scope:

Scope and Field of Application

This standard specifies a set of 128 characters (control characters and graphic characters, such as letters, digits, and symbols) with their coded representation. The American National Standard Code for Information Interchange may also be identified by the acronym ASCII (pronounced ask-ee). To explicitly designate a particular (perhaps prior) edition of this standard, the last two digits of the year of issue may be appended, as in "ASCII 68" or ASCII 86."

This standard is the U.S. national version of the International Standard for Information Processing - ISO 7-Bit Coded Character Set for Information Interchange, IS0 646-1983.

This character set is primarily intended for interchange of information among data processing systems and associated equipment, and within data communication systems. The need for graphic characters and control functions in data processing has also been taken into account in determining this character set.

No specific meaning is prescribed for any of the graphics in the code table except that which is understood by the users. Furthermore, this standard does not specify a type style for the printing or display of the various graphic characters. In specific applications it may be desirable to employ distinctive styling of individual graphics to facilitate their use for specific purposes.

This character set includes control characters for code extension where its 128 characters are insufficient for particular applications. The use of code extension control characters is not defined by this standard. Procedures for the use of these control characters are specified in American National Standard Code Extension Techniques for Use with the 7-Bit Coded Character Set of American National Standard Code for Information Interchange, ANSI X3.41-1974.

This standard defines a few format effector control codes. Additional control functions for use with character imaging devices are defined in American National Standard Additional Controls for Use with American National Standard Code for Information Interchange, ANSI X3.64-1979, and Information Processing - ISO 7-Bit and 8-Bit Coded Character Sets - Additional Control Functions for Character-Imaging Devices, ISO 6429-1983.

In the definitions of some control characters in this standard, it is assumed that the data associated with them are to be processed serially in a forward direction. When they are included in strings of data that are processed other than serially in a forward direction, or when they are included in data formatted for fixed-record processing, they may have undesirable effects or may require additional special treatment to ensure that they result in their desired functions.

Although some collation requirements were part of the original criteria for assigning code table positions to graphic characters, collation is considered outside the scope of this standard.

This standard does not define the structure of the data transmission characters or the formats for data transmission. Such information may be found in American National Standard for the Use of the Communication Control Characters of American National Standard Code for Information Interchange in Specified Data Communication Links, ANSI X3.28-1976.

This standard does not define a graphic representation of control characters. Such representations may be found in American National Standard Graphic Representation of the Control Characters of American National Standard Code for Information Interchange, ANSI X3.32-1973.