Abstract: The present invention provides translation circuitry, which in one mode of operation acts to encode variable length data words into fixed rate data coded words for use with a communication channel, or a recording means, such as a magnetic recording medium and which in another mode of operation acts to decode the coded words to data words. The translation circuitry functions such that in an encoding operation, the second and third bits of a three-bit coded word respectively have the same binary values as the first and second bits of the data word, which the coded word represents and the second and sixth bits of a six-bit coded word respectively have the same binary values as the third and fourth bits of the data word which the coded word represents.