Functional features: 
        Intercom two lines are connected. (open the lock and add two lines)
·        With unlock function.
·        Aluminum alloy outdoor machine has anti-oxidation and wear-resistant surface treatment, durable.
·        The outdoor unit can display the name or number of the resident, and has LED light indication.
·        Excellent sound elimination circuit, intercom sound clear.
·        Effective intercom distance over 100 meters (2×0.3mm)2) connecting wires.
·        Indoor machine with plug wire plug can be directly inserted into the home appliances 220V installation convenience, users can install by themselves.
Effective intercom distance of connection line      100 m (2x0.3mm) 
                                     150 m (2x0.8 mm)
                                      250 m (2x1.0mm)
                                     300 m (2x1.2mm)