ASCII (American Standard Code for Information Interchange)

•ASCII  is the most often used code to represent information.

•A binary field of 7 bits to represent each character, so the total of 27 = 128 unique characters can be represented by 7 bits.

•But some systems use an expanded version of the ASCII code with 8 bits (256 characters).

•To represents a typed word, such as HELLO, the ASCII patterns for each letter are used.

•H    1001000

•E     1000101

•L     1001100

•L     1001100

•O    1001111

•ASCII codes can be used for numbers or for alphanumeric combinations.

•More than half of the 128 characters of the ASCII codes are used for letters,  numbers and punctuations symbols.

•These code set are known as printable codes because they can be actually printed out on a printer or be visible on a computer terminal screen.

•The remainder of the code set are called non-printing codes or control codes.

•It indicates  things like line feed, shifting, or that the end-of-line or warning bell should be sounded.

ISCII (Indian Script Code for Information Interchange)

ASCII has been standardized for English letters.

•There is also Indian scripts to use computers to process information using Indian languages.

•This has been done by the Indian Standard Organization, published a document IS: 13194-91 on this based on International Standard, i.e., 7-bit and 8-bit coded character set code extension technique.

•The Indian Standard maintains the seven-bit code for English letters exactly as inn ASCII and allows eight-bit codes extensions for other scripts.

•The approach followed in the Indian Standard is to have a common code and keyboard for all the Indian scripts.

•A new coding scheme for characters called Unicode has been standardized specifically to accommodate a large number of symbols of languages other than English and mathematical symbols.

•It uses 16 bits, means 216 = 65536, the number of different types of characters which can be coded in Unicode.

•Actually every character of every language in the world can be represented in this international standard code.