220-1101 Hardware and Network Troubleshooting Practice Question
A user reports that their desktop computer loses network connection intermittently. The technician notices that the LED on the NIC is off but other computers on the same switch work fine. The cable run is long, passing through a ceiling. Which tool should the technician use FIRST?
⚠ Common exam trap
A common mix-up: candidates choose the tone generator (Option D) because they think of tracing the long cable run through the ceiling, but the question asks for the tool to diagnose the intermittent connection, not to locate the 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
✓
Cable tester
The intermittent loss of connection and the NIC LED being off strongly suggest a physical layer issue with the cable. Since other computers on the same switch work fine, the problem is isolated to this specific cable run, which is long and passes through a ceiling where it could be damaged or pinched. A cable tester is the correct first tool because it can quickly verify continuity, wiring faults, and signal integrity without requiring the network to be active, allowing the technician to isolate the fault before moving to more complex diagnostics.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Loopback plug
Why it's wrong here
A loopback plug connects the transmit pins directly to the receive pins on the NIC, which verifies the adapter's transceiver and port operation. However, the NIC's link LED is off, indicating the NIC is not receiving a valid link signal from the network, so the fault lies in the cable or the far-end connection, not the NIC itself. A loopback test would still pass because it bypasses the cabling entirely, making it an inappropriate diagnostic for this symptom.
- ✓
Cable tester
Why this is correct
A cable tester applies test signals to each of the twisted pairs and reports continuity, pin-to-pin wiring, and commonly the approximate length of the cable, which directly reveals opens, shorts, split pairs, or reversed pairs. Given the symptom of intermittent connectivity over a long cable run, this is the correct first step because it can expose physical-layer problems that cause the link to drop unpredictably. Modern digital testers can also verify that the cable achieves the required category performance.
- ✗
Multimeter
Why it's wrong here
A multimeter measures static electrical properties like DC resistance, voltage, and continuity, but it cannot assess the high-frequency characteristics such as return loss and near-end crosstalk that are critical for Ethernet transmission. Even a simple continuity check on the eight conductors would require disconnecting both ends and probing each pin individually, which is impractical for an intermittent issue that may only appear under load or with a specific connection angle. Therefore, a multimeter is not suited for structured cabling validation or for isolating a physical-layer fault in a twisted-pair Ethernet cable.
When this WOULD be correct
A multimeter would be the correct first tool if the question described a scenario where the NIC LED is off and the technician suspects a power issue, such as a faulty power supply or a short circuit in the network cable that could cause voltage drops.
- ✗
Tone generator
Why it's wrong here
A tone generator sends an analog audio signal along the copper pairs, which you then trace with an inductive probe to identify which physical cable corresponds to a given jack or patch panel port. It only lets you follow a cable path, and it does not measure signal integrity, impedance, or continuity under data transmission conditions, so it cannot reveal intermittent breaks or marginal terminations. It is best used for cable identification after you have already suspected a specific link, not for diagnosing the root cause of a signal drop.
When this WOULD be correct
A technician needs to identify which physical cable in a bundle corresponds to a specific network port in a wiring closet. The correct tool is a tone generator and probe to trace the cable.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓Cable testerCorrect answer▾
Why this is correct
A cable tester applies test signals to each of the twisted pairs and reports continuity, pin-to-pin wiring, and commonly the approximate length of the cable, which directly reveals opens, shorts, split pairs, or reversed pairs. Given the symptom of intermittent connectivity over a long cable run, this is the correct first step because it can expose physical-layer problems that cause the link to drop unpredictably. Modern digital testers can also verify that the cable achieves the required category performance.
✗MultimeterWrong answer — click to see why▾
Why this is wrong here
A multimeter measures electrical properties like voltage, continuity, and resistance, but it cannot test data transmission integrity or wiring faults specific to Ethernet standards. The issue is intermittent connectivity, likely due to a damaged cable, which requires a cable tester to verify pinouts and signal quality.
★ When this WOULD be the correct answer
A multimeter would be the correct first tool if the question described a scenario where the NIC LED is off and the technician suspects a power issue, such as a faulty power supply or a short circuit in the network cable that could cause voltage drops.
Why candidates choose this
Candidates may think a multimeter can check for cable breaks or shorts because it can measure continuity, but they overlook that a cable tester is specifically designed for Ethernet cabling and can detect faults like split pairs or crosstalk that a multimeter cannot.
✗Tone generatorWrong answer — click to see why▾
Why this is wrong here
A tone generator is used to trace and identify specific cables among many, not to test cable integrity or connectivity. The issue is intermittent connectivity with a long cable run, so a cable tester is needed first to check for faults like breaks or shorts.
★ When this WOULD be the correct answer
A technician needs to identify which physical cable in a bundle corresponds to a specific network port in a wiring closet. The correct tool is a tone generator and probe to trace the cable.
Why candidates choose this
Candidates may confuse tone generators with cable testers, thinking any tool that works with cables can diagnose connectivity issues, or they may recall using tone generators for network troubleshooting in other contexts.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.