Mi band sleep mode is set to call reminder. When the phone calls, the bracelet will vibrate to remind and display the incoming number. You can refuse to answer the phone by pressing the button of the bracelet for a long time, and you can't hang up with the bracelet during the call.
Mi band is a smart wearable device, which can be connected with a mobile phone to realize functions such as pedometer, alarm clock, incoming call reminder, and mobile phone unlocking.