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Tuesday, October 15, 2013

Code 28 : ASCII


ascii code chart ASCII is a code used by computers to represent characters as numbers. This allows computers to store a letter as one byte of information. One byte of information allows you to represent 256 different values, which is enough to encode all the letters (uppercase and lowercase) as well as the numbers 0-9 and other special characters such as the @ symbol.
















 

The American Standard Code for Information Interchange (ASCII /ˈæski/ ASS-kee)is a character-encoding scheme originally based on the English alphabet that encodes 128 specified characters - the numbers 0-9, the letters a-z and A-Z, some basic punctuation symbols, some control codes that originated with Teletype machines, and a blank space - into the 7-bit binary integers.
ASCII codes represent text in computers, communications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, though they support many additional characters.
ASCII developed from telegraphic codes. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began on October 6, 1960, with the first meeting of the American Standards Association's (ASA) X3.2 subcommittee. The first edition of the standard was published during 1963, a major revision during 1967, and the most recent update during 1986. Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists, and added features for devices other than teleprinters.
ASCII includes definitions for 128 characters: 33 are non-printing control characters (many now obsolete) that affect how text and space are processed and 95 printable characters, including the space (which is considered an invisible graphic).
The IANA prefers the name US-ASCII to avoid ambiguity. ASCII was the most commonly used character encoding on the World Wide Web until December 2007, when it was surpassed by the ASCII-derived UTF-8.

ASCII control code chart

Binary Oct Dec Hex Abbr [a] [b] [c] Name
000 0000 000 0 00 NUL ^@ \0 Null character
000 0001 001 1 01 SOH ^A
Start of Header
000 0010 002 2 02 STX ^B
Start of Text
000 0011 003 3 03 ETX ^C
End of Text
000 0100 004 4 04 EOT ^D
End of Transmission
000 0101 005 5 05 ENQ ^E
Enquiry
000 0110 006 6 06 ACK ^F
Acknowledgment
000 0111 007 7 07 BEL ^G \a Bell
000 1000 010 8 08 BS ^H \b Backspace[d][e]
000 1001 011 9 09 HT ^I \t Horizontal Tab[f]
000 1010 012 10 0A LF ^J \n Line feed
000 1011 013 11 0B VT ^K \v Vertical Tab
000 1100 014 12 0C FF ^L \f Form feed
000 1101 015 13 0D CR ^M \r Carriage return[g]
000 1110 016 14 0E SO ^N
Shift Out
000 1111 017 15 0F SI ^O
Shift In
001 0000 020 16 10 DLE ^P
Data Link Escape
001 0001 021 17 11 DC1 ^Q
Device Control 1 (oft. XON)
001 0010 022 18 12 DC2 ^R
Device Control 2
001 0011 023 19 13 DC3 ^S
Device Control 3 (oft. XOFF)
001 0100 024 20 14 DC4 ^T
Device Control 4
001 0101 025 21 15 NAK ^U
Negative Acknowledgement
001 0110 026 22 16 SYN ^V
Synchronous idle
001 0111 027 23 17 ETB ^W
End of Transmission Block
001 1000 030 24 18 CAN ^X
Cancel
001 1001 031 25 19 EM ^Y
End of Medium
001 1010 032 26 1A SUB ^Z
Substitute
001 1011 033 27 1B ESC ^[ \e[h] Escape[i]
001 1100 034 28 1C FS ^\
File Separator
001 1101 035 29 1D GS ^]
Group Separator
001 1110 036 30 1E RS ^^[j]
Record Separator
001 1111 037 31 1F US ^_
Unit Separator

111 1111 177 127 7F DEL ^?
Delete[k][e]   

  1. ^ The Unicode characters from the area U+2400 to U+2421 reserved for representing control characters when it is necessary to print or display them rather than have them perform their intended function. Some browsers may not display these properly.
  2. ^ Caret notation often used to represent control characters on a terminal. On most text terminals, holding down the Ctrl key while typing the second character will type the control character. Sometimes the shift key is not needed, for instance ^@ may be typable with just Ctrl and 2.
  3. ^ Character Escape Codes in C programming language and many other languages influenced by it, such as Java and Perl (though not all implementations necessarily support all escape codes).
  4.  ^ The Backspace character can also be entered by pressing the ← Backspace key on some systems.
  5. ^ a b The ambiguity of Backspace is due to early terminals designed assuming the main use of the keyboard would be to manually punch paper tape while not connected to a computer. To delete the previous character, one had to back up the paper tape punch, which for mechanical and simplicity reasons was a button on the punch itself and not the keyboard, then type the rubout character. They therefore placed a key producing rubout at the location used on typewriters for backspace. When systems used these terminals and provided command-line editing, they had to use the "rubout" code to perform a backspace, and often did not interpret the backspace character (they might echo "^H" for backspace). Other terminals not designed for paper tape made the key at this location produce Backspace, and systems designed for these used that character to back up. Since the delete code often produced a backspace effect, this also forced terminal manufacturers to make any Delete key produce something other than the Delete character.
  6.  ^ The Tab character can also be entered by pressing the Tab key on most systems.
  7. ^ The Carriage Return character can also be entered by pressing the Enter or Return key on most systems.
  8. ^ The '\e' escape sequence is not part of ISO C and many other language specifications. However, it is understood by several compilers, including GCC.
  9.  ^ The Escape character can also be entered by pressing the Esc key on some systems.
  10. ^ ^^ means Ctrl+^ (pressing the "Ctrl" and caret keys).
  11. ^ The Delete character can sometimes be entered by pressing the ← Backspace key on some systems.
Other representations might be used by specialist equipment, for example ISO 2047 graphics or hexadecimal numbers.

ASCII printable characters

Codes 20hex to 7Ehex, known as the printable characters, represent letters, digits, punctuation marks, and a few miscellaneous symbols. There are 95 printable characters in total.
Code 20hex, the space character, denotes the space between words, as produced by the space-bar of a keyboard. Since the space character is considered an invisible graphic (rather than a control character) and thus would not normally be visible, it is represented here by Unicode character U+2420 "␠"; Unicode characters U+2422 "␢" and U+2423 "␣" are also available for use when a visible representation of a space is necessary.
Code 7Fhex corresponds to the non-printable "Delete" (DEL) control character and is therefore omitted from this chart; it is covered in the previous section's chart.
Earlier versions of ASCII used the up-arrow instead of the caret (5Ehex) and the left-arrow instead of the underscore (5Fhex).
Binary Oct Dec Hex Glyph
010 0000 040 32 20
010 0001 041 33 21 !
010 0010 042 34 22 "
010 0011 043 35 23 #
010 0100 044 36 24 $
010 0101 045 37 25 %
010 0110 046 38 26 &
010 0111 047 39 27 '
010 1000 050 40 28 (
010 1001 051 41 29 )
010 1010 052 42 2A *
010 1011 053 43 2B +
010 1100 054 44 2C ,
010 1101 055 45 2D -
010 1110 056 46 2E .
010 1111 057 47 2F /
011 0000 060 48 30 0
011 0001 061 49 31 1
011 0010 062 50 32 2
011 0011 063 51 33 3
011 0100 064 52 34 4
011 0101 065 53 35 5
011 0110 066 54 36 6
011 0111 067 55 37 7
011 1000 070 56 38 8
011 1001 071 57 39 9
011 1010 072 58 3A :
011 1011 073 59 3B ;
011 1100 074 60 3C <
011 1101 075 61 3D =
011 1110 076 62 3E >
011 1111 077 63 3F ?
Binary Oct Dec Hex Glyph
100 0000 100 64 40 @
100 0001 101 65 41 A
100 0010 102 66 42 B
100 0011 103 67 43 C
100 0100 104 68 44 D
100 0101 105 69 45 E
100 0110 106 70 46 F
100 0111 107 71 47 G
100 1000 110 72 48 H
100 1001 111 73 49 I
100 1010 112 74 4A J
100 1011 113 75 4B K
100 1100 114 76 4C L
100 1101 115 77 4D M
100 1110 116 78 4E N
100 1111 117 79 4F O
101 0000 120 80 50 P
101 0001 121 81 51 Q
101 0010 122 82 52 R
101 0011 123 83 53 S
101 0100 124 84 54 T
101 0101 125 85 55 U
101 0110 126 86 56 V
101 0111 127 87 57 W
101 1000 130 88 58 X
101 1001 131 89 59 Y
101 1010 132 90 5A Z
101 1011 133 91 5B [
101 1100 134 92 5C \
101 1101 135 93 5D ]
101 1110 136 94 5E ^
101 1111 137 95 5F _
Binary Oct Dec Hex Glyph
110 0000 140 96 60 `
110 0001 141 97 61 a
110 0010 142 98 62 b
110 0011 143 99 63 c
110 0100 144 100 64 d
110 0101 145 101 65 e
110 0110 146 102 66 f
110 0111 147 103 67 g
110 1000 150 104 68 h
110 1001 151 105 69 i
110 1010 152 106 6A j
110 1011 153 107 6B k
110 1100 154 108 6C l
110 1101 155 109 6D m
110 1110 156 110 6E n
110 1111 157 111 6F o
111 0000 160 112 70 p
111 0001 161 113 71 q
111 0010 162 114 72 r
111 0011 163 115 73 s
111 0100 164 116 74 t
111 0101 165 117 75 u
111 0110 166 118 76 v
111 0111 167 119 77 w
111 1000 170 120 78 x
111 1001 171 121 79 y
111 1010 172 122 7A z
111 1011 173 123 7B {
111 1100 174 124 7C |
111 1101 175 125 7D }
111 1110 176 126 7E ~
 
ASCII codes table - Format of standard characters




ASCII

Hex

Symbol

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F

NUL
SOH
STX
ETX
EOT
ENQ
ACK
BEL
BS
TAB
LF
VT
FF
CR
SO
SI


ASCII

Hex

Symbol

16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

10
11
12
13
14
15
16
17
18
19
1A
1B
1C
1D
1E
1F

DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US


ASCII

Hex

Symbol

32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47

20
21
22
23
24
25
26
27
28
29
2A
2B
2C
2D
2E
2F

(space)
!
"
#
$
%
&
'
(
)
*
+
,
-
.
/


ASCII

Hex

Symbol

48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63

30
31
32
33
34
35
36
37
38
39
3A
3B
3C
3D
3E
3F

0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?


ASCII

Hex

Symbol

64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79

40
41
42
43
44
45
46
47
48
49
4A
4B
4C
4D
4E
4F

@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O


ASCII

Hex

Symbol

80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95

50
51
52
53
54
55
56
57
58
59
5A
5B
5C
5D
5E
5F

P
Q
R
S
T
U
V
W
X
Y
Z
[
\
]
^
_


ASCII

Hex

Symbol

96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111

60
61
62
63
64
65
66
67
68
69
6A
6B
6C
6D
6E
6F

`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o


ASCII

Hex

Symbol

112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127

70
71
72
73
74
75
76
77
78
79
7A
7B
7C
7D
7E
7F

p
q
r
s
t
u
v
w
x
y
z
{
|
}
~



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