<p>The system has a printing machine control panel (11) with an interface (12) e.g. universal serial bus (USB)-interface, and identification devices (13-17) e.g. USB-key-sticks, of a potential operator. One of the identification devices is attached to the interface. The control panel reads a data set from the identification device when the identification device is attached to the interface. An access to the functions of the control panel is enabled or disabled based on the read data set.</p>
