United States Military Telegraph
Two-Element Code for Telegraph Operation
Two element code consists of the numbers "1" and "2". Two Element code for the telegraph is adapted from the two element code from the use of signal flags.
Notice there is a quick pause between each "element" of the letter you are sending, a short pause between letters, and a long pause between words.
Click here for an example of how to use/send DOT code.
The source for the above information is from F.T. Miller's book, "Soldier Life and the Secret Service" (1957)