ASCII, American Standard Code for Information Interchange reads like "astkey" and defines the English letters or the same result and meaning represented by the 127 numbers ranging from 0 to one hundred and twenty-eight. Because only seven digits (bit) can be used to represent numbers from 0 to 127, most computers use eight digits to access the character set (character set ), therefore, numbers between 128 and 255 can be used to represent another group of one hundred and twenty-eight symbols, which are called extended ASCII. |
ASCII code |
Keyboard |
ASCII code |
Keyboard |
ASCII code |
Keyboard |
ASCII code |
Keyboard |
27 |
ESC |
32 |
SPACE |
33 |
! |
34 |
" |
35 |
# |
36 |
$ |
37 |
% |
38 |
& |
39 |
' |
40 |
( |
41 |
) |
42 |
* |
43 |
+ |
44 |
' |
45 |
- |
46 |
. |
47 |
/ |
48 |
0 |
49 |
1 |
50 |
2 |
51 |
3 |
52 |
4 |
53 |
5 |
54 |
6 |
55 |
7 |
56 |
8 |
57 |
9 |
58 |
: |
59 |
; |
60 |
< |
61 |
= |
62 |
> |
63 |
? |
64 |
@ |
65 |
A |
66 |
B |
67 |
C |
68 |
D |
69 |
E |
70 |
F |
71 |
G |
72 |
H |
73 |
I |
74 |
J |
75 |
K |
76 |
L |
77 |
M |
78 |
N |
79 |
O |
80 |
P |
81 |
Q |
82 |
R |
83 |
S |
84 |
T |
85 |
U |
86 |
V |
87 |
W |
88 |
X |
89 |
Y |
90 |
Z |
91 |
[ |
92 |
\ |
93 |
] |
94 |
^ |
95 |
_ |
96 |
` |
97 |
A |
98 |
B |
99 |
C |
100 |
D |
101 |
E |
102 |
F |
103 |
G |
104 |
H |
105 |
I |
106 |
J |
107 |
K |
108 |
L |
109 |
M |
110 |
N |
111 |
O |
112 |
P |
113 |
Q |
114 |
R |
115 |
S |
116 |
T |
117 |
U |
118 |
V |
119 |
W |
120 |
X |
121 |
Y |
122 |
Z |
123 |
{ |
124 |
| |
125 |
} |
126 |
~ |
Currently, the most widely used character set and Its Encoding in computers are American Standard Code for Information Interchange (American Standard Code for Information Interchange) developed by the National Bureau of Standards (ANSI ), it has been set as an international standard by the International Organization for Standardization (ISO), known as the ISO 646 standard. It is applicable to all Latin characters, including 7-digit ASCII code and 8-digit ASCII code. Because the number of one-bit binary data can be expressed as (21 =) two states: 0 and 1, while the number of two-bit binary data can be expressed as (22) = four states: 00, 01, 10, 11, and so on. A 7-bit binary number can represent (27 =) 128 States. Each State is uniquely encoded as a 7-bit binary code, corresponds to one character (or control code), which can be arranged into a decimal number ranging from 0 ~ 127. Therefore, the 7-bit ASCII code is encoded using the seven-bit binary number, which can represent 128 characters. 0th ~ 32 and 127th (34 in total) are control characters or communication special characters, such as control characters: LF (line feed), CR (Press ENTER), FF (page feed), DEL (delete), BEL (zhenling); Communication special characters: SOH (Text header), EOT (Text tail), ACK (confirmation), etc; 33rd ~ 126 (94 in total) is a character, of which 48th ~ Number 57 is 0 ~ 9. 10 Arabic numerals; 65 ~ The 90 is 26 uppercase English letters, 97 ~ There are 26 lower-case English letters, and the remaining are some punctuation marks and operator numbers. Note: In a computer's storage unit, an ASCII code value occupies one byte (eight binary digits), and its highest bit (b7) is used as the parity bit. The so-called parity check refers to a method used to check whether an error occurs during code transfer. It is generally divided into two types: Odd checksum and even verification. Odd check rules: correct code must contain an odd number of 1 bytes. If the number is not an odd number, 1 is added to the highest bit b7. Even check rules: correct code: the number of 1 in a byte must be an even number. If the number is not an even number, 1 is added to the highest bit of b7. Appendix: ASCII table
ASCII Value |
Control characters |
ASCII Value |
Control characters |
ASCII Value |
Control characters |
ASCII Value |
Control characters |
0 |
NUT |
32 |
(Space) |
64 |
@ |
96 |
, |
1 |
SOH |
33 |
! |
65 |
A |
97 |
A |
2 |
STX |
34 |
" |
66 |
B |
98 |
B |
3 |
ETX |
35 |
# |
67 |
C |
99 |
C |
4 |
EOT |
36 |
$ |
68 |
D |
100 |
D |
5 |
ENQ |
37 |
% |
69 |
E |
101 |
E |
6 |
ACK |
38 |
& |
70 |
F |
102 |
F |
7 |
BEL |
39 |
, |
71 |
G |
103 |
G |
8 |
BS |
40 |
( |
72 |
H |
104 |
H |
9 |
HT |
41 |
) |
73 |
I |
105 |
I |
10 |
LF |
42 |
* |
74 |
J |
106 |
J |
11 |
VT |
43 |
+ |
75 |
K |
107 |
K |
12 |
FF |
44 |
, |
76 |
L |
108 |
L |
13 |
CR |
45 |
- |
77 |
M |
109 |
M |
14 |
SO |
46 |
. |
78 |
N |
110 |
N |
15 |
SI |
47 |
/ |
79 |
O |
111 |
O |
16 |
DLE |
48 |
0 |
80 |
P |
112 |
P |
17 |
DCI |
49 |
1 |
81 |
Q |
113 |
Q |
18 |
DC2 |
50 |
2 |
82 |
R |
114 |
R |
19 |
DC3 |
51 |
3 |
83 |
X |
115 |
S |
20 |
DC4 |
52 |
4 |
84 |
T |
116 |
T |
21 |
NAK |
53 |
5 |
85 |
U |
117 |
U |
22 |
SYN |
54 |
6 |
86 |
V |
118 |
V |
23 |
TB |
55 |
7 |
87 |
W |
119 |
W |
24 |
CAN |
56 |
8 |
88 |
X |
120 |
X |
25 |
EM |
57 |
9 |
89 |
Y |
121 |
Y |
26 |
SUB |
58 |
: |
90 |
Z |
122 |
Z |
27 |
ESC |
59 |
; |
91 |
[ |
123 |
{ |
28 |
FS |
60 |
< |
92 |
\ |
124 |
| |
29 |
GS |
61 |
= |
93 |
] |
125 |
} |
30 |
RS |
62 |
> |
94 |
^ |
126 |
~ |
31 |
US |
63 |
? |
95 |
- |
127 |
DEL |
NUL |
VT vertical tabulation |
SYN idling Synchronization |
SOH title starts |
FF Paper Control |
ETB Information Group Transfer ended |
Start of STX text |
CR press ENTER |
CAN void |
ETX text ended |
SO shift output |
EM paper |
EOY transmission ends |
SI shift Input |
SUB placement |
ENQ query characters |
DLE Space |
ESC code change |
ACK acknowledge |
DC1 Device Control 1 |
FS text Separator |
BEL alarm |
DC2 Device Control 2 |
GS group Separator |
BS returns to one grid |
DC3 Device Control 3 |
RS record delimiter |
HT horizontal list |
DC4 Device Control 4 |
US unit Separator |
LF line feed |
NAK no |
DEL Delete |
Common ASCII codes for keyboards |
ESC key VK_ESCAPE (27) Enter the key: VK_RETURN (13) TAB key: VK_TAB (9) Caps Lock key: VK_CAPITAL (20) Shift key: VK_SHIFT ($10) Ctrl: VK_CONTROL (17) Alt key: VK_MENU (18) Space key: VK_SPACE ($20/32) Backspace key: VK_BACK (8) Left logo key: VK_LWIN (91) Right logo key: VK_LWIN (92) Right-click the shortcut key: VK_APPS (93)Insert key: VK_INSERT (45) Home Key: VK_HOME (36) Page Up: VK_PRIOR (33) PageDown: VK_NEXT (34) End key: VK_END (35) Delete key: VK_DELETE (46) Direction key (Direction): VK_LEFT (37) Direction key (Direction): VK_UP (38) Direction key (→): VK_RIGHT (39) Direction key (Direction): VK_DOWN (40) F1 key: VK_F1 (112) F2 key: VK_F2 (113) F3 key: VK_F3 (114) F4 key: VK_F4 (115) F5 key: VK_F5 (116) F6 key: VK_F6 (117) F7 key: VK_F7 (118) F8: VK_F8 (119) F9 key: VK_F9 (120) F10 key: VK_F10 (121) F11 key: VK_F11 (122) F12 key: VK_F12 (123) Num Lock key: VK_NUMLOCK (144) Keypad 0: VK_NUMPAD0 (96) Keypad 1: VK_NUMPAD0 (97) Keypad 2: VK_NUMPAD0 (98) Keypad 3: VK_NUMPAD0 (99) Keypad 4: VK_NUMPAD0 (100) Keypad 5: VK_NUMPAD0 (101) Keypad 6: VK_NUMPAD0 (102) Keypad 7: VK_NUMPAD0 (103) Keypad 8: VK_NUMPAD0 (104) Keypad 9: VK_NUMPAD0 (105) Keypad.: VK_DECIMAL (110) Keypad *: VK_MULTIPLY (106) Keypad +: VK_MULTIPLY (107) Keypad-: VK_SUBTRACT (109) Keypad/: VK_DIVIDE (111) Pause Break Key: VK_PAUSE (19) Scroll Lock key: VK_SCROLL (145) |
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