ELFEXT stands for Equal Level Far End Crosstalk; how is it defined?

• A. Equal Level Far End Crosstalk; far-end crosstalk measured with equal drive levels on all pairs
• B. Equivalent Length Front End Crosstalk
• C. Electric Field Crosstalk End
• D. End-Limited Frequency Crosstalk

Answer: (A)

ELFEXT is a measurement of how much crosstalk appears at the far end when all pairs are driven at the same level. It’s defined as the far-end crosstalk voltage on the victim pair, divided by the near-end drive voltage, with equal drive levels applied to every pair. This equal-level normalization lets you compare cables' inherent susceptibility to crosstalk regardless of how strong the transmitter is. In practice, you’ll see it expressed as a ratio (often in dB) of V_fext to V_source.