1. Early warning: ring for 36 seconds, stop for 24 seconds, repeat for 3 times as a cycle, and the time is 3 minutes. Citizens immediately stop all "work", turn off the power supply at home, turn off the gas, put out the fire, close the doors and windows, carry valid documents, daily necessities and protective equipment, and quickly evacuate to nearby underground air defense bunkers, civil air defense projects and air-raid shelters.
2. Air raid alarm: sound for 6 seconds, stop for 6 seconds, and repeat 15 times as a cycle, lasting for 3 minutes. Unable to enter underground air defense bunkers, civil air defense projects, and air-raid shelters, citizens used the terrain and landforms to escape nearby, kneeling on the ground with their hands on their heads.
3. Disarm the alarm: If the alarm is sounded continuously for 3 minutes, citizens can get out of underground air defense bunkers, civil air defense projects and air-raid shelters and return to normal "work".