view/161936 |title=Г. – Bell Labs – Model V |website=oplib.ru |language=ru |trans-title=G. – Bell Labs – Model V |access-date=October 11, 2017 |archive-date=October 12, 2017 |archive-url=https://web.archive.org/web/20171012044238/http://oplib.ru/random/view/161936 |url-status=dead }}</ref> General-purpose electromechanical computer, of which two were built, July 1946 and February 1947<ref>{{Cite book |url=https://books.google.com/books?id=yQ9LAQAAIAAJ |title=Encyclopedia of Computer Science |last1=Reilly |first1=Edwin D. |last2=Ralston |first2=Anthony |last3=Hemmendinger |first3=David |date=2000 |publisher=Nature Publishing Group |isbn=9781561592487 |page=548 |language=en |access-date=January 17, 2019 |archive-date=October 17, 2023 |archive-url=https://web.archive.org/web/20231017050002/https://books.google.com/books?id=yQ9LAQAAIAAJ |url-status=live }}</ref><ref name=":1" /><ref>
* {{Cite journal |last=Alt |first=Franz L. |date=1948 |title=A Bell Telephone Laboratories' computing machine. I |journal=Mathematics of Computation |language=en-US |volume=3 |issue=21 |pages=1–13 |doi=10.1090/S0025-5718-1948-0023118-1 |issn=0025-5718 |doi-access=free}}
* {{Cite journal |last=Alt |first=Franz L. |date=1948 |title=A Bell Telephone Laboratories' computing machine. II |journal=Mathematics of Computation |language=en-US |volume=3 |issue=22 |pages=69–84 |doi=10.1090/S0025-5718-1948-0025271-2 |issn=0025-5718 |doi-access=free}}
</ref>
* [[Model V#Model VI|Model VI]]: 1949, an enhanced Model V.{{Citation needed|date=February 2025}}