Math171-UTK

Math 171 - Alexiades - UTK

ASCII

ASCII = American Standard Code for Information Interchange:

128 (=2⁷) character symbols encoded as 7-bit numbers

encodes 32 control codes (0–31 decimal) and 95 printable characters, for example:

char	Decimal	Hex	Octal	Binary 7bit
NULL	0	0	000	000 0000
space	32	20	040	010 0000
A	65	41	101	100 0000
Z	90	5A	132	101 1010
@	96	60	140	110 0000
a	97	61	141	110 0001
z	122	7A	172	111 1010
delete	127	7F	177	111 1111

ASCII was published as ASA X3.4-1963

first used commercially in 1963 as a seven-bit teleprinter code for AT&T TWX (TeletypeWriter eXchange)

ASCII was the common encoding on WWW till Dec 2007, then UTF-8

Unicode (UTF-8, UTF-16, UTF-32) vastly extends ASCII but starts with ASCII, so 7-bit codes match.
It encodes more than 128,000 characters and symbols, covering 135 modern and ancient scripts,
and Braille, and musical notation, and geometric shapes, and emoticons,... and room for more!

ascii table (0-127) and extended ascii (128-255)

ascii conversions

unicode conversions