This is the best example of MTConnect and StepNC working together.
Just as a reminder (from wikipedia):
MTConnect is a manufacturing industry standard to facilitate the organized retrieval of process information from numerically controlled machine tools.
STEP-NC is a machine tool control language that extends the ISO 10303 STEP standards with the machining model in ISO 14649, adding geometric dimension and tolerance data for inspection, and the STEP PDM model for integration into the wider enterprise. The combined result has been standardized as ISO 10303-238 (also known as AP238).
STEP-NC was designed to replace ISO 6983/RS274D G-codes with a modern, associative communications protocol that connects computer numerical controlled (CNC) process data to a product description of the part being machined.
Below are the first two paragraphs to give you a preview of this great work.