1.
What led to the development of very high frequency (VHF) and ultrahigh frequency (UHF) radio systems during the World War II?
Correct Answer
B. The need for more reliable high-capacity communications
Explanation
During World War II, there was a need for more reliable high-capacity communications. This was due to the increasing complexity and scale of military operations, which required efficient and secure communication systems. Very high frequency (VHF) and ultrahigh frequency (UHF) radio systems were developed to meet this need. These systems offered improved signal quality, greater bandwidth, and reduced interference, allowing for more reliable and efficient communication between military units.
2.
The two primary types of radio waves are:
Correct Answer
C. Ground and sky
Explanation
Radio waves can be classified into two primary types based on their propagation characteristics. Ground waves are radio waves that travel close to the Earth's surface and follow the curvature of the Earth. These waves are used for long-distance communication as they can travel over large distances by bending around obstacles. Sky waves, on the other hand, are radio waves that are reflected off the ionosphere, a layer of charged particles in the Earth's upper atmosphere. These waves can be used for long-distance communication as they can be reflected back to the Earth's surface. Therefore, the correct answer is 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?
Correct Answer
C. Diffraction
Explanation
Diffraction is the correct answer because it refers to the bending or spreading out of a wave as it encounters an obstacle or passes through a narrow opening. In the case of a radio wave grazing the top of an obstruction, such as a mountain peak, the wave will experience diffraction, causing it to bend downward. This phenomenon occurs because the radio wave interacts with the edges of the obstruction and spreads out, resulting in a change in its direction.
4.
During periods of maximum sunspot activity, what is the density level and altitude effect of the F layer?
Correct Answer
D. More dense and at a higher altitude
Explanation
During periods of maximum sunspot activity, the F layer of the ionosphere becomes more dense and moves to a higher altitude. This is because the increased solar radiation during sunspot activity causes more ionization in the F layer, leading to an increase in the number of free electrons. These free electrons then recombine with ions in the F layer, resulting in a denser layer. Additionally, the increased ionization also causes the F layer to move to higher altitudes due to the increased electron density and interaction with the Earth's magnetic field.
5.
What type of frequency is the higher frequency that returns to earth when it is transmitted vertically under given ionospheric conditions?
Correct Answer
D. Critical frequency
Explanation
The critical frequency is the highest frequency that can be transmitted vertically and return to Earth under specific ionospheric conditions. It represents the point at which the ionosphere becomes too dense to allow the radio waves to pass through and be reflected back to Earth. This frequency is important for determining the maximum usable frequency for communication purposes.
6.
A satellite system that requires numerous satellites in randomly spaced orbits to provide acceptable coverage is
Correct Answer
A. An active system
Explanation
An active satellite system requires numerous satellites in randomly spaced orbits to provide acceptable coverage. This means that the satellites actively transmit and receive signals, allowing for continuous communication and coverage. In contrast, a passive system would rely on reflectors or other passive elements to redirect signals, while a synchronous system would involve satellites in geostationary orbits. A low-altitude system would refer to satellites in orbits closer to the Earth's surface. Therefore, the correct answer is an active system.
7.
What is a major disadvantages of a geostationary satellite?
Correct Answer
D. The two-way propagation delay is about 0.6 seconds
Explanation
A major disadvantage of a geostationary satellite is the two-way propagation delay of about 0.6 seconds. This delay occurs due to the large distance that signals have to travel between the satellite and the ground station. It can cause noticeable delays in real-time communication, such as telephone conversations or video calls, making them less efficient and sometimes even impractical.
8.
Above what frequency does the propagation loss because of oxygen and water absorption become very serious in satellite communications?
Correct Answer
A. 10 gigahertz (GHz)
Explanation
Oxygen and water absorption causes propagation loss in satellite communications due to their interaction with electromagnetic waves. As the frequency of the waves increases, the absorption by oxygen and water molecules also increases. At frequencies above 10 gigahertz (GHz), the absorption becomes very serious, resulting in significant signal degradation and loss.
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
Correct Answer
C. Free space attenuation
Explanation
Free space attenuation refers to the reduction in amplitude of a radio signal as it travels through a propagation medium without any obstructions, scattering, or reflecting effects. This means that the signal weakens as it moves away from the source in an unobstructed environment. The Faraday effect is the rotation of the plane of polarization of a light wave as it passes through a magnetic field, while the Doppler effect is the change in frequency of a wave due to the relative motion between the source and the observer. Therefore, neither of these options accurately describes the given scenario.
10.
The Doppler effect, inherent to satellite communications, is caused by
Correct Answer
C. The satellite's motion in space relative to ground stations
Explanation
The Doppler effect refers to the change in frequency of a wave as a result of the relative motion between the source of the wave and the observer. In the context of satellite communications, the satellite's motion in space relative to the ground stations causes the Doppler effect. As the satellite moves towards or away from the ground stations, the frequency of the transmitted signal appears to shift higher or lower, respectively, to the observer on the ground. This phenomenon needs to be taken into account in order to accurately receive and interpret satellite signals.
11.
Which satellite communications subsytem consists of a satellite antenna array and a transportation
Correct Answer
B. Space
Explanation
The correct answer is "space." In satellite communications, the space subsystem refers to the satellite itself, which includes the satellite antenna array and the transportation of signals to and from Earth. This subsystem is responsible for transmitting and receiving signals between the satellite and ground stations, enabling communication over long distances.
12.
What satellite device receives, amplifies, and retransmits signals from earth terminals
Correct Answer
C. Satellite transponder
Explanation
A satellite transponder is a device that receives signals from earth terminals, amplifies them, and then retransmits them back to earth. It acts as a communication relay between the earth terminals and the satellite. This allows for the signals to be transmitted over long distances and ensures that they maintain their strength and quality during the transmission process.
13.
At a minimum, a typical link involves
Correct Answer
B. An active satellite and two earth terminals
Explanation
A typical link involves an active satellite and two earth terminals. This is because the satellite acts as a relay station between the two earth terminals, allowing communication between them. One earth terminal sends the signal to the satellite, which then transmits it to the other earth terminal. Having two earth terminals ensures that there is a two-way communication link, allowing for data transmission in both directions.
14.
Maintaining optimum performance of a satellite's transponder is a function of
Correct Answer
A. Satellite control
Explanation
Maintaining optimum performance of a satellite's transponder is achieved through satellite control. This involves monitoring and controlling various aspects of the satellite's operations, such as power levels, frequency management, and signal quality. Satellite control ensures that the transponder operates efficiently and effectively, allowing for reliable communication and data transmission. Station keeping, satellite ground track, and communications control are important factors in satellite operations, but they are not specifically related to the performance of the transponder.
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
Correct Answer
D. Time division multiple access (TDMA)
Explanation
Time Division Multiple Access (TDMA) is a type of multiple-access service used in satellite communications that provides each earth terminal exclusive use of the satellite transponder for a specified time interval. In TDMA, the available bandwidth is divided into time slots, and each earth terminal is allocated a specific time slot to transmit its data. This allows multiple terminals to share the same frequency channel by taking turns transmitting their data during their allocated time slots. By dividing the time, TDMA ensures that each earth terminal has exclusive access to the satellite transponder during its assigned time interval, ensuring efficient and reliable communication.
16.
Two system control problems with time division multiple access are in the area of network timing and
Correct Answer
C. Synchronization
Explanation
Time division multiple access (TDMA) is a communication technique that allows multiple users to share the same frequency channel by dividing it into different time slots. One of the control problems with TDMA is network timing, which refers to the synchronization of the different devices in the network to ensure accurate transmission and reception of data. Another control problem is synchronization with power frequency, which involves aligning the timing of the TDMA system with the power grid frequency to prevent interference and maintain reliable communication. Therefore, synchronization is a crucial aspect in TDMA systems to ensure efficient and accurate data transmission.
17.
What satellite access system lets several users occupy the same frequency spectrum in the transponder simultaneously
Correct Answer
C. Spread spectrum multiple access (SSMA)
Explanation
Spread spectrum multiple access (SSMA) is a satellite access system that allows several users to occupy the same frequency spectrum in the transponder simultaneously. SSMA uses a technique called spread spectrum, which spreads the signal across a wide frequency band. This allows multiple users to share the same frequency band without interfering with each other. SSMA is known for its ability to provide secure and reliable communication, as well as its resistance to jamming and interference.
18.
Which organization is responsible for the design, acquisition, and single systems management of the defense switched network
Correct Answer
D. Defense information systems agency (DISA)
Explanation
The defense information systems agency (DISA) is responsible for the design, acquisition, and single systems management of the defense switched network. DISA is an agency within the Department of Defense that provides information technology and communications support to the military. They are responsible for ensuring the secure and efficient operation of the defense network infrastructure, including the defense switched network.
19.
How is survivability provided in the defense switched network
Correct Answer
A. End offices are multiple-homed
Explanation
Survivability in the defense switched network is provided by having end offices that are multiple-homed. This means that each end office is connected to multiple network paths or links, ensuring redundancy and fault tolerance. If one link or path fails, the end office can still maintain connectivity and communication through the alternate paths. This multiple-homing feature increases the network's resilience and ability to withstand disruptions or attacks, thereby enhancing survivability.
20.
How is preonsiveness provided in the defense switched ntework (DSN)
Correct Answer
D. The DSN offers single mulitlevel precedence and preemption (MLPP)
Explanation
The correct answer is the DSN offers single multilevel precedence and preemption (MLPP). This means that the DSN is able to prioritize and preempt certain types of traffic over others based on their level of importance. This allows for more responsive communication within the network, as critical information can be given priority over less important data.
21.
What type of defense switched network (DSN) precedence call cannot be preempted
Correct Answer
D. Flash override
Explanation
A flash override call in a switched network (DSN) precedence cannot be preempted. This means that when a flash override call is made, it will take precedence over any other type of call in the network, regardless of their priority or importance. This ensures that critical and urgent messages are immediately relayed without any delay or interruption.
22.
What type of precedence is assigned to defense switched network (DSN) calls pertaining to situations that gravely affect the security of national allied forces
Correct Answer
C. Intermediate
Explanation
The correct answer is "intermediate." In a defense switched network (DSN), calls pertaining to situations that gravely affect the security of national allied forces are given an intermediate precedence. This means that these calls are of significant importance but not as urgent as flash or flash override calls. Intermediate precedence ensures that these calls are prioritized and given attention, but they may not be as time-sensitive as other types of calls.
23.
Which encryption devices makes end-to-end encryption available to any user of the defense switched network
Correct Answer
D. Secure telepHone unit- III (STU-III)
Explanation
The correct answer is secure telephone unit- III (STU-III). STU-III is an encryption device that enables end-to-end encryption for any user of the defense switched network. It provides secure communication by encrypting voice and data transmissions, ensuring that only authorized users can access the information. STU-III is widely used in military and government organizations to protect sensitive and classified information from unauthorized access or interception.
24.
What is the primary difference in the defense switched network (DSN) subsystems
Correct Answer
C. Internal call processing features and functions
Explanation
The primary difference in the defense switched network (DSN) subsystems is the internal call processing features and functions. This means that each subsystem within the DSN has its own unique set of call processing features and functions that are specific to its role and responsibilities within the network. These features and functions determine how calls are routed, managed, and processed within each subsystem, ensuring efficient and effective communication within the network.
25.
Why should high-priority users not be terminated on a remote switching unit (RSU)?
Correct Answer
D. RSU can become isolated from the parent switch
Explanation
High-priority users should not be terminated on a remote switching unit (RSU) because the RSU can become isolated from the parent switch. This means that if the RSU loses connectivity with the parent switch, the high-priority users will not have access to the necessary resources and services provided by the parent switch. Therefore, it is important to ensure that high-priority users are connected to a reliable and stable network to maintain uninterrupted communication and access to essential services.
26.
An end office is part of what subsystem of Defense Switched Network (DSN)?
Correct Answer
D. Switching
Explanation
An end office is part of the switching subsystem of Defense Switched Network (DSN). The switching subsystem is responsible for routing and connecting calls within the network. End offices are the points where individual users connect to the network and are responsible for handling incoming and outgoing calls. They act as the interface between the user's telephone line and the network, routing calls to the appropriate destination.
27.
Which Defense Switched network (DSN) switch functions primarily as a tandem switch?
Correct Answer
B. Stand-alone
Explanation
A stand-alone DSN switch is primarily designed to function as a tandem switch. Tandem switches are used to connect multiple end offices and handle call routing between them. In this case, the stand-alone switch is not connected to any other switches or systems, making it an ideal choice for handling call routing between different end offices in a Defense Switched Network (DSN). The other options, such as End office (EO), Multifunction, and Private branch exchange (PBX), do not specifically serve the purpose of a tandem switch in a DSN.
28.
What type of Defense Switched Network (DSN) switch provides services to a Private Branch Exchange (PBX)?
Correct Answer
C. EO and multifunction only
Explanation
An EO (End Office) switch is a type of Defense Switched Network (DSN) switch that provides services to a Private Branch Exchange (PBX). This means that it is capable of connecting the PBX to the DSN network and enabling communication services. Additionally, the EO switch is multifunctional, meaning it can perform various tasks and provide multiple services. Therefore, the correct answer is "EO and multifunction only".
29.
Which type of connection provides the transmission links between two Defense Switched Network (DSN) switches?
Correct Answer
A. Access lines only
Explanation
Access lines only provide the transmission links between two Defense Switched Network (DSN) switches. This means that the connection between the switches is established using physical lines that directly connect them. Interswitch trunks, on the other hand, are used to connect multiple switches together, while baseband links refer to the transmission of digital signals using a single channel. Since the question specifically asks about the type of connection between two switches, the correct answer is access lines 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)?
Correct Answer
A. Access-lines only
Explanation
Access-lines only is the correct answer because it refers to a single or multichannel connection that allows user equipment to gain access to the Defense Switched Network (DSN). This means that access-lines provide the necessary connection for users to connect their equipment to the DSN, without the need for interswitch trunks or baseband links.
31.
Which organization provides theater-wide administration and network management in the Defense Switched Network (DSN)?
Correct Answer
B. Regional network Operations and Security Control Center (RNOSC)
Explanation
The Regional Network Operations and Security Control Center (RNOSC) provides theater-wide administration and network management in the Defense Switched Network (DSN). The RNOSC is responsible for overseeing and maintaining the DSN infrastructure within a specific region, ensuring its availability and security. This includes managing network resources, troubleshooting issues, and implementing security measures to protect the network from cyber threats. The GNOSC, on the other hand, is responsible for global network operations and security control, overseeing multiple RNOSCs and providing higher-level coordination and support. The SRCF and Local Control Center are not responsible for theater-wide administration and network management in the DSN.
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?
Correct Answer
C. Synchronizing channel and alarm channel
Explanation
In a digital multiplex switching system, in addition to the 30 channels of encoded speech, a synchronizing channel and an alarm channel appear between the peripheral module and the network. The synchronizing channel is responsible for maintaining synchronization between the different modules in the system, ensuring that data is transmitted and received correctly. The alarm channel is used to transmit alarm signals in case of any issues or faults in the system, allowing for timely detection and resolution of problems.
33.
Which digital multiplex switch module encodes and multiplexes incoming speech from a maximum of 30 analog trunks into 8-bit PCM format/
Correct Answer
C. Trunk Modules
Explanation
Trunk modules are responsible for encoding and multiplexing incoming speech from analog trunks into 8-bit PCM format. These modules are designed to handle a maximum of 30 analog trunks and convert the analog signals into digital format for transmission over the digital carrier modules. The trunk modules play a crucial role in the digital multiplex switch by converting and combining multiple analog trunks into a single digital stream, thereby increasing the efficiency and capacity of the system.
34.
Which digital multiplex switch module is used for direct interfacing with the T-1 office repeater?
Correct Answer
D. Digital Carrier
Explanation
The digital carrier module is used for direct interfacing with the T-1 office repeater. This module is responsible for transmitting and receiving digital signals over the T-1 line. It handles the conversion of analog signals to digital and vice versa, ensuring efficient communication between the office repeater and the multiplex switch.
35.
Which digital multiplex switch module consists of a duplicated central message controller?
Correct Answer
D. Central Control (CC)
Explanation
The correct answer is Central Control (CC). The Central Control module in a digital multiplex switch consists of a duplicated central message controller. This controller is responsible for managing and controlling the flow of messages within the switch. It ensures that messages are properly routed and delivered to their intended destinations. The duplication of the controller provides redundancy and ensures that the system remains operational even if one controller fails.
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?
Correct Answer
A. The line module reports a subscriber origination to the central control (CC)
Explanation
When a subscriber lifts the handset to make a dial pulse intra-office call, the line module in the defense switched network (DSN) switch reports a subscriber origination to the central control (CC). This means that the line module notifies the CC that a subscriber has initiated a call. The CC then proceeds with the necessary actions to establish the call, such as routing and connecting the call to the appropriate destination.
37.
When a called a defense switched network (DSN) subscriber answers, what action is taken by the switch's central control (CC) module?
Correct Answer
D. A message is sent to the originating peripHeral processor to remove ringing tone
Explanation
The correct answer is "A message is sent to the originating peripheral processor to remove ringing tone." When a called DSN subscriber answers the call, the switch's central control (CC) module sends a message to the originating peripheral processor to remove the ringing tone. This indicates that the call has been successfully answered and the ringing tone needs to be stopped.
38.
The Red switch program provides which subscriber(s) a Red telephone?
Correct Answer
B. Command and Control (C2) only
Explanation
The Red switch program provides a Red telephone to the Command and Control (C2) only. This means that only subscribers involved in command and control activities can access and use the Red telephone provided by the Red switch program. It excludes subscribers who are involved in operational support, logistics, or both.
39.
What is the major type(s) of terminal used in the Defense Red Switched Network?
Correct Answer
D. STU-III and STE
Explanation
The major type(s) of terminal used in the Defense Red Switched Network are the Secure Telephone Unit III (STU-III) and Secure Terminal Equipment (STE).
40.
What type of device is used to provide the cryptographic engine for the secure terminal equipment (STE) terminal?
Correct Answer
C. FORTEZZA card
Explanation
A FORTEZZA card is used to provide the cryptographic engine for the secure terminal equipment (STE) terminal. The FORTEZZA card is a type of smart card that contains encryption algorithms and keys necessary for secure communication. It is specifically designed to meet the requirements of the National Security Agency (NSA) for secure communications.
41.
Which encryption device will support asynchronous secure voice modes up to 38.4Kbps and high-speed secure data transfers up to 128 Kbps when connected to the 2B + B Integrated Services Digital Network (ISDN)?
Correct Answer
A. Secure Terminal Equipment (STE)
Explanation
The Secure Terminal Equipment (STE) is the correct answer because it supports asynchronous secure voice modes up to 38.4Kbps and high-speed secure data transfers up to 128 Kbps when connected to the 2B + B Integrated Services Digital Network (ISDN). The other options, Secure Telephone Unit-III (STU-III), KG-84, and KG-94, do not have the same capabilities to support these modes and speeds.
42.
What is the maximum asynchronous data rate for the Defense Red Switch Network (DRSN)?
Correct Answer
C. 19.2 Kbps
Explanation
The maximum asynchronous data rate for the Defense Red Switch Network (DRSN) is 19.2 Kbps.
43.
What type of capability is provided by Defense Red Switched network (DRSN) to define the needs, the capabilities, and limitations of individual trunks and trunk groups?
Correct Answer
B. Class of service marks
Explanation
The Defense Red Switched network (DRSN) provides the capability of defining the needs, capabilities, and limitations of individual trunks and trunk groups through class of service marks. Class of service marks allow for the prioritization and differentiation of different types of traffic on the network, ensuring that certain types of communication receive higher priority and better quality of service. This capability helps in efficiently managing and controlling the flow of traffic on the network, based on the specific requirements and priorities of different users or applications.
44.
Which piece of equipment is used to provide secure connectivity to the Red switch via an attendant and local-site radio facilities?
Correct Answer
C. Interface and control unit
Explanation
The interface and control unit is the correct answer because it is the piece of equipment used to provide secure connectivity to the Red switch via an attendant and local-site radio facilities. This unit is responsible for managing the interface between the Red switch and the attendant's equipment, ensuring secure and reliable communication.
45.
What interface provides the Red switch 24-channel digital interswitch trunk group service at 1.544 Mbps?
Correct Answer
C. Digital trunk group circuits
Explanation
Digital trunk group circuits provide the Red switch 24-channel digital interswitch trunk group service at 1.544 Mbps.
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
Correct Answer
B. Interface ancillary device
Explanation
The interface ancillary device is 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. This device acts as a bridge between the switch and the cryptographic equipment, facilitating the secure communication process. It handles the necessary signaling and control functions to establish a secure connection, ensuring the integrity and confidentiality of the call.
47.
The Non-Secure Internet Protocol Router Network (NIPRNET) is
Correct Answer
D. Partially protected by encryption devices
Explanation
The NIPRNET is partially protected by encryption devices. This means that while some measures are in place to secure the network, it is not fully encrypted. Encryption is a method of encoding data to make it unreadable to unauthorized users, and it provides an additional layer of security. However, since the NIPRNET is only partially protected by encryption devices, there may still be some vulnerabilities or risks associated with the network.
48.
What is the difference between a Hub router and a premise router?
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)?
Correct Answer
D. Network Encryption System (NES)
Explanation
The Network Encryption System (NES) is an internet protocol (IP) encryption device that can be directly connected to Red local area networks (LAN). It is designed to provide secure communication and protect sensitive information transmitted over the network. The other options, KG-84, KG-194, and KIV-7, are encryption devices, but they may not be specifically designed for direct connection to LANs or for IP encryption.
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?
Correct Answer
A. Microwave and laser
Explanation
Microwave and laser systems are used to interconnect integrated communications access package access nodes on a deployed base within the same theater area. This means that in addition to fiber-optic and copper cables, microwave and laser technology is utilized for communication purposes. These systems provide a wireless connection that allows for the transmission of data and information between access nodes, ensuring efficient and reliable communication within the deployed base.