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Radio Communication
3C251 - Volume 4 - Section 1
67
Communication
Professional
10/02/2010

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Cards

Term
What led to the development of VHF and UHF radio systems during World War II?
Definition
The need for more reliable high-capacity communications.
Term
The two primary types of radio waves are
Definition
ground and sky
Term
What condition causes the downward bending of a radio wave as it grazes the top of an obstruction such as a mountain peak?
Definition
Diffraction
Term
During periods of maximum sunspot activity, what is the density level and altitude effect of the F layer?
Definition
More dense and at a higher altitude
Term
What type of frequency is the highest frequency that returns to earth when it is transmitted vertically under given ionoshperic conditions?
Definition
Critical frequency
Term
A satellite system that requires numerous satellites in randomly spaced orbits to provide acceptable coverage is
Definition
a passive system
Term
What is a major disadvantage of a geostationary satellite?
Definition
The two-way propagation delay is about 0.6 seconds.
Term
Above what frequency does the propagation loss because of oxygen and water absorption become very serious in satellite communications?
Definition
10 GHz
Term
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
Definition
free space attenuation
Term
The Doppler effect, inherent to satellite communications, is caused by
Definition
the satellite's motion is space relative to ground stations
Term
Which satellite communications subsystem consists of a satellite antenna array and a transponder?
Definition
Space
Term
What satellite device receives, amplifies, and retransmits signals from earth terminals?
Definition
Satellite transponder
Term
At a minimum, a typical link involves
Definition
an active satellite and two earth terminals
Term
maintaining optimum performance of a satellite's transponder is a function of
Definition
satellite control
Term
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?
Definition
TDMA
Term
Two system control problems with time division multiple access are in the area of network timing and
Definition
synchronization
Term
What satellite access system lets several users occupy the same frequency spectrum in the transponder simultaneously?
Definition
SSMA
Term
What organization is responsible for the design, acquisition, and single systems management of the Defense Switched Network?
Definition
DISA
Term
How is survivability provided in the DSN?
Definition
End offices are multiple-homed
Term
How is responsiveness provided in the DSN?
Definition
The DSN offers precedence access thresholding (PAT)
Term
What type of DSN precedence call cannot be preempted?
Definition
Flash Override
Term
What type of precedence is assigned to DSN calls pertaining to situations that gravely affect the security of national and allied forces?
Definition
Intermediate
Term
Which encryption device makes end-to-end encryption available to any user of the DSN?
Definition
STU-III
Term
What is the primary difference in the DSN subsystems?
Definition
Internal call processing features and functions
Term
Why should high-priority users not be terminated on RSU?
Definition
RSU can become isolated from the parent switch
Term
An end office is part of what subsystem of DSN?
Definition
Switching
Term
Which DSN switch functions primarily as a tandem switch?
Definition
Stand-alone
Term
What type of DSN switch provides services to a PBX?
Definition
EO and multifunction only
Term
Which type of connection provides the transmission links between two DSN switches?
Definition
Interswitch trunks only
Term
Which type of connection is a single or multichannel connection that allows user equipment to gain access to the DSN?
Definition
Access lines only
Term
Which organization provides theater-wide administration and network management in the DSN?
Definition
RNOSC
Term
In a digital multiplex switching system, what appears between the peripheral module and the network in addition to the 30 channels of encoded speech?
Definition
Synchronizing channel and signaling channel
Term
Which digital multiplex switch module encodes and multiplexes incoming speech from a maximum of 30 analog trunks into 8-bit PCM format?
Definition
Trunk module
Term
Which digital multiplex switch module is used for direct interfacing with the T-1 office repeater?
Definition
Digital carrier
Term
Which digital multiplex switch module consists of a duplicated central message controller?
Definition
Central control (CC)
Term
When a subscriber lifts the handset to make a dial pulse intra=office call, what process occurs in the DSN switch?
Definition
The line module reports a subscriber origination to the CC
Term
When a called DSN subscriber answers, what action is taken by the switch's CC module?
Definition
A message is sent to the originating peripheral processor to remove ringing tone
Term
The Red switch program provides which subscriber(s) a Red telephone?
Definition
Command and control (C^2) only
Term
What is the major types of terminal used in the Defense Red Switched Network?
Definition
STU-III and STE
Term
What type of device is used to provide the cryptographic engine for the secure terminal equipment (STE) terminal?
Definition
FORTEZZA card
Term
Which encryption device will support asynchronous secure voice modes up to 38.4 Kbps and high-speed data transfers up to 128 Kbps when connected to the 2B+D Integrated Services Digital Network (ISDN)?
Definition
STE
Term
What is the maximum asynchronous data rate for the DRSN?
Definition
19.2 Kbps
Term
What type of capability is provided by DRSN to define the needs, capabilities, and limitations of individual trunks and trunk groups?
Definition
Class of service marks
Term
Which piece of equipment is used to provide secure connectivity to the Red switch via an attendant and local-site radio facilities?
Definition
Interface and control unit
Term
What interface provides the Red switch 24-channel digital interswitch trunk group service at 1.544 Mbps?
Definition
Digital trunk group circuits
Term
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
Definition
interface ancillary device
Term
The NIPRNET is
Definition
partially protected by encryption devices
Term
What is the difference between a Hub router and a premise router?
Definition
Interconnected via the Defense Information Systems Agency Asynchronous Transfer Mode (DATM) network
Term
Which is an IP encryption device that can be directly connected to Red LAN?
Definition
Network Encryption System (NES)
Term
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?
Definition
Microwave and laser
Term
Which is the design architecture of TDC?
Definition
MAN and hub spoke
Term
What type of connectivity does TDC provide to the voice backbone?
Definition
1.544 Mbps ISDN PRI connectivity
Term
What equipment is included in the customer access node to provide the intra-site connectivity?
Definition
Voice switch and Promina multiplexer
Term
What is the major component(s) of the TDC system that provides mobile units with flexible, lightweight, secure, modular, and integrated deployable communications?
Definition
LMST and ICAP
Term
What is the long-haul transmission component of TDC?
Definition
LMST
Term
What integrated communications access package module contains circuit switches that implement PBX?
Definition
Basic access module (BAM)
Term
What integrated communications access package module provides secure conferencing capability?
Definition
Secure voice module and STU-III
Term
What's the difference between the BAM and the CAM?
Definition
The BAM has a fixed capability
Term
What ICAP node module provides the RF LOS link function for internodal connnectivity?
Definition
Microwave
Term
What is the maximum number of personnel a medium size ICAP node can support?
Definition
150-200
Term
What support does the multi-channel standard tactical entry point provide to deploying forces?
Definition
Communications capability to connect to the DISN
Term
Upon arrival in a theater, what frequency band does the LMST use for initial communications connectivity to the defense satellite communications system?
Definition
X only
Term
What type of equipment is included in TDC sustaining packages and is deployed to the area of operations to form a large network?
Definition
The same versions of modules in the TDC initial communication support packages
Term
What LMST capability reduces the limitations of the DSCS?
Definition
C- and Ku-band access
Term
What deployed system is used to provide secure/nonsecure routers and data packet capability?
Definition
TASDAC and TDC
Term
What TDC system provides defense message system (DMS) message handling services?
Definition
Stand-alone message processing system
Term
What must customers do to connect their own telephones and computer workstations to the TDC backbone network?
Definition
Adhere to various open system standards and interfaces such as Ethernet
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