Home About Us Contact Romana  GPS AVL Systems  CNC Foam Cutters  Intercoms    Central Unit    Interior Unit    Digital Key    Electromagnetic Lock    Floor Distributor    Power Supply    Door Shock Absorber  PC Audio   DIGITAL KEY INTERCOM SYSTEMS Interior Unit - one for each apartment; - semiduplex communication; - three positions volume switch:   closed, intermediate, maximum; - connection button: speak / listen; - outside door unlocking button; - audio commands signals; - connected with two wires to the   floor distributor.         © ERC - 2005