- A
Multimeter
Why wrong: A multimeter measures voltage, current, and resistance. It cannot measure electromagnetic interference on a network cable.
- B
Cable tester
Why wrong: A standard cable tester checks for continuity, wire mapping, and basic crosstalk but is not designed to confirm external EMI. Advanced certification testers can measure some noise, but the spectrum analyzer is more appropriate for confirming EMI.
- C
Loopback plug
Why wrong: A loopback plug is used to test network ports by sending data back to the device; it does not detect interference.
- D
Spectrum analyzer
A spectrum analyzer can detect and measure electromagnetic interference by analyzing the frequency spectrum of signals. It is the best tool to confirm excessive EMI from nearby power cables.
220-1201 Electromagnetic Interference (EMI) Practice Question
This 220-1201 practice question tests your understanding of networking tools. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: electromagnetic Interference (EMI). Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user complains that their wired connection drops randomly for a few seconds then reconnects. The technician suspects electromagnetic interference (EMI) from nearby power cables. Which tool can best confirm the presence of excessive EMI on the network cable?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Spectrum analyzer
A spectrum analyzer is the correct tool because it can detect and measure electromagnetic interference (EMI) by analyzing the frequency spectrum of signals radiated from the cable. This allows the technician to identify excessive EMI from nearby power cables. A standard cable tester checks for continuity, wire mapping, and basic crosstalk but does not directly measure external EMI. A multimeter measures electrical properties like voltage and resistance, not interference. A loopback plug is used to test network ports by sending data back to the device; it does not detect interference.
Key principle: Electromagnetic Interference (EMI)
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Multimeter
Why it's wrong here
A multimeter measures voltage, current, and resistance. It cannot measure electromagnetic interference on a network cable.
- ✗
Cable tester
Why it's wrong here
A standard cable tester checks for continuity, wire mapping, and basic crosstalk but is not designed to confirm external EMI. Advanced certification testers can measure some noise, but the spectrum analyzer is more appropriate for confirming EMI.
- ✗
Loopback plug
Why it's wrong here
A loopback plug is used to test network ports by sending data back to the device; it does not detect interference.
- ✓
Spectrum analyzer
Why this is correct
A spectrum analyzer can detect and measure electromagnetic interference by analyzing the frequency spectrum of signals. It is the best tool to confirm excessive EMI from nearby power cables.
Related concept
Electromagnetic Interference (EMI)
Common exam traps
Common exam trap: answer the scenario, not the keyword
A common mistake is to think a cable tester can confirm EMI, but standard cable testers do not measure external interference. The spectrum analyzer is the correct tool for detecting EMI on network cables.
Detailed technical explanation
How to think about this question
Cable testers for copper Ethernet (e.g., Fluke DSX-8000) perform wiremap, length, and insertion loss tests, but EMI confirmation relies on measuring Alien Crosstalk (AXT) and Power Sum NEXT at frequencies up to 500 MHz for Cat6a. In real-world scenarios, a technician might observe high 'noise margin' failures on a cable tester when the cable runs parallel to fluorescent ballasts or motor drives, causing packet retransmissions that manifest as random drops.
KKey Concepts to Remember
- Electromagnetic Interference (EMI)
- Spectrum analyzer
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Electromagnetic Interference (EMI)
Real-world example
How this comes up in practice
A practitioner preparing for the 220-1201 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Electromagnetic Interference (EMI) Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Review electromagnetic Interference (EMI), then practise related 220-1201 questions on the same topic to reinforce the concept.
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FAQ
Questions learners often ask
What does this 220-1201 question test?
Networking Tools — This question tests Networking Tools — Electromagnetic Interference (EMI).
What is the correct answer to this question?
The correct answer is: Spectrum analyzer — A spectrum analyzer is the correct tool because it can detect and measure electromagnetic interference (EMI) by analyzing the frequency spectrum of signals radiated from the cable. This allows the technician to identify excessive EMI from nearby power cables. A standard cable tester checks for continuity, wire mapping, and basic crosstalk but does not directly measure external EMI. A multimeter measures electrical properties like voltage and resistance, not interference. A loopback plug is used to test network ports by sending data back to the device; it does not detect interference.
What should I do if I get this 220-1201 question wrong?
Review electromagnetic Interference (EMI), then practise related 220-1201 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
Electromagnetic Interference (EMI)
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Last reviewed: Jul 4, 2026
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