How many unique characters can be represented using the standard ASCII code?

The correct answer is 128.

Key Points

• The standard ASCII (American Standard Code for Information Interchange) is a character encoding standard used in computers and electronic devices.
• It was developed in the early 1960s and assigns a unique numerical value to each character.
• Standard ASCII uses 7 bits to represent characters, allowing for 2⁷ = 128 unique characters.
• The 128 characters include control characters (0–31), printable characters (32–126), and the DEL (delete) character (127).
• Examples of characters in the ASCII set include letters (A-Z, a-z), numbers (0-9), punctuation marks, and special symbols.

Additional Information

• Extended ASCII:
  • Extended ASCII uses 8 bits and can represent 256 characters, adding an additional 128 characters to the standard ASCII set.
  • The extra characters include symbols, foreign language characters, and graphical symbols.
• Control Characters:
  • Control characters (ASCII values 0–31) are non-printable and are used for device control, such as newline (10) and tab (9).
  • These characters are essential in communication protocols and data formatting.
• Printable Characters:
  • Printable characters (ASCII values 32–126) include visible symbols like letters, numbers, and punctuation marks.
  • For example, the ASCII value for 'A' is 65, and for 'a' is 97.
• Unicode:
  • Unicode is a modern encoding standard that extends beyond ASCII, supporting over 140,000 characters from various scripts and languages globally.
  • It is backward compatible with ASCII, meaning the first 128 characters in Unicode are identical to standard ASCII.