What is ASCII (American Standard Code for Information Interchange)?

The ASCII (American Standard Code for Information Interchange) is the model or character model to be used during information exchange based on the Latin alphabet used in modern English and other western languages.

ASCII History and Computer Codes

The ASCII code was developed in the telegraph field and was first used as a teleprint code that is commercially supported by Bell’s data services.

Bell had planned to use a six-bit code derived from Fieldata, which added punctuation and lowercase letters to the old Baudot teleprinting code, but was persuaded to join the ASA (American Standards Agency) subcommittee, which began developing the ASCII code.

Baudot automated the sending and receiving of telegram messages and received many features from the Morse code. However, unlike the Morse code, Baudot used fixed-length codes.

Compared to the early telegram codes, the code proposed by Bell and ASA resulted in a more convenient rearrangement to add additional features such as lists and escape sequences.

ASA, which will later become the ANSI (American National Standards Institute), first published the code ASCII in 1963.

In ASCII, published in 1963, there was an arrow pointing up (↑) instead of circumflex (^) and an arrow pointing left instead of underscore (_).

The 1967 version added lowercase letters, changed the names of some control codes, and two control codes moved ACK and ESC from the lowercase region to the control code region.

ASCII has been updated accordingly and published as ANSI X3.4-1968, ANSI X3.4-1977, and finally ANSI X3.4-1986.

Other standardization agencies have published character data that are the same as ASCII. Although they are only defined by ASA/ANSI standards, they are often called ASCII.

The ECMA (European Computer Manufacturers Association) released its publications of the ASCII clone ECMA-6 in 1965, 1967, 1970, 1973, 1983, and 1991. The 1991 version is the same as ANSI X3.4-1986.

ISO (International Organization for Standardization) published the ISO 646 product in 1967, 1972, 1983, and 1991.

Specifically, “ISO 646: 1972” created a country-specific set of versions where punctuation was replaced with non-English characters. ISO/IEC 646: 1991 International Reference Edition is the same as in ANSI X3.4-1986.

ITU (International Telecommunication Union) published ANSI X3.4-1986, ITU Recommendation T.50 in 1992. In the early 1970s, it released a version as “CCITT Recommendation V.3”.

DIN published a version of ASCII in 1974 as standard DIN 66003.

The Internet Engineering Working Group (IETF) released a version as RFC 20 in 1969, and with the release of RFC 1345 in 1992, it created the standard version for the Internet-based on ANSI X3.4-1986.

The IBM version of ANSI X3.4-1986 has been published in the IBM technical literature as code page 367.

ASCII Code

A computer’s memory stores all information digitally. There is no way to save characters directly. Each character has an equivalent digital code. This digital data is called the ASCII and represents characters using 7 bits.

Codes from 0 to 31 are not used for characters. These are called control characters because they are used for actions such as Carriage Return (CR) or Ring (BEL). Codes 65 to 90 represent uppercase letters, and 97 to 122 codes represent the lower case. If we change the 6th bit, it is equivalent to adding 32 to the code in decimal.

Control Characters

ASCII was not originally developed to carry printable information. It was developed to store the first 32 codes for control character codes to control devices using the same array or provide meta-information about data streams stored on the tape.

For example, character 10 represents the line feed function and character 8 represents the backspace key.

Control characters that do not contain carriage return, line feed, or white spaces are called control characters without spaces.

It does not define any mechanism, such as profit margin languages, address page, and other schemes such as document layout and format, to define the structure or appearance of text in a document, except for control characters that specify the basic line-oriented format.

The original standard used only brief descriptive statements for each control character. This uncertainty is sometimes slightly different from the data flow in a character’s terminal connection, sometimes it was deliberate when used accidentally.

Printable Characters

Code 32 (space character) specifies the space between words produced by a keyboard spacer. The space character is treated as an invisible graphic instead of the control character.

Codes 33 to 126, known as printable characters, represent letters, numbers, punctuation, and some miscellaneous symbols.

Seven-bit ASCII provided seven national characters, and if combined hardware and software allows, you can use extreme strokes to simulate some additional international characters in such a scenario.

It supports ASCII art, a minority artistic discipline that involves creating images using printable characters.

The effect obtained is compared with point techniques, since images produced by this technique are generally appreciated in more detail when viewed from a distance.

ASCII art began as an experimental art but soon became popular as a resource for representing images in non-graphic media such as teletypes, terminals, emails or some printers.

Although you can create ASCII art manually using a text editor, you can automatically convert images and videos to ASCII using software such as the popular Aalib library.

Aalib is supported by some graphic design programs, games, and video players.

Extended Table

   ASCII Control Characters Table (0-31)

   ASCII Printable Characters Table (32-127)

   Extended ASCII Codes Table (128-255)

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