This International Standard defines a file structure format and a language format for the representation of CLDATA on physical media. The CLDATA reference language (RL) is used for the machining of parts. It provides for the control of technological functions and movement at the numerical control machine. Each processor using one of the numerical control programming languages shall be capable of producing CLDATA as defined in this International Standard. Each post processor shall be capable of using the CLDATA defined in this International Standard as input. The RL has been developed primarily for numerically controlled machine tools.