1. In a quiet and noisy environment, such as classrooms, conferences, libraries, etc. , mobile phone ringing should be muted, or mute vibration;

2. When walking, eating or other environmental sounds are moderate, you can adjust the volume of incoming calls in the middle position, which is subject to the sound you overhear;

3. In noisy environments such as downtown areas and karaoke bars, in order to avoid being unable to answer important calls, the volume of incoming calls should be adjusted to the maximum, so that you can also hear telephone calls in noisy environments.