The Code lives on: how Morse is still not dead

Few inventions survive essentially unaltered for over 170 years, but the telegraphic code devised by Samuel FB Morse, Joseph Henry, and Alfred Vail in the early nineteenth century has. Not only that, but sciences which had not even been conceived then have subsequently demonstrated its superiority to anything before or since.

The Telegraph

In the late 1830s, two groups were developing wired telegraphy systems intended to transmit messages over long distances, and supersede the networks of optical semaphore telegraphs which had sprung up since their invention in 1792.

Although Cooke and Wheatstone, in the UK, came up with the first wired electric telegraph in 1841, it was Morse and his colleagues in the USA who achieved first commercial success from about 1844. During the latter half of the nineteenth century the world was spanned by overhead telegraph lines and undersea cables, all of them carrying messages encoded in Morse.

International Morse Code. By Rhey T. Snodgrass and Victor F. Camp, via Wikimedia Commons.
International Morse Code. By Rhey T. Snodgrass and Victor F. Camp, via Wikimedia Commons.

Looking for the most efficient way of expressing the English alphabet and numerals using on-off signals, Morse’s team decided to use sequences of short dots and longer dashes, constructed so that the most frequently-used letters required the fewest dots and dashes. Vail went off to the local newspaper’s print room, where he estimated the frequency of use of letters according to the numbers held for printing.

Thus they arrived at a code which, for English at least, is almost as efficient as the theoretical optimum predicted by information theory, which was not invented until a century later. This is neatly illustrated in the structure of Morse codes, in the form of a tree.

Tree diagram showing the structure of Morse code. By Aris00 at en.wikipedia, from Wikimedia Commons.
Tree diagram showing the structure of Morse code. By Aris00 at en.wikipedia, from Wikimedia Commons.

Minor changes were made to Morse’s original ‘American’ code over the years, resulting in the current International Morse Code, as defined by the Radio Bureau of the International Telecommunication Union (ITU). Morse code flourished at the height of the telegraphic system during the late nineteenth century, and later swept the world as radio was adopted.

The evolution of current International Morse Code. Courtesy Spinningspark at Wikipedia, via Wikimedia Commons.
The evolution of current International Morse Code. Courtesy Spinningspark at Wikipedia, via Wikimedia Commons.


Radio was not the invention of Guglielmo Marconi alone, but emerged from the work of many others, including Popov, Fessenden, Lodge, Bose, Edison, and more. However, in 1895 Marconi demonstrated the first complete system for transmission and reception of radio waves, and in 1897 established the world’s first radio station by the lighthouse at Saint Catherine’s Point, just a few miles away from where I live on the Isle of Wight, UK.

The Saint Catherine's Lighthouse site of the world's first radio station, Isle of Wight, UK. © EHN & DIJ Oakley.
The Saint Catherine’s Lighthouse site of the world’s first radio station, Isle of Wight, UK. © EHN & DIJ Oakley.

Early transmitters were very crude and used a ‘spark gap’ system, which spattered their signal across much of the usable frequency band, and as a result are now illegal. However they, and their much improved successors, were an ideal vehicle for Morse code, which became known as ‘Continuous Wave’ (CW) mode. Within a few years, Morse jumped from telegraph systems to radio, where it literally filled the airwaves.

Although modulation systems for transmitting speech by radio were invented and used quite early, when it came to maintaining reliable long-distance communications, there was (and remains) nothing to beat Samuel Morse’s code. Morse-based transceivers are far simpler than those for speech, so are more compact, and still very effective when using tiny amounts of power, as little as milliwatts. Experienced Morse code operators can also read and key in Morse at rates of more than 25 words per minute, with the best attaining 40 or more.

Morse encouraged great economy of characters, and the development of the ‘Q’ codes which are still used as shorthand between radio operators even working speech: terms such as QTH (station location), QRP (low or reduce power), and QSL (confirm either as a question or response).

During the first half of the twentieth century, radio was one of the leading edge technologies, and everyone who aspired to be a nerd had to have built their own radio receiver, such as one of the impressive new ‘superheterodyne’ designs.


Ships carrying Radio Officers plied the seas poised to send SOS when in distress, radio communications were critical to the armed forces, and you could walk into a Wireless Telegraphy station anywhere in the world and send a ‘cable’ back home. All of these were heavily dependent on Morse code, and huge numbers of those staff were trained to send and receive the Code.

Unlike languages, Morse code is entirely audio, and is almost unintelligible when written down. This may explain why no one has tried translating Shakespeare into Morse code, although there used to be audio files of his sonnets transmitted in the Code (these seem to have been lost from the Internet, sadly).

Traditional ‘straight’ keys for sending Morse were redesigned into ‘paddles’ to enable high transmission speeds without fatiguing the hand, and there remains a small corner of engineering design devoted to such keys.

A 'modern' Morse 'paddle' key. By Henryk Kotowski (en.wikipedia), via Wikimedia Commons.
A ‘modern’ Morse ‘paddle’ key. By Henryk Kotowski (en.wikipedia), via Wikimedia Commons.

During the Second World War, most regular military and all ‘special’ operations were arranged by encrypted messages in Morse code, Alan Turing and his colleagues at Bletchley Park worked out how to crack German military messages sent using Morse, and countless people survived thanks to tiny radio transmitters and their emergency Morse messages.


In the latter half of the twentieth century, Morse went into steep decline. Electronic warfare drove the military to more ingenious communication systems, ultimately using satellite links over longer distances.

Among the last military personnel to use Morse code were signallers on ships, who used it with signal lamps to communicate over short distances, and Special Forces. Merchant shipping adopted more sophisticated systems including satellites, which replaced the Morse-based service in 1999. As the world entered the new millenium, the Code looked to be about to die.

The only Morse users left since then have been licensed amateur radio enthusiasts, hams. The Code had long been a requirement for an amateur radio licence, so that hams could understand distress and other important traffic, and as the means of last resort when voice was unable.

In 2003, the international requirement for proficiency in Morse code was dropped, and many hams (like myself) are no longer able to use it. However there remain large numbers of hams around the world who still choose to use ‘CW’, and there is no sign of that dying out for a good while yet.


When military and commercial users ceased Morse services in the late 1990s, many sent final messages foreseeing the perpetual silence which they thought would result. But you only have to listen around the lower end of any of the amateur radio bands to hear it still being used today. Indeed, in the very lowest frequencies used by amateurs, it remains the standard, still the only way to get the message through.

Morse code may now be almost as little-used as Sanskrit, but neither appears in imminent danger just now.