Morse code
Gerke's refinement of Morse's code

The Morse code, as specified in the current international standard, International Morse Code Recommendation, ITU-R M.1677-1, was derived from a much-improved proposal by Friedrich Gerke in 1848 that became known as the "Hamburg alphabet", its only real defect being the use of an excessively long code (▄ ▄ ▄ ▄ ▄ ▄ ▄ and later the equal duration code ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄ ▄) for the frequently used vowel O.

Gerke changed many of the codepoints, in the process doing away with the different length dashes and different inter-element spaces of American Morse, leaving only two coding elements, the dot and the dash. Codes for German umlauted vowels and CH were introduced. Gerke's code was adopted in Germany and Austria in 1851.

This finally led to the International Morse code in 1865. The International Morse code adopted most of Gerke's codepoints. The codes for O and P were taken from a code system developed by Steinheil. A new codepoint was added for J since Gerke did not distinguish between I and J. Changes were also made to X, Y, and Z. This left only four codepoints identical to the original Morse code, namely E, H, K and N, and the latter two had their dahs extended to full length. The original American code being compared dates to 1838; the later American code shown in the table was developed in 1844.
change_case:english_capital