RS2376 parallel ASCII keyboard with ECMA23/ISO layout.Acorn BBC Microcomputer with ECMA23/ANSI layout, @ is a singleton key and Shift-underline generates £ as character 96.Modern Dell keyboard customised with ECMA23/ISO layout.IBM keyboard with Japanese EMCA23/ANSI layout.
ECMA-23 is a standard for a bit-paired keyboard layout adopted in 1969 and revised in 1975. As a bit-paired layout, shifted keys correspond to toggling bits in the ASCII keycode. This is most visible in the digits on the top row, where shifting 6789 give &'(), and ;+, :* and -= are paired.
The ECMA-23 layout has two options, being the same as the ISO 2530 or the ANSI-X4.14 bit-paired layout.
In the UK, ECMA-23 layout keyboards were used on most 8-bit computers such as the Acorn BBC computers and the earlier Atom and Systems, the Amstrad CPC series, and (to an extent) the ZX Spectrum. While bit-paired layouts have generally given way to typewriter layouts it remains as the Japanese keyboard layout.
Technical details
The _ and \| keys may be at the left as per ISO2530 or at the right as per ANSI-X4.14.
Character 96 is generated either with Shift-_ with @ a singleton key, or with Shift-@ with _ a singleton key.
Underline may be generated with Shifted-0 instead of with its own key. If this is done then Shift-@ is used to generate character 96.
If a key is labelled ← Backspace it should be at the top-right; if a key is labelled DELETE it should be at the bottom-right.
If the key to the left of 1 is not _, it is ESCAPE.
The most common layouts are:
"BBC Micro": ECMA23/ANSI with Shift-_ generating character 96
"Japan": ECMA23/ANSI with Shift-@ generating character 96 and an extra key to the right of /? generating \_
"PC": ECMA23/ISO with Shift-_ generating character 96
ASCII, abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Most modern character-encoding schemes are based on ASCII, although they support many additional characters.
The Amstrad CPC is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom, France, Spain, and the German-speaking parts of Europe.
In computing and telecommunication, a control character or non-printing character (NPC) is a code point in a character set, that does not represent a written symbol. They are used as in-band signaling to cause effects other than the addition of a symbol to the text. All other characters are mainly printing, printable, or graphic characters, except perhaps for the "space" character.
ANSI escape sequences are a standard for in-band signaling to control cursor location, color, font styling, and other options on video text terminals and terminal emulators. Certain sequences of bytes, most starting with an ASCII escape character and a bracket character, are embedded into text. The terminal interprets these sequences as commands, rather than text to display verbatim.
In computing, a Control keyCtrl is a modifier key which, when pressed in conjunction with another key, performs a special operation ; similar to the Shift key, the Control key rarely performs any function when pressed by itself. The Control key is located on or near the bottom left side of most keyboards, with many featuring an additional one at the bottom right.
The VT220 is a computer terminal introduced by Digital Equipment Corporation (DEC) in November 1983. The VT240 added monochrome ReGIS vector graphics support to the base model, while the VT241 did the same in color. The 200 series replaced the successful VT100 series, providing more functionality in a much smaller unit with a much smaller and lighter keyboard. Like the VT100, the VT200 series implemented a large subset of ANSI X.364. Among its major upgrades was a number of international character sets, as well as the ability to define new character sets.
The pound sign£ is the symbol for the pound unit of sterling – the currency of the United Kingdom and previously of Great Britain and of the Kingdom of England. The same symbol is used for other currencies called pound, such as the Gibraltar, Egyptian, Manx and Syrian pounds. The sign may be drawn with one or two bars depending on personal preference, but the Bank of England has used the one-bar style exclusively on banknotes since 1975.
ISO/IEC 2022Information technology—Character code structure and extension techniques, is an ISO/IEC standard in the field of character encoding. Originating in 1971, it was most recently revised in 1994.
The backtick` is a typographical mark used mainly in computing. It is also known as backquote, grave, or grave accent.
The Alt keyAlt on a computer keyboard is used to change (alternate) the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing A will type the letter 'a', but holding down the Alt key while pressing A will cause the computer to perform an Alt+A function, which varies from program to program. The international standard ISO/IEC 9995-2 calls it Alternate key. The key is located on either side of the space bar, but in non-US PC keyboard layouts, rather than a second Alt key, there is an 'Alt Gr' key to the right of the space bar. Both placements are in accordance with ISO/IEC 9995-2. With some keyboard mappings, the right Alt key can be reconfigured to function as an AltGr key although not engraved as such.
Box-drawing characters, also known as line-drawing characters, are a form of semigraphics widely used in text user interfaces to draw various geometric frames and boxes. Box-drawing characters typically only work well with monospaced fonts. In graphical user interfaces, these characters are much less useful as it is more simple and appropriate to draw lines and rectangles directly with graphical APIs. However, they are still useful for command-line interfaces and plaintext comments within source code.
The LK201 is a detachable computer keyboard introduced by Digital Equipment Corporation of Maynard, Massachusetts in 1982. It was first used by Digital's VT220 ANSI/ASCII terminal and was subsequently used by the Rainbow-100, DECmate-II, and Pro-350 microcomputers and many of Digital's computer workstations such as the VAXstation and DECstation families.
The currency sign¤ is a character used to denote an unspecified currency. It can be described as a circle the size of a lowercase character with four short radiating arms at 45° (NE), 135° (SE), 225° (SW) and 315° (NW). It is raised slightly above the baseline. The character is sometimes called scarab.
On computer keyboards, the enter key⌅ Enter and return key↵ Return are two closely related keys with overlapping and distinct functions dependent on operating system and application.
Caret notation is a notation for control characters in ASCII. The notation assigns ^A to control-code 1, sequentially through the alphabet to ^Z assigned to control-code 26 (0x1A). For the control-codes outside of the range 1–26, the notation extends to the adjacent, non-alphabetic ASCII characters.
The C0 and C1 control code or control character sets define control codes for use in text by computer systems that use ASCII and derivatives of ASCII. The codes represent additional information about the text, such as the position of a cursor, an instruction to start a new line, or a message that the text has been received.
There are two major English language computer keyboard layouts, the United States layout and the United Kingdom layout defined in BS 4822. Both are QWERTY layouts. Users in the United States do not frequently need to make use of the £ (pound) and € (euro) currency symbols, which are common needs in the United Kingdom and Ireland, although the $ symbol is also provided as standard on UK and Irish keyboards. In other countries which predominantly use English as a common working language, such as Australia, Canada, and New Zealand, the US keyboard is commonly used.
A keyboard layout is any specific physical, visual or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer keyboard, mobile phone, or other computer-controlled typographic keyboard.
ISO 2047 is a standard for graphical representation of the control characters for debugging purposes, such as may be found in the character generator of a computer terminal; it also establishes a two-letter abbreviation of each control character. It started out as ANSI X3.32-1973 (American National Standard – Graphic Representation of the Control Characters of American National Standard Code for Information Interchange in 1973 and became an ISO standard in 1975. In addition, RFC 1345 "Character Mnemonics & Character Sets" is cited as the ISO 2047 two-letter abbreviation of the control character. ISO 2047, ECMA-17 in Europe, GB/T 3911-1983 in China, that corresponds to KS X 1010 in Korea has been established as a standard. It was enacted "graphical representation of information exchange capabilities for character" JIS X 0209:1976 in Japan, and was abolished on January 20, 2010.
A bit-paired keyboard is a keyboard where the layout of shifted keys corresponds to columns in the ASCII (1963) table, archetypally the Teletype Model 33 (1963) keyboard. This was later contrasted with a typewriter-paired keyboard, where the layout of shifted keys corresponds to electric typewriter layouts, notably the IBM Selectric (1961). The difference is most visible in the digits row : compared with mechanical typewriters, bit-paired keyboards remove the _ character from 6 and shift the remaining &* from 7890 to 6789, while typewriter-paired keyboards replace 3 characters: ⇧ Shift+2 from " to @⇧ Shift+6 from _ to ^ and ⇧ Shift+8 from ' to *. An important subtlety is that ASCII was based on mechanical typewriters, but electric typewriters became popular during the same period that ASCII was adopted, and made their own changes to layout. Thus differences between bit-paired and (electric) typewriter-paired keyboards are due to the differences of both of these from earlier mechanical typewriters.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
