This audio kit with two-wire technology includes: • one external audio unit with one bell push button for surface mounting (10-151), • one internal audio unit (10-520), • one power supply 20 (10-801). The external unit is equipped with an adjustable microphone and loudspeaker as well as an illuminated text field for personalisation. The ring volume can be adjusted and switched off on the internal unit. The communication with the external unit is hands-free. The door lock can be directly connected to the power supply. The kit is pre-programmed so that all you have to do is connect it. The kit is expandable with: • one internal audio unit (10-520) or one compact intercom for surface mounting (10-505), • one external audio unit, • one DIN rail relay (10-831) for controlling an extra gate or fence, • one table-top support (10-519) for the internal audio unit