Morse code chart

A short mark is a dot and a long one a dash. Read each letter left to right: A is a dot then a dash. On the air, a dash lasts three times as long as a dot, the gap inside a letter is one dot long, the gap between letters three, and the gap between words seven.

Print chart puts the charts on a sheet of their own, with a code linking back here. The translator at the top is there to check yourself: type what you think a message says and see if it matches.

Letters come in opposite pairs, where every dot in one is a dash in the other. E and T are a single dot and a single dash. I and M are two of each, S and O three. A and N are dot-dash and dash-dot, and D and U swap in the same way.

The numbers follow a rule of their own. Every digit is five marks long. 1 is a dot and four dashes, and each digit after it swaps one more dash for a dot, until 5 is five dots. From 6 the dots turn back into dashes from the front, until 0 is five dashes.

The punctuation marks above are the ones the translator writes. Most are in the international standard, ITU-R M.1677-1. The exclamation mark, ampersand, semicolon, dollar sign and the low line character (_) aren't, but they're in wide use.

Some signals are sent as one unbroken run rather than as letters. SOS is the famous one: three dots, three dashes, three dots, keyed without the usual gaps between the S, the O and the S. Eight dots in a row signals an error.