# Mixed Practice: Data Transmission

- **Track:** Cambridge IGCSE™ Computer Science (0478 / 0984) (CAMBRIDGE IGCSE 0478)
- **Module:** Section 2: Data Transmission
- **Estimated Duration:** 20 minutes
- **Access:** Open Theory (All-Access for Interactive IDE & Autotests)

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## Theory & Conceptual Background

Close your notes and try the mixed questions. Write calculations or a diagram on paper where useful. If you miss an item, explain the misconception and revisit its lesson before trying again.

## Delayed review

Return to these questions after studying another module, rather than only repeating them immediately. Change a value or a condition and predict how the answer changes. Explain one answer aloud without relying on a memorised keyword.

## Written transfer

Choose a practical example from this module and explain the mechanism, one benefit and one limitation. Check that each point refers to the example. Structured automatic checks cannot judge the quality of this explanation; use the lesson's worked examples and a teacher's feedback for that.

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## Interactive Exercises & Autotest Specifications

### Exercise 1: Cumulative Check: Apply earlier ideas (Fill in blank, 30 XP)

**Instructions:**
Work out each answer before submitting. Packet field used for ordering: Two-way communication with one party at a time: Parity detects every even number of flipped bits: yes or no? No ACK before timeout: retransmit or assume success?


**Starter Code:**
```text
{"prompt":"Cumulative Check: Apply earlier ideas","template":"1. Packet field used for ordering: [blank_1]\n2. Two-way communication with one party at a time: [blank_2]\n3. Parity detects every even number of flipped bits: yes or no? [blank_3]\n4. No ACK before timeout: retransmit or assume success? [blank_4]","blanks":[{"id":"blank_1"},{"id":"blank_2"},{"id":"blank_3"},{"id":"blank_4"}],"word_bank":["sequence number","half-duplex","no","retransmit","checksum","full-duplex","yes","assume success"]}
```