How did punched tape store instructions for early numerical-control machine tools?

In early numerical-control (NC) systems, instructions were stored on a one-inch-wide ribbon of paper or plastic tape. The process of storing these instructions involved several steps:

• Data Coding: Machining instructions—such as the sequence of operations, coordinate dimensions, feed rates, and spindle speeds—were derived from part drawings and written in a coded format on a program manuscript.1
• Punching: Using a machine similar to a typewriter, these coded instructions were physically punched into the tape.1
• Interpretation: The completed tape was inserted into an NC system connected to the machine tool. The system read and interpreted the punched data, activating relays and electrical circuits that directed the machine's servomechanisms to perform the programmed operations automatically.1

This method allowed for the storage of complex manufacturing instructions, which could be reused on the same or similar machines at any location. While punched tape was standard, some systems utilized punched cards or magnetic tape to achieve similar automated control.1