DCI Copper Cable Termination 3 — Questions and Answers
Question 1: Which of the following is a characteristic unique to shielded twisted pair (STP) termination compared to UTP?
- The shield must be bonded to the connector's grounding point (Correct answer)
- Pairs must be untwisted further for proper seating
- A 110 punch-down tool cannot be used
- T568B wiring is not permitted
Correct answer: The shield must be bonded to the connector's grounding point
STP terminations require the foil or braid shield to be properly bonded to the connector's grounding element to maintain EMI protection.
Question 2: A Cat 6 horizontal link passes all wire-map tests but fails the NEXT (near-end crosstalk) limit. The MOST likely cause is:
- Excessive pair untwisting at the termination point (Correct answer)
- Using T568A instead of T568B
- Cable routed near a power conduit
- Insufficient cable jacket removed at the jack
Correct answer: Excessive pair untwisting at the termination point
Untwisting pairs beyond the 13 mm limit significantly degrades NEXT performance at the termination.
Question 3: When does a 'crossed pair' fault appear on a cable tester?
- When conductors from two different pairs are terminated on pins belonging to a third pair (Correct answer)
- When both conductors within a pair are swapped
- When all eight conductors test open
- When pin 1 and pin 8 are shorted
Correct answer: When conductors from two different pairs are terminated on pins belonging to a third pair
A crossed pair occurs when wires from two pairs swap their pin positions, mixing pair identities across the termination.
Question 4: What is the recommended minimum distance between copper data cable and a 120V electrical conduit running parallel?
- 50 mm (2 in) (Correct answer)
- 25 mm (1 in)
- 100 mm (4 in)
- 150 mm (6 in)
Correct answer: 50 mm (2 in)
TIA-569 specifies a minimum 50 mm (2-inch) separation from unshielded power conductors carrying 120V.
Question 5: A technician terminates both ends of a cable using T568A at one end and T568B at the other. The result is:
- A crossover cable (Correct answer)
- A straight-through patch cable
- An open circuit on pairs 2 and 3
- A correctly wired horizontal link
Correct answer: A crossover cable
Mixing T568A at one end and T568B at the other reverses pairs 2 and 3, creating a crossover cable.
Question 6: Which conductor color, per T568B, is terminated on pin 4 of an RJ-45?
- Blue (Correct answer)
- Blue-white
- Green
- Brown-white
Correct answer: Blue
Under T568B, pin 4 is assigned to the solid blue conductor of pair 1.
Question 7: When terminating a 25-pair backbone cable, which standard governs the color code used?
- ANSI/TIA-598-C (Correct answer)
- TIA-568-C.2
- IEEE 802.3
- EIA-310
Correct answer: ANSI/TIA-598-C
ANSI/TIA-598-C defines the color-coding scheme for multi-pair copper and fiber cables including 25-pair backbone cable.
DCI Copper Cable Termination 3
Which of the following is a characteristic unique to shielded twisted pair (STP) termination compared to UTP?