What is ASCII?


Usually when the term ASCII is used, it is to refer to a text document. If a file is described as "ASCII text", this means you can view the contents of the file, change it with an editor, or print it with a printer. It does not contain any special embedded control characters. "ASCII" is an acronym that stands for American National Standard Code for Information Interchange. It is a widely used standard for encoding text documents on computers.

As part of this system, every letter, number, and punctuation symbol has a corresponding number, or "ASCII code". For example, the character for the number 1 has the code 49, capital letter A has the code 65, and a blank space has the code 32. This encoding system not only lets a computer store a document as a series of numbers, but also lets it share such documents with other computers that use the ASCII system.

Documentation files or program source code files are usually stored as ASCII text. In contrast, "binary" files, such as executable programs or graphical images, contain other characters that cannot be normally displayed or printed, and are usually illegible to human beings.

The format of a file, whether ASCII or binary, becomes an issue when you are transferring files between computers. For example, when using FTP, ASCII text files may be transferred without any special consideration. To exchange binary files, however, you must enter the command "set binary" in many FTP clients to instruct the computer to correctly transmit the special characters in the file. See the references below for more information about how to correctly transfer files.

A table of ASCII character codes.

Note: Dec refers to the decimal number of a character (Char) and Hex refers to its hexadecimal equivalent.

Dec Hex Char   Dec Hex Char   Dec Hex Char   Dec Hex Char



 


 


 


0 00 NUL   32 20     64 40 @   96 60 `
1 01 SOH   33 21 !   65 41 A   97 61 a
2 02 STX   34 22 "   66 42 B   98 62 b
3 03 ETX   35 23 #   67 43 C   99 63 c
4 04 EOT   36 24 $   68 44 D   100 64 d
5 05 ENQ   37 25 %   69 45 E   101 65 e
6 06 ACK   38 26 &   70 46 F   102 66 f
7 07 BEL   39 27 '   71 47 G   103 67 g
8 08 BS   40 28 (   72 48 H   104 68 h
9 09 TAB   41 29 )   73 49 I   105 69 i
10 0A LF   42 2A *   74 4A J   106 6A j
11 0B VT   43 2B +   75 4B K   107 6B k
12 0C FF   44 2C ,   76 4C L   108 6C l
13 0D CR   45 2D -   77 4D M   109 6D m
14 0E SO   46 2E .   78 4E N   110 6E n
15 0F SI   47 2F /   79 4F O   111 6F o
16 10 DLE   48 30 0   80 50 P   112 70 p
17 11 DC1   49 31 1   81 51 Q   113 71 q
18 12 DC2   50 32 2   82 52 R   114 72 r
19 13 DC3   51 33 3   83 53 S   115 73 s
20 14 DC4   52 34 4   84 54 T   116 74 t
21 15 NAK   53 35 5   85 55 U   117 75 u
22 16 SYN   54 36 6   86 56 V   118 76 v
23 17 ETB   55 37 7   87 57 W   119 77 w
24 18 CAN   56 38 8   88 58 X   120 78 x
25 19 EM   57 39 9   89 59 Y   121 79 y
26 1A SUB   58 3A :   90 5A Z   122 7A z
27 1B ESC   59 3B ;   91 5B [   123 7B {
28 1C FS   60 3C <   92 5C \   124 7C |
29 1D GS   61 3D =   93 5D ]   125 7D }
30 1E RS   62 3E >   94 5E ^   126 7E ~
31 1F US   63 3F ?   95 5F _   127 7F DEL

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