A method for examining an interface to a plurality of peripheral units of a numeric control system includes, firstly, an initialization step in which an unequivocal identification character is written into an identification character register of each peripheral unit, the register functioning in response to an address bus. The identification character register is read out in an examination step and is -compared with an expected value. If an identification character does not tally with the corresponding expected value, an error message is produced, and if all of the identification characters tally with the corresponding expected values, the addressing of all of the peripheral units by the address bus is deemed successful.