The camera transmits sounds to the mobile phone or tablet when the camera is switched on and transmits the image to the display. In my case, the settings are such that the recording on the memory card and the activity notification (the alarm, the bi-bi) only occur when motion is detected. From then on, the recording starts on the memory card and can be tracked in real time (via WLAN or mobile phone network, 4G/LTE in my case). There is a feature in the app called Tapo Care, which is chargeable after 30 days free. It allows AI recognition, including baby crying, but avoids false alarms, for example due to cat movements. I don't use this feature, you can find out more about it at https://www.tp-link.com.