Red Seal Electrician Practice
Signalling and communicationQuestion 43 of 1506

Which pairing of serial standards is correct for the signal method?

  1. RS-232C is differential, RS-422A is ground-referenced
  2. Both are differential, but RS-232C runs on fibre
  3. Both are ground-referenced, but RS-422A runs on fibre
  4. RS-232C is ground-referenced, RS-422A is differential
Show answer

Correct answer: RS-232C is ground-referenced, RS-422A is differential

RS-232C suits short, quiet environments. RS-422A suits long runs near AC power wiring.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 14.4: Electrical Signal Types

Practice signalling and communication

Questions last reviewed: 18 October 2026