Ascii character set encoded in octal, decimal, and hexadecimal
ASCII is the American Standard Code for Information Interchange. It is a 7-bit code. Many 8-bit codes (e.g., ISO 8859-1) contain ASCII as their lower half. The international counterpart of ASCII is known as ISO 646-IRV.
The following table contains the 128 ASCII characters.
C program '\X' escapes are noted.
Oct | Dec | Hex | Char | Oct | Dec | Hex | Char |
---|---|---|---|---|---|---|---|
000 | 0 | 00 | NUL '\0' (null character) | 100 | 64 | 40 | @ |
001 | 1 | 01 | SOH (start of heading) | 101 | 65 | 41 | A |
002 | 2 | 02 | STX (start of text) | 102 | 66 | 42 | B |
003 | 3 | 03 | ETX (end of text) | 103 | 67 | 43 | C |
004 | 4 | 04 | EOT (end of transmission) | 104 | 68 | 44 | D |
005 | 5 | 05 | ENQ (enquiry) | 105 | 69 | 45 | E |
006 | 6 | 06 | ACK (acknowledge) | 106 | 70 | 46 | F |
007 | 7 | 07 | BEL '\a' (bell) | 107 | 71 | 47 | G |
010 | 8 | 08 | BS '\b' (backspace) | 110 | 72 | 48 | H |
011 | 9 | 09 | HT '\t' (horizontal tab) | 111 | 73 | 49 | I |
012 | 10 | 0A | LF '\n' (new line) | 112 | 74 | 4A | J |
013 | 11 | 0B | VT '\v' (vertical tab) | 113 | 75 | 4B | K |
014 | 12 | 0C | FF '\f' (form feed) | 114 | 76 | 4C | L |
015 | 13 | 0D | CR '\r' (carriage ret) | 115 | 77 | 4D | M |
016 | 14 | 0E | SO (shift out) | 116 | 78 | 4E | N |
017 | 15 | 0F | SI (shift in) | 117 | 79 | 4F | O |
020 | 16 | 10 | DLE (data link escape) | 120 | 80 | 50 | P |
021 | 17 | 11 | DC1 (device control 1) | 121 | 81 | 51 | Q |
022 | 18 | 12 | DC2 (device control 2) | 122 | 82 | 52 | R |
023 | 19 | 13 | DC3 (device control 3) | 123 | 83 | 53 | S |
024 | 20 | 14 | DC4 (device control 4) | 124 | 84 | 54 | T |
025 | 21 | 15 | NAK (negative ack.) | 125 | 85 | 55 | U |
026 | 22 | 16 | SYN (synchronous idle) | 126 | 86 | 56 | V |
027 | 23 | 17 | ETB (end of trans. blk) | 127 | 87 | 57 | W |
030 | 24 | 18 | CAN (cancel) | 130 | 88 | 58 | X |
031 | 25 | 19 | EM (end of medium) | 131 | 89 | 59 | Y |
032 | 26 | 1A | SUB (substitute) | 132 | 90 | 5A | Z |
033 | 27 | 1B | ESC (escape) | 133 | 91 | 5B | [ |
034 | 28 | 1C | FS (file separator) | 134 | 92 | 5C | \ '\\' |
035 | 29 | 1D | GS (group separator) | 135 | 93 | 5D | ] |
036 | 30 | 1E | RS (record separator) | 136 | 94 | 5E | ^ |
037 | 31 | 1F | US (unit separator) | 137 | 95 | 5F | _ |
040 | 32 | 20 | SPACE | 140 | 96 | 60 | ` |
041 | 33 | 21 | ! | 141 | 97 | 61 | a |
042 | 34 | 22 | " | 142 | 98 | 62 | b |
043 | 35 | 23 | # | 143 | 99 | 63 | c |
044 | 36 | 24 | $ | 144 | 100 | 64 | d |
045 | 37 | 25 | % | 145 | 101 | 65 | e |
046 | 38 | 26 | & | 146 | 102 | 66 | f |
047 | 39 | 27 | ' | 147 | 103 | 67 | g |
050 | 40 | 28 | ( | 150 | 104 | 68 | h |
051 | 41 | 29 | ) | 151 | 105 | 69 | i |
052 | 42 | 2A | * | 152 | 106 | 6A | j |
053 | 43 | 2B | + | 153 | 107 | 6B | k |
054 | 44 | 2C | , | 154 | 108 | 6C | l |
055 | 45 | 2D | - | 155 | 109 | 6D | m |
056 | 46 | 2E | . | 156 | 110 | 6E | n |
057 | 47 | 2F | / | 157 | 111 | 6F | o |
060 | 48 | 30 | 0 | 160 | 112 | 70 | p |
061 | 49 | 31 | 1 | 161 | 113 | 71 | q |
062 | 50 | 32 | 2 | 162 | 114 | 72 | r |
063 | 51 | 33 | 3 | 163 | 115 | 73 | s |
064 | 52 | 34 | 4 | 164 | 116 | 74 | t |
065 | 53 | 35 | 5 | 165 | 117 | 75 | u |
066 | 54 | 36 | 6 | 166 | 118 | 76 | v |
067 | 55 | 37 | 7 | 167 | 119 | 77 | w |
070 | 56 | 38 | 8 | 170 | 120 | 78 | x |
071 | 57 | 39 | 9 | 171 | 121 | 79 | y |
072 | 58 | 3A | : | 172 | 122 | 7A | z |
073 | 59 | 3B | ; | 173 | 123 | 7B | { |
074 | 60 | 3C | < | 174 | 124 | 7C | | |
075 | 61 | 3D | = | 175 | 125 | 7D | } |
076 | 62 | 3E | > | 176 | 126 | 7E | ~ |
077 | 63 | 3F | ? | 177 | 127 | 7F | DEL |
For convenience, below are more compact tables in hex and decimal.
2 3 4 5 6 7 30 40 50 60 70 80 90 100 110 120 ------------- --------------------------------- 0: 0 @ P ` p 0: ( 2 < F P Z d n x 1: ! 1 A Q a q 1: ) 3 = G Q [ e o y 2: " 2 B R b r 2: * 4 > H R \ f p z 3: # 3 C S c s 3: ! + 5 ? I S ] g q { 4: $ 4 D T d t 4: " , 6 @ J T ^ h r | 5: % 5 E U e u 5: # - 7 A K U _ i s } 6: & 6 F V f v 6: $ . 8 B L V ` j t ~ 7: \' 7 G W g w 7: % / 9 C M W a k u DEL 8: ( 8 H X h x 8: & 0 : D N X b l v 9: ) 9 I Y i y 9: \' 1 ; E O Y c m w A: * : J Z j z B: + ; K [ k { C: , < L \ l | D: - = M ] m } E: . > N ^ n ~ F: / ? O _ o DEL
An ascii manual page appeared in Version 7 of AT&T UNIX.
On older terminals, the underscore code is displayed as a left arrow, called backarrow, the caret is displayed as an up-arrow and the vertical bar has a hole in the middle.
Uppercase and lowercase characters differ by just one bit and the ASCII character 2 differs from the double quote by just one bit, too. That made it much easier to encode characters mechanically or with a non-microcontroller-based electronic keyboard and that pairing was found on old teletypes.
The ASCII standard was published by the United States of America Standards Institute (USASI) in 1968.
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