Introduction
ASCII (American Standard Code for Information Interchange, ASCⅡ) is a computer coding system based on the Latin alphabet. It is mainly used to display modern English and other Western European languages. It is the most common single-byte encoding system today and is equivalent to the international standard ISO/IEC 646.
ASCII was first published in a standardized form in 1967, and the last update was in 1986. So far, 128 characters have been defined, 33 of which cannot be displayed (this is based on the current operating system. But in DOS mode, it can display some 8-bit symbols such as smiley faces, playing card fancy, etc.), and most of these 33 characters are obsolete control characters. The control characters are mainly used to manipulate the processed ones. In addition to 33 characters, there are 95 displayable characters, including the blank character generated by hitting the blank key with the keyboard, which is also considered as 1 displayable character (displayed as blank).
ASCII control characters
| Binary | Decimal | Hexadecimal | abbreviation | Notation that can be displayed | Name/meaning |
|---|---|---|---|---|---|
| 0000 0000 | 0 | 00 | NO | ␀ | Null character |
| 0000 0001 | 1 | 01 | SOH | ␁ | Start of title |
| 0000 0010 | 2 | 02 | STX | ␂ | Start of this article |
| 0000 0011 | 3 | 03 | ETX | ␃ | End of this article |
| 0000 0100 | 4 | 04 | ROT | ␄ | End of transmission |
| 0000 0101 | 5 | 05 | ENQ | ␅ | request |
| 0000 0110 | 6 | 06 | ACK | ␆ | Confirm response |
| 0000 0111 | 7 | 07 | BEL | ␇ | Ring the bell |
| 0000 1000 | 8 | 08 | BS | ␈ | backspace |
| 0000 1001 | 9 | 09 | HT | ␉ | Horizontal positioning symbol |
| 0000 1010 | 10 | 0A | LF | ␊ | Line feed |
| 0000 1011 | 11 | 0B | VT | ␋ | Vertical positioning symbol |
| 0000 1100 | 12 | 0C | FF | ␌ | Page change button |
| 0000 1101 | 13 | 0D | CR | ␍ | Home key |
| 0000 1110 | 14 | 0E | SO | ␎ | Cancel transformation (Shift out) |
| 0000 1111 | 15 | 0F | AND | ␏ | Enable transformation (Shift in) |
| 0001 0000 | 16 | 10 | ACCORDING TO | ␐ | Out of data communication |
| 0001 0001 | 17 | 11 | DC1 | ␑ | Device control one (XON enables software speed control) |
| 0001 0010 | 18 | 12 | DC2 | ␒ | Device control two |
| 0001 0011 | 19 | 13 | DC3 | ␓ | Device control three (XOFF disables software speed control) |
| 0001 0100 | 20 | 14 | DC4 | ␔ | Device control four |
| 0001 0101 | 21 | 15 | NAK | ␕ | Confirm failure response |
| 0001 0110 | 22 | 16 | SYN | ␖ | Pause for synchronization |
| 0001 0111 | 23 | 17 | ETB | ␗ | End of block transfer |
| 0001 1000 | 24 | 18 | CAN | ␘ | cancel |
| 0001 1001 | 25 | 19 | IN | ␙ | Interrupted connection medium |
| 0001 1010 | 26 | 1A | SUB | ␚ | replace |
| 0001 1011 | 27 | 1B | ESC | ␛ | Jump out |
| 0001 1100 | 28 | 1C | FS | ␜ | File separator |
| 0001 1101 | 29 | 1D | GS | ␝ | Group separator |
| 0001 1110 | 30 | 1E | RS | ␞ | Record separator |
| 0001 1111 | 31 | 1F | US | ␟ | Unit separator |
| 0111 1111 | 127 | 7F | OF THE | ␡ | delete |
ASCII displayable characters
| Binary | Decimal | Hexadecimal | Graphics |
|---|---|---|---|
| 0010 0000 | 32 | 20 | (Space) (␠) |
| 0010 0001 | 33 | 21 | ! |
| 0010 0010 | 34 | 22 | " |
| 0010 0011 | 35 | 23 | # |
| 0010 0100 | 36 | 24 | $ |
| 0010 0101 | 37 | 25 | % |
| 0010 0110 | 38 | 26 | & |
| 0010 0111 | 39 | 27 | ’ |
| 0010 1000 | 40 | 28 | ( |
| 0010 1001 | 41 | 29 | ) |
| 0010 1010 | 42 | 2A | * |
| 0010 1011 | 43 | 2B | + |
| 0010 1100 | 44 | 2C | , |
| 0010 1101 | 45 | 2D | - |
| 0010 1110 | 46 | 2E | . |
| 0010 1111 | 47 | 2F | / |
| 0011 0000 | 48 | 30 | 0 |
| 0011 0001 | 49 | 31 | 1 |
| 0011 0010 | 50 | 32 | 2 |
| 0011 0011 | 51 | 33 | 3 |
| 0011 0100 | 52 | 34 | 4 |
| 0011 0101 | 53 | 35 | 5 |
| 0011 0110 | 54 | 36 | 6 |
| 0011 0111 | 55 | 37 | 7 |
| 0011 1000 | 56 | 38 | 8 |
| 0011 1001 | 57 | 39 | 9 |
| 0011 1010 | 58 | 3A | : |
| 0011 1011 | 59 | 3B | ; |
| 0011 1100 | 60 | 3C | < |
| 0011 1101 | 61 | 3D | = |
| 0011 1110 | 62 | 3e | > |
| 0011 1111 | 63 | 3F | ? |
| 0100 0000 | 64 | 40 | @ |
| 0100 0001 | 65 | 41 | A |
| 0100 0010 | 66 | 42 | B |
| 0100 0011 | 67 | 43 | C |
| 0100 0100 | 68 | 44 | D |
| 0100 0101 | 69 | 45 | E |
| 0100 0110 | 70 | 46 | F |
| 0100 0111 | 71 | 47 | G |
| 0100 1000 | 72 | 48 | H |
| 0100 1001 | 73 | 49 | I |
| 0100 1010 | 74 | 4A | J |
| 0100 1011 | 75 | 4B | K |
| 0100 1100 | 76 | 4C | L |
| 0100 1101 | 77 | 4D | M |
| 0100 1110 | 78 | 4E | N |
| 0100 1111 | 79 | 4F | O |
| 0101 0000 | 80 | 50 | P |
| 0101 0001 | 81 | 51 | Q |
| 0101 0010 | 82 | 52 | R |
| 0101 0011 | 83 | 53 | S |
| 0101 0100 | 84 | 54 | T |
| 0101 0101 | 85 | 55 | U |
| 0101 0110 | 86 | 56 | V |
| 0101 0111 | 87 | 57 | W |
| 0101 1000 | 88 | 58 | X |
| 0101 1001 | 89 | 59 | Y |
| 0101 1010 | 90 | 5A | Z |
| 0101 1011 | 91 | 5B | [ |
| 0101 1100 | 92 | 5C | \ |
| 0101 1101 | 93 | 5D | ] |
| 0101 1110 | 94 | 5E | ^ |
| 0101 1111 | 95 | 5F | _ |
| 0110 0000 | 96 | 60 | ` |
| 0110 0001 | 97 | 61 | a |
| 0110 0010 | 98 | 62 | b |
| 0110 0011 | 99 | 63 | c |
| 0110 0100 | 100 | 64 | d |
| 0110 0101 | 101 | 65 | e |
| 0110 0110 | 102 | 66 | f |
| 0110 0111 | 103 | 67 | g |
| 0110 1000 | 104 | 68 | h |
| 0110 1001 | 105 | 69 | i |
| 0110 1010 | 106 | 6A | j |
| 0110 1011 | 107 | 6B | k |
| 0110 1100 | 108 | 6C | l |
| 0110 1101 | 109 | 6D | m |
| 0110 1110 | 110 | 6E | n |
| 0110 1111 | 111 | 6F | o |
| 0111 0000 | 112 | 70 | p |
| 0111 0001 | 113 | 71 | q |
| 0111 0010 | 114 | 72 | r |
| 0111 0011 | 115 | 73 | s |
| 0111 0100 | 116 | 74 | t |
| 0111 0101 | 117 | 75 | u |
| 0111 0110 | 118 | 76 | v |
| 0111 0111 | 119 | 77 | w |
| 0111 1000 | 120 | 78 | x |
| 0111 1001 | 121 | 79 | y |
| 0111 1010 | 122 | 7A | z |
| 0111 1011 | 123 | 7B | { |
| 0111 1100 | 124 | 7C | |
| 0111 1101 | 125 | 7D | } |
| 0111 1110 | 126 | 7E | ~ |