Feature: 1. The 2-wire system requires only two wires, namely power, audio, video and control signals. All signals are transmitted through the 2-wire non-polar central power supply. Use plug-in connectors and DIP switches for quick installation. 2. Flexible cable connection. Support in and out, branch and mixed mode. Dual intercom communication between indoor units. Using integrated power supply, it supports up to 2 outdoor units and 6 indoor monitors (including only 1 outdoor unit and 3 indoor units). 3. The durable aluminum alloy outdoor unit has rain‑proof and anti‑oxidation effects. With white LED night vision device, support night vision effect 4. 7in color TFT LCD, no radiation, low power consumption and high definition. Support unlocking 2 locks at the same time, support 500 fingerprints, 1000 IC card unlocking, password unlocking. 5. Support hands-free intercom. With mute indoor intercom function. The outside of the door can be monitored. The volume, brightness and contrast are adjustable. With group call/intercom function. Specification: Item Type: Doorbell Material: Aluminium Alloy+ABS Plastic Outdoor Camera: Aluminum alloy external device with white LED night vision goggles Camera: 1/3in CMOS 1000TV line Viewing Angle: 92° Minimum Illumination: 0.5 LM Unlock Type: Support 500 fingerprints, 1000 IC card unlock, password unlock Connection Method: BUS 2-wire Installation Method: Wall-mounted Working Temperature: -30℃ to 50℃ Size: Approx. 200x100x55mm/7.9x3.9x2.2in Monitor: Screen: 7-inch LCD Effective Pixels: 800 x 480 Connection Method: BUS 2-wire Size: Approx. 238x169x24mm/9.4x6.6x0.9in How To Use: 1. The indoor unit, outdoor unit, and power supply are connected by cables, and the power cord is connected to the electricity. 2. Adjust the color and brightness of the display, and use the intercom function of the doorbell. 3. Connect the electronic lock at home to open the doorbell.. Package List: 1 x Outdoor Unit (Camera)3 x Indoor Unit (Display)1 x DC 24V 2.5A Power Supply5 x IC Cards1 x 4 Core Connection Lock Terminal Wire1 x 2 Core Connecting Terminal Line1 x Screw Pack3 x Bracket3 x 2 Hole Terminal1 x 3 Hole Terminal1 x 4 Hole Terminal1 x User Manual