1. ASCII
• It stands for American Standard Code for Information
Interchange
• ASCII is a character encoding based on the English
alphabet.
• It is an ANSI (American National Standards Institute)
standard
• It defines codes for 128 characters:
– 33 are non-printing, mostly obsolete control characters that
affect how text is processed
– 95 are printable characters
2. ASCII
• ASCII is a seven-bit code, meaning it uses patterns of seven binary digits (a
range of 0 to 127 decimal) to represent each character.
– When ASCII was introduced, many computers used eight-bit bytes as the
native data type. The eighth bit was commonly used as a parity bit for error
checking on communication lines
0 1 0 0 0 0 0 1
3. ASCII
• Different versions of ASCII were created for different
applications
– Windows-1252 - Changed some of the character encodings
– Mac OS Roman - Extended the encoding beyond 7 bits (the
7-bit characters were the same)
5. ASCII
• The good
– Encode all characters in 1 byte
– Almost every computer supports/supported ASCII
• The bad
– Can only encode English (with a limited number of
accented characters)
