Introduction to ASCII

(American Standard Code for Information Interchange)

Coded messages have been used for many years. Sometimes spies would scramble the letters in a message or use numbers to represent the letters of the alphabet. Morse Code was invented to send messages across the telegraph line by using a series of short and long pulses. Codes such as ASCII were developed to represent characters as groups of ones and zeros. Ones and zeros can be used easily by computers and communication equipment. The most popular codes for computers are ASCII and EBCDIC (Extended Binary Coded Decimal Interchange Code). The EBCDIC code set is used on large IBM mainframe computers, while ASCII is used almost everywhere else.

Each character is assigned a numeric value. The value can be expressed in decimal for BASIC programs, or in octal or hexadecimal for most other programs. The first 32 codes are used as control characters. These can be used to ring the bell (BEL), move the paper up one line (LF), backspace (BS), indicate the start or end of text (STX, ETX) etc. ASCII uses only seven bits, giving 128 combinations. Several computer manufactures use all eight bits giving 256 printable characters. These extra codes are called "Extended-ASCII" and are not uniformly defined from one manufacture to the next.

The ASCII character set is fine for characters used in English. ASCII does not have the ability to display characters with accents or characters in other languages such as Greek, Hebrew, Japanese, Chinese, Arabic, Korean, Thai and many others. Unicode extends ASCII and uses 16 or more bits and includes almost every character or glyph used in the world.

American Standard Code for Information Interchange - ASCII

 DEC OCT HEX CHAR  DEC OCT HEX CHAR  DEC OCT HEX CHAR   DEC OCT HEX CHAR
  0  000  00  NUL
  1  001  01  SOH
  2  002  02  STX
  3  003  03  ETX
  4  004  04  EOT
  5  005  05  ENQ
  6  006  06  ACK
  7  007  07  BEL
  8  010  08  BS
  9  011  09  HT
 10  012  0A  LF
 11  013  0B  VT
 12  014  0C  FF
 13  015  0D  CR
 14  016  0E  SO
 15  017  0F  SI
 16  020  10  DLE
 17  021  11  DC1
 18  022  12  DC2
 19  023  13  DC3
 20  024  14  DC4
 21  025  15  NAK
 22  026  16  SYN
 23  027  17  ETB
 24  030  18  CAN
 25  031  19  EM
 26  032  1A  SUB
 27  033  1B  ESC
 28  034  1C  FS
 29  035  1D  GS
 30  036  1E  RS
 31  037  1F  US
 32  040  20 space
 33  041  21   !
 34  042  22   "
 35  043  23   #
 36  044  24   $
 37  045  25   %
 38  046  26   &
 39  047  27   '
 40  050  28   (
 41  051  29   )
 42  052  2A   *
 43  053  2B   +
 44  054  2C   ,
 45  055  2D   -
 46  056  2E   .
 47  057  2F   /
 48  060  30   0
 49  061  31   1
 50  062  32   2
 51  063  33   3
 52  064  34   4
 53  065  35   5
 54  066  36   6
 55  067  37   7
 56  070  38   8
 57  071  39   9
 58  072  3A   :
 59  073  3B   ;
 60  074  3C   <
 61  075  3D   =
 62  076  3E   >
 63  077  3F   ?
 64  100  40   @
 65  101  41   A
 66  102  42   B
 67  103  43   C
 68  104  44   D
 69  105  45   E
 70  106  46   F
 71  107  47   G
 72  110  48   H
 73  111  49   I
 74  112  4A   J
 75  113  4B   K
 76  114  4C   L
 77  115  4D   M
 78  116  4E   N
 79  117  4F   O
 80  120  50   P
 81  121  51   Q
 82  122  52   R
 83  123  53   S
 84  124  54   T
 85  125  55   U
 86  126  56   V
 87  127  57   W
 88  130  58   X
 89  131  59   Y
 90  132  5A   Z
 91  133  5B   [
 92  134  5C   \
 93  135  5D   ]
 94  136  5E   ^
 95  137  5F   _
  96  140  60   `
  97  141  61   a
  98  142  62   b
  99  143  63   c
 100  144  64   d
 101  145  65   e
 102  146  66   f
 103  147  67   g
 104  150  68   h
 105  151  69   i
 106  152  6A   j
 107  153  6B   k
 108  154  6C   l
 109  155  6D   m
 110  156  6E   n
 111  157  6F   o
 112  160  70   p
 113  161  71   q
 114  162  72   r
 115  163  73   s
 116  164  74   t
 117  165  75   u
 118  166  76   v
 119  167  77   w
 120  170  78   x
 121  171  79   y
 122  172  7A   z
 123  173  7B   {
 124  174  7C   |
 125  175  7D   }
 126  176  7E   ~
 127  177  7F   DEL