When the key ‘A’ is pressed (Figure 2.1), it is internally mapped to a decimal value 65 (code value), which is then converted to its equivalent binary value for the computer to understand.

![A simple left-to-right flow diagram: a keyboard key labelled "A" - an arrow to a box "D

Question

When the key ‘A’ is pressed (Figure 2.1), it is internally mapped to a decimal value 65 (code value), which is then converted to its equivalent binary value for the computer to understand.

![A simple left-to-right flow diagram: a keyboard key labelled "A" -> an arrow to a box "Decimal code value 65 (ASCII)" -> an arrow to a box — Computer Science question](/figures/encoding-schemes-and-number-system/simple-left-right-flow-diagram-keyboard-key-fig-pyq-wsroua.svg)

Accepted Answer

> [!TLDR]
> A pressed key never reaches the computer as a letter — 'A' is first mapped to its ASCII code value 65, and that decimal code is stored and processed as its binary equivalent (1000001)2.

**The idea (what Figure 2.1 illustrates).** A computer's circuits understand only two states (0/1), so every character must become a number, and every number must become bits:

1. **Key press** — you press 'A' on the keyboard.
2. **Code mapping** — the keyboard/system maps the key to its ASCII code value: 'A' -> 65.
3. **Binary conversion** — 65 is represented in binary for storage and processing.

Converting 65 to binary by repeated division by 2:

| Division | Quotient | Remainder |
|---|---|---|
| 65 / 2 | 32 | 1 |
| 32 / 2 | 16 | 0 |
| 16 / 2 | 8 | 0 |
| 8 / 2 | 4 | 0 |
| 4 / 2 | 2 | 0 |
| 2 / 2 | 1 | 0 |
| 1 / 2 | 0 | 1 |

Reading remainders bottom-up: (65)10 = (1000001)2 — a 7-bit ASCII pattern.

Check in Python:
```python
print(ord("A"), format(ord("A"), "07b"))
```
```text …

Q.When the key ‘A’ is pressed (Figure 2.1), it is internally mapped to a decimal value 65 (code value), which is then converted to its equivalent binary value for the computer to understand.

Concept understanding — ASCII Character Encoding

ASCII Character Encoding

The Core Idea

The Precise Statement

Q.When the key ‘A’ is pressed (Figure 2.1), it is internally mapped to a decimal value 65 (code value), which is then converted to its equivalent binary value for the computer to understand.

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