Fully Guaranteed Security: With the PIR motion detection function, when people enter a video, they can immediately notify the phone connected to the doorbell. The Dingdong bell and the indoor receiver will ring at the same time (a Dingdong machine is included in the package). Additional new features: the person knocking at the door can hear your voice, and the surrounding noise reduction function can ensure the quality of audio communication between other people and other people. To charge the doorbell via USB cable, 36 different ringtones can be upgraded to the Dingdong doorbell. Updated Technology: 1280*720 HD resolution doorbell camera with 166 rotation angle, which can detect any movement in front of the door. Infrared night vision allows you to distinguish deeper actions. The maximum supported TF card storage capacity is 128GB, and the cloud storage capacity of video storage is 120 hours. 2.4 GHz Wi-Fi provides high quality audio and video images and stable connections. Easy to use: Pair the doorbell with the phone by connecting to 2.4GHz Wi-Fi (not 5GHz). The doorbell can be compatible with iOS and Android systems via APP. "The doorbell can be used with the unified 5V1A USB charger. When charging, you can check the charging status on the APP.