It was Morse Code (not just used by the military).
Tapping Code
tapping
mailSemaphore, message couriers, tapping, carrier pigeons, and sign language
Semaphore, message couriers, tapping, carrier pigeons, and sign language are all possible communication alternatives.
maritime communication is what was used for communication at sea for the military.
Tapping on a door or a window is commonly referred to as "knocking." This action is typically used to gain attention or signal one's presence before entering a space. In some contexts, it can also be a form of communication, such as in Morse code.
You must have heard about tapping of phone . Tapping data is same as tapping a phone , all the data entered into the database will be visible during tapping.
Military secrets.
point to point military communication
In-die tapping is the process of tapping stamped parts in a progressive die while in a punch press. In-die tapping eliminates the need for a secondary tapping operation of stamped parts.
Chest tapping is a technique often used in various contexts, including sports and music, to create a rhythmic sound or to signal a specific action. In music, it may refer to the act of tapping or drumming on the chest to produce beats or enhance a performance. In sports, particularly in basketball or football, it can indicate a player's acknowledgment or communication with teammates. Additionally, in some therapeutic practices, chest tapping may be used as a method to promote relaxation or release emotional tension.
yes it is, it is annoying