Editing Baudot code (section)

==={{anchor|ITA1}}Baudot code (ITA1)===
{{Infobox character encoding
| name = Baudot code (ITA1)
| alias = International Telegraph Alphabet 1
| image = Baudot Code - from 1888 patent.png
| caption = An early version from Baudot's 1888 US patent, listing A through Z, {{du|t}} and ∗&nbsp;(Erasure)
| prev = [[Morse code]]
| next = [[#ITA2|ITA2]]
| status = Replaced by [[#ITA2|ITA2]] (not mutually compatible).
| classification = 5-bit [[state (computer science)|stateful]]{{citation needed|date=October 2023}} [[ISO Basic Latin alphabet|basic Latin]] encoding
}}
In the below table, Columns I, II, III, IV, and V show the code; the Let. and Fig. columns show the letters and numbers for the Continental and UK versions; and the sort keys present the table in the order: alphabetical, Gray and UK
{|class="wikitable collapsible sortable" style="border:none"
|+Baudot code (Continental and UK versions).<ref>in [[gray code|RBK order]]</ref>
|-
!scope="col" colspan="7" | Europe
!scope="col" colspan="2" |sort keys
!scope="col" colspan="8" | UK
!scope="col" | sort keys
|-
! scope="col" class="unsortable"|  V
! scope="col" width="10" class="unsortable"| IV 
! scope="col" width="25" colspan=2 class="unsortable"|  
! scope="col" width="10" class="unsortable"| I
! scope="col" width="10" class="unsortable"| II
! scope="col" width="10" class="unsortable"| III 
! scope="col" width="15" | Con&shy;ti&shy;nen&shy;tal
! scope="col" width="15" | [[Gray code|Gray]]
! scope="col" width="15" class="unsortable"| Let.
! scope="col" width="15" class="unsortable" | Fig. 
! scope="col" width="15" class="unsortable"  | V
! scope="col" width="15" class="unsortable" | IV
! scope="col" width="0" class="unsortable" | 
! scope="col" width="15" class="unsortable" | I
! scope="col" width="15" class="unsortable" | II
! scope="col" width="15"  class="unsortable" | III 
! scope="col" width="15" | UK
|-
|   ||   ||   ||   ||   ||   ||     || data-sort-value="32" |  -       || data-sort-value="000"|- ||  ||     ||   ||   ||||   ||   ||      ||data-sort-value="08"|-
|-
|   ||   || A || 1 || ● ||   ||     || data-sort-value="01" |         || data-sort-value="001"| || A || 1 ||   ||   |||| ● ||   ||    ||data-sort-value="01"|
|-
|   ||   || É || & || ● || ● ||     || data-sort-value="06" |         || data-sort-value="002"| || / || <sup>1</sup>/||   ||   |||| ● || ● ||    ||data-sort-value="04"|
|-
|   ||   || E || 2 ||   || ● ||     || data-sort-value="05" |        || data-sort-value="003"| || E || 2 ||   ||   ||||   || ● ||    ||data-sort-value="02"|
|-
|   ||   || I || {{du|o}} ||   || ● || ● || data-sort-value="10" |         || data-sort-value="004"| || I || <sup>3</sup>/||   ||   ||||   || ● || ●   ||data-sort-value="05"|
|-
|   ||   || O || 5 || ● || ● || ●  || data-sort-value="16" |          || data-sort-value="005"| || O || 5 ||   ||   |||| ● || ● || ●    ||data-sort-value="07"|
|-
|   ||   || U || 4 || ● ||   || ●  || data-sort-value="22" |          || data-sort-value="006"| || U || 4 ||   ||   |||| ● ||   || ●   ||data-sort-value="06"|
|-
|   ||   || Y || 3 ||   ||   || ●  || data-sort-value="26" |          || data-sort-value="007"| || Y || 3 ||   ||   ||||   ||   || ●    ||data-sort-value="03"|
|-
|   || ● || B || 8 ||   ||   || ●  || data-sort-value="02" |         || data-sort-value="010"| || B || 8 ||   || ● ||||   ||   || ●    ||data-sort-value="11"|
|-
|   || ● || C || 9 || ● ||   || ●  || data-sort-value="03" |         || data-sort-value="011"| || C || 9 ||   || ● |||| ● ||   || ●   ||data-sort-value="14"|
|-
|   || ● || D || 0 || ● || ● || ●  || data-sort-value="04" |         || data-sort-value="012"| || D || 0 ||   || ● |||| ● || ● || ●    ||data-sort-value="15"|
|-
|   || ● || F || {{du|f}} ||   || ● || ●   || data-sort-value="07"|         || data-sort-value="013"| || F || <sup>5</sup>/||   || ● ||||   || ● || ●   ||data-sort-value="13"|
|-collapsed
|   || ● || G || 7 ||   || ● ||     || data-sort-value="08" |         || data-sort-value="014"| || G || 7 ||   || ● ||||   || ● ||     ||data-sort-value="10"|
|-
|   || ● || H || {{du|h}} || ● || ● ||    || data-sort-value="09" |         || data-sort-value="015" | || H || ¹ ||   || ● |||| ● || ● ||     ||data-sort-value="12"|
|- 
|   || ● || J || 6 || ● ||   ||  || data-sort-value="11" |         || data-sort-value="016 " | || J || 6 ||   || ● |||| ● ||   ||     ||data-sort-value="09"|
|-
|   || ● ||  ''Figure''  || ''Blank'' || || || ||data-sort-value="30" |         || data-sort-value="017" | ||  ''Fig.''  || ''Bl.'' ||   || ● ||||   ||   ||   ||data-sort-value="16"|
|-
| ● || ● ||   ''Erasure'' ||   ''Erasure'' || || || ||data-sort-value="29" |         || data-sort-value="020" | || * || * || ● || ● ||||   ||   ||   ||data-sort-value="32"|
|-
| ● || ● || K || ( || ● ||   ||    || data-sort-value="12" |         || data-sort-value="021" | || K || ( || ● || ● |||| ● ||   ||   ||data-sort-value="25"|
|-
| ● || ● || L || = || ● || ● ||    || data-sort-value="13" |         || data-sort-value="022" | || L || = || ● || ● |||| ● || ● ||   ||data-sort-value="28"|
|-
| ● || ● || M || ) ||   || ● ||    || data-sort-value="14" |         || data-sort-value="023" | || M || ) || ● || ● ||||   || ● ||   ||data-sort-value="26"|
|-
| ● || ● || N || N°||   || ● || ●  || data-sort-value="15" |         || data-sort-value="024" | || N || £ || ● || ● ||||   || ● || ● ||data-sort-value="29 "|
|-
| ● || ● || P || % || ● || ● || ●  || data-sort-value="17" |         || data-sort-value="025" | || P || + || ● || ● |||| ● || ● || ● ||data-sort-value="31"|
|-
| ● || ● || Q || / || ● ||   || ●  || data-sort-value="18" |         || data-sort-value="026" | || Q || / || ● || ● |||| ● ||   || ● ||data-sort-value="30"|
|-
| ● || ● || R || – ||   ||   || ●  || data-sort-value="19" |         || data-sort-value="027" | || R || – || ● || ● ||||   ||   || ● ||data-sort-value="27"|
|-
| ● ||   || S || ; ||   ||   || ●  || data-sort-value="20" |         || data-sort-value="030" | || S || <sup>7</sup>/|| ● ||   ||||   ||   || ●  ||data-sort-value="19"|
|-
| ● ||   || T || ! || ● ||   || ●  || data-sort-value="21" |         || data-sort-value="031" | || T || ² || ● ||   |||| ● ||   || ● ||data-sort-value="22"|
|-
| ● ||   || V || ' || ● || ● || ●  || data-sort-value="23" |         || data-sort-value="032" | || V || ¹ || ● ||   |||| ● || ● || ● ||data-sort-value="23"|
|-
| ● ||   || W || ? ||   || ● || ●  || data-sort-value="24" |         || data-sort-value="033" | || W || ? || ● ||   ||||   || ● || ● ||data-sort-value="21"|
|-
| ● ||   || X ||, ||   || ● ||     || data-sort-value="25" |         || data-sort-value="034" | || X || <sup>9</sup>/|| ● ||   ||||   || ● ||  ||data-sort-value="18"|
|-
| ● ||   || Z || : || ● || ● ||    || data-sort-value="27" |         || data-sort-value="035" | || Z || : || ● ||   |||| ● || ● ||    ||data-sort-value="20"|
|-
| ● ||   || {{du|t}} || . || ● ||   ||   || data-sort-value="28" |          || data-sort-value="036" | || – || . || ● ||   |||| ● ||   ||     ||data-sort-value="17"|
|-
| ● ||   ||   ''Blank'' ||''Letter'' ||  || || ||data-sort-value="31" |         || data-sort-value="037" | ||  ''Bl.''||   ''Let.''    || ● ||   ||||   ||   ||   ||data-sort-value="24"|
|}

Baudot developed his first multiplexed telegraph in 1872<ref name=emmons/><ref name="Fischer_2000">{{cite web |author-last=Fischer |author-first=Eric N. |date=2000-06-20 |title=The Evolution of Character Codes, 1874–1968 |url=https://archive.org/details/enf-ascii |access-date=2020-12-20 |id=ark:/13960/t07x23w8s |quote=[...] In 1872, [Baudot] started research toward a telegraph system that would allow multiple operators to transmit simultaneously over a single wire and, as the transmissions were received, would print them in ordinary alphabetic characters on a strip of paper. He received a patent for such a system on June 17, 1874. [...] Instead of a variable delay followed by a single-unit pulse, Baudot's system used a uniform six time units to transmit each character. [...] his early telegraph probably used the six-unit code [...] that he attributes to [[Edward Davy|Davy]] in an 1877 article. [...] in 1876 Baudot redesigned his equipment to use a five-unit code. Punctuation and digits were still sometimes needed, though, so he adopted from [[David Edward Hughes|Hughes]] the use of two special letter space and figure space characters that would cause the printer to shift between cases at the same time as it advanced the paper without printing. The five-unit code he began using at this time [...] was structured to suit his keyboard [...], which controlled two units of each character with switches operated by the left hand and the other three units with the right hand. [...]}} [https://web.archive.org/web/20180919020435/http://index-of.es/Varios-2/ASCII%20The%20Evolution%20of%20Character%20Codes.pdf][https://archive.org/details/enf-ascii]</ref> and patented it in 1874.<ref name="Fischer_2000"/><ref name="Baudot_1874">{{cite web |author-first=Jean-Maurice-Émile |author-last=Baudot |author-link=Jean-Maurice-Émile Baudot |title=Système de télégraphie rapide |language=fr |date=June 1874 |id=Patent Brevet 103,898 |publisher=Archives [[Institut National de la Propriété Industrielle]] (INPI) |url=http://leoferres.info/images/baudot_cp1874.jpg |url-status=dead |archive-url=https://web.archive.org/web/20171216144029/http://leoferres.info/images/baudot_cp1874.jpg |archive-date=2017-12-16}}</ref> In 1876, he changed from a six-bit code to a five-bit code,<ref name="Fischer_2000"/> as suggested by [[Carl Friedrich Gauss]] and [[Wilhelm Eduard Weber|Wilhelm Weber]] in 1834,<ref name=emmons>{{cite journal
|journal=Wire & Radio Communications
|title=Printer Systems
|author=H. A. Emmons
|date=1 May 1916
|volume=34
|url = https://books.google.com/books?id=ozopAAAAYAAJ&pg=PA209
|page=209
}}</ref><ref>{{cite journal
|journal=Transactions
|publisher=American Institute of Electrical Engineers
|title=A New Page-Printing Telegraph
|author=William V. Vansize
|date=25 January 1901
|volume=18
|page=22
|url=https://books.google.com/books?id=WlNLAAAAMAAJ&q=gauss+weber+baudot&pg=PA22
}}</ref>
with equal on and off intervals, which allowed for transmission of the Roman alphabet, and included punctuation and control signals. The code itself was not patented (only the machine) because French patent law does not allow concepts to be patented.<ref>Procès d'Amiens Baudot vs Mimault</ref>

Baudot's 5-bit code was adapted to be sent from a manual keyboard, and no teleprinter equipment was ever constructed that used it in its original form.<ref name = "TomJennings-Baudot">{{Cite web |last1=Jennings |first1=Tom |author-link=Tom Jennings |title=An annotated history of some character codes: Baudot's code |year=2020 |url=https://www.sr-ix.com/Archive/CharCodeHist/index.html#BAUDOT}}</ref> The code was entered on a keyboard which had just five piano-type keys and was operated using two fingers of the left hand and three fingers of the right hand. Once the keys had been pressed, they were locked down until mechanical contacts in a distributor unit passed over the sector connected to that particular keyboard, at which time the keyboard was unlocked ready for the next character to be entered, with an audible click (known as the "cadence signal") to warn the operator. Operators had to maintain a steady rhythm, and the usual speed of operation was 30 words per minute.<ref>{{cite book |last=Beauchamp |first=K.G. |title=History of Telegraphy: Its Technology and Application |publisher=[[Institution of Engineering and Technology]] |year=2001 |pages=394–395 |isbn=0-85296-792-6}}</ref>

The table "shows the allocation of the Baudot code which was employed in the [[General Post Office#New communication systems|British Post Office]] for continental and inland services. A number of characters in the continental code are replaced by fractionals in the inland code. Code elements 1, 2 and 3 are transmitted by keys 1, 2 and 3, and these are operated by the first three fingers of the right hand. Code elements 4 and 5 are transmitted by keys 4 and 5, and these are operated by the first two fingers of the left hand."<ref name = "TomJennings-Baudot" /><ref>Alan G. Hobbs, ''[http://www.nadcomm.com/?p=95 5 Unit Codes]'', section ''Baudot Multiplex System''</ref><ref>{{cite book |last=Gleick |first=James |title=The Information: A History, a Theory, a Flood |year=2011 |publisher=Fourth Estate |location=London |isbn=978-0-00-742311-8 |pages=203 |url=http://around.com/the-information}}</ref>

Baudot's code became known as the '''International Telegraph Alphabet No. 1''' ('''ITA1'''). It is no longer used.