ASCII Code

Alphanumeric codes are used to represent different data, letters, and numbers by distinguishing symbols and characters.

There are three types of alphanumeric codes: ASCII code, EBCDIC code, and Unicode. ASCII Code is the most commonly used of these (although the others are used in specific situations).

What is ASCII code

ASCII stands for ‘American Standard Code for Information Interchange’, and is pronounced as ‘ask-ee’. ASCII code is used to represent alphanumeric data in computers, communication equipment, and electronic devices in a more scientific manner. ASCII code was first published as a standard in 1967. From then it is constantly being updated and revised. In 1986 the latest version was called and published as ANSI X3.4.

ASCII code is a 7 bit code and is hence able to represent 27 = 128 characters. Currently, a total number of 95 printable characters are represented by this code including 26 upper case letters (A – Z), 26 lower case letters (a – z), 10 numerals (0 – 9), and 33 special characters which include mathematical symbols, punctuation marks and space characters.

The latest development in the field of ASCII code is the development of 8 bit code – which is known as US ASCII-8 or ASCII-8. As it is an 8 bit code, it can represent 28 = 256 characters. The tabulated form of the ASCII code is given below.

ASCII Code Table

DECOCTHEXBINSymbolDescription
0000NULNull char
1111SOHStart of Heading
22210STXStart of Text
33311ETXEnd of Text
444100EOTEnd of Transmission
555101ENQEnquiry
666110ACKAcknowledgment
777111BELBell
81081000BSBack Space
91191001HTHorizontal Tab
10120A1010LFLine Feed
11130B1011VTVertical Tab
12140C1100FFForm Feed
13150D1101CRCarriage Return
14160E1110SOShift Out / X-On
15170F1111SIShift In / X-Off
16201010000DLEData Line Escape
17211110001DC1Device Control 1 (oft. XON)
18221210010DC2Device Control 2
19231310011DC3Device Control 3 (oft. XOFF)
20241410100DC4Device Control 4
21251510101NAKNegative Acknowledgement
22261610110SYNSynchronous Idle
23271710111ETBEnd of Transmit Block
24301811000CANCancel
25311911001EMEnd of Medium
26321A11010SUBSubstitute
27331B11011ESCEscape
28341C11100FSFile Separator
29351D11101GSGroup Separator
30361E11110RSRecord Separator
31371F11111USUnit Separator
324020100000Space
334121100001!Exclamation mark
344222100010Double quotes (or speech marks)
354323100011#Number
364424100100$Dollar
374525100101%Procenttecken
384626100110&Ampersand
394727100111Single quote
405028101000(Open parenthesis (or open bracket)
415129101001)Close parenthesis (or close bracket)
42522A101010*Asterisk
43532B101011+Plus
44542C101100,Comma
45552D101101Hyphen
46562E101110.Period, dot or full stop
47572F101111/Slash or divide
4860301100000Zero
4961311100011One
5062321100102Two
5163331100113Three
5264341101004Four
5365351101015Five
5466361101106Six
5567371101117Seven
5670381110008Eight
5771391110019Nine
58723A111010:Colon
59733B111011;Semicolon
60743C111100<Less than (or open angled bracket)
61753D111101=Equals
62763E111110>Greater than (or close angled bracket)
63773F111111?Question mark
64100401000000@At symbol
65101411000001AUppercase A
66102421000010BUppercase B
67103431000011CUppercase C
68104441000100DUppercase D
69105451000101EUppercase E
70106461000110FUppercase F
71107471000111GUppercase G
72110481001000HUppercase H
73111491001001IUppercase I
741124A1001010JUppercase J
751134B1001011KUppercase K
761144C1001100LUppercase L
771154D1001101MUppercase M
781164E1001110NUppercase N
791174F1001111OUppercase O
80120501010000PUppercase P
81121511010001QUppercase Q
82122521010010RUppercase R
83123531010011SUppercase S
84124541010100TUppercase T
85125551010101UUppercase U
86126561010110VUppercase V
87127571010111WUppercase W
88130581011000XUppercase X
89131591011001YUppercase Y
901325A1011010ZUppercase Z
911335B1011011[Opening bracket
921345C1011100\Backslash
931355D1011101]Closing bracket
941365E1011110^Caret – circumflex
951375F1011111_Underscore
96140601100000`Grave accent
97141611100001aLowercase a
98142621100010bLowercase b
99143631100011cLowercase c
100144641100100dLowercase d
101145651100101eLowercase e
102146661100110fLowercase f
103147671100111gLowercase g
104150681101000hLowercase h
105151691101001iLowercase i
1061526A1101010jLowercase j
1071536B1101011kLowercase k
1081546C1101100lLowercase l
1091556D1101101mLowercase m
1101566E1101110nLowercase n
1111576F1101111oLowercase o
112160701110000pLowercase p
113161711110001qLowercase q
114162721110010rLowercase r
115163731110011sLowercase s
116164741110100tLowercase t
117165751110101uLowercase u
118166761110110vLowercase v
119167771110111wLowercase w
120170781111000xLowercase x
121171791111001yLowercase y
1221727A1111010zLowercase z
1231737B1111011{Opening brace
1241747C1111100|Vertical bar
1251757D1111101}Closing brace
1261767E1111110~Equivalency sign – tilde
1271777F1111111Delete

From the table we can see that numbers 0 – 9 are represented with binary values with prefix 0011. In a similar fashion in case of upper-case letters -‘P’ to ‘Z’ are represented by 0101 0000 to 0101 1010, lower-case letters ‘p’ to ‘z’ are represented by 0111 0000 to 0111 1010.

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