The term binary code can mean several different things:
There are a variety of different methods of coding numbers or symbols into strings of, including fixed-length binary numbers, prefix codes such as Huffman code, and other arithmetic coding.
Made up of only zeros and ones, and used in computers to stand for letters and digits.
8-bit ISO 8859-1 uses 8 digits for one letter e.g. "R" is "01010010" and "b" is "01100010" this is called a byte. 7-bit ASCII uses 7 bits to represent 128 characters (0-128).
Binary can produce a number between 0 and 255 (often stated as 1-256 for numerical purposes). It is a string of 8 characters consisting of only 1s and 0s.
Decoding a Single Binary Sequence Into an Integer (0-255)
Binary can be read from right to left. If any number is 0, it is ignored. If the first number from the right is 1, you add 1 to the number. If the second number from the right is 1, you add 2. And if the third number from the right is 1, you add 4. This pattern continues, doubling the numbers added until the left-most digit (which equals 128) is reached.
1st digit from right = 1: add 1
2nd digit from right = 1: add 2
3rd digit from right = 1: add 4
4th digit from right = 1: add 8
5th digit from right = 1: add 16
6th digit from right = 1: add 32
7th digit from right = 1: add 64
8th digit from right = 1: add 128
00000001 = 1
00000010 = 2
00000011 = 3
00000100 = 4
00000101 = 5
00000110 = 6
00000111 = 7
00001000 = 8
etc.
Binary is also similar to hexadecimal in that it is a computer code that produces a value of 0-255, although hexadecimal uses 2 numbers with 16 digits 0-F (0123456789ABCDEF).
See also: Unicode