A device for manipulating interface signals includes a slave interface, which is connectable to a master interface of a control device, a master interface, which is connectable to a slave interface of a measuring device, and a circuit configuration, which is supplied with at least one data-input signal per interface, and which outputs a corresponding data-output signal per data-input signal to the respective other interface. The circuit configuration includes at least one manipulation unit, to which a data-input signal and a substitute-data signal are supplied and which outputs a corresponding data-output signal, as well as a protocol unit, to which at least one protocol-relevant interface signal is supplied and which, based on manipulation rules and information received with the at least one protocol-relevant interface signal, chooses when the at least one manipulation unit outputs the corresponding data-input signal or the substitute-data signal as data-output signal.