Encoding Schemes

Contents:

• Introduction:
• ASCII
• ISCII
• UNICODE

Introduction:

The mechanism of converting data into an equivalent cipher using specific code is called encoding.The process of encoding must be standardised so as to bring uniformity.The standard encoding pairs each letter, numeral and symbol is encoded or assigned a unique code. Some of the standard encoding are ASCII, ISCII and UNICODE

ASCII(American Standard Code for Information Interchange)

Encoding scheme ASCII was developed for standardising the character representation.ASCII uses 7 bit to represent character. Total number of different characters on the English keyboard that can be encoded by 7-bit ASCII code is 2₇ = 128. The ASCII table is represented below:

Sample Conversion: Convert DATA into ASCII

ISCII( Indian Script Code for Information Interchange)

In order to facilitate the use of Indian languages on computers, a common standard for coding Indian scripts called ISCII was developed. It is an 8-bit code representation for Indian languages which means it can represent 2₈=256 characters. It retains all 128 ASCII codes and uses rest of the codes (128) for additional Indian language character set.Additional codes have been assigned in the upper region (160–255) for the ‘aksharas’ of the language.

UNICODE:

Text created using one encoding scheme was not recognised by another machine using different encoding scheme.a standard called UNICODE has been developed to incorporate all the characters of every written language of the world. UNICODE provides a unique number for every character, irrespective of device, OS etc. Commonly used UNICODE encodings are UTF-8, UTF-16 and UTF-32. It is a superset of ASCII. Few of the character is given below.

References:

• NCERT for CS class 11