Instruction Manual
Numbering Systems
Appendix A
A5
Binary Coded Octal
Binary coded octal (BCO) format expresses an octal value as an arrangement of
binary digits (eight bits or one byte). The 8 bits are broken down into three
groups: 2 bits, 3 bits and 3 bits. Each group of binary digits is used to represent
a decimal number from 0 to 9. All BCO numbers are composed of these digits.
Each place value in a BCD number represents a power of two 1 starting with
two raised to the zero power (2
0
= 1) (Figure A.5).
Figure A.5
Binary
Coded Octal
1110 11 11
10242
2
1
2
0
2
2
2
1
2
0
2
2
2
1
2
0
35 7
8
You can compute the octal number for each group of bits by multiplying the
binary digit by its corresponding place value and adding these numbers together
(Table A.C).
Table A.C
Octal
Representation
Place Value
Octal Equivalent
2
2
(4)
2
1
(2)
2
0
(1)
0 0 0 0
001 1
010 2
011 3
100 4
101 5
110 6
111 7