ASCII (American Standard Code for Information Interchange)

Definition

ASCII (American Standard Code for Information Interchange) is a standardized character encoding scheme adopted in 1963 by the American National Standards Institute (ANSI). ASCII assigns a unique 7-bit binary number to each textual character. The standard includes printable characters (such as letters, digits, and punctuation marks) and control characters (such as carriage return, backspace, and bell). Each ASCII code represents a specific character; for example, the binary sequence 01000001 corresponds to the letter ‘A’.

Examples

Character Representation:
- ‘A’: ASCII code 65 (Binary: 01000001)
- ‘a’: ASCII code 97 (Binary: 01100001)
- ‘0’: ASCII code 48 (Binary: 00110000)
- Space (’ ‘): ASCII code 32 (Binary: 00100000)
Control Characters:
- Carriage Return (CR): ASCII code 13 (Binary: 00001101)
- Line Feed (LF): ASCII code 10 (Binary: 00001010)
- Backspace (BS): ASCII code 8 (Binary: 00001000)

Frequently Asked Questions

Q1. What is the purpose of ASCII?

A1. The purpose of ASCII is to provide a standard way to represent text characters in digital devices, enabling communication and data interchange between different systems.

Q2. Why is ASCII limited to 128 characters?

A2. ASCII uses 7-bit patterns to represent characters, which allows for 128 unique combinations. This was sufficient for basic English text and control characters when initially developed.

Q3. How does ASCII differ from Unicode?

A3. ASCII is a 7-bit character set limited to 128 characters, primarily designed for the English language. Unicode, on the other hand, is a more extensive character encoding system designed to cover virtually every character from all written languages, utilizing 8-bit, 16-bit, or 32-bit codes.

Q4. What replaced ASCII in modern applications?

A4. ASCII has not been replaced but rather extended through systems like ISO/IEC 8859 and Unicode, which accommodate characters from multiple languages and symbols beyond the ASCII set.

Q5. How are control characters used in ASCII?

A5. Control characters in ASCII manage formatting and control device actions, such as new line (LF), tab (HT), and end of text (ETX).

Unicode: A universal character encoding standard that provides a unique code point for every character across languages and scripts, designed to support text interchange globally.
Binary Code: A system of representing text or computer processor instructions using the binary number system’s two-symbol (0 and 1) format.
Control Characters: Non-printable characters in the ASCII standard used to control devices’ behavior such as printers or to format text.

Online References

Suggested Books for Further Studies

“Understanding Unicode: The Basics of Modern Codings” by Jukka K. Korpela
“Code: The Hidden Language of Computer Hardware and Software” by Charles Petzold
“Programming with Unicode” by Reynaldo Hahn

Fundamentals of ASCII: Computers and the Internet Basics Quiz

### What does the 'A' in ASCII stand for? - [x] American - [ ] Automatic - [ ] Analog - [ ] Arbitrary > **Explanation:** 'A' in ASCII stands for "American," as ASCII was developed under the American National Standards Institute. ### How many bits are used in standard ASCII code? - [ ] 8 bits - [ ] 16 bits - [ ] 32 bits - [x] 7 bits > **Explanation:** Standard ASCII uses 7-bit binary numbers to represent each character, allowing for 128 unique characters. ### What ASCII code is used to represent the space character? - [ ] 65 - [ ] 97 - [x] 32 - [ ] 16 > **Explanation:** The ASCII code for the space character is 32, represented in binary as `00100000`. ### Which of the following is a control character in ASCII? - [x] Backspace (BS) - [ ] Asterisk (*) - [ ] Dollar Sign ($) - [ ] Plus Sign (+) > **Explanation:** Backspace (BS) is one of the control characters in ASCII with a code of 8. ### What is the binary representation of the ASCII letter 'B'? - [ ] 01000001 - [x] 01000010 - [ ] 01000011 - [ ] 01000100 > **Explanation:** The binary representation of the ASCII letter 'B' is 01000010. ### In ASCII, what is the decimal code for the character 'z'? - [ ] 90 - [ ] 97 - [x] 122 - [ ] 126 > **Explanation:** The ASCII decimal code for the lowercase letter 'z' is 122. ### Can the ASCII standard represent emojis? - [x] No - [ ] Yes, with additional codes - [ ] Yes, directly - [ ] Only a limited set > **Explanation:** ASCII cannot represent emojis, as it is limited to 128 characters, primarily covering English letters, digits, and basic punctuation. ### What is the main modern encoding standard that extends ASCII to represent more characters? - [ ] ASCII++ - [x] Unicode - [ ] ISO/IEC 8859 - [ ] UTF-64 > **Explanation:** Unicode is the modern encoding standard that extends ASCII and includes characters from all written languages. ### Which ASCII character has a decimal code of 50? - [ ] '(' - [ ] '&' - [x] '2' - [ ] 'T' > **Explanation:** The ASCII character '2' has a decimal code of 50. ### When was the ASCII standard first published? - [ ] 1983 - [ ] 1973 - [x] 1963 - [ ] 1953 > **Explanation:** The ASCII standard was first published in 1963 by the American National Standards Institute.

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