1 u2032 there the transmitted further signal is compared with a reference signal the reference signal used is the previously detected code of the mobile communication unit 20 in fig5 if the further signal from the transmission reception unit does not match the reference signal a further signal state change is produced as a comparison result for the further signal from the transmission reception unit and the currently premarked second functional descriptor 16 u2032 from the top in fig6 is marked completely for the further signal state change in fig7 the user confirms a completely marked functional descriptor 16 16 u2032 16 u2033 by lowering the right hand the mobile communication unit 20 is taken back into the detection range of the transmission reception unit and the communication between the transmission reception unit and the mobile communication unit 20 is set up again this change of position by the user is denoted by a downward pointing vertical arrow the transmission reception unit detects that the communication with the mobile communication unit 20 has been set up again as yet a further signal the further signal from the transmission reception unit is transmitted to the call input apparatus 1 1 u2032 the transmitted yet further signal is compared with a reference signal the reference signal used is the previously detected code from.