Practice Test Geeks(VDV) Voice Data Video Technician Certified Practice Test
← All VDV Flashcard Decks

Testing & Troubleshooting Flashcards

7 cards from real VDV practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Testing & Troubleshooting flashcards as text

  1. A technician is certifying a Cat6A cable channel and the test fails for 'alien crosstalk' (AXT). What is the most effective corrective action?

    Answer: Increase physical separation between parallel cable runs or use F/UTP shielded cable

    Alien crosstalk occurs between adjacent cables; increasing separation, using bundling best practices, or switching to shielded F/UTP cable are the recognized remedies.

  2. A technician uses a visual fault locator (VFL) on a fiber cable and sees the red laser light glowing through the jacket 2 meters from the end. What does this indicate?

    Answer: A macrobend or physical damage causing light to escape the fiber at that location

    A visible red glow through the fiber jacket indicates that light is escaping due to a tight bend, kink, or physical damage that disrupts total internal reflection.

  3. During a cable TV service call, a customer complains of a pixelating picture on all channels. The technician measures the signal level and finds it is +15 dBmV. What is the most likely problem?

    Answer: The signal level is too high, causing receiver overload and distortion

    Signal levels above +8 dBmV can overload cable TV receivers and cause digital pixelation or analog distortion, even though the power is high.

  4. A network switch port shows a link light but a laptop connected to that port cannot get an IP address. Cable certification passes. What should the technician check next?

    Answer: Verify DHCP server availability and VLAN assignment on the switch port

    A passing cable certification rules out physical layer issues; the inability to get an IP address with an active link points to a Layer 2/3 issue such as an incorrect VLAN, DHCP scope exhaustion, or server availability.

  5. A technician suspects a ground loop is causing hum bars on a video display. Which test confirms a ground potential difference between equipment?

    Answer: Measure the AC voltage between the chassis grounds of the two connected devices with a multimeter

    Measuring AC voltage between the chassis grounds of two devices reveals a ground potential difference, which is the root cause of hum bars induced by ground loop current.

  6. A fiber link passes insertion loss testing but fails to support 10GBase-SR at the specified distance. Which test should the technician perform next to diagnose the limitation?

    Answer: Perform an OTDR trace to check for excessive connector losses or bandwidth-limiting events, and verify fiber modal bandwidth

    Modal bandwidth of the fiber and discrete loss events revealed by OTDR can limit 10G reach even when the total insertion loss budget appears acceptable.

  7. A technician terminates a 25-pair telephone cable and some pairs have dial tone while others are silent. After using a butt set to confirm the silent pairs have no signal from the demarc, what is the correct next step?

    Answer: Notify the carrier/provider that the affected pairs are not active or have a fault on the service provider side

    If the pairs have no signal at the demarcation point (demarc), the fault is on the carrier's side and must be reported to the service provider for resolution.