N10-009 Question 326
Single answerHardware tools: Toner, Cable tester, Taps, Wi-Fi analyzer, Visual fault locatorA network technician is troubleshooting a newly installed multimode fiber link between a wiring closet and a distribution switch on another floor. The switch ports show no link light, and the patch panels at both ends are labeled correctly. The technician needs a quick way to verify whether light is passing through the correct strand and to identify a possible break, sharp bend, or bad termination in the fiber run without using a full OTDR. Which tool is the BEST choice?
- A
Toner probe
- B
Cable tester
- C
Wi-Fi analyzer
- D
Visual fault locator
- E
Network tap
Show answer and explanation
Correct answer: D
Explanation
The best answer is Visual fault locator. In real-world fiber troubleshooting, a VFL is commonly used as a fast, practical tool to check whether a fiber strand is continuous and to identify visible light leakage caused by breaks, excessive bends, or poor connector termination. This aligns with common fiber-optic maintenance practices and vendor guidance for first-line troubleshooting before moving to more advanced tools such as an optical loss test set or OTDR. The other tools listed serve different purposes: a toner traces copper cable runs, a Wi-Fi analyzer evaluates wireless conditions, and a network tap captures traffic for monitoring. While some cable testers support fiber validation, the scenario specifically emphasizes quick visual confirmation of the correct strand and locating a likely physical defect, which is exactly what a VFL is designed to do.
- A. Incorrect.
Incorrect. A toner probe is primarily used to trace copper cabling, such as twisted-pair Ethernet runs, by sending a tone over the wire and locating it at the far end. It is not the appropriate tool for checking continuity or visible light leakage in a fiber-optic link.
- B. Incorrect.
Incorrect. A cable tester can validate some aspects of cabling, depending on the model, but the scenario specifically asks for a quick method to verify light on the correct strand and identify a break, bend, or bad termination without using an OTDR. A generic cable tester is not the best answer here because a visual fault locator is designed specifically for this type of fiber troubleshooting.
- C. Incorrect.
Incorrect. A Wi-Fi analyzer is used to assess wireless networks, such as channel utilization, signal strength, interference, and SSID visibility. It has no role in testing a fiber-optic link between switches.
- D. Correct.
Correct. A visual fault locator (VFL) injects visible light, typically red, into a fiber so the technician can verify continuity, confirm the correct strand, and often spot breaks, severe bends, or poor terminations where light escapes. This makes it an effective field tool for quick fiber troubleshooting when a full OTDR is unnecessary or unavailable.
- E. Incorrect.
Incorrect. A network tap is used to passively monitor traffic on a network segment for analysis or security purposes. It does not help identify physical faults in a fiber run such as breaks or macro-bends.