Aiken code

A group of four bits is assigned to the decimal digits from 0 to 9 according to the following table.

The code was developed by Howard Hathaway Aiken and is still used today in digital clocks, pocket calculators and similar devices[citation needed].

The following weighting is obtained for the Aiken code: 2-4-2-1.

One might think that double codes are possible for a number, for example 1011 and 0101 could represent 5.

However, here one makes sure that the digits 0 to 4 are mirror image complementary to the numbers 5 to 9.