Extended ASCII, an 8-bit evolution of the original 7-bit ASCII standard, supports international text by expanding the character set. How many total codes does it provide?
- AOption (a)
1024 codes for video compression
- BOption (b)
512 codes for voice recordings
- COption (c)
128 codes limited to English letters
- DOption (d)
256 codes including accented characters
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Correct answer
256 codes including accented characters
Why this answer is correct
The correct answer is 256 codes including accented characters.
Key Points
- Extended ASCII is an 8-bit character encoding scheme that doubles the capacity of the original 7-bit Standard ASCII.
- The number of unique codes in a binary system is calculated as 2n, where n is the number of bits. For an 8-bit system, this results in 28 = 256 unique character representations.
- The original ASCII set occupies the first 128 positions (0 to 127), which include English letters, digits, and control characters.
- The additional 128 positions (128 to 255) provided by the Extended ASCII set are used to map accented characters (such as á, é, ñ), mathematical symbols, and box-drawing glyphs.
- This expansion was critical for supporting Western European languages and other international symbols that could not be represented within the original 7-bit constraint.
Additional Information
- Evolution of Encoding Standards:
- Standard ASCII: Developed in 1963, it only utilized 7 bits, allowing for 128 codes, which was sufficient for basic English but lacked international support.
- ISO 8859-1: Also known as Latin-1, this is one of the most common implementations of Extended ASCII, catering specifically to Western European alphabets.
- Unicode: To solve the limitations of the 256-code ceiling, Unicode (such as UTF-8) was introduced, which can represent over 1.1 million characters across all global languages.
- Data Representation:
- In 7-bit ASCII, the eighth bit of a byte was often used as a parity bit for error detection during data transmission.
- In Extended ASCII, the eighth bit is repurposed as a data bit to expand the addressable character space to 256.