When the visitor presses the button of the door machine, the indoor unit emits a crisp ringtone and displays the visitor 's image. The owner can press the intercom button on the display to talk to the visitor. The intercom and image delay time is about 5 seconds. If the electronic lock is connected, when the display is open, press the display. With the unlock button, the electric lock can be opened (to prevent accidental unlocking, the display must be in the open state, the unlock button can be unlocked); in the standby state, presses the monitor button of the diaplay , and the door is monitored, and the delay is about 30 seconds each time.; press the monitor button and then press the intercom button to monitor the door and talk to the person at the door. If the intercom is finished, press the intercom button to end the talk and close the image. Features: It is environmentally friendly, durable, non-toxic, tasteless, impact resistant and low temperature resistant. Screen 800 x 480 resolution, original TFT-LCD, 7-inch digital LCD screen, high-definition quality, mirror elements, touch screen buttons. Alloy casting, waterproof, dust-proof and explosion-proof, durable, professional audio, SDP noise reduction, night vision fill light. High-definition camera automatic sensitization, microphone, house number with luminous display, doorbell button. The door machine uses a 700-line camera for good image quality. The door machine uses an anti-oxidation and wear-resistant metal casing. dust-proof, waterproof and explosion proof. The display is hands-free, intercom, electronically controlled to unlock, and monitors the door machine function. The display color, ringtone, and intercom volume can be adjusted. The display has 8 polyphonic ring tones to switch freely. It can be used by an external surveillance camera for easy installation. Specifications: Condition: Brand New Material: ABS Color: White Camera angle: 70° Plug Type: AU Plug Night vision illumination: 2 meters Gain control: automatic Working temperature: -35 to 55 ℃ Camera: 700 TVL Light intensity: 0.5Lux Package List: 1 * Monitor 1 * Camera 1 * Power Supply 1 * Screw Package 1 * Instruction Manual .