Character Encoding

ANSI

ANSI (American National Standards Institute) codes are standardized numeric or alphabetic codes that have been established by the American National Standards Institute. These codes ensure consistent identification of geographic entities across all federal government agencies. Serving as the coordinator of the U.S. private sector's voluntary standardization system for over 90 years, ANSI has played a crucial role in maintaining uniformity in coding practices.

An extension of the ASCII character set, ANSI incorporates all ASCII characters while introducing an additional set of 128 character codes. While ASCII defines a 7-bit code page consisting of 128 symbols, ANSI expands this to an 8-bit code system. As a result, multiple code pages are available to represent symbols ranging from 128 to 255 within the ANSI encoding scheme.

Unicode

Unicode stands as a universally adopted standard that governs the internal text coding system employed in the majority of present-day computer operating systems. Irrespective of whether it is Windows, Unix, Macintosh, Linux, or any other system, Unicode serves as the underlying foundation due to its comprehensive support for a vast array of modern and even ancient languages. It enables the handling of characters from diverse linguistic backgrounds simultaneously, provided that the user's system possesses the requisite fonts for the specific languages involved.

UTF

Unicode is a standard that assigns a unique code point to each character, providing a universal character encoding system. It encompasses various mapping methods, including UTF (Unicode Transformation Format) and UCS (Universal Character Set) encodings. Unicode-based encodings, such as UTF-8, UTF-16, and UTF-32/UCS-4, surpass the limitations of 8-bit encoding by supporting a vast range of languages worldwide.

1. UTF-8, widely adopted as the dominant international encoding for the web, utilizes 1 byte for ASCII characters, 2 bytes for characters in additional alphabetic blocks, 3 bytes for the remaining Basic Multilingual Plane (BMP) characters, and 4 bytes for supplementary characters.
2. UTF-16 employs 2 bytes for any character within the BMP, while supplementary characters require 4 bytes.
3. UTF-32, on the other hand, allocates 4 bytes for all characters, providing a fixed-length encoding scheme.

Code Unit

In Unicode, a code unit refers to the specific sequence of bits used to encode each character within a character repertoire. The size of a code unit varies depending on the encoding scheme being used.

1. For US-ASCII, which is a 7-bit encoding, the code unit consists of 7 bits.
2. In the case of UTF-8, the most commonly used Unicode encoding, the code unit comprises 8 bits.
3. EBCDIC, another encoding scheme, also uses 8-bit code units.
4. UTF-16, a variable-length encoding, utilizes 16-bit code units to represent characters.
5. UTF-32, a fixed-length encoding, employs 32-bit code units for character encoding.

Conclusion

Character encoding is a vital aspect of digital communication, enabling computers to interpret and represent characters in various languages and scripts. Standards such as ASCII, ANSI, and Unicode provide different encoding schemes to facilitate the consistent representation and exchange of characters. The evolution of encoding systems, such as UTF-8, UTF-16, and UTF-32, has expanded the capabilities of character encoding to encompass a wide range of languages, ensuring compatibility and effective communication in today's globalized world.