Individual video indoor unit for setting up a video door intercom system you can choose between 1 or 2 family outdoor units from the vdv series this entry phone system impresses with its sophisticated ultra thin design and excellent voice quality this system is expandable to 4 outdoor and 4 indoor units regardless of the numerous components you need only one mains adapter for the power supply of the entire entry phone address field and doorbell button of the stainless steel external statio