Morse code was later made the standard by the International Telecommunication Union (ITU). Morse's original code specification, largely limited to use in the United States and Canada, became known as American Morse code or "railroad code". American Morse code is now seldom used except in historical re-enactments. In aviation, pilots use radio navigation aids. To ensure that the stations the pilots are using are serviceable, the stations transmit a set of identification letters (usually a two-to-five-letter version of the station name) in Morse code. Station identification letters are shown on air navigation charts. For example, the VOR-DME based at Vilo Acuña Airport
Hog-Morse For instance, the international code has only two symbols, dots and dashes, but the American code has several lengths of dash. There is a distinction between "L" () and "T" (). Also, in the international code the space between symbols within a character is always the same, but American Morse has two different spaces. The letters "S" (), "C" (), and "R" () all consist of three dots, but the timing is different in each case. A frequently quoted, but possibly apocryphal, story from the historical period concerns the similarity of "L" and "T" in the American code. A company