RCDD PRACTICE TEST WITH CORRECT QUESTIONS
AND ANSWERS GRADED A+ 2025/2026
C .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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
B. .Singlemode
C. .UTP
D. .STP
, A .- .CORRECT .ANSWER-Two .sinusoidal .signals .have .the .same .amplitude .(A) .and .the .same
.frequency .(f). .They .differ .in .phase .by .180 .degrees. .If .these .two .signals .are .added
.together, .the .result .is .a .sinusoidal .signal .having .an .amplitude .of:
A. .Zero
B. .0.707A .and .a .frequency .of .f
C. .A .and .a .frequency .of .2f
D. .2A .and .a .frequency .of .f
E. .2A .and .a .frequency .of .2f
A .- .CORRECT .ANSWER-Composite .conductors, .although .not .generally .recommended, .may
.be .used .in .special .circumstances .because .they .provide .all .of .the .following .advantages
.EXCEPT:
A. .Have .good .digital .transmission .characteristics
B. .Lightweight
C. .Inexpensive
D. .Easy .to .produce
E. .Easily .embedded .into .other .materials
D .- .CORRECT .ANSWER-Which .is .an .advantage .of .stranded .conductors .over .solid
.conductors?
A. .Less .costly
B. .Simpler .terminations
C. .Better .high .frequency .performance
D. .More .flexible
E .- .CORRECT .ANSWER-The .conversion .of .an .analog .speech .signal .to .a .pulse .code
.modulation .(PCM) .digital .signal .involves .all .of .the .following .steps .EXCEPT:
A. .Low .pass .filtering
B. .Periodic .sampling
C. .Quantizing
AND ANSWERS GRADED A+ 2025/2026
C .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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 .- .CORRECT .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
B. .Singlemode
C. .UTP
D. .STP
, A .- .CORRECT .ANSWER-Two .sinusoidal .signals .have .the .same .amplitude .(A) .and .the .same
.frequency .(f). .They .differ .in .phase .by .180 .degrees. .If .these .two .signals .are .added
.together, .the .result .is .a .sinusoidal .signal .having .an .amplitude .of:
A. .Zero
B. .0.707A .and .a .frequency .of .f
C. .A .and .a .frequency .of .2f
D. .2A .and .a .frequency .of .f
E. .2A .and .a .frequency .of .2f
A .- .CORRECT .ANSWER-Composite .conductors, .although .not .generally .recommended, .may
.be .used .in .special .circumstances .because .they .provide .all .of .the .following .advantages
.EXCEPT:
A. .Have .good .digital .transmission .characteristics
B. .Lightweight
C. .Inexpensive
D. .Easy .to .produce
E. .Easily .embedded .into .other .materials
D .- .CORRECT .ANSWER-Which .is .an .advantage .of .stranded .conductors .over .solid
.conductors?
A. .Less .costly
B. .Simpler .terminations
C. .Better .high .frequency .performance
D. .More .flexible
E .- .CORRECT .ANSWER-The .conversion .of .an .analog .speech .signal .to .a .pulse .code
.modulation .(PCM) .digital .signal .involves .all .of .the .following .steps .EXCEPT:
A. .Low .pass .filtering
B. .Periodic .sampling
C. .Quantizing
