Which statement correctly defines delay skew in copper cabling?

• A. It is the total delay of the signal from source to destination
• B. It is the difference in signal amplitude between pairs
• C. It is the difference in arrival times between pairs
• D. It is unrelated to Ethernet performance

Answer: (C)

Delay skew is the difference in arrival times of signals on different copper pairs. In Ethernet and other multi-pair copper systems, each pair can have a slightly different propagation delay because of length variations, connector impedance, and routing through panels and patch cords. Because the data on all pairs is expected to arrive in sync, this timing mismatch can cause parts of the signal to arrive at different moments, which can degrade the ability of the receiver to reconstruct the data correctly or to sample the signals reliably. So the key idea is about how evenly the signals line up in time across all pairs, not how large the total travel time is or how strong the signal is on one pair. Skew is also not something separate from Ethernet performance; large skew can limit performance by causing timing errors, which is why keeping skew within the specified limits is important.