The History of Morse Code

Who invented Morse code?

Samuel F. B. Morse (1791–1872) is the name on the code, and he deserves it: he conceived the single-wire electric telegraph, built the first working models, fought for the patents and persuaded Congress to fund the first line. But Morse was a painter, not an engineer, and the system that bears his name was a collaboration.

Alfred Vail (1807–1859), a young machinist from a family of ironworkers in Morristown, New Jersey, saw Morse's crude 1837 demonstration at New York University, joined him, and put up money in exchange for a share of the patent. Vail built the telegraph key and register, and most historians credit him with reworking the code into the dot-and-dash alphabet we recognize. Morse also drew on the electromagnet research of physicist Joseph Henry.

The story of why Morse turned from painting to telegraphy is often told: in 1825, while he was painting a portrait in Washington, a letter arrived by horse saying his wife was ill. By the time he reached home in Connecticut she had already been buried. Whether or not that was the whole motive, Morse spent the rest of his life trying to make distance disappear.

When was Morse code invented?

There is no single date, which is why you will see 1836, 1837, 1838 and 1844 quoted. Here is what happened when:

• 1832: Morse sketches the idea on the voyage home from Europe.
• 1837: first working demonstrations and the patent caveat. Vail joins.
• 1838: the dot-and-dash letter code replaces Morse's original numbered-codebook scheme; public demonstration on January 11 at Speedwell Ironworks.
• 1840: the US patent is granted.
• 1844: the first public message over a real line, Washington to Baltimore, on May 24.

If you want one answer for a quiz: Morse code was invented in 1837–1838 and first used publicly in 1844.

Why was Morse code invented?

Because the telegraph needed it. Earlier electrical telegraphs, such as Cooke and Wheatstone's in England, used several wires and needles that pointed at letters on a dial. They were expensive and slow. Morse's insight was to use one wire and a single electromagnet that simply pulled a lever when current flowed. A one-wire system can only say "on" or "off", so the letters had to be encoded as patterns of short and long pulses. That constraint is Morse code.

Morse's first scheme sent numbers only; each number stood for a word in a printed codebook. Vail's alphabet of dots and dashes did away with the book. The two men reportedly visited a local print shop and counted the type in the compositor's cases to find which letters were most common, giving E a single dot and T a single dash. That frequency-based design is why Morse code is still remarkably efficient.

The first Morse code message

What hath God wrought

On May 24, 1844, Samuel Morse sat in the chamber of the Supreme Court inside the US Capitol and tapped out a verse from the Book of Numbers, chosen by Annie Ellsworth, the daughter of the Commissioner of Patents. Alfred Vail received it at the Baltimore and Ohio Railroad depot in Baltimore and sent it straight back. In International Morse it reads:

.-- .... .- - / .... .- - .... / --. --- -.. / .-- .-. --- ..- --. .... -

Play the first message (Morse himself would have used the original American code, which differs slightly; see American vs International Morse.)

From American Morse to International Morse

The original code had quirks: some letters used internal spaces, and there were dashes of two different lengths. It worked for the clicking "sounder" of American railroads but was awkward over the long undersea and overland lines being built in Europe. In 1848 Friedrich Clemens Gerke, a telegraph inspector in Hamburg, published a cleaner version with only dots and standard dashes. The German-Austrian Telegraph Union adopted it in 1851, and in 1865 the International Telegraph Union (the ancestor of today's ITU) made it the continental standard. American Morse survived on US landlines into the 20th century, but radio spread the international version everywhere, and it is the one defined today in ITU-R Recommendation M.1677.

Radio, CQD and the birth of SOS

Guglielmo Marconi showed in the 1890s that Morse could travel without wires, and by 1901 he had sent the letter S across the Atlantic. Ships were the obvious customers. Marconi's operators used CQD as a distress call: CQ was the general "attention all stations" signal, and D was added for distress. People later said it meant "Come Quick, Danger", but that was never official.

Different companies used different calls, which was dangerous. In 1906 the International Radiotelegraph Convention in Berlin settled on SOS (··· ––– ···), already in use in Germany, because its nine evenly spaced elements are easy to send and impossible to confuse. It became binding in 1908. SOS stands for nothing; "Save Our Souls" came later. Read more on the SOS in Morse code page and the abbreviations reference.

Titanic, 1912

When the Titanic struck an iceberg late on April 14, 1912, senior wireless operator Jack Phillips began sending CQD, then, at junior operator Harold Bride's suggestion, alternated it with the newer SOS. The Carpathia, about 58 miles away, heard the call and steamed to the scene, picking up just over 700 survivors. Phillips kept sending until power failed and did not survive. The disaster produced the Radio Act of 1912 in the United States and international rules requiring ships to keep a continuous radio watch, with Morse at its heart for the next 87 years.

Two world wars and a blink

Morse was the backbone of military communications in both world wars: field telegraphs in the trenches, naval signal lamps, aircraft radios and the clandestine sets of resistance operators. Intercepting and breaking enemy Morse traffic became a science; intelligence services learned to recognize individual operators by the rhythm of their sending.

The most famous single Morse message of the Cold War had no key at all. In 1966, Commander Jeremiah Denton, a US Navy pilot held prisoner in North Vietnam, was put in front of cameras for a propaganda interview. While answering questions he blinked T-O-R-T-U-R-E in Morse, the first confirmation that American prisoners were being tortured. He survived and later became a US senator. Our guide to Morse with light and blinking tells the story in full.

The end of commercial Morse

Satellites and automated digital distress systems made the Morse watch obsolete. France's coastal stations closed their Morse service in 1997 with a last message that has become famous: "Calling all. This is our last cry before our eternal silence." On February 1, 1999, the Global Maritime Distress and Safety System (GMDSS) took over worldwide. Western Union sent its final telegram in 2006, and in 2007 the United States dropped the Morse exam for amateur radio licenses. None of this killed Morse: it is still used by radio amateurs, aviation beacons, naval signalmen and accessibility tools, as our page on whether Morse code is still used explains. And every April 27, Samuel Morse's birthday, enthusiasts mark Morse Code Day.