3c251 Volume 4
3C251 Volume 4. UREs only.
- 1.
What led to the development of very high frequency (VHF) and ultra high frequency (UHF) radio systems during World War II?
- A.
The longer distances involved in communications with forces of Europe
- B.
The need for more reliable high-capacity communications
- C.
The development of line of sight (LOS) communications
- D.
The need for more resistance to nuclear blast
Correct Answer
B. The need for more reliable high-capacity communications -
- 2.
The two primary types of radio waves are
- A.
Direct and surface
- B.
Sky and surface
- C.
Ground and sky
- D.
Direct and sky
Correct Answer
C. Ground and sky -
- 3.
What condition causes the downward bending of a radio wave as it grazes the top of an obstruction such as a mountain peak?
- A.
Reflection
- B.
Refraction
- C.
Diffraction
- D.
Diffusion
Correct Answer
C. Diffraction -
- 4.
During periods of maximum sunspot activity, what is the density level and altitude effect of the F layer?
- A.
Less dense and at a lower altitude
- B.
More dense and at a lower altitude
- C.
Less dense and at a higher altitude
- D.
More dense and at a higher altitude
Correct Answer
D. More dense and at a higher altitude -
- 5.
What type of frequency is the highest frequency that returns to earth when it is transmitted vertically under given ionospheric conditions?
- A.
Frequency of optimum traffic
- B.
Maximum usable frequency
- C.
Most usable frequency
- D.
Critical frequency
Correct Answer
D. Critical frequency -
- 6.
A satellite system that requires numerous satellites in randomly spaced orbits to provide acceptable coverage is
- A.
An active system
- B.
A passive system
- C.
A synchronous system
- D.
A low-altitude system
Correct Answer
B. A passive system -
- 7.
What is a major disadvantage of a geostationary satellite?
- A.
It can't amplify signals
- B.
It orbits the earth in a figure eight pattern
- C.
The transmitted frequency is below 10-gigahertz (GHz)
- D.
The two-way propagation delay is about 0.6 seconds
Correct Answer
D. The two-way propagation delay is about 0.6 seconds -
- 8.
Above what frequency does the propagation loss because of oxygen and water absorption become very serious in satellite communication?
- A.
10 gigahertz (GHz)
- B.
8 GHz
- C.
6 GHz
- D.
4 GHz
Correct Answer
A. 10 gigahertz (GHz) -
- 9.
The reduction in amplitude of a radio signal as it travels away from the source through a propagation medium that's free of obstructing, scattering, or reflecting effects is called
- A.
Faraday effect
- B.
Doppler effect
- C.
Free space attenuation
- D.
None of the above
Correct Answer
C. Free space attenuation -
- 10.
The Doppler effect, inherent to satellite communications, is caused by
- A.
Transmit frequency drift
- B.
Transmit frequency drift off phase-lock ground receivers
- C.
The satellite's motion in space relative to ground stations
- D.
Rotation of the polarization of radio waves
Correct Answer
C. The satellite's motion in space relative to ground stations -
- 11.
Which satellite communications subsystem consist of a satellite antenna array and a transponder?
- A.
Earth
- B.
Space
- C.
Orbital
- D.
Control
Correct Answer
B. Space -
- 12.
What satellite device receives, amplifies, and retransmits signals from earth to terminals?
- A.
Station keeper
- B.
Satellite amplifier
- C.
Satellite transponder
- D.
Regenerative repeater
Correct Answer
C. Satellite transponder -
- 13.
At a minimum, a typical link involves
- A.
An active satellite and one earth terminal
- B.
An active satellite and two earth terminal
- C.
Two active satellite and one earth terminal
- D.
Two active satellite and two earth terminal
Correct Answer
B. An active satellite and two earth terminal -
- 14.
Maintaining optimum performance of a satellite's transponder is a function of
- A.
Satellite control
- B.
Station keeping
- C.
Satellite ground track
- D.
Communications control
Correct Answer
A. Satellite control -
- 15.
What type of multiple-access service used in satellite communications provides each earth terminal exclusive use of the satellite transponder for a specified time interval?
- A.
Spread spectrum multiple access (SSMA)
- B.
Frequency division multiple access (FDMA)
- C.
Demand assignment multiple access (DAMA)
- D.
Time division multiple access (TDMA)
Correct Answer
D. Time division multiple access (TDMA) -
- 16.
Two system control problems with time division multiple access are in the area of network timing and
- A.
Power
- B.
Frequency
- C.
Synchronization
- D.
Transponder complexity
Correct Answer
C. Synchronization -
- 17.
What satellite access system lets several users occupy the same frequency spectrum in the transponder simultaneously?
- A.
Frequency division multiple access (FDMA)
- B.
Time division multiple access (TDMA)
- C.
Spread spectrum multiple access (SSMA)
- D.
Band spreading multiple access
Correct Answer
C. Spread spectrum multiple access (SSMA) -
- 18.
Which organization is responsible for the design, acquisition, and single systems management of the Defense Switched Network?
- A.
Defense Logistics Agency
- B.
Communications Squadron
- C.
Air Force Communications Agency
- D.
Defense Information Systems Agency (DISA)
Correct Answer
D. Defense Information Systems Agency (DISA) -
- 19.
How is survivability provided in the Defense Switched Network (DSN)?
- A.
End offices are multiple-homed
- B.
End offices do not interoperate with allied networks
- C.
The DSN offers precedence access thresholding (PAT)
- D.
The DSN offers single multilevel precedence and preemption (MLPP)
Correct Answer
A. End offices are multiple-homed -
- 20.
How is responsiveness provided in the Defense Switched Network (DSN)?
- A.
End offices are multiple-homed
- B.
End offices do not interoperate with allied networks
- C.
The DSN offers precedence access thresholding (PAT)
- D.
The DSN offers single multilevel precedence and preemption (MLPP)
Correct Answer
C. The DSN offers precedence access thresholding (PAT) -
- 21.
What type of Defense Switched Network (DSN) precedence call cannot be preempted?
- A.
Flash
- B.
Priority
- C.
Intermediate
- D.
Flash Override
Correct Answer
D. Flash Override -
- 22.
What type of precedence is assigned to Defense Switched Network (DSN) calls pertaining to situations that gravely affect the security of national and allied forces?
- A.
Flash
- B.
Priority
- C.
Intermediate
- D.
Flash Override
Correct Answer
C. Intermediate -
- 23.
Which encryption device makes end-to-end encryption available to any user of the Defense Switched Network (DSN)?
- A.
KG-84
- B.
KG-94
- C.
KIV-7
- D.
Secure telephone unit-III (STU-III)
Correct Answer
D. Secure telephone unit-III (STU-III) -
- 24.
What is the primary difference in the Defense Switched Network (DSN) subsystems?
- A.
Access line protocol functions
- B.
Network management functions
- C.
Internal call processing features and functions
- D.
Administrative, operations and maintenance functions
Correct Answer
C. Internal call processing features and functions -
- 25.
Why should high-priority users not be terminated on a remote switching unit (RSU)?
- A.
A Secure telephone unit-III (STU-III) cannot make calls through a RSU
- B.
Precedence calling is not available with a RSU
- C.
RSU can become saturated and deny all service
- D.
RSU can become isolated from the parent switch
Correct Answer
D. RSU can become isolated from the parent switch -
- 26.
An end office is part of what subsystem of Defense Switched Network (DSN)?
- A.
Timing and synchronization
- B.
Network management
- C.
Transmission
- D.
Switching
Correct Answer
D. Switching -
- 27.
Which Defense Switched Network (DSN) switch functions primarily as a tandem switch?
- A.
End office (EO)
- B.
Stand-alone
- C.
Multifunction
- D.
Private branch exchange (PBX)
Correct Answer
B. Stand-alone -
- 28.
What type of Defense Switched Network (DSN) switch provides services to a Private Branch Exchange (PBX)?
- A.
End office (EO) only
- B.
Stand-alone only
- C.
EO and multifunction only
- D.
Stand-alone and multifunction only
Correct Answer
C. EO and multifunction only -
- 29.
Which type of connection provides the transmission links between two Defense Switched Network (DSN) switches? Languagesde>en GoogleDicCE Verbindung, Beziehung, Vermittlung, Anschluss, Zusammenhang, Zwischenstück
- A.
Access lines only
- B.
Interswitch trunks only
- C.
Baseband links and access lines
- D.
Baseband links and interswitch trunks
Correct Answer
B. Interswitch trunks only -
- 30.
Which type of connection is a single or multichannel connection that allows user equipment to gain access to the Defense Switched Network (DSN)?
- A.
Access lines only
- B.
Interswitch trunks only
- C.
Baseband links and access lines
- D.
Baseband links and interswitch trunks
Correct Answer
A. Access lines only -
- 31.
Which organization provides theater-wide administration and network management in the Defense Switched Network (DSN)?
- A.
Global Network Operations and Security Control Center (GNOSC)
- B.
Regional Network Operations and Security Control Center (RNOSC)
- C.
Subregional Control Facility (SRCF)
- D.
Local control center (CC)
Correct Answer
B. Regional Network Operations and Security Control Center (RNOSC) -
- 32.
In a digital multiplex switching system, what appears between the peripheral module and the network in addition to the 30 channels of encoded speech?
- A.
Orderwide channel and timing channel
- B.
Supervisory channel and alarm channel
- C.
Synchronizing channel and alarm channel
- D.
Synchronizing channel and signaling channel
Correct Answer
D. Synchronizing channel and signaling channel -
- 33.
Which digital multiplex switch module encodes and multiplexes incoming speech from a maximum of 30 analog trunks into 8-bit PCM format?
- A.
Digital carrier module
- B.
Control module
- C.
Trunk module
- D.
Line module
Correct Answer
C. Trunk module -
- 34.
Which digital multiplex switch module is used for direct interfacing with the T-1 office repeater?
- A.
Line
- B.
Trunk
- C.
Control
- D.
Digital carrier
Correct Answer
D. Digital carrier -
- 35.
Which digital multiplex switch module consists of a duplicated central message controller?
- A.
Controller digital carrier
- B.
Input/output controller (IOC)
- C.
Network module (NM)
- D.
Central control (CC)
Correct Answer
D. Central control (CC) -
- 36.
When a subscriber lifts the handset to make a dial pulse intra-office call, what process occurs in the defense switched network (DSN) switch?
- A.
The line module reports a subscriber origination to the central control (CC)
- B.
The trunk module reports a subscriber origination to the CC
- C.
The CC sends a message to the terminating peripheral processor to send ringing tone
- D.
The CC sends a message to the originating peripheral processor module to remove ringing tone
Correct Answer
A. The line module reports a subscriber origination to the central control (CC) -
- 37.
When a called defense network switch (DSN) subscriber answers, what action is taken by the switch's central control (CC) module?
- A.
The line module reports a subscriber origination to the CC
- B.
The trunk module reports a subscriber origination to the CC
- C.
The message is sent to the terminating peripheral processor to send ringing tone
- D.
The message is sent to the originating peripheral processor module to remove ringing tone
Correct Answer
D. The message is sent to the originating peripheral processor module to remove ringing tone -
- 38.
The Red switch program provides which subscriber(s) a Red telephone?
- A.
Operational support only
- B.
Command and control (C2) only
- C.
Logistics and operational support
- D.
Logistics and C2
Correct Answer
B. Command and control (C2) only -
- 39.
What is the major type(s) of terminal used in the Defense Red Switched Network?
- A.
KG-84 only
- B.
Secure telephone unit-III (STU-III) only
- C.
KG-84 and secure telephone equipment (STE)
- D.
STU-III and STE
Correct Answer
D. STU-III and STE -
- 40.
What type of device is used to provide the cryptographic engine for the secure terminal equipment (STE) terminal?
- A.
Crypto key card
- B.
FORTEZZA key
- C.
FORTEZZA card
- D.
Crypto ignition key
Correct Answer
C. FORTEZZA card -
- 41.
Which encryption device will support asynchronous secure voice modes up to 38.4 Kbps and high-speed secure data transfers up to 128 Kbps when connected to the 2B + D Integrated Services Digital Network (ISDN)?
- A.
Secure terminal equipment (STE)
- B.
Secure telephone unit-III (STU-III)
- C.
KG-84
- D.
KG-94
Correct Answer
A. Secure terminal equipment (STE) -
- 42.
What is the maximum asynchronous data rate for the Defense Red Switch Network (DRSN)?
- A.
9.6 Kbps
- B.
14.4 Kbps
- C.
19.2 Kbps
- D.
28.8 Kbps
Correct Answer
C. 19.2 Kbps -
- 43.
What type of capability is provided by the Defense Red Switch Network (DRSN) to define the needs, capabilities, and limitations of individual trunks and trunk groups?
- A.
Multilevel security
- B.
Class of service marks
- C.
Precedence access thresholding (PAT)
- D.
Multilevel precedence and preemption (MLPP)
Correct Answer
B. Class of service marks -
- 44.
Which piece of equipment is used to provide secure connectivity to the Red switch via an attendant and local-site radio facilities?
- A.
Line module
- B.
Interface ancillary device
- C.
Interface and control unit
- D.
Network termination device
Correct Answer
C. Interface and control unit -
- 45.
What interface provides the Red switch 24-channel digital interswitch trunk group service at 1.544 Mbps?
- A.
Secure telephone unit-III (STU-III) trunk circuits
- B.
Digital subscriber voice telephone (DSVT) trunk circuits
- C.
Digital trunk group circuits
- D.
Digital trunk circuits
Correct Answer
C. Digital trunk group circuits -
- 46.
The piece of equipment that allows a secure digital switch to interface with cryptographic equipment and passes supervisory and address signaling in setting up a secure call is the
- A.
Line module
- B.
Interface ancillary device
- C.
Interface and control unit
- D.
Network termination device
Correct Answer
B. Interface ancillary device -
- 47.
The Non-Secure Internet Protocol Router Network (NIPRNET) is
- A.
Operated and managed as a base communications asset
- B.
Considered one of the primary components of the Defense Information Systems Network (DISN)
- C.
Interconnected via the Defense Information Systems Agency Asynchronous Transfer Mode (DATM) network
- D.
Partially protected by encryption devices
Correct Answer
D. Partially protected by encryption devices -
- 48.
What is the difference between a Hub router and a premise router?
- A.
Operated and managed as a base communications asset
- B.
Considered one of the primary components of the Defense Information Systems Network (DISN)
- C.
Interconnected via the Defense Information Systems Agency Asynchronous Transfer Mode (DATM) network
- D.
Completely protected by encryption devices
Correct Answer
C. Interconnected via the Defense Information Systems Agency Asynchronous Transfer Mode (DATM) network -
- 49.
Which is an internet protocol (IP) encryption device that can be directly connected to Red local area networks (LAN)?
- A.
KG-84
- B.
KG-194
- C.
KIV-7
- D.
Network Encryption System (NES)
Correct Answer
D. Network Encryption System (NES) -
- 50.
In addition to fiber-optic and copper cables, what type of system is used to interconnect integrated communications access package access nodes on a deployed base within the same theater area?
- A.
Microwave and laser
- B.
Microwave only
- C.
Satellite and laser
- D.
Satellite only
Correct Answer
A. Microwave and laser -
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Jan 16, 2013Quiz Edited by
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