Both directions, including punctuation. Words are separated by a slash, which is what keeps a decoded message from collapsing into one long string.
Morse code is defined entirely in multiples of a single duration called the dot, or dit. Everything else is derived from it: a dash is three units, the gap between symbols inside a letter is one unit, the gap between letters is three, and the gap between words is seven.
That means the gaps are not spacing around the code, they are part of it. `..` with one-unit gaps is the letter S. The same three dots separated by three-unit gaps are E, E, E. An operator who sends the right symbols with the wrong rhythm sends a different message, which is why learning Morse by memorising visual patterns of dots and dashes tends to fail the moment real audio starts.
Speed is quoted in words per minute against the standard word PARIS, chosen because it happens to be exactly 50 units long including its trailing word gap. At 20 words per minute a unit is 60 milliseconds. Farnsworth timing sends each character at full speed while stretching the gaps, which is how most people learn: it stops you counting individual elements and forces you to hear each letter as one sound.
The seven-unit word gap has no natural representation in text. Written down, it is whitespace, and whitespace does not survive. Copy Morse out of a page into a chat box and runs of spaces collapse; paste it into a document and the line rewraps; save it through a form and trailing spaces are trimmed. The letter gaps and the word gaps become indistinguishable and the message cannot be decoded.
This tool writes the word gap as a slash separator, which is the convention in printed Morse for exactly this reason. A slash is a visible character, so it survives copying, quoting, reformatting and line wrapping. Decoding accepts either the slash form or unusually wide runs of spaces, so Morse pasted from elsewhere generally works.
SOS is not an abbreviation. It does not stand for save our souls or save our ship; those are backronyms invented afterwards. It was adopted at the 1906 Berlin radiotelegraph conference because its pattern (three dots, three dashes, three dots) is unmistakable, symmetrical, and hard to confuse with anything else in noise.
It is also properly sent as a prosign: one continuous nine-element symbol with no letter gaps, written with an overbar rather than as three separate letters. Sent as S, O, S with normal three-unit gaps it is technically a different transmission, though any operator would understand it.
Other prosigns work the same way. AR ends a message, SK ends a contact, BT separates sections, and the error signal is eight rapid dots. None of them are letters, and none of them have an unambiguous text form, which is why this tool converts letters, digits and punctuation and leaves prosigns to the operator.
Morse survives because it degrades better than anything that replaced it. Speech needs enough bandwidth and signal-to-noise ratio to reconstruct a waveform. Morse needs only the ability to distinguish present from absent, so a signal far too weak, noisy or intermittent to carry a voice can still carry a message. Amateur radio operators still make contacts on a few watts across continents this way.
It is also indifferent to the medium. The same code works as radio tone, lamp flashes, a torch, a car horn, tapping on a pipe, or blinking, most famously by Jeremiah Denton in 1966, who blinked T-O-R-T-U-R-E during a televised propaganda interview as a prisoner of war.
Aviation and marine navigation still use it: VOR and NDB beacons identify themselves by transmitting their two or three letter identifier in Morse on a continuous loop, and pilots are expected to verify the identifier by ear before trusting the navigation signal.
The full International Morse Code letter set, digits zero to nine, and the common punctuation: full stop, comma, question mark, apostrophe, exclamation mark, slash, brackets, ampersand, colon, semicolon, equals, plus, hyphen, underscore, quotation mark and the at sign, which was added in 2004 for email addresses and is the most recent addition to the standard.
It does not cover the accented characters that appear in some national variants, and it does not cover American Morse, the older and different code used on landline telegraphy in the United States, which had internal gaps inside some characters and is not interchangeable with the international code.
Decoding is forgiving about input: it strips anything that is not a dot, dash or separator, so Morse copied with odd spacing or stray characters usually still resolves.
Almost everyone starts with a printed table of dots and dashes, and almost everyone stalls. The table teaches you to translate a visual pattern into a letter, which means that on hearing a real signal you must first convert sound to dots, then dots to a letter. Two steps under time pressure, and the second one fails as soon as the sender speeds up.
The Koch method avoids building that habit. You start at full target speed with just two characters, and add a third only once you are copying the current set at ninety per cent accuracy. Because the speed is never slow, you never learn to count elements; each character is heard as a single rhythmic shape from the first session.
Farnsworth timing is the companion trick. Characters are sent at full speed (twenty words per minute, say) while the gaps between them are stretched to an effective overall speed of five. You get thinking time between letters without ever hearing a slowed-down character, so the sound you learn is the sound you will meet at speed.
The practical consequence for this tool: what it shows you is the written form, which is useful for reading, composing and checking, and is not how the code is actually learned. Treat the dots and dashes as notation, in the way sheet music is notation, rather than as the thing itself.
Because the real word gap is a seven-unit pause, and pauses written as whitespace do not survive copying, wrapping or form submission. A slash separator is a visible character, so word boundaries stay intact through reformatting.
No. It was chosen at the 1906 Berlin conference for its unmistakable symmetrical rhythm, not as an abbreviation. Save our souls and save our ship were both invented afterwards.
Duration only. A dash is exactly three times the length of a dot, and every other timing in Morse code (the gaps inside a letter, between letters, and between words) is also a multiple of that same base unit.
Yes. Switch to decode and it accepts slash-separated words or unusually wide spacing, ignoring any character that is not a dot, dash or separator.
Speed is quoted in words per minute against the standard word PARIS, which is exactly 50 units long. Twenty words per minute is a common proficiency target and puts a single dot at about 60 milliseconds.
Almost always spacing. If the gap between letters and the gap between words are the same width, the decoder cannot tell where one word ends, so it runs them together. Use the slash form.
By sound, at full speed, using the Koch method with Farnsworth spacing. Learning from a visual chart of dots and dashes builds a two-step translation habit that breaks down as soon as the sending speed rises.