Constitutes a general introduction to coded character sets for text communication and, in particular, defines terms used in this and subsequent parts of the Standard, describes the general structure of text communication code and specifies conformance requirements for the coded representation of communicated text at the coding interface. In addition, it gives, in annexes, a description of the method used to identify each graphic character and control function defined, a description of some general concepts of text communication, suggestions for equipment conformance requirements and recommendations for fall-back implementations.