character set

<character, standard> One of several standard collections of characters, or a non-standard collection selected for a particular need. The most widely used character set is ASCII; others such as ISO Latin 1 and Kanji are becoming more common while EBCDIC and Unicode are less common.

A character set may include letters, digits, punctuation, control codes, graphics, mathematical symbols, and other signs. Each character in the set is represented by a unique character code, which is a binary number used for storage and transmission. For example, the letter "A" has code 65 in the ASCII set. Different sets have different mappings between codes and characters.

Some but not all character sets include an escape character which indicates that the following character(s) are to be treated specially. Escape sequences can be used to extend a character set to include non-standard meanings within the domain where they are defined and used, but lead to problems when transmitted to equipment without the appropriate software.

In order for a computer to handle a particular character set, it must be possible to enter all the characters from the keyboard and to display them on the screen or printer. Some computers are able to switch between several character sets, which allows both compatibility with other systems and the representation of multiple languages. A few systems are unable to use sets with more than 128 characters (see eight bit clean).

A character set defines the representation of characters as binary data whereas a font defines how characters appear on the screen or printer.

(21 Jun 1996)