This standard is intended to serve as a guide in the coordination of system design, to minimize the variety of program manuscripts required, to promote uniformity of programming techniques, and to foster interchangeability of input data between numerically controlled machines of the same classification by type, process function, size, and accuracy. It is intended that simple numerically controlled machines be programmed using a simple format, which is systematically expandable for more complex machines.

This standard applies wherever a variable block data format is used with numerically controlled machines.

The variable block data format, as described in the following sections, may be used interchangeably among numerically controlled machines with compatible input media and which conform to the same Format Classification as shown in Appendix A. (NOTE: The degree of interchangeability will depend on the conformity of the machines with respect to function, capacity, range, horsepower, geometric relationship of axes, preparatory, miscellaneous, and tooling functions, and use of absolute or incremental dimensions.)

If perforated tape is used as the input medium, it shall be in accordance with EIA Automation Bulletin 3C "Glossary of Terms for Numerically Controlled Machines"

The definition of terms used in this standard are in accordance with EIA Automation Bulletin 3C "Glossary of Terms for Numerically Controlled Machines."

Axis and motion nomenclature used in this standard is in accordance with EIA Standard RS-267-A "Axis and Motion Nomenclature for Numerically Controlled Machines."

Revisions to these standards will be proposed as technical progress warrants or as future standards are adopted which conflict with these standards.