This key facts covers Extended ASCII (8-bit) within Character Sets for GCSE Computer Science. Revise Character Sets in Memory & Storage for GCSE Computer Science with 15 exam-style questions and 18 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 4 of 10 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 10
Practice
15 questions
Recall
18 flashcards
Extended ASCII (8-bit)
The 8-bit Expansion:
- 8 bits: 2⁸ = 256 possible characters (0-255)
- Codes 0-127: Same as standard ASCII (backward compatible)
- Codes 128-255: Extended characters (accented letters, symbols, box-drawing)
- Problem: Different "code pages" for different languages (no universal standard!)
Extended ASCII Characters (128-255):
- Accented letters: é (130), ñ (164), ü (129)
- Currency symbols: £ (156), ¥ (157), ¢ (155)
- Box-drawing: ─ │ ┌ ┐ └ ┘
- Math symbols: ± × ÷ ≈
The Extended ASCII Problem:
Code 130 might mean 'é' in Western Europe, but 'â' in Central Europe, or 'ב' in Hebrew. Files became unreadable when moved between systems. Unicode solved this chaos!