What Is Morse Code?

How it works

Everything is measured in one unit of time. A dot lasts one unit and a dash three. The gap inside a letter is one unit, between letters three, and between words seven. The most common letters got the shortest codes: E is a single dot (· ▶) and T a single dash (− ▶). Speed is measured in words per minute, using the word PARIS (▶) as the standard word.

Who invented Morse code?

Samuel Morse, the physicist Joseph Henry and the engineer Alfred Vail built an electrical telegraph in the United States in the 1830s. Morse's first proposal for a code was replaced by an alphabet code of dots and dashes developed by Vail, first used in 1844. That version is now called American Morse. In 1848 Friedrich Gerke simplified it in Germany, and his version became the basis of International Morse code in 1865. Most of the letters in today's standard come from Gerke.

The first message

On 24 May 1844 Morse sent “What hath God wrought” from Washington to Baltimore in a public demonstration of the telegraph (▶ hear it).

The standard today

International Morse code is defined by the International Telecommunication Union in Recommendation ITU-R M.1677-1. It covers the letters A to Z, the numbers, common punctuation and one accented letter, É. The @ sign was added in 2004. Other alphabets, such as Cyrillic, Greek, Arabic, Japanese or Korean, have their own national codes, and the translator on this site supports them.

Is Morse code still used?

• Aviation: radio navigation beacons (VOR and NDB) still identify themselves in Morse code, so pilots can check they are tuned to the right station.
• Amateur radio: many radio amateurs still use Morse code, which they call CW, and clubs such as CWops exist just for Morse operators.
• Ships: Morse was the maritime distress standard until 1999, when the Global Maritime Distress and Safety System replaced it. Navies have long used signal lamps to send Morse between ships.
• Assistive technology: people with limited movement can type with Morse code; Android 5.0 and later accept Morse input.
• SOS: ··· −−− ··· is still recognised everywhere as a call for help.

How fast can people go?

The record for copying Morse by ear, 75.2 words per minute, was set by Ted McElroy in 1939 in Asheville, North Carolina.