Telegraph Simulator
An interactive Morse code telegraph. Click and hold the key (or press spacebar) to tap out dots and dashes. The system decodes your input in real time. Switch to receive mode and decode messages sent to you.
Morse code timing
The standard timing for International Morse Code: a dot is one unit. A dash is three units. The gap between elements within a letter is one unit. The gap between letters is three units. The gap between words is seven units. At 15 WPM, one unit is 80 milliseconds.
The telegraph
Samuel Morse and Alfred Vail demonstrated the first practical telegraph in 1844, sending “What hath God wrought” between Washington and Baltimore. The code they developed assigned shorter sequences to more common letters — E is a single dot, T a single dash — an early form of data compression based on letter frequency.
Why it matters
The telegraph was the first technology to break the link between the speed of communication and the speed of physical travel. Before 1844, the fastest a message could travel was the fastest a horse or ship could carry it. The telegraph made communication essentially instantaneous across any distance — arguably the most consequential shift in communication technology until the internet.