What do 7 dots mean in morse code?

Runs of dits stop at five

ITU-R M.1677-1 contains exactly five characters made of dits alone, and they climb one mark at a time:

• E is one dit
• I is two
• S is three
• H is four
• the digit 5 is five

There is nothing above that. Six dits in a row, or seven, is not a character in the standard, so a count of seven dots is either more than one character with the gaps lost, or a miscount.

That is the usual answer when someone is staring at a pasted string. Written morse loses its timing the moment it is copied without spaces, and a reader counting marks has no way to tell where one letter ends. Paste the string into the morse code translator and it will put the characters back together.

Eight dits is a real signal

There is one long run of dits in the standard, and it is not seven but eight. Sent as a single group with no letter gap inside it, eight dits is the error signal: the operator has made a mistake, the last word should be thrown away, and the next thing sent is that word again. Press Play above to hear it.

It is written as a prosign, a pattern sent as one character rather than as the letters it would otherwise spell. The SOS distress signal works the same way, which is why it is nine marks run together rather than the three letters S, O and S.

Where seven does belong

Seven is a real number in morse, but it measures silence rather than sound. The standard fixes three gaps:

• one unit between the marks inside a character
• three units between characters
• seven units between words

So the space between two words is as long as seven dits laid end to end. At 20 words per minute (WPM) a unit is 60 milliseconds, which makes the word gap 420 milliseconds. Anyone counting units in a message will meet seven there, and nowhere else.

Counting marks is the hard way

Reading morse by counting dots on a page is slow and easy to get wrong, which is exactly what produces questions about seven dots. The printable morse code chart draws every character to true proportions so the shapes can be recognized rather than counted, and does morse code have spaces covers the three gap lengths in more detail.