Text Encoding
Every computer ever made has had some method of displaying and
encoding text. A computer doesn't recognize the letter 'A' in its
microprocessor; everything within the computer is dealt with
using hexadecimal bytes like 00, F1, and AC. In order for the
computer to be able to translate these hexadecimal numbers into
letters and numbers that you and I read, a conversion table is
used. There will usually be 255 possible entries within a
table since bytes only go up to FF (255 in decimal numbers). But,
usually only about 1/2 of them are used, since alphabets hardly
take up 255 slots. For IBM compatible computers, the table
standard has been known as 'ASCII'.
Within the ASCII table, hexadecimal number $41 (hexadecimal
numbers are usually denoted with a $ in front of them) represents
the letter 'A'. From then on, $42 stands for 'B', $43 for 'C',
etc... up to 'Z'. The lower case letters start at $61 ($61 for 'a').
Also, the characters '0..9' are represented by $30 to $39. The
other bytes consist of less common characters such as the 1/2
symbol (½), the copyright symbol (©), and the asterisk (*).
Also, some of them are used for control codes like $07, which is
reserved for the system beep you hear when you turn on your
computer.
Not all computers use the ASCII standard. The Macintosh does not
use the ASCII standard, and neither do gaming consoles.
Certain platforms, after encoding the alphabet, numbers, and
punctuation use what is left of the 255 possible table entries as
DTE (Dual Tile Encoding) and MTE (Multiple Tile Encoding) values.