Feature:1. The 2-wire system only needs two wires, namely power, audio, video and control signals. All signals are transmitted through the 2-wire non-polar central power supply.2. Use plugin connectors and DIP switches for quick installation. The integrated multifunctional functions and simple operation make the system more practical.3. Cable 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 4 indoor units).4. The outdoor unit is made of durable aluminum alloy, which is rainproof and antioxidant. It has a builtin white LED night vision device to support night vision. Can be used to monitor the outside of the door.5. 7in color TFT LCD has no radiation, low power consumption and high definition. Can unlock 2 locks at the same time. Support hands-free intercom. With mute indoor intercom function. The volume, brightness and contrast are adjustable. With group call/intercom function.Specification:Item Type: Visual Doorbell KitMaterial: Aluminium Alloy+ABS PlasticOutdoor Camera: Aluminum alloy external device with white LED night vision lensCamera: 1/3in CMOS 1000TV lineViewing Angle: 92Minimum Illumination: 0.5LuxVideo Output: 1Vp-p /75Connection Method: BUS 2-wireInstallation Method: Wall-mountedWorking Temperature: -30C to 50CSize: Approx. 240x169x24mm/9.4x6.7x0.9inMonitor: Screen: 7-inch LCDEffective Pixels: 1024 x 600Connection Method: BUS 2-wireSize: Approx. 151x80x38mm/5.9x3.1x1.5inHow to Use: 1. The indoor unit, outdoor unit, and power supply are connected by cables, and the power cord is connected to 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 unlock the doorbell..Package List:1 x Outdoor Unit (Camera)4 x Indoor Unit (Monitor)1 x DC24V 2.5A Power Supply1 x 4 Core Terminal Wire2 x 2 Core Connection Terminal Wire4 x 2 Hole Terminal1 x 3 Hole Terminal1 x 4 Hole Terminal4 x Bracket1 x Screws Pack1 x Manual