Literary Braille Code, also called Grade 2 braille, is used for most works of fiction and nonfiction, including textbooks, except math, science, foreign languages, and music. Punctuation marks may require one or two cells. Composition signs are symbols unique to braille. There are similar signs for italics, letters that mean letters and not single-cell words, etc. Single-cell words are letters of the alphabet or contractions that, when they stand alone, mean words.
Some symbols have multiple meanings.
Computer Braille Code was developed in order more precisely transcribe materials relating to computers. For example, CBC addresses such needs as file names, exact count of blank spaces, and other details that are required for the programming and use of computers. CBC uses some symbols from Literary Braille, some from Nemeth Code, and some symbols of its own. The symbols and rules for CBC are published in Code for Computer Braille Notation. Music Braille Code is a completely separate code.