What Is Morse Code? History and How It Works
Morse code is a communication system that encodes letters, digits, and punctuation as sequences of short signals (dots, ·) and long signals (dashes, —). Developed by Samuel Morse and Alfred Vail in the 1830s for use with the electrical telegraph, it became the world's first practical digital communication system and enabled real-time communication across continents.
The Morse Code System
Each character maps to a unique pattern of dots and dashes. Common letters have short codes (E = ·, T = —, A = ·—) while rare letters have longer codes (Z = ——··, Q = ——·—). Numbers use five-element codes (1 = ·————, 2 = ··———). Words are separated by a gap of seven units (or a slash in written form). The timing ratios are: dot = 1 unit, dash = 3 units, inter-element gap = 1 unit, inter-character gap = 3 units, inter-word gap = 7 units.
SOS — The International Distress Signal
SOS is the internationally recognized distress signal in Morse code: ··· ——— ··· (three dots, three dashes, three dots). It was adopted because it is easy to send and distinct from other patterns — not because it stands for 'Save Our Souls' (that is a backronym). Maritime radio operators were required to monitor the 500 kHz SOS frequency internationally until 1999.
Morse Code Today
Morse code is still used by licensed amateur (ham) radio operators for long-distance HF communication, where its narrow bandwidth and low power requirements outperform voice. Aviation NDB and VOR navigation beacons broadcast their identifier in Morse code. It is also used as an assistive communication method for people with severe physical disabilities who can produce only single-switch input.