The development of computer systems required the implementation of coding systems to convert alphanumeric characters into binary notation. One of the earliest codes used to convert data to a computer-acceptable form was the binary coded decimal (BCD) system. This coding technique permits numeric information to be represented by 4 binary bits and permits an alphanumeric character set to be represented through the6 bits of information. This code is illustrated in Figure 2.2. One advantage of this code is that 2 decimal digits can be stored in an 8-bit computer word and manipulated with appropriate computer instructions. Although only 36 characters are shown, a BCD code is capable of containing a set of 2^6 or 64 different characters.