Single indoor station for setting up a door intercom system. You can choose between 1 to 6-family outdoor stations from the ADV series. This door intercom system impresses with its sophisticated, ultra-slim design and excellent sound quality. The system can be expanded to include up to 4 outdoor and 4 indoor stations each. Regardless of the number of individual components, you only need one power supply for the entire door intercom system. The address field and doorbell button of the stainless steel outdoor station are automatically illuminated in the dark.