Numerical control unit

A numerical control unit, comprising;

• a main controller for carrying out a numerical controlling step,
• a personal computer connected to the main controller through a bus-line,
• an operating panel including a keyboard having keys, and
• a key-encoder connected to the main controller, the personal computer and the keyboard for assigning the keys of the keyboard as key or keys for the main controller or as a key or keys for the personal computer respectively,
• wherein the key-encoder has:
• a key reading part for reading key information inputted from the keyboard,
• a code discriminating part for judging whether the key information has been assigned as a key for the main controller or as a key for the personal computer, on the basis of a predetermined key assignment which defines a relationship between the key information and the key for the main controller or the key for the personal computer,
• a main controller key interface for sending the key information to the main controller when the code discriminating part judges the key information has been assigned as the key for the main controller, and
• a personal computer key interface for sending the key information to the personal computer when the code discriminating part judges the key information has been assigned as the key for the personal computer.