BICSI Certification BICSI Copper Cabling Systems 1 — Questions and Answers
Question 1: What is the characteristic impedance of standard twisted-pair telecommunications cabling as specified in ANSI/TIA-568?
- 50 ohms
- 75 ohms
- 100 ohms (Correct answer)
- 120 ohms
Correct answer: 100 ohms
ANSI/TIA-568 specifies 100 ohms as the characteristic impedance for twisted-pair telecommunications cabling used in horizontal and backbone applications.
Question 2: Which test parameter measures the difference in attenuation between a pair and the crosstalk on that same pair, indicating signal-to-noise margin?
- NEXT
- ACR-N (Attenuation-to-Crosstalk Ratio, Near-end) (Correct answer)
- Return Loss
- Propagation Delay
Correct answer: ACR-N (Attenuation-to-Crosstalk Ratio, Near-end)
ACR-N (Attenuation-to-Crosstalk Ratio, Near-end) measures the difference between signal attenuation and NEXT, indicating the available signal-to-noise margin at the near end.
Question 3: What is 'alien crosstalk' (AXT) in copper cabling systems, and which category of cable introduced it as a critical test parameter?
- Crosstalk from adjacent cables in a bundle; became critical with Category 6A (Correct answer)
- Crosstalk from the far end of a cable; became critical with Category 5e
- Signal loss at connector terminations; became critical with Category 6
- Interference from power cables; became critical with Category 3
Correct answer: Crosstalk from adjacent cables in a bundle; became critical with Category 6A
Alien crosstalk is electromagnetic interference coupling from adjacent cables (rather than pairs within the same cable) and became a critical test parameter with the introduction of Category 6A cabling for 10GBASE-T.
Question 4: In a punch-down (IDC) termination, what is the correct technique to minimize crosstalk degradation?
- Untwist pairs as far back as possible for easy termination
- Maintain pair twist as close to the termination point as possible (max 13 mm untwist) (Correct answer)
- Use a 110-tool at 45 degrees to the block
- Separate pairs by color group before punching down
Correct answer: Maintain pair twist as close to the termination point as possible (max 13 mm untwist)
To minimize crosstalk, pairs should be maintained with their twist as close to the termination point as possible, with a maximum untwist of 13 mm (0.5 inches) per ANSI/TIA-568.
Question 5: What is the maximum allowed propagation delay for a Category 6 channel at 100 MHz?
- 370 ns
- 498 ns (Correct answer)
- 555 ns
- 800 ns
Correct answer: 498 ns
The maximum allowed propagation delay for a Category 6 channel at 100 MHz is 498 nanoseconds, as specified in ANSI/TIA-568-C.2.
Question 6: Which field test instrument certification level is required by BICSI to certify Category 6A cabling for 10GBASE-T?
- Level I
- Level IIe (Correct answer)
- Level III
- Level IV
Correct answer: Level IIe
Level IIe field test instruments are required to certify Category 6A cabling for 10GBASE-T, as they meet the accuracy requirements for measurements up to 500 MHz.
BICSI Certification BICSI Copper Cabling Systems 1
What is the characteristic impedance of standard twisted-pair telecommunications cabling as specified in ANSI/TIA-568?