RCDD TEST QUESTIONS 2025
WITH CORRECT ANSWERS
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 - ANSWER✔✔-C. 30 dB
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 - ANSWER✔✔-B. 30 dB
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 - ANSWER✔✔-C. 2.5 Gbps
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 - ANSWER✔✔-A. 700 nm
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 - ANSWER✔✔-A. Balun
The public telephone system is an example of a __________ system.
A. Simplex
, B. Half-duplex
C. Full-duplex
D. Purely analog
E. Purely digital - ANSWER✔✔-C. Full-duplex
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) - ANSWER✔✔-D.
Frequency division multiplexing
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
WITH CORRECT ANSWERS
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 - ANSWER✔✔-C. 30 dB
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 - ANSWER✔✔-B. 30 dB
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 - ANSWER✔✔-C. 2.5 Gbps
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 - ANSWER✔✔-A. 700 nm
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 - ANSWER✔✔-A. Balun
The public telephone system is an example of a __________ system.
A. Simplex
, B. Half-duplex
C. Full-duplex
D. Purely analog
E. Purely digital - ANSWER✔✔-C. Full-duplex
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) - ANSWER✔✔-D.
Frequency division multiplexing
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
