Civil defense
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[edit] Warning the population in case of a coming disaster
 Thunderbolt 1003 |
 AL-8000 |
 Flood siren |
 SD-10 |
 Warning-Signal of a german Siren |
[edit] France
 Beginning of the alert: the sound warning is made of three sequences of sound going up and down lasting one minute, separated by a silence lasting five seconds. End of the alert: continuous signal of 380 Hz, lasting thirty seconds. |
 In case of a signal generated by electronics, a cycle is made of a two second rise from 300 Hz to 600 Hz, then a two second decrease back to 300 Hz; in case of an electromechanical siren, a cycle is made of seven second where the motor is on (the sound rises to 380 Hz), then five seconds where the motor is shut down. |
