Dits and Dahs

There are so many alphabets and so little time to learn them. I used to spend summers studying Semephore and Morse. Now there doesn’t seem to be any need. But just in case . . .

The Semaphore flag signaling system (above) is an alphabet system based on the waving of a pair of hand-held flags in a particular pattern. The flags are usually square, red and yellow, divided diagonally with the red portion in the upper hoist. The flags are held, arms extended, in various positions representing each of the letters of the alphabet. The pattern resembles a clock face divided into eight positions: up, down, out, high, low, for each of the left and right hands (LH and RH) six letters require the hand to be brought across the body so that both flags are on the same side.

The Morse code method (below) transmits letters/words as a series of on-off tones, lights, or clicks. The International Morse Code encodes the Roman alphabet, the Arabic numerals and a small set of punctuation as standardized sequences of short and long “dots” and “dashes,” also known as “dits” and “dahs.” Morse code speed is measured in words per minute.

“Morse is associated with an “element time” equal to 1.2 seconds divided by the speed in WPM. A dot consists of an “on” element followed by an “off” element, and a dash is three “on” elements and one “off” element. Each character is a sequence of dots and dashes, with the shorter sequences assigned to the more frequently used letters in English – the letter ‘E’ represented by a single dot, and the letter ‘T’ by a single dash. A speed of 12 WPM is therefore associated with an element time of 100 milliseconds, so each dot is 100 ms long and each dash is 300 ms long, each followed by 100 ms of silence.”

COMMENT