Practice Test Geeks(VDV) Voice Data Video Technician Certified Practice Test
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Voice Systems 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 Voice Systems flashcards as text

  1. Which standard defines Power over Ethernet delivering up to 30 watts per port?

    Answer: IEEE 802.3at

    IEEE 802.3at (PoE+) defines delivery of up to 30 watts per port, which supports higher-power devices like PTZ cameras and wireless access points.

  2. What is the purpose of Automatic Gain Control (AGC) in a telephone system?

    Answer: Normalize audio levels so quiet and loud voices are heard equally

    AGC automatically adjusts the gain of incoming audio signals so that voice levels remain consistent regardless of the speaker's volume.

  3. In a structured cabling installation, where should voice patch panels be terminated to allow easy moves, adds, and changes?

    Answer: At the MDF/IDF on a 110 or RJ-45 patch panel

    Terminating voice pairs at a centralized patch panel in the MDF/IDF allows technicians to reconfigure circuits with short patch cords without re-pulling cable.

  4. What happens to VoIP calls when the IP network goes down if the phones have a PSTN analog backup (POTS survivability) configured?

    Answer: Calls are routed over the analog PSTN lines automatically

    PSTN survivability allows VoIP systems to automatically fail over to analog POTS lines so that inbound and outbound calling continues during an IP network outage.

  5. Which SIP response code indicates that a called party is temporarily unavailable (e.g., phone is off or unregistered)?

    Answer: 480 Temporarily Unavailable

    SIP response code 480 (Temporarily Unavailable) indicates the endpoint exists but cannot accept calls at this moment, often because the device is unregistered.

  6. What is the function of a Direct Inward Dialing (DID) number in a PBX system?

    Answer: Allow outside callers to reach a specific extension without going through a receptionist

    DID numbers map individual PSTN phone numbers to specific internal extensions, allowing external callers to reach employees directly without an operator.

  7. A VDV technician is installing a new IP phone and the phone cannot register with the call manager. The phone obtains an IP address but shows 'TFTP timeout.' What should be checked first?

    Answer: The DHCP option 150 or 66 pointing to the correct TFTP server address

    Cisco and many other IP phones use DHCP Option 150 (or Option 66) to discover the TFTP server address for downloading their configuration and firmware files.