This standard covers the establishment of a series of dimensional systems and nomenclature to serve as a guide in the coordination of equipment design and design of machinery for automatic manufacture.

Basic Module: In the design of electronic equipment which may be built on automatic machines, it shall be standard to make all dimensions, which must be controlled for automation purposes, to be multiples of ,025 inches (.635 mm), that is decimal in form and English in units of length.

This modular dimension shall apply to all three axes of Cartesian coordinates and shall apply to the following quantities among others: spacing between holes in printed wire boards, between matrix points in wire wrap, between leads in two or multi-leaded components or electron devices, spacing of terminals. or other types of larger components, overall printed board dimensions, lengths, test point locations, inter-board connections, etc.