Interchangcable Perforated Tape Variable Block Formats for Positioning and Straight Cut (RS-273) and Contouring and Contouring/Positioning (RS-274) Numerically Controlled Machine Tools (Proposed American Standards) CACM August, 1964 CA640814 JB March 9, 1978 6:43 PM 1016 5 1016 1016 5 1016 1016 5 1016