BS ISO/IEC 6429:1992 - Page 3

Information technology. Control functions for coded character sets. | Status: Current

1 Scope This International Standard defines control functions and their coded representations for use in a 7-bit code, an extended 7-bit code, an 8-bit code or an extended 8-bit code, if such a code is structured in accordance with International Standard ISO 2022. This International Standard specifies technical means to handle bi-directional texts in character-imaging devices in the case of

• - texts in a single script of which specific parts need to be presented in an opposite direction (for example, numbers in Arabic or Hebrew text);
• - texts in different scripts presented in opposite directions (like texts in Latin and Arabic or texts in Latin and Hebrew;
• - texts like the above with a horizontal line orientation and a top-to-bottom line progression.

The control functions defined in this International Standard are intended to be used embedded in character-coded data for interchange, in particular with character-imaging devices. In general, the control functions are defined by their effects on a character-imaging input/output device. It is, therefore, necessary to make certain assumptions about the architecture of such a device. These assumptions are as unrestrictive as possible; they are specified in clause 6. In addition to being performed the control functions may need to be represented by a graphic symbol. The structure of this International Standard is open-ended, so that more control functions can be included in future editions. Other standards specifying control functions may define more restricted definitions of them than those in this International Standard. The devices to which this International Standard applies can vary greatly from each other depending on the application for which a device has been specifically designed. It is technically and economically impractical for one device to implement all the facilities specified in this International Standard. The intention is that in any type of device only a limited selection of the facilities appropriate to the application will be implemented.