Flag Semaphore

The semaphore alphabet is a visual communication system using 2 flags (or 2 sticks) to transmit messages over a distance. It is/was used by marine sailors to communicate between ships or with the mainland.

Semaphore encryption uses 2 flags/flags (or other visual element, generally it is the red and yellow Oscar flag from the Maritime Signals code) handled by a person raising his arms, if possible standing (so as not to hinder the movements of the arms).

Each letter A-Z is represented by a flag, the numbers (1234567890) are represented by the letters from A to K.

A		B		C		D
E		F		G		H
I		J		K		L
M		N		O		P
Q		R		S		T
U		V		W		X
Y		Z
dCode.fr

There are 5 special flags:

which signals a pause, a space, a rest, sometimes the end of the message

which indicates a switch from letters to digits

(=J) that indicates a switch from digits to letters

which indicates an error or danger (⚠)

which indicates an annulation (ignore/disregard previous signal) (🗙)

Semaphores signals decryption is done by matching the positions of the flags with the letters of the alphabet.

The message consists of humanoids with flags (or any other object) presented at the end of a stretched arm with multiple angles of 45 degrees (0, 45, 90, 135, 180, 225, 270, 315, 360).

Any reference to the navy/marine/boats, the aviation/planes, or any places where these flags are used is a clue.

Clock hands (set to hours, half hours or quarter hours) are a way of hiding semaphores.

Sometimes the flags are used to code Morse, with 2 defined positions corresponding to point and dash.

Maritime signal code uses another principle of flags to encode words.

The semaphore alphabet has several limitations in terms of the speed and accuracy of message transmission. For example, it may be difficult to distinguish the different positions of flags or sticks when visibility is poor, or when the signal is weak. Also, it can be difficult to transmit long or complex messages quickly using the semaphore alphabet.

Learning requires knowing the letters by heart and practicing. If necessary, buy a book or guide that explains the different combinations of positions here (affiliate link)

Thanks to the advent of wireless technology, the semaphore alphabet is much less used than before, it remains used in certain exceptional situations where it is necessary to communicate remotely without access (or desire to access) to modern communication equipment.

The system of flags and the alphabet spread throughout the world in the 19th century.