American Morse code standard for U.S. landline telegraph companies, including the dominant company, Western Union, in part because the original code, with fewer dashes, could be sent about 5% faster than International Morse. American Morse also was commonly used for domestic radio transmissions on the Great Lakes, and along the Atlantic and Pacific coasts. However, International Morse predominated for ocean-going vessels, and many U.S. shipboard operators became skilled in transmitting both versions of the Code as needed. As already mentioned, American Morse is less suitable for use on cables because of the high density of dots. However, this same feature, together with the
Morse code are used to indicate changes in communications protocol status or white space text formatting actions. The symbols !, $ and & are not defined inside the ITU recommendation on Morse code, but conventions for them exist. The @ symbol was formally added in 2004. There is no standard representation for the exclamation mark (!), although the KW digraph () was proposed in the 1980s by the Heathkit Company (a vendor of assembly kits for amateur radio equipment). While Morse code translation software prefers the Heathkit version, on-air use is not yet universal as some amateur radio operators in North America