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Six-bit character code

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A six-bit character code is a character encoding designed for use on computers with word lengths a multiple of 6. Six bits can only encode 64 distinct characters, so these codes generally include only the upper-case letters, the numerals, some punctuation characters, and sometimes control characters. The 7-track magnetic tape format was developed to store data in such codes, along with an additional parity bit .

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58-624: An early six-bit binary code was used for Braille , the reading system for the blind that was developed in the 1820s. The earliest computers dealt with numeric data only, and made no provision for character data. Six-bit BCD , with several variants, was used by IBM on early computers such as the IBM 702 in 1953 and the IBM 704 in 1954. Six-bit encodings were replaced by the 8-bit EBCDIC code starting in 1964, when System/360 standardized on 8-bit bytes . There are some variants of this type of code (see below ). Six-bit character codes generally succeeded

116-400: A braille embosser (printer) or a refreshable braille display (screen). Braille has been extended to an 8-dot code , particularly for use with braille embossers and refreshable braille displays. In 8-dot braille the additional dots are added at the bottom of the cell, giving a matrix 4 dots high by 2 dots wide. The additional dots are given the numbers 7 (for the lower-left dot) and 8 (for

174-526: A word space . Dot configurations can be used to represent a letter, digit, punctuation mark, or even a word. Early braille education is crucial to literacy, education and employment among the blind. Despite the evolution of new technologies, including screen reader software that reads information aloud, braille provides blind people with access to spelling, punctuation and other aspects of written language less accessible through audio alone. While some have suggested that audio-based technologies will decrease

232-563: A 36-bit word (capable of storing six such reduced FIELDATA characters). Braille characters are represented using six dot positions, arranged in a rectangle. Each position may contain a raised dot or not, so Braille can be considered to be a six-bit binary code. Some more modern Braille systems add an extra two dots, making these systems an eight-bit code instead. Transmission of binary data over systems which are designed for text only can sometimes introduce problems. For example, email historically supported only 7-bit ASCII codes and would strip

290-475: A Frenchman who lost his sight as a result of a childhood accident. In 1824, at the age of fifteen, he developed the braille code based on the French alphabet as an improvement on night writing . He published his system, which subsequently included musical notation , in 1829. The second revision, published in 1837, was the first binary form of writing developed in the modern era. Braille characters are formed using

348-638: A combination of six raised dots arranged in a 3 × 2 matrix, called the braille cell. The number and arrangement of these dots distinguishes one character from another. Since the various braille alphabets originated as transcription codes for printed writing, the mappings (sets of character designations) vary from language to language, and even within one; in English braille there are three levels: uncontracted  – a letter-by-letter transcription used for basic literacy; contracted  – an addition of abbreviations and contractions used as

406-419: A few punctuation characters with the most useful control characters—including SO/SI , allowing code extension—was specified as ECMA - 1 in 1963 (see below ). FIELDATA was a seven-bit code (with optional parity) of which only 64 code positions (occupying six bits) were formally defined. A variant was used by UNIVAC 's 1100-series computers. Treating the code as a six-bit code these systems used

464-548: A generalization of the US Air Force 's SAGE system that was being created at about the same time. Unlike SAGE, FIELDATA was intended to be much larger in scope, allowing information to be gathered from any number of sources and forms. Much of the FIELDATA system was the specifications for the format the data would take, leading to a character set that would be a huge influence on ASCII a few years later. FIELDATA also specified

522-459: A greater number of symbols. (See Gardner–Salinas braille codes .) Luxembourgish Braille has adopted eight-dot cells for general use; for example, accented letters take the unaccented versions plus dot 8. Braille was the first writing system with binary encoding . The system as devised by Braille consists of two parts: Within an individual cell, the dot positions are arranged in two columns of three positions. A raised dot can appear in any of

580-466: A keyboard's shift key and selected between a lower-case and digits repertoire, and an upper-case and symbols one. A second pair of Linotype-specific "lower rail" and "upper rail" shift codes would select an alternate (usually italic) font. Six-bit BCD code was the adaptation of the punched card code to binary code . IBM applied the terms binary-coded decimal and BCD to the variations of BCD alphamerics used in most early IBM computers, including

638-405: A maximum of 42 cells per line (its margins are adjustable), and typical paper allows 25 lines per page. A large interlining Stainsby has 36 cells per line and 18 lines per page. An A4-sized Marburg braille frame, which allows interpoint braille (dots on both sides of the page, offset so they do not interfere with each other), has 30 cells per line and 27 lines per page. A Braille writing machine

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696-607: A single 36-bit word of the PDP-10 , and three characters fit in each word of the PDP-1 and two characters fit in each word of the PDP-8 . See table below . Another, less common, variant is obtained by just stripping the high bit of an ASCII code in 32 - 95 range (codes 32 - 63 remain at their positions, higher values have 64 subtracted from them). Such variant was sometimes used on DEC's PDP-8 (1965). A six-bit code similar to DEC's, but replacing

754-611: A space-saving mechanism; and grade 3  – various non-standardized personal stenographies that are less commonly used. In addition to braille text (letters, punctuation, contractions), it is also possible to create embossed illustrations and graphs, with the lines either solid or made of series of dots, arrows, and bullets that are larger than braille dots. A full braille cell includes six raised dots arranged in two columns, each column having three dots. The dot positions are identified by numbers from one to six. There are 64 possible combinations, including no dots at all for

812-601: A system much more like shorthand. Today, there are braille codes for over 133 languages. In English, some variations in the braille codes have traditionally existed among English-speaking countries. In 1991, work to standardize the braille codes used in the English-speaking world began. Unified English Braille (UEB) has been adopted in all seven member countries of the International Council on English Braille (ICEB) as well as Nigeria. For blind readers, braille

870-469: A text interfered with following the alignment of the letters, and consequently made texts more difficult to read than Braille's more arbitrary letter assignment. Finally, there are braille scripts that do not order the codes numerically at all, such as Japanese Braille and Korean Braille , which are based on more abstract principles of syllable composition. Texts are sometimes written in a script of eight dots per cell rather than six, enabling them to encode

928-436: Is a tactile writing system used by people who are visually impaired . It can be read either on embossed paper or by using refreshable braille displays that connect to computers and smartphone devices. Braille can be written using a slate and stylus , a braille writer , an electronic braille notetaker or with the use of a computer connected to a braille embosser . Braille is named after its creator, Louis Braille ,

986-592: Is a typewriter with six keys that allows the user to write braille on a regular hard copy page. The first Braille typewriter to gain general acceptance was invented by Frank Haven Hall (Superintendent of the Illinois School for the Blind ), and was presented to the public in 1892. The Stainsby Brailler, developed by Henry Stainsby in 1903, is a mechanical writer with a sliding carriage that moves over an aluminium plate as it embosses Braille characters. An improved version

1044-658: Is also able to transmit human-readable text. IBM, which dominated commercial data processing use a variety of six-bit codes, which were tied to the character set used on punched cards , see BCD (character encoding) . Other vendor character codes are shown below, with their Unicode equivalents. The following table shows the arrangement of characters, with the hex value, corresponding ASCII character, Braille 6-bit codes (dot combinations), Braille Unicode glyph, and general meaning (the actual meaning may change depending on context). Braille Braille ( / ˈ b r eɪ l / BRAYL , French: [bʁɑj] )

1102-517: Is an independent writing system, rather than a code of printed orthography. Braille is derived from the Latin alphabet, albeit indirectly. In Braille's original system, the dot patterns were assigned to letters according to their position within the alphabetic order of the French alphabet of the time, with accented letters and w sorted at the end. Unlike print, which consists of mostly arbitrary symbols,

1160-530: Is dot 5, which combines with the first letter of words. With the letter ⠍ m , the resulting word is ⠐ ⠍ mother . There are also ligatures ("contracted" letters), which are single letters in braille but correspond to more than one letter in print. The letter ⠯ and , for example, is used to write words with the sequence a-n-d in them, such as ⠛ ⠗ ⠯ grand . Most braille embossers support between 34 and 40 cells per line, and 25 lines per page. A manually operated Perkins braille typewriter supports

1218-399: Is extended by adding the decade dots, whereas in the fifth decade it is extended by shifting it downward. Originally there had been nine decades. The fifth through ninth used dashes as well as dots, but they proved to be impractical to distinguish by touch under normal conditions and were soon abandoned. From the beginning, these additional decades could be substituted with what we now know as

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1276-555: Is read as capital 'A', and ⠼ ⠁ as the digit '1'. Basic punctuation marks in English Braille include: ⠦ is both the question mark and the opening quotation mark. Its reading depends on whether it occurs before a word or after. ⠶ is used for both opening and closing parentheses. Its placement relative to spaces and other characters determines its interpretation. Punctuation varies from language to language. For example, French Braille uses ⠢ for its question mark and swaps

1334-506: Is representative of a reference version of the military set, as described in Leubbert (1960b) . Various other variants exist, with in some cases dramatic differences in the supervisory code (the first four rows 0–3). The letters in the first two rows are intended for use in "alphabetic supervisory information". The code version used on the UNIVAC was based on the second half (6-bit primary code) of

1392-648: The IBM 1620 , IBM 1400 series , and non- decimal architecture members of the IBM 700/7000 series . A six-bit code was also used in COBOL databases, where end-of-record information was stored separately. A six-bit code, with added odd parity bit , is used on Track 1 of magnetic stripe cards , as specified in ISO/IEC 7811 -2. A popular six-bit code was DEC SIXBIT. This is simply the ASCII character codes from 32 to 95 coded as 0 to 63 by subtracting 32 (i.e., columns 2, 3, 4, and 5 of

1450-453: The slate and stylus is a portable writing tool, much like the pen and paper for the sighted. Errors can be erased using a braille eraser or can be overwritten with all six dots ( ⠿ ). Interpoint refers to braille printing that is offset, so that the paper can be embossed on both sides, with the dots on one side appearing between the divots that form the dots on the other. Using a computer or other electronic device, Braille may be produced with

1508-448: The 5-level International Telegraph Alphabet was used to remotely control Linotype machines beginning around 1930. By 1950 it was widely used by wire services to send preformatted news stories to participating newspapers. It supported the 90 printable characters characters of a Linotype machine, plus whitespace characters . The TTS code had two pairs of shift codes allowing a total of four shift states. The first operated much like

1566-616: The 8th bit, thus corrupting binary data sent directly through any troublesome mail server. Other systems can cause issues by improperly interpreting control characters during storage or transmission. A number of schemes exist to pack 8-bit data into text-only representations which can pass through text mail systems, to be decoded at the destination. Examples of 6-bit character subsets used for packing binary data include Uuencode and Base64 . These sets contain no control characters (only printable numbers, letters, some punctuation, and maybe space) and allow data to be transmitted over any medium which

1624-420: The ASCII table (16 characters to a column), shifted to columns 0 through 3, by subtracting 2 from the high bits); it includes the space, punctuation characters, numbers, and capital letters, but no control characters. Since it included no control characters, not even end-of-line, it was not used for general text processing. However, six-character names such as filenames and assembler symbols could be stored in

1682-456: The FIELDATA characters are not represented in ASCII, the Unisys 2200 uses '^', '"' and '_' characters for codes 004 oct , 076 oct and 077 oct respectively. The FIELDATA project ran from 1956 until it was stopped during a reorganization in 1962. The code version used on the UNIVAC was based on the second half (primary code) of the military version with some changes. The following table

1740-422: The French order of the decade was u v x y z ç é à è ù ( ⠥ ⠧ ⠭ ⠽ ⠵ ⠯ ⠿ ⠷ ⠮ ⠾ ). The next ten letters, ending in w , are the same again, except that for this series position 6 (purple dot in the bottom right corner of the cell in the table above) is used without a dot at position 3. In French braille these are the letters â ê î ô û ë ï ü œ w ( ⠡ ⠣ ⠩ ⠹ ⠱ ⠫ ⠻ ⠳ ⠪ ⠺ ). W had been tacked onto

1798-465: The addition of a dot at position 3 (red dots in the bottom left corners of the cells in the table below): ⠅ ⠇ ⠍ ⠝ ⠕ ⠏ ⠟ ⠗ ⠎ ⠞ : The next ten letters (the next " decade ") are the same again, but with dots also at both position 3 and position 6 (green dots in the bottom rows of the cells in the table above). Here w was left out as it was not part of the official French alphabet in Braille's time;

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1856-401: The alphabet – thus the code was unable to render the orthography of the words. Second, the 12-dot symbols could not easily fit beneath the pad of the reading finger. This required the reading finger to move in order to perceive the whole symbol, which slowed the reading process. (This was because Barbier's system was based only on the number of dots in each of two 6-dot columns, not

1914-460: The braille alphabet follows a logical sequence. The first ten letters of the alphabet, a – j , use the upper four dot positions: ⠁ ⠃ ⠉ ⠙ ⠑ ⠋ ⠛ ⠓ ⠊ ⠚ (black dots in the table below). These stand for the ten digits 1 – 9 and 0 in an alphabetic numeral system similar to Greek numerals (as well as derivations of it, including Hebrew numerals , Cyrillic numerals , Abjad numerals , also Hebrew gematria and Greek isopsephy ). Though

1972-546: The braille letters according to the sort order of the print alphabet being transcribed; and reassigning the letters to improve the efficiency of writing in braille. Under international consensus, most braille alphabets follow the French sorting order for the 26 letters of the basic Latin alphabet , and there have been attempts at unifying the letters beyond these 26 (see international braille ), though differences remain, for example, in German Braille . This unification avoids

2030-540: The chaos of each nation reordering the braille code to match the sorting order of its print alphabet, as happened in Algerian Braille , where braille codes were numerically reassigned to match the order of the Arabic alphabet and bear little relation to the values used in other countries (compare modern Arabic Braille , which uses the French sorting order), and as happened in an early American version of English Braille, where

2088-399: The dots are assigned in no obvious order, the cells with the fewest dots are assigned to the first three letters (and lowest digits), abc = 123 ( ⠁ ⠃ ⠉ ), and to the three vowels in this part of the alphabet, aei ( ⠁ ⠑ ⠊ ), whereas the even digits 4 , 6 , 8 , 0 ( ⠙ ⠋ ⠓ ⠚ ) are right angles. The next ten letters, k – t , are identical to a – j respectively, apart from

2146-469: The end of 39 letters of the French alphabet to accommodate English. The a – j series shifted down by one dot space ( ⠂ ⠆ ⠒ ⠲ ⠢ ⠖ ⠶ ⠦ ⠔ ⠴ ) is used for punctuation. Letters a ⠁ and c ⠉ , which only use dots in the top row, were shifted two places for the apostrophe and hyphen: ⠄ ⠤ . (These are also the decade diacritics, on the left in the table below, of the second and third decade.) In addition, there are ten patterns that are based on

2204-678: The first braille translator written in a portable programming language. DOTSYS III was developed for the Atlanta Public Schools as a public domain program. FIELDATA FIELDATA (also written as Fieldata ) was a pioneering computer project run by the US Army Signal Corps in the late 1950s that intended to create a single standard (as defined in MIL-STD-188A/B/C ) for collecting and distributing battlefield information. In this respect it could be thought of as

2262-462: The first two letters ( ⠁ ⠃ ) with their dots shifted to the right; these were assigned to non-French letters ( ì ä ò ⠌ ⠜ ⠬ ), or serve non-letter functions: ⠈ (superscript; in English the accent mark), ⠘ (currency prefix), ⠨ (capital, in English the decimal point ), ⠼ ( number sign ), ⠸ (emphasis mark), ⠐ (symbol prefix). The first four decades are similar in that the numeric sequence

2320-436: The five-bit Baudot code and preceded seven-bit ASCII . Six-bit codes could encode more than 64 characters by the use of Shift Out and Shift In characters , essentially incorporating two distinct 62-character sets and switching between them. For example, the popular IBM 2741 communications terminal supported a variety of character sets of up to 88 printing characters plus control characters. A special 6-level extension of

2378-507: The left column and at the top of the right column: that is, the letter ⠍ m . The lines of horizontal braille text are separated by a space, much like visible printed text, so that the dots of one line can be differentiated from the braille text above and below. Different assignments of braille codes (or code pages ) are used to map the character sets of different printed scripts to the six-bit cells. Braille assignments have also been created for mathematical and musical notation. However, because

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2436-443: The letters w , x , y , z were reassigned to match English alphabetical order. A convention sometimes seen for letters beyond the basic 26 is to exploit the physical symmetry of braille patterns iconically, for example, by assigning a reversed n to ñ or an inverted s to sh . (See Hungarian Braille and Bharati Braille , which do this to some extent.) A third principle was to assign braille codes according to frequency, with

2494-514: The lower-right dot). Eight-dot braille has the advantages that the casing of each letter is coded in the cell and that every printable ASCII character can be encoded in a single cell. All 256 (2 ) possible combinations of 8 dots are encoded by the Unicode standard. Braille with six dots is frequently stored as Braille ASCII . The first 25 braille letters, up through the first half of the 3rd decade, transcribe a–z (skipping w ). In English Braille,

2552-403: The message formats and even the electrical standards for connecting FIELDATA-standard machines together. Another part of the FIELDATA project was the design and construction of computers at several different scales, from data-input terminals at one end, to theatre-wide data processing centers at the other. Several FIELDATA-standard computers were built during the lifetime of the project, including

2610-408: The need for braille, technological advancements such as braille displays have continued to make braille more accessible and available. Braille users highlight that braille remains as essential as print is to the sighted. ⠏ ⠗ ⠑ ⠍ ⠊ ⠑ ⠗ Braille was based on a tactile code , now known as night writing , developed by Charles Barbier . (The name "night writing" was later given to it when it

2668-481: The number sign ( ⠼ ) applied to the earlier decades, though that only caught on for the digits (the old 5th decade being replaced by ⠼ applied to the 1st decade). The dash occupying the top row of the original sixth decade was simply omitted, producing the modern fifth decade. (See 1829 braille .) Historically, there have been three principles in assigning the values of a linear script (print) to Braille: Using Louis Braille's original French letter values; reassigning

2726-399: The on-screen braille input keyboard, to type braille symbols on to their device by placing their fingers on to the screen according to the dot configuration of the symbols they wish to form. These symbols are automatically translated into print on the screen. The different tools that exist for writing braille allow the braille user to select the method that is best for a given task. For example,

2784-445: The pattern of the dots.) Third, the code did not include symbols for numerals or punctuation. Braille's solution was to use 6-dot cells and to assign a specific pattern to each letter of the alphabet. Braille also developed symbols for representing numerals and punctuation. At first, braille was a one-to-one transliteration of the French alphabet, but soon various abbreviations (contractions) and even logograms were developed, creating

2842-537: The quotation marks and parentheses (to ⠶ and ⠦ ⠴ ); it uses ( ⠲ ) for both the period and the decimal point, and the English decimal point ( ⠨ ) to mark capitalization. Braille contractions are words and affixes that are shortened so that they take up fewer cells. In English Braille, for example, the word afternoon is written with just three letters, ⠁ ⠋ ⠝ ⟨afn⟩ , much like stenoscript . There are also several abbreviation marks that create what are effectively logograms . The most common of these

2900-417: The rest of that decade is rounded out with the ligatures and, for, of, the, and with . Omitting dot 3 from these forms the 4th decade, the ligatures ch, gh, sh, th, wh, ed, er, ou, ow and the letter w . (See English Braille .) Various formatting marks affect the values of the letters that follow them. They have no direct equivalent in print. The most important in English Braille are: That is, ⠠ ⠁

2958-542: The simplest patterns (quickest ones to write with a stylus) assigned to the most frequent letters of the alphabet. Such frequency-based alphabets were used in Germany and the United States in the 19th century (see American Braille ), but with the invention of the braille typewriter their advantage disappeared, and none are attested in modern use – they had the disadvantage that the resulting small number of dots in

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3016-414: The six positions, producing 64 (2 ) possible patterns, including one in which there are no raised dots. For reference purposes, a pattern is commonly described by listing the positions where dots are raised, the positions being universally numbered, from top to bottom, as 1 to 3 on the left and 4 to 6 on the right. For example, dot pattern 1-3-4 describes a cell with three dots raised, at the top and bottom in

3074-415: The six-dot braille cell allows only 64 (2 ) patterns, including space, the characters of a braille script commonly have multiple values, depending on their context. That is, character mapping between print and braille is not one-to-one. For example, the character ⠙ corresponds in print to both the letter d and the digit 4 . In addition to simple encoding, many braille alphabets use contractions to reduce

3132-404: The size of braille texts and to increase reading speed. (See Contracted braille .) Braille may be produced by hand using a slate and stylus in which each dot is created from the back of the page, writing in mirror image, or it may be produced on a braille typewriter or Perkins Brailler , or an electronic Brailler or braille notetaker. Braille users with access to smartphones may also activate

3190-551: The transportable MOBIDIC from Sylvania , and the BASICPAC and LOGICPAC from Philco . Another system, ARTOC , was intended to provide graphical output (in the form of photographic slides ), but was never completed. Because FIELDATA did not specify codes for interconnection and data transmission control, different systems (like " STANDARD FORM ", " COMLOGNET Common language code ", " SACCOMNET (465L) Control Code " ) used different control functions. Intercommunication between them

3248-454: Was considered as a means for soldiers to communicate silently at night and without a light source, but Barbier's writings do not use this term and suggest that it was originally designed as a simpler form of writing and for the visually impaired.) In Barbier's system, sets of 12 embossed dots were used to encode 36 different sounds. Braille identified three major defects of the code: first, the symbols represented phonetic sounds and not letters of

3306-518: Was difficult. FIELDATA is the original character set used internally in UNIVAC computers of the 1100 series , each six-bit character contained in six sequential bits of the 36-bit word of that computer. The direct successor to the UNIVAC 1100 is the Unisys 2200 series computers, which used FIELDATA (although ASCII is now also common with each character encoded in 1/4 of a word, or 9 bits). Because some of

3364-749: Was introduced around 1933. In 1951 David Abraham, a woodworking teacher at the Perkins School for the Blind , produced a more advanced Braille typewriter, the Perkins Brailler . Braille printers or embossers were produced in the 1950s. In 1960 Robert Mann, a teacher in MIT, wrote DOTSYS , a software that allowed automatic braille translation , and another group created an embossing device called "M.I.T. Braillemboss". The Mitre Corporation team of Robert Gildea, Jonathan Millen, Reid Gerhart and Joseph Sullivan (now president of Duxbury Systems) developed DOTSYS III,

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