More interesting are the differences caused by the medium of Morse Code. The characters are variable length and the dashes are 3x as long as the dots. So dash

More interesting are the differences caused by the medium of Morse Code. The characters are variable length and the dashes are 3x as long as the dots. So dash-heavy letters* are more likely to be dropped. Also why you rarely see numbers: the longest letter is four symbols but every digit is five symbols. In many cases it would be faster to use roman numerals. * 3 dashes: J O Q Y. 2 dashes: C G K M P W X Z.