3D152 Flashcards
How many B and D channels does the standard configuration in North American Integrated
Services Digital Network (ISDN) primary rate interface (PRI) application use?
23, 1
What is the most serious threat to voice network system integrity?
Subversion.
In the event of a power failure, how many hours can the vertical taut-wire sensor (VTWS) remain operational?
4
What is an example of analog-to-digital and digital-to-analog techniques?
Pulse code modulation (PCM) and continuously variable slope delta (CVSD) modulation.
What is the range of the alternate current (AC) presence time delay relay in the AN/GSS-39
system before a power loss is reported?
1.5 to 15 seconds
What converts analog signal information into a digital carrier signal?
Digital modulation
Amplitude modulation (AM) requires a bandwidth that is
twice that of the modulating signal.
The information-carrying components that occur on either side of a carrier are called
sidebands.
The upper sideband in a single-sideband suppressed carrier (SSBSC) modulation is eliminated by
filtering.
We can express the 6-to-1 improvement of the single-sideband suppressed carrier (SSBSC)
modulation over conventional amplitude modulation (AM) as
8 dB of improvement.
A modulated waveform that contains a carrier plus two sidebands for each modulation frequency is a description of
an amplitude modulation (AM).
If 100 percent modulation is exceeded and there is distortion in the modulating signal, additional sidebands are generated. We identify these sidebands as what?
Splatter.
The only basic waveform in nature is a
pure sine wave
The amount of deviation in a frequency modulation (FM) signal is directly proportional to the modulating signal’s
amplitude
The amount of phase shift in a phase modulation (PM) signal is directly proportional to the
amplitude of the modulating signal.
In quadrature-phase shift keying (QPSK) the radio frequency (RF) bandwidth for a quadriphase signal is what of that required by a bi-phase signal, given the same data rate.
half
What form of modulation is insensitive to signal variations?
Binary-phase shift keying or bi-phase shift keying (BPSK).
What is the main advantage of differential phase shift keying (DPSK)?
It requires a less complex receiver than a basic phase shift keying (PSK) signal.
How many bits per character of a 16-step pulse-code modulation (PCM) system are used to describe the quantized analog sample?
4
Quantized analog modulation is actually
analog-to-digital conversion
The form of pulse modulation in which the pulse is varied within a set range of positions is known as
pulse-position modulation (PPM)
The process of coding pulse code modulation (PCM) quantized pulses to make them a constant duration and amplitude is
encoding
Which of the following is not considered an analog modulation techniques?
Pulse-Code Modulation
In Time Division Multiplexing (TDM), the transmitting multiplexer will put a bit or a byte from each of the incoming lines into a specifically allocated what?
Time Slot
The method of multiplexing the T1 multiplexer uses is
time division
The two major types of frame structures are
CCITT and low speed.
The most common wave-division multiplexing (WDM) system uses how many wavelengths?
Two wavelengths.
Wave-division multiplexing (WDM) creates the virtual channels for multiplexing them together for transmission by using different
wavelengths or lambdas.
Bit count integrity problems are primarily caused by
system timing faults.
Individual pulses within a digital signal are
bits.
What unit is most commonly used in data systems to express signaling speed?
Baudot.
A digital signal that contains synchronizing bits within the signal stream describes
asynchronous operation.
Three categories of synchronization used in digital data circuits are
synchronous, asynchronous, and isochronous.
Which option is a characteristic of synchronous data operation?
All data bits are the same length in time.
In what type of signal does the signal level move to one of the discrete signal levels, but returns to the zero level after a predetermined time?
Return-to-zero.
Digital coding techniques such as binary with eight-zero substitution (B8ZS) are becoming more popular because they are designed to
operate at higher data rates.
The major difference between conditioned di-phase (CDI) and other schemes is the
use of mid-bit transitions for timing.
Which statement best describes a binary with eight-zero substitution (B8ZS) signal?
Bipolar violations are intentionally inserted into a data signal to break up long strings of zeros
Which statement best describes an alternate mark inversion (AMI) signal?
A logic one is transmitted as positive voltage if the previous logic one was negative.
How many bits are in the D4 framing sequence?
12
How many bits are in the extended superframe format (ESF) framing sequence?
24
What communications information signal uses a continuous 350- and 440-Hz frequency pair?
Dial tone.
What communications supervisory signal uses a continuous application of direct current voltage for signaling?
Loop-start
In common associated signaling (CAS), what is the seventh bit in frames 6 and 12 used to convey signaling information known as?
Bit robbing
In what common channel signaling (CCS) mode are the messages relating to signaling between two points conveyed directly interconnecting these signaling points?
Associated mode
While timing makes sure the equipment is sending and receiving bits at the same time intervals, synchronization makes sure that the
receive equipment can find its place in the bit stream.
What term is associated with the delay or lag introduced in the application of voltage from one section to the next?
Latency
Jamming a portion of the frequency spectrum is an example of
electronic attack.
The definition of electronic attack can be found in which publication?
Air Force Doctrine Document 2-5.1.
Any actions we take to protect our forces, facilities, and equipment for electronic action that can destroy or degrade our capabilities is considered
electronic protection.
Varying the pulse repetition frequency on a radar set is an example of
electronic protection.
When a multimeter has three input terminal jacks, which jack is always used?
Voltage terminal.
When using a multimeter, which mode should be used if the reading fluctuates and a more accurate reading is desired?
Minimum/maximum (MIN/MAX).
When using an ohmmeter to take a resistance reading, what preliminary precaution should you take?
Disconnect the power from the circuit being tested.
What principle of operation does the time domain reflectometer use to test cables?
Radar
Which push-buttons would you select to get 125-ohm (Ω) impedance on the time domain reflectometer?
50Ω and 75Ω
What are the two major sections of a bit error rate test (BERT) set?
Extended superframe.
When performing a bit error rate test (BERT), what determines the size of a test pattern segment?
The number of bits that can represent the total number of bits in the test pattern.
Which section of a bit error rate test (BERT) set measures the received test pattern?
Receiver.
On a breakout box, how many RS-232 key interface signals can be monitored and accessed individually?
12.
The purpose of the miniature ON/OFF switches on a breakout box is to
allow the interruption of the individual interface conductors.
What communications control signal uses a two-frequency dialing combination?
Tone dialing.
What communications information signal uses a signal cycled on and off for 0.5 second and contains the generation of a 480- and 620-Hz frequency pair?
Busy signal.
When is the voltage applied in loop-start signaling?
Off-hook condition.
What are the two principle weighting characteristics in use with telecommunication circuit noise?
CCITT psophometric and C-message.
Attenuation distortion is caused by
differing attenuation rates for the various frequency components comprising a voice frequency transmission.
Electronic warfare support includes devices such as
radar warning receivers and intelligence systems.
When using a multimeter, which mode should be used if the reading is unreadable due to fluctuations?
Display hold.
What is the power that is reflected back to an optical source in the time domain reflectometer (TDR)?
Backscatter.
How many possible symbols can 4 bits represent?
16
What happens when more bits are added to a digital signal arranged in a sequence understood by the sender and receiver?
A code set is established.
In networking, a byte is identified as a/an
octet.
What Electronic Industries Alliance (EIA)/Telecommunications Industry Association (TIA)
standard is used for commercially building telecommunications cabling?
568A.
What organization sets important computer networking wiring standards for residential and
commercial network cabling?
Electronic Industries Alliance (EIA).
A collection of standards for local area network (LAN) architectures, protocols, and technologies called Project 802 were developed by the
Institute of Electrical and Electronics Engineers (IEEE).
The definition of the Open System Interconnect (OSI) reference model was a major contribution to networking made by the
International Organization for Standardization (ISO).
The “parent” organization, headquartered in Geneva, Switzerland, for all other telecommunications organizations is the
International Telecommunication Union (ITU).
There is a worldwide nonprofit association of technical professionals that promotes the
development of standards called the
Institute of Electrical and Electronics Engineers (IEEE).
What organization is responsible for the X-series and V-series standards?
International Telecommunication Union Telecommunications Standardization Sector (ITU-T)
Which of the following is an International Telecommunication Union (ITU) standardized
format used for digital telecommunications services backbone system?
E-carrier.
Which series of standards are recommended for data transmission using the telephone network?
V
What transmission rates does Electronic Industries Alliance (EIA) RS-530 accommodate?
20 Kbps to 2 megabits per second (Mbps).
Which Electronics Industries Alliance (EIA) interface standard has the ability to work in either balanced or unbalanced electrical circuits?
RS-530
Within how many feet of the data communications equipment (DCE) connection does the
Electronics Industries Alliance (EIA) RS-232-C standard prescribes bipolar-voltage serial data transmission?
50.
At what Open System Interconnect (OSI) layer are common data compression and encryption schemes used?
Presentation.
What Open System Interconnect (OSI) layer is closest to the end user?
Application.
What two sublayers did the Institute of Electrical and Electronics Engineers (IEEE) divide the Open System Interconnect (OSI) data link layers into?
Logical Link Control (LLC) and Media Access Control (MAC).
In the Open System Interconnect (OSI) model, a layer will communicate with three other OSI layers. Which one is not one of those layers?
Lowest layer.
Which information unit, whose source and destination are network-layer entities, uses connectionless network service?
Datagram
In binary-synchronous protocol, what character is used to establish and maintain character
synchronization prior to the message block and during transmission?
SYN.
What data communication protocol is used to govern the flow and format of information between systems?
Character-oriented.
What data communication protocol ensures that the receiving station can distinguish information from garbage?
High-Level Data Link Control (HDLC)
What data communication protocol is based on bits and the position of the bits?
Bit-oriented.
A group of computers and associated devices that share a common communications line within a small geographic area is a
Local area network (LAN).
The interconnection of several networks in a city into a single larger network is a
Metropolitan area network (MAN).
What type of network connects networks that are typically separated by geographical distances?
Wide area network (WAN).
What type of network enables a group of two or more computer systems to communicate over the public Internet?
Virtual private network (VPN).
Which type network enables users to share resources, files, and printers in a decentralized way?
Peer-to-peer.
What Network layer protocol provides information about how and where data should be delivered, including the data’s source and destination addresses?
Internet protocol (IP).
Which Network layer protocol matches a known internet protocol (IP) address for a destination device to a Media Access Control (MAC) address?
Address Resolution Protocol (ARP).
Which Network layer protocol provides the internet protocol (IP) address for a device that knows its own Media Access Control (MAC) address?
Reverse Address Resolution Protocol (RARP).
Which Transport layer protocol does not guarantee that packets will be received at all?
User Datagram Protocol (UDP).
