Data Transmission

Worked examples (6)

• 1Identify features of USB (2 marks)
• 2Parts of a data packet (3 marks)
• 3Serial vs parallel — distinguish (6 marks)
• 4Simplex, half-duplex, full-duplex (6 marks)
• 5Explain packet switching (5 marks)
• 6Choose u0026 justify a transmission method (6 marks)

Model answers (6)

• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style

Worked examples (6)

• 1Parity bit calculation — even parity (2 marks)
• 2Parity bit calculation — odd parity (2 marks)
• 3Detect a transmission error using parity (3 marks)
• 4Calculate and verify a checksum (4 marks)
• 5Locate the corrupted bit in a parity block (5 marks)
• 6Explain Automatic Repeat reQuest (ARQ) (6 marks)

Model answers (6)

• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style

Worked examples (6)

• 1Purpose of encryption (2 marks)
• 2Plaintext, ciphertext and key (2 marks)
• 3Why use encryption (4 marks)
• 4Symmetric encryption and the key-distribution problem (4 marks)
• 5How public and private keys work (6 marks)
• 6Symmetric vs asymmetric encryption (8 marks)

Model answers (6)

• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — 0478 Paper 1 — style
• ✓Model answer — Adapted from 0478/12 May/Jun 2024 Q7