New IEEE Standard - Inactive - Withdrawn.The standard covers three areas: the basic dimensions of subracks, this range of modular subracks conforming to IEC 297-3-1984, for mounting in equipment according to IEC 297-1-1986, and ANSI/EIA RS-310, together with the basic dimensions of a compatible range of plug-in units, printed boards, and backplanes; the dimensions of plug-in units and connectors, this standard gives the dimensions of associated plug-in units and connectors standardized by IEC 603-2-1980, together with applicable detail dimensions of the subrack; and the environmental requirements of subracks, this standard states environmental requirements of subracks and their associated plug-in units. The purpose of the standard is the specification of dimensions that will ensure the mechanical interchangeability and environmental requirements of subracks and of plug-in units.