1. tapping sound: the length of sound is expressed by interval. For example, knock (stop for 3 seconds) and knock (stop for 3 seconds) are three lengths, knock (stop 1 second) and knock (stop 1 second) are three lengths.
2. Lighting: The duration of sound is expressed by the time of lighting. For example, lighting-off-bright-off-bright-off-bright-off-means three lengths, and lighting-off-bright-off-bright-off-means three lengths.
If the lights are displayed according to the rule of "short bright, dark, short bright, dark, short bright, dark, long bright, dark, short bright, dark, short bright, dark, short bright, dark, short bright, dark, short bright, dark, short bright, dark, short bright, short bright", it means SOS.
In case of danger, you can use Morse code to send SOS distress signal, which is an international emergency distress method.
Extended data:
SOS was first adopted in April 1905, which was stipulated by the German government in the Regulations on Radio Management. It became an international standard on 1906 1 1.3 (CQD distress signal was also used before, but it did not become a standard).
Although SOS signal is formulated in 1906, British radio operators seldom use SOS signal, and they prefer the old CQD distress signal.
1In August, 909, the American ship "Arap" was unable to sail because of the broken stern shaft, so it sent out a "SOS" signal to the nearby coast and passing ships. This is the first time to use this signal.
19 12, when the famous Titanic cruise ship was in distress on its maiden voyage, it sent out CQD (Marconi Radio Company of Britain decided to use CQD as a distress signal), but because D (——) was easily confused with other letters, the surrounding ships didn't realize that it was a distress signal, and there was no quick rescue, so they only used a new distress signal SOS (————).
Baidu encyclopedia -sos
Baidu encyclopedia -SOS distress signal