220-1101 Question 171
Single answerToner probeA technician is asked to activate a network drop in a newly remodeled office. The patch panel in the telecom room is labeled incorrectly, and several unmarked Cat 6 cables terminate there. The wall jack in the office has no link light because the switch port is currently disconnected. Which tool should the technician use FIRST to identify which patch-panel cable corresponds to the office wall jack?
- A
Connect a toner generator to the office wall jack and use a probe at the patch panel to locate the matching cable
- B
Use a loopback plug at the office wall jack and check the switch for the active port
- C
Use a cable tester at the patch panel to measure wire map and identify the correct cable
- D
Use a crimper on each patch-panel cable until the correct office jack regains link
Show answer and explanation
Correct answer: A
Explanation
A toner generator and inductive probe are standard tools for tracing copper cabling when documentation is poor or labels are missing. In this scenario, the correct action is to attach the toner to the wall jack side and sweep the patch panel with the probe until the matching cable is identified. After the cable is found, the technician could then label it properly and, if needed, use a cable tester to validate pinout and continuity. This aligns with common structured cabling best practices: first identify the run, then verify termination quality, then connect it to the appropriate switch port. Toner probes are primarily used on non-energized copper cabling and are especially useful in telecom rooms, patch panels, and bundles of unmarked twisted-pair cables.
- A. Correct.
Correct. A toner probe kit is specifically used to trace and identify cables when labels are missing or inaccurate. The technician places the tone generator on the cable at the office jack, then uses the inductive probe at the patch panel to detect the tone on the matching cable. This is the practical first step when trying to locate an endpoint-to-panel run without an active network connection.
- B. Incorrect.
Incorrect. A loopback plug is used to test ports or NIC functionality, not to trace one unidentified horizontal cable among many at a patch panel. It also would not help if the switch port is disconnected and the problem is identifying the correct cable run.
- C. Incorrect.
Incorrect. A cable tester can verify continuity, pair order, and faults such as opens, shorts, or split pairs, but it is not the best first tool for locating one unknown cable in a large bundle unless both ends are already known. The main issue in the scenario is cable identification, which is what a toner probe is designed for.
- D. Incorrect.
Incorrect. A crimper is used to terminate or repair cable ends, not to identify cable runs. Re-terminating random patch-panel cables would be improper, could damage cabling, and would not be a valid troubleshooting method.