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In A Nutshell

ASCII:
What is It and Why Should I Care?

ASCII, pronounced "ask-ee" is the acronym for American Standard Code for Information Interchange. It's a set of characters which, unlike the characters in word processing documents, allow no special formatting like different fonts, bold, underlined or italic text. All the characters used in email messages are ASCII characters and so are all the characters used in HTML documents. (Web browsers read the ASCII characters between angle brackets, "<" and ">", to interpret how to format and display HTML documents.)

An "ASCII file" is a data or text file that contains only characters coded from the standard ASCII character set. Characters 0 through 127 comprise the Standard ASCII Set and characters 128 to 255 are considered to be in the Extended ASCII Set. These codes, however, may not be the same in all computers and files containing these characters may not display or convert properly by another ASCII program.

Knowing something about ASCII can be helpful. ASCII files can be used as a common denominator for data conversions. For example, if program A can't convert its data to the format of program B, but both programs can input and output ASCII files, the conversion may be possible.

ASCII characters are the ones used to send and receive email. If you're familiar with email, you already know that formatting like italic type and underlines are not possible. Email transmissions are limited to ASCII characters and because of that, graphics files and documents with non-ASCII characters created in word processers, spreadsheet or database programs must be "ASCII-fied" and sent as email file attachments. When the files reach their destination they are "deASCII-fied" (i.e. decoded) and therefore, reconstructed to restore them for use.


Standard ASCII

The first 32 characters (0-31) are control codes.

ASCII  

Description
0  
NUL Null
1  
SOH Start of heading
2  
STX Start of text
3  
ETX End of text
4  
EOT End of transmit
5  
ENQ Enquiry
6  
ACK Acknowledge
7  
BEL Audible bell
8  
BS Backspace
9  
HT Horizontal tab
10  
LF Line feed
11  
VT Vertical tab
12  
FF Form feed
13  
CR Carriage return
14  
SO Shift out
15  
SI Shift in
16  
DLE Data link escape
17  
DC1 Device control 1
18  
DC2 Device control 2
19  
DC3 Device control 3
20  
DC4 Device control 4
21  
NAK Neg. acknowledge
22  
SYN Synchronous idle
23  
ETB End trans. block
24  
CAN Cancel
25  
EM End of medium
26  
SUB Substitution
27  
ESC Escape
28  
FS Figures shift
29  
GS Group separator
30  
RS Record separator
31  
US Unit separator
32  
SP Blank Space (Space Bar)
ASCII  
DISPLAY
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  
~  
127  
  


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