Question

What does a KNX TP bus device actually evaluate on the wire pair?

KNX BasicLearnSystem OverviewMedium
Answer

C — Only the difference of the AC voltage between the two wires

Correct: The bus device evaluates only the difference of the AC voltage between the two wires.

Source

KNX Basic Course Documentation — 9 — p. 50

All proposed choices (exam context)
  1. A.The absolute voltage of each wire measured against ground
  2. B.The DC supply voltage level only
  3. C.Only the difference of the AC voltage between the two wires
  4. D.The sum of the voltages on both wires
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Last updated: 19 May 2026

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