RCDD Practice Test Latest Questions With Complete
Solutions.
C
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
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
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
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
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
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
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
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
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
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
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
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
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
D. Companding
E. Amplitude modulation
B
Assume that the optical power transmitted by a 62.5/125 multimode fiber is distributed
uniformly across its core. If this fiber is perfectly coupled (i.e., the two fibers are aligned
and abutted) to a 50/125 fiber, what is the percent of power that is lost?
A. 0 percent
B. 36 percent
C. 50 percent
D. 80 percent
E. 100 percent
A
Which of the following correctly lists the lowest frequency band to the highest frequency
band?
A. MF, HF, VHF, UHF
B. UHF, VHF, HF, MF
C. HF, MF, UHF, VHF
D. VHF, UHF, MF, HF
E. HF, MF, UHF, VHF
B
Time division multiplexing (TDM) systems are designed to transport ________ between
end point systems.
A. Only analog signals
B. Only digital signals
C. A mix of both analog and digital signals
D. Both analog and digital signals, but only one type at a time
C
A reasonable approximation for the signal speed in 100 ohm balanced twisted pair
cable is__________, where c is the velocity of light in free space.
A. 0.2 c
B. 0.4 c
, C. 0.6 c
D. 08 c
E. 0.9 c
C
Which characteristic is an advantage of copper based media over optical fiber cable?
A. Weight
B. Corrosion resistance
C. Ability to handle analog signals
D. Susceptibility to EMI
E. Very high data rates
A
Which electrical characteristic is displayed with the correct preferred value?
A. Dielectric constant - high value
B. Dielectric strength - high value
C. Dissipation factor - low value
D. Insulation resistance - high value
E
Optical transmitters are typically one of the following types EXCEPT:
A. Light-emitting diode (LED)
B. Short wavelength laser compact disc (CD)
C. Vertical cavity surface emitting laser (VCEL)
D. Laser diode (LD)
E. Overfilled launch (OFL)
A
You are placing Category 6 unshielded twisted-pair (UTP) in cable tray down a hallway
past the elevator mechanical room. What action should you take to avoid effects of
electromagnetic interference (EMI)?
A. Provide a minimum separation of 1194 mm (47 in)
B. Provide a minimum separation of 2060 mm (81 in)
C. Require the architect to install metallic foil shielding on the mechanical room walls
D. Provide RMC/IMC (rigid metallic conduit/intermediate metal conduit) through all
areas within 4.6 m (15 ft) of the mechanical room
B
You have discovered a common mode current on the metallic cable sheaths of your
building riser cables. What is the MOST likely cause for you to investigate?
A. Lack of cable protection
B. Two separate and distinct ground references
C. Improper secondary protection
D. Improper physical protection of cable
E. Improper placement and/or termination of cables
B
What is the recommended MINIMUM separation of unshielded twisted-pair (UTP)
cables from fluorescent light fixtures?
A. 77 mm (3 in)
B. 30 mm (5.12 in)
C. 203 mm (8 in)
Solutions.
C
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
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
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
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
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
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
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
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
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
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
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
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
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
D. Companding
E. Amplitude modulation
B
Assume that the optical power transmitted by a 62.5/125 multimode fiber is distributed
uniformly across its core. If this fiber is perfectly coupled (i.e., the two fibers are aligned
and abutted) to a 50/125 fiber, what is the percent of power that is lost?
A. 0 percent
B. 36 percent
C. 50 percent
D. 80 percent
E. 100 percent
A
Which of the following correctly lists the lowest frequency band to the highest frequency
band?
A. MF, HF, VHF, UHF
B. UHF, VHF, HF, MF
C. HF, MF, UHF, VHF
D. VHF, UHF, MF, HF
E. HF, MF, UHF, VHF
B
Time division multiplexing (TDM) systems are designed to transport ________ between
end point systems.
A. Only analog signals
B. Only digital signals
C. A mix of both analog and digital signals
D. Both analog and digital signals, but only one type at a time
C
A reasonable approximation for the signal speed in 100 ohm balanced twisted pair
cable is__________, where c is the velocity of light in free space.
A. 0.2 c
B. 0.4 c
, C. 0.6 c
D. 08 c
E. 0.9 c
C
Which characteristic is an advantage of copper based media over optical fiber cable?
A. Weight
B. Corrosion resistance
C. Ability to handle analog signals
D. Susceptibility to EMI
E. Very high data rates
A
Which electrical characteristic is displayed with the correct preferred value?
A. Dielectric constant - high value
B. Dielectric strength - high value
C. Dissipation factor - low value
D. Insulation resistance - high value
E
Optical transmitters are typically one of the following types EXCEPT:
A. Light-emitting diode (LED)
B. Short wavelength laser compact disc (CD)
C. Vertical cavity surface emitting laser (VCEL)
D. Laser diode (LD)
E. Overfilled launch (OFL)
A
You are placing Category 6 unshielded twisted-pair (UTP) in cable tray down a hallway
past the elevator mechanical room. What action should you take to avoid effects of
electromagnetic interference (EMI)?
A. Provide a minimum separation of 1194 mm (47 in)
B. Provide a minimum separation of 2060 mm (81 in)
C. Require the architect to install metallic foil shielding on the mechanical room walls
D. Provide RMC/IMC (rigid metallic conduit/intermediate metal conduit) through all
areas within 4.6 m (15 ft) of the mechanical room
B
You have discovered a common mode current on the metallic cable sheaths of your
building riser cables. What is the MOST likely cause for you to investigate?
A. Lack of cable protection
B. Two separate and distinct ground references
C. Improper secondary protection
D. Improper physical protection of cable
E. Improper placement and/or termination of cables
B
What is the recommended MINIMUM separation of unshielded twisted-pair (UTP)
cables from fluorescent light fixtures?
A. 77 mm (3 in)
B. 30 mm (5.12 in)
C. 203 mm (8 in)
