ASCII

Description

ASCII, which stands for American Standard Code for Information Interchange, is a character encoding standard that represents text and control characters using a 7-bit binary code. In ASCII, each character is assigned a unique numeric value, which can be represented in decimal, hexadecimal, or binary notation. ASCII includes both printable characters (letters, numbers, and symbols) and control characters (such as carriage return and line feed) for communication and data storage.

Here's a brief overview of how ASCII works:

• Character Encoding: ASCII represents text and control characters using a 7-bit binary code. Each character is assigned a unique 7-bit binary number (ranging from 0000000 to 1111111). These binary values can be converted into decimal, hexadecimal, or octal representations for human-readable notation.


• Character Assignments: ASCII includes 128 character assignments. These characters cover a range of printable characters (letters, numbers, punctuation, and symbols) as well as control characters. The first 32 characters are control characters used for various formatting and communication functions, such as line feed, carriage return, and escape.


• Uniformity: One of the key design principles of ASCII was to ensure uniformity across different computer systems and communication devices. This means that an ASCII character, such as the letter 'A' (represented by 65 in decimal or 1000001 in binary), would have the same meaning and representation on any system that adhered to the ASCII standard.


• Compatibility: ASCII was designed to be backward compatible with earlier character codes, making it relatively easy to transition from older codes to ASCII. For example, many of the characters from the widely used telegraph code (Morse code) were included in the ASCII standard.


• Practical Use: ASCII was initially developed for telegraph communication but soon found widespread use in early computer systems. It allowed computers and devices from different manufacturers to communicate and exchange text data reliably.

It's important to note that while ASCII served as a fundamental standard for character encoding, it only provided codes for English characters and a limited set of symbols. As computing evolved and became more global, character encoding standards like UTF-8 and Unicode were developed to accommodate a broader range of characters, scripts, and languages. UTF-8, for example, uses 8 bits and is backward compatible with ASCII while supporting the representation of characters from various languages and scripts.

Alphabet ASCII Table

Letter	ASCII Code	Binary value	Letter	ASCII Code	Binary value
A	65	01000001	a	97	01100001
B	66	01000010	b	98	01100010
C	67	01000011	c	99	01100011
D	68	01000100	d	100	01100100
E	69	01000101	e	101	01100101
F	70	01000110	f	102	01100110
G	71	01000111	g	103	01100111
H	72	01001000	h	104	01101000
I	73	01001001	i	105	01101001
J	74	01001010	j	106	01101010
K	75	01001011	k	107	01101011
L	76	01001100	l	108	01101100
M	77	01001101	m	109	01101101
N	78	01001110	n	110	01101110
O	79	01001111	o	111	01101111
P	80	01010000	p	112	01110000
Q	81	01010001	q	113	01110001
R	82	01010010	r	114	01110010
S	83	01010011	s	115	01110011
T	84	01010100	t	116	01110100
U	85	01010101	u	117	01110101
V	86	01010110	v	118	01110110
W	87	01010111	w	119	01110111
X	88	01011000	x	120	01111000
Y	89	01011001	y	121	01111001
Z	90	01011010	z	122	01111010

Why use ASCII Codes

ASCII codes are used for several important reasons:

• Universal Compatibility: ASCII provides a standardized way to represent characters and control codes, ensuring that data can be exchanged between different computer systems and communication devices with ease. This universal compatibility is particularly important for data transmission and communication protocols.


• Simplicity: ASCII is a simple character encoding system, with each character represented by a 7-bit binary code. This simplicity makes it easy to work with, especially in early computing systems. It allows for efficient data storage and processing.


• Interoperability: ASCII is widely supported and understood by software, hardware, and programming languages. This makes it a common choice for representing text in a format that various applications and systems can process.


• Support: Many legacy systems and devices still use ASCII for data communication. As a result, knowledge of ASCII is essential for maintaining and interfacing with older technology. Basic Text Representation: ASCII covers the basic Latin alphabet, numerals, punctuation marks, and a range of control characters. For applications that only require simple text representation, ASCII is a lightweight and efficient choice.


• with Other Standards: Many other character encoding standards and protocols, such as UTF-8 (which is backward compatible with ASCII), use ASCII as their foundation. This means that ASCII is an integral part of more comprehensive character encoding systems.


• Network and Communication Protocols: Many network protocols and data formats, such as HTTP, SMTP, and plain text email, rely on ASCII for encoding and transmitting text data. This ensures that data can be reliably exchanged over the internet and other communication networks.

While ASCII has been fundamental in the history of computing and data communication, it's important to note that it primarily represents characters from the English language. As the need for character representation in other languages and scripts grew, more comprehensive character encoding standards like Unicode were developed to accommodate a wider range of characters. Nonetheless, ASCII remains relevant and widely used in various computing contexts, particularly where basic text representation and compatibility with legacy systems are essential.

FULL ASCII TABLE

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