A coding system applicable to communication is provided so that variable length code representations of a set of characters may be transmitted. The system transmits a data stream made up of a series of variable length code representations of the characters in the set. A fixed code representation follows the end of each character representation. This data stream is received by apparatus which includes coding apparatus which reads the fixed code representations in order to determine the ends of each variable length character representation. The coding is set up so that the code is a binary code in which the most commonly used characters in the set are represented by code having the minimum number of digits, and the progressively less commonly used characters are respectively represented by code having progressively increasing numbers of digits. Preferably the fixed code representing the end of each character is 01.