Telegraph code and sentence gaps should be 5 or 7 dots long (change from earlier standard – 5 dots). The speed of sending is also referred to as words per minute, and is classically based on the 'paris' formula - as 'paris' is considered to be an average length word. See main article on Morse Code. Morse code can even be used to transmit Chinese characters. There already existed dictionaries which numbered the Chinese characters. It is simply a case of sending the numbers by Morse Code, and these numbers are then looked up in the dictionary at the receiving end. In
Morse code to transmit only numerals, and to use a codebook to look up each word according to the number which had been sent. However, the code was soon expanded by Alfred Vail in 1840 to include letters and special characters, so it could be used more generally. Vail estimated the frequency of use of letters in the English language by counting the movable type he found in the type-cases of a local newspaper in Morristown. The shorter marks were called "dots", and the longer ones "dashes", and the letters most commonly used were assigned the shorter sequences of dots and dashes.