Text Codes

Text Codes

• Computer programmers realized that they need a commonly agreed standard code in which numbers stood for alphabets, special characters and digits.

• EBCDIC, ASCII and Unicode are three most popular coding systems.

EBCDIC

• BCD (Binary Coded Decimal) system with six bits represent maximum 64 symbols defined by IBM was first system to represent symbols with bits.

• Need to represent more characters led to EBCDIC (Extended Binary Coded Decimal Interchange Code) system with 8 bit and represents 256 symbols.

ASCII• The ANSI (American National Standard

Institute) represented ASCII (American Standard Code for Information Interchange) character set.

• It is most common today. • The characters from 0 to 31 are

control characters, 32 to 64 special characters, 65 to 96 uppercase letters and few symbols, 97 to 127 lowercase letters and other symbols and 128 to 255 are other symbols.

Unicode

• An developing standard is Unicode Worldwide Character Standard.

• It has two bytes 16 bits to represent each symbol.

• It can represent 65536 symbols, which include international symbols, and alphabets from different languages in the world.