20 Questions
What is the maximum limit for propagation delay skew expressed in microseconds?
50ns
What is the primary cause of delay skew in twisted-pair cables?
Twists per foot (lay lengths)
Which measurements are required for compliance of Category 6A systems, as identified by ANSI/TIA-568-C.2 and ANSI/TIA-1152?
PS ANEXT and PS AACR-F
What is the requirement for power sum crosstalk from the adjacent cable in comparison to the PSNEXT requirement of the single cable?
6 dB greater
What must the DC parallel resistance between pairs not exceed to fully support IEEE 802.3bt (PoE++)?
7%
What is alien crosstalk?
Noise coupling from one cable link to another
What happens if delay skew is significant in a cable bundle?
Data transmitted over one wire pair arrives out of sync with data over another wire pair
What does ANEXT stand for in the context of crosstalk?
Alien Near-End Crosstalk
What is the purpose of identifying cables as Disturbers and Disturbed (Victim) in the context of ANEXT loss?
To determine the impact of noise coupling from other cables
What is the requirement for the DC parallel resistance between pairs to fully support IEEE 802.3bt (PoE++)?
Not exceed the greater of 7% or 50 mΩ
What does IEEE Std 802.3-2012 specify as the maximum DC resistance unbalance between conductors?
3%
What is the formula for calculating the DC resistance unbalance within a pair?
$\text{DC Resistance Unbalance} = \frac{|R_1 - R_2|}{R_{total}}$
What is the DC resistance unbalance within a pair if $R_1 = 1.87 , \Omega$ and $R_2 = 1.85 , \Omega$?
0.02 $\Omega$
What is the sum of the individual resistances of two conductors known as?
DC Loop Resistance
What problem can resistance unbalance in a cabling channel cause?
Saturation in PSE transformers
What is the maximum DC resistance unbalance between pairs as per the example?
0.11 $\Omega$
What is the first step to calculate the parallel resistance of pair 1,2-3,6?
Measure the individual resistances of each wire
What is the difference in DC resistance between two conductors if $R_1 = 2.5 , \Omega$ and $R_2 = 2.2 , \Omega$?
0.3 $\Omega$
What is the total DC loop resistance if $R_1 = 3.2 , \Omega$ and $R_2 = 2.8 , \Omega$?
6.0 $\Omega$
What could resistance unbalance result in, affecting Power over Ethernet (PoE) delivery?
Current imbalance
Test your knowledge of propagation delay skew with this quiz. Explore the concept of delay skew and its impact on data transmission. Learn about the limiting values and units used to measure propagation delay skew in cables.
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