aiken code

from The Free On-line Dictionary of Computing (8 July 2008)
Aiken code

   <data> An alternative form of the {Binary Coded Decimal} (BCD)
   system for encoding numbers.  Where BCD encodes each decimal
   digit in normal binary, Aiken code uses the encoding shown
   below.  This is supposed to be less prone to corruption.

   The following table shows the encoding of each decimal digit,
   D, in BCD and Aiken code:

    D  BCD  Aiken
    0  0000  0000
    1  0001  0001
    2  0010  0010
    3  0011  0011
    4  0100  0100
    5  0101  1011 (inverted 4)
    6  0110  1100 (inverted 3)
    7  0111  1101 (inverted 2)
    8  1000  1110 (inverted 1)
    9  1001  1111 (inverted 0)

   The Aiken code was probably designed by {Howard Aiken} in the
   1940s or 1950s for use in data transmission.

   Compare: {Gray code}.

   [What is it good for and why?]

   (2007-07-16)