Digital Non-visual Building Intercom System Door Phone/doorbell Indoor Unit. Features: Digital Non-visual Building Intercom System Audio Door Phone/audio Doorbell Indoor Unit,Top Quality Luxury Indoor Machin Three Wire Bus Two Cores into the Household , 1.Adopt Press-type Buttons, the Service Life of Up to Five Times More Than Ordinary Button, Use the Number Could Reach 50 Million Times; 2.Metal Casting Shell, Durable; 3.using Micro-controller for a Variety of Different Floors of the Structure Uses; 4.Function: Call, Two-way Dialogue, Extension Lock, Password Lock, Card Lock Function; 5.circuit Using SMT Production Process, More Stable Performance 6.Anti-whistle Features Intercom Voice Clarity, the Use of High-fidelity Speakers 2W; 7.door Phone Waterproof and Dustproof Design, Suitable for a Variety of Harsh Environments; 8.Adopt Blu-ray Technology, Can Clearly Use at Night, Luminous Buttons; 9.Power Supply with Lock Function, to Ensure the Normal Remote Unlocking 10.Cable Connection: Mains RVV5x0.3mm, into the Family Line RVV2x0.3mm 11.Cable Connection: Three-wire Bus, into the Family Two Wire Polarity, into the Family Line Can Be User Terminal; 12.Automatic Detection of Subscriber Lines Shorted or Open, Reducing the Difficulty of Maintenance and Maintenance Costs; 13.Simple Installation, Stable Performance, Easy Maintenance; Technical Parameters: 1.Working Voltage: DC12V 2.Operating Current: 400mA Quiescent 50mA Dynamic 3.Frequency Response: 300Hz ~ 3.4kHz 4.Audio Output Distortion Power: 0.1W 5.Operating Temperature: -25degrees ~ +55degrees 6.Ambient Humidity: <95% 7.door Installation: Flush Mounting 8.Extension Installation: Wall-mounted (matching Mounting Bracket) Specifications: Certification: CE Model Number: SUB-008A Digital Door Machine ZDL-328R Dimensions: Length 335 X Width 124 X 63mm Thick Embedded Dimensions: Length 295 X Width 115 X 45mm Thick . We are an international seller, your order will be shipped from abroad so please allow the necessary time of minimum 14 working days for delivery right now depending on where you ship to, due to ongoing delays in postal deliveries globally.