A survival whistle does not necessarily have to be used in emergencies, such as to greet those in front or behind, to determine the distance, and to determine the direction of the sound source, and so on and so forth. However, there is a problem here. Sometimes, when climbing a mountain, one might just feel like blowing the whistle, and if one does it too often, everyone gets used to it and stops responding when they hear others blowing. They go about their own business, and if one of them twists their ankle or needs help, or if a new hiker who is far away from the group gets lost at an intersection, it is very urgent to have no one respond to the whistle because the others might think nothing has happened. They are busy silently toiling, and they don't have the time or energy to pay attention to it. It's like the story of "The Wolf Came."

Symbol Explanation:

Short tone (one second).■■■ Long sound (over 3 seconds); Whistle sound within the command with an interval of 2-3 seconds, and the interval between commands is over 30 seconds (e.g., to repeat the command, you need to wait over 30 seconds).

Communication (T):■■■ (long sound) is used for voice communication among teams to determine the direction of each other's whistle signals. After receiving a whistle command, it is used to indicate that the command has been received (similar to shouting 'Hey~~~~~').

集合（U）：●● ■■■ (two short and one long) Assemble towards the whistle direction (similar to the shout "Assemble!!!")

前进（V）：● ■■■ (一?桃怀ぃ? 休息时发出代表全队出发、行进中发出代表加速前进 （同喊话 冲啊~~~~ 相似）

Front of the queue (W):●■■■ ■■■ (一短两长) is used when the distance of the team's march is too long, requiring the front team to wait for the rear team (similar to the shout "Please wait~~~ wait~~~~")

Support requested (S):●● ● (Three short beeps) When encountering difficulties and needing help, send out this signal. The receiver responds with a communication tone (T) to indicate that they will come to assist (similar to shouting out 'urgent! urgent! urgent!')

SOS：●"● ● ■■■ ■■■ ■■■ ● ● ● （三短 三长 三短） 这是国际通用的SOS代码，请大家熟记" This is the international SOS code, which is widely recognized. Please remember it well.