SIGNALS

It is obvious, at the slightest glance, that this mode of instantaneous communication must inevitably become an instrument of immense power, to be wielded for good or for evil … Samuel Morse, 1838

MORSE CODE 

  • How to learn Morse code
    Telegraphers had to use a code within a code:  The 92 code 
  • Amateur (Ham) radio operators use Morse code since its narrow-band signal cuts through background noise;
  • People using assistive technology often use Morse code to blink instructions to computer systems;
  • Navigation aids, like VORs (VHF Omni-directional Ranges) and NDBs (Non-Directional Beacons), constantly transmit their identifying call letters in Morse code so pilots can tune in and verify they have the correct frequency.
  • During the Vietnam war,  US prisoners being held in Hanoi communicated with Morse code between cells.  One US pilot  held prisoner, Jeremiah Denton, blinked his eyes in morse code to spell out “torture” on a propaganda film in 1966.

SEMAPHORE AND SIGNAL FLAGS 

 

Wigwag code (General Service Code)
A B C D E F G H I J K L M
22 2112 121 222 12 2221 2211 122 1 1122 2121 221 1221
N O P Q R S T U V W X Y Z
11 21 1212 1211 211 212 2 112 1222 1121 2122 111 2222