Signalling and communicationQuestion 46 of 1506

A control cable run goes past large motor drives that cause heavy electrical noise. Which cable type is totally immune to electromagnetic interference?

  1. Shielded twisted pair
  2. Optical fibre
  3. Unshielded twisted pair
  4. Coaxial cable
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Correct answer: Optical fibre

Light signals are not affected by inductive or capacitive coupling.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 14.5: Optical Data Communication

Practice signalling and communication

Questions last reviewed: 18 October 2026