RCDD Practice Test 2025 Questions
and Answers
C - ANSWER✔✔-If the input signal power to a communication system is 1 W and the
output power is 1 mW, the system attenuation is:
A. 3 dB
B. 20 dB
C. 30 dB
D. 40 dB
E. 1000 dB
B - ANSWER✔✔-The signal at the input to a balanced twisted pair cable is 10 mW. The
cable is 1000 feet long and has an attenuation of 1 dB per 100 feet. This cable is
connected to the input of a receiver. The noise level at the input to the receiver is 1
microwatt. What is the signal-to- noise ratio (SNR) (dB) at the receiver input?
A. 10 dB
,B. 30 dB
C. 40 dB
D. 60 dB
E. 100 dB
C - ANSWER✔✔-A SONET OC-1 channel can carry 672 voice signals and has a data
rate of 51.84 Mbps. ASONET OC-48 channel can carry 32,256 voice channels. What
MINIMUM data rate is required for the OC-48 channel?
A. 155 Mbps
B. 622 Mbps
C. 2.5 Gbps
D. 5 Gbps
E. 10 Gbps
A - ANSWER✔✔-All of the following are nominal wavelengths for laser light sources
EXCEPT:
A. 700 nm
B. 850 nm
C. 1300 nm
,D. 1310 nm
E. 1550 nm
A - ANSWER✔✔-A video camera has a coaxial cable output. The video signal is to be
distributed to devices that have balanced twisted pair inputs. The transition between
these two different transmission media can be accomplished by using a:
A. Balun
B. Converter
C. Modulator
D. Cross connect
E. Transceiver
C - ANSWER✔✔-The public telephone system is an example of a __________ system.
A. Simplex
B. Half-duplex
C. Full-duplex
D. Purely analog
E. Purely digital
D - ANSWER✔✔-Wave division multiplexing (WDM) is most similar to:
, A. Amplitude modulation
B. Frequency modulation
C. Time division multiplexing
D. Frequency division multiplexing
E. Carrier sense multiple access with collision detection (CSMA/CD)
C - ANSWER✔✔-You must place CAT6 cable above a factory floor with automated
welding machines and hammer forges. Of the following, what type of shielding would
be most effective?
A. Multi-layer braid
B. Foil and braid
C. Solid metallic conduit
D. Flex metallic conduit
E. Sch. 40 PVC conduit
D - ANSWER✔✔-You must place a cable between 2 equipment locations with separate
grounds having a potential difference between them of 2.1 V rms. Which one of the
following cables shouldNOT be used?
A. Multimode
and Answers
C - ANSWER✔✔-If the input signal power to a communication system is 1 W and the
output power is 1 mW, the system attenuation is:
A. 3 dB
B. 20 dB
C. 30 dB
D. 40 dB
E. 1000 dB
B - ANSWER✔✔-The signal at the input to a balanced twisted pair cable is 10 mW. The
cable is 1000 feet long and has an attenuation of 1 dB per 100 feet. This cable is
connected to the input of a receiver. The noise level at the input to the receiver is 1
microwatt. What is the signal-to- noise ratio (SNR) (dB) at the receiver input?
A. 10 dB
,B. 30 dB
C. 40 dB
D. 60 dB
E. 100 dB
C - ANSWER✔✔-A SONET OC-1 channel can carry 672 voice signals and has a data
rate of 51.84 Mbps. ASONET OC-48 channel can carry 32,256 voice channels. What
MINIMUM data rate is required for the OC-48 channel?
A. 155 Mbps
B. 622 Mbps
C. 2.5 Gbps
D. 5 Gbps
E. 10 Gbps
A - ANSWER✔✔-All of the following are nominal wavelengths for laser light sources
EXCEPT:
A. 700 nm
B. 850 nm
C. 1300 nm
,D. 1310 nm
E. 1550 nm
A - ANSWER✔✔-A video camera has a coaxial cable output. The video signal is to be
distributed to devices that have balanced twisted pair inputs. The transition between
these two different transmission media can be accomplished by using a:
A. Balun
B. Converter
C. Modulator
D. Cross connect
E. Transceiver
C - ANSWER✔✔-The public telephone system is an example of a __________ system.
A. Simplex
B. Half-duplex
C. Full-duplex
D. Purely analog
E. Purely digital
D - ANSWER✔✔-Wave division multiplexing (WDM) is most similar to:
, A. Amplitude modulation
B. Frequency modulation
C. Time division multiplexing
D. Frequency division multiplexing
E. Carrier sense multiple access with collision detection (CSMA/CD)
C - ANSWER✔✔-You must place CAT6 cable above a factory floor with automated
welding machines and hammer forges. Of the following, what type of shielding would
be most effective?
A. Multi-layer braid
B. Foil and braid
C. Solid metallic conduit
D. Flex metallic conduit
E. Sch. 40 PVC conduit
D - ANSWER✔✔-You must place a cable between 2 equipment locations with separate
grounds having a potential difference between them of 2.1 V rms. Which one of the
following cables shouldNOT be used?
A. Multimode
