Extended ASCII

What does Extended ASCII mean?

Extended ASCII, also known as high ASCII, refers to the range of character codes that extend beyond the standard 7-bit ASCII (American Standard Code for Information Interchange). Standard ASCII defines 128 characters, primarily for use in the English language. Extended ASCII, however, incorporates additional characters to support various alphabets, symbols, and special characters used in languages and applications worldwide. It encompasses character codes from 128 to 255, resulting in a total of 256 possible characters.

Extended ASCII includes characters for currency symbols, mathematical symbols, fractions, arrows, geometric shapes, and many other characters commonly used in text processing, scientific notation, and other specialized fields. It enables computers to represent and process a wider range of characters, enhancing the capabilities of text editors, programming languages, and communication protocols to handle international languages and technical content.

Applications

Extended ASCII finds applications in various technological domains:

• Internationalization: Extended ASCII allows computers to display and process text in multiple languages, supporting characters from different alphabets. It facilitates the creation and exchange of multilingual documents, emails, and websites.
• Technical Writing: Extended ASCII provides symbols and special characters essential in scientific, mathematical, and engineering applications. It enables the representation of complex equations, chemical formulas, and technical diagrams, enhancing communication and understanding.
• Programming: Extended ASCII characters are used in programming languages to represent non-alphanumeric characters, such as Line breaks, carriage returns, and special symbols. These characters play a crucial role in defining code structure, Formatting, and special commands.
• Data Communication: Extended ASCII is leveraged in data communication protocols, such as email and file transfer protocols, to handle characters that fall outside the standard ASCII range. It ensures proper transmission and interpretation of international characters and special symbols.
• Graphics and Multimedia: Extended ASCII characters are used in computer graphics and multimedia applications to represent special symbols, arrows, and geometric shapes. These characters enhance user interfaces, create graphical elements, and improve the visual appeal of digital content.

History

The development of Extended ASCII can be traced back to the 1960s when the need arose to represent characters beyond the standard ASCII set. Various groups and organizations proposed different extensions, leading to the existence of multiple incompatible versions.

In 1981, the International Organization for Standardization (ISO) released ISO 646, which standardized a 7-bit character set that included some extended characters. However, it lacked a definitive range for extended characters, leaving room for variations.

In the 1980s, IBM introduced the IBM PC with the code page 437, which became widely adopted in MS-DOS and early Microsoft Windows systems. Code page 437 defined a set of Extended ASCII characters that included accented letters, currency symbols, and other symbols.

Over time, various other code pages emerged, each defining its own set of Extended ASCII characters. This led to compatibility issues, making it challenging to exchange text files and data across different systems.

To address this fragmentation, the Unicode Consortium was formed in 1991 to develop a universal character encoding standard. Unicode incorporates all Extended ASCII characters and supports a vast range of alphabets and symbols from multiple languages. Today, Unicode has become the dominant character encoding standard, enabling seamless text handling and character representation across various platforms and applications.