Free Telecommunications Electronics Technician - TCM Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Telecommunications Electronics Technician - TCM practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What nominal impedance is associated with UTP used as an Ethernet networking medium?

   1. A.50 ohms
   2. B.75 ohms
   3. C.100 ohmsCorrect answer: C
   4. D.150 ohms

   Explanation: The Cisco Press chapter states, "UTP used as a networking medium has an impedance of 100 ohms". This distinguishes Ethernet UTP from common coaxial and other twisted-pair impedances.

   Reference: Network Media (The Physical Layer) — Chapter 4, p. 122, Twisted-Pair Cable

2. 2On a Cisco IP Phone 7800, which control stops the microphone from sending the user's speech during a call?

   1. A.MuteCorrect answer: A
   2. B.Volume
   3. C.Conference
   4. D.Speakerphone

   Explanation: Cisco describes Mute as "Toggle the microphone on or off." It acts on the microphone rather than merely changing listening volume, adding participants, or selecting the speakerphone audio path.

   Reference: Cisco IP Phone 7800 Series User Guide — Your Phone — Buttons and Hardware, Table 14, Mute

3. 3Which service defines the local-exchange carrier role, rather than another communications-provider role?

   1. A.Long-distance carriage between separate exchange areas
   2. B.Telephone exchange service or exchange accessCorrect answer: B
   3. C.Radio program distribution to a broadcast audience
   4. D.Private extension switching within one enterprise

   Explanation: The FCC defines a LEC through provision of "telephone exchange service or exchange access." Interexchange carriage, broadcasting, and private enterprise switching describe other service roles, even when a larger company conducts more than one business.

   Reference: FCC Small Entity Compliance Guide — Competitive LEC Access Charges — p. 3, Important Definitions, item a, Local Exchange Carrier

4. 4What role does a host computer primarily perform in the Internet architecture described by RFC 1122?

   1. A.It routes only transit packets between separate networks.
   2. B.It switches link-layer frames using destination MAC addresses.
   3. C.It executes applications that use network communication services.Correct answer: C
   4. D.It regenerates physical signals without application processing.

   Explanation: RFC 1122 says a host "generally executes application programs on behalf of user(s)". This identifies an end system's application role, rather than transit-only routing, link switching, or physical regeneration.

   Reference: RFC 1122: Requirements for Internet Hosts — Communication Layers — Section 1.1.1, Internet Hosts, p. 6

5. 5Why can an on-premises FXS gateway use a lower source ringing voltage than a central-office line while still operating compatible nearby telephones?

   1. A.Shorter wiring increases voltage drop and therefore calls for a lower source.
   2. B.Shorter wiring reduces the voltage-drop allowance needed at the source.Correct answer: B
   3. C.Longer wiring increases ringer voltage, so the CO must reduce its output.
   4. D.Cable length changes ring frequency but not the required source voltage.

   Explanation: Cisco explains that ring-source requirements account for "load and cabling voltage drop". A gateway near the phones needs less allowance for cable voltage drop than a CO serving long loops. The other choices reverse the voltage-drop relationship or substitute a ring-frequency effect.

   Reference: Cisco — Ringing and Idle Voltages on FXS Interfaces — Ringing Voltages, load and distance discussion

6. 6Which description best captures the Internet's overall structure?

   1. A.A single local network with one shared link
   2. B.A network of interconnected networksCorrect answer: B
   3. C.A dedicated circuit reserved for each user
   4. D.A central host with directly attached terminals

   Explanation: RFC 1122 states, "The Internet is a network of networks." Individual participating networks are interconnected; the Internet is not one local link or a set of individually reserved circuits.

   Reference: RFC 1122: Requirements for Internet Hosts — Communication Layers — Section 1.1.2(a), Networks

7. 7Which ANSI/TIA standard in the TIA standards chart addresses balanced twisted-pair telecommunications cabling and components?

   1. A.ANSI/TIA-568.2-ECorrect answer: A
   2. B.ANSI/TIA-569-E
   3. C.ANSI/TIA-606-D
   4. D.ANSI/TIA-607-E

   Explanation: The chart lists "Balanced Twisted-Pair Telecommunications Cabling and Components" under ANSI/TIA-568.2-E. The other listed standards address pathways and spaces, administration, and bonding and grounding respectively.

   Reference: TIA Family of Standards — TIA Table, Balanced Twisted-Pair Telecommunications Cabling and Components row

8. 8To measure DC voltage across a telecom equipment supply with a digital multimeter, how should the meter be configured and connected?

   1. A.Current mode, inserted in series with the supply
   2. B.Resistance mode, connected across the energized supply
   3. C.DC voltage mode, connected in parallel across the supplyCorrect answer: C
   4. D.DC voltage mode, inserted in series with the supply

   Explanation: Fluke's voltage procedure says, "Touch the probe tips to the circuit across a load or power source (in parallel to the circuit)." Select the DC voltage function and voltage input terminals. Series current measurement and energized resistance measurement are different and inappropriate configurations.

   Reference: ABCs of DMMs: Multimeter Features and Functions Explained — p. 3, How to make voltage measurements, steps 1–4

9. 9A 24 V DC test supply drives a 1,200 Ω resistive load. Ignoring lead resistance, what current flows?

   1. A.2 mA
   2. B.50 mA
   3. C.20 mACorrect answer: C
   4. D.200 mA

   Explanation: Fluke states that Ohm's law means "voltage equals current times resistance". Therefore I = V/R = 24/1,200 A = 0.020 A = 20 mA. The other values reflect a misplaced decimal or an incorrect rearrangement.

   Reference: ABCs of DMMs: Multimeter Features and Functions Explained — p. 2, Ohm's law

10. 10Which access-link characteristic distinguishes a cellular handset connection from a traditional wired subscriber loop?

    1. A.A dedicated copper pair extends all the way to the mobile handset.
    2. B.The handset reaches the network through a radio-equipped cell site.Correct answer: B
    3. C.The handset must connect directly to an optical splitter by fiber.
    4. D.The mobile access link carries only in-building extension wiring.

    Explanation: The FCC describes cellular base stations as equipped with "radio transmitters/receivers and associated antennas." The handset's access is through the cell's radio system, rather than a continuous wired pair or fiber attachment to the moving handset.

    Reference: Twelfth Report on Commercial Mobile Services — Footnote 302, cellular-system architecture