A whistle isn’t only for emergencies — for example, you can use it to greet someone ahead or behind you, estimate how far away they are, or figure out the general direction of their sound source, and so on...;
Symbol Key: ● short sound (within one second); ■■■ long sound (3 seconds or more); there should be a 2–3 second interval between whistle signals within a command, and a 30-second or longer interval between commands (for example, repeating a command requires a gap of at least 30 seconds)
Communication (T): ■■■ (one long sound) Used for voice communication within the group to determine the direction of each other’s whistles; responding to a whistle signal indicates the message has been received (similar to shouting “Hey~~~~~”)
Assemble (U): ● ● ■■■ (two short, one long) Gather toward the direction of the whistle (similar to shouting “Let’s gather~~~~”)
Move Out (V): ● ■■■ (one short, one long) When resting, this signals the whole team to start moving; when moving, it signals to speed up (similar to shouting “Go go go~~~~”)
Front Team Wait (W): ● ■■■ ■■■ (one short, two long) Used when the team is spread too far apart, signaling the front team to wait for the rear team (similar to shouting “Please wait~~~wait~~~”)
Request Support (S): ● ● ● (three short) Used when encountering difficulties and needing help; the person who receives the signal should respond with a communication sound (T) to indicate they will come to assist (similar to shouting “Urgent!! Urgent!! Urgent!!”)
SOS (Distress Signal): ● ● ● ■■■ ■■■ ■■■ ● ● ● (three short, three long, three short) This is the internationally recognized SOS code — please memorize it.