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172 Cards in this Set

  • Front
  • Back
What does PWM affect
width or duration
RS-232 transmit pin
2
What is dispersion
light pulses spread out as they travel down the fiber
Color code for UTP
blue, orange, green, brown
what does dispersion limit
fiber's bandwidth
What does ARQ do
reciever sends retransmit signal if error found
In FM, what does the carrier phase shifts at
rate of modulating signal
What year did the EIA develop telecomm cabling standards
1985
RS-232 receive pin
3
What does PIM diode do
converts one photon to one electron
What is V.35 used for
internodal trunks between X.25
Two types of dispersion
modal & material
When does employment phase begin
when first element of convoy departs
principals of refraction include what
normal, angle of refraction, angle of incidence
RS-232 data set ready pin
6
2 sidebands, no carrier
DSBSC
Fiber connector w/no keying device
Sub-minature, Type A (SMA)
What is the spectral range of LED
700-900 nm
what is spelled out on the frag order
frequencies and configurations
5 parts of fiber optics link
driver, source, optic fiber, detector, output circuit
What is AEFC
nerve center for all deployment activity
What does PAM affect
amplitude
RS-232 terminal ready pin
20
RS-232 9.6 Kbps length
5,000 feet
RS-530 connector type
25-pin D-type (DB-25)
What authority does AEFC not have
No chain of command over AEF units
First step in the recovery
safety briefing
Why twist multipair cable
reduce crosstalk
Most common error correction technique
automatic retransmit on request (ARQ)
What do sidebands take power from
modulated carrier
The two reasons to modulate
ease of radiation & channel allocation
NACC says how many network problems are cable related
70%
RS-232 stop bits
1, 1.5, 2
Three requirements of fiber light source
Risetime fast enough to meet bandwidth, Provide enough optical power, wavelengh must take advantage of low-loss propagation
What is block check sum used with
LRC
What does modulation index equal
frequency deviation/frequency modulating signal
What must be done to radiate over long distances
change to analog format
What determines what light detectors can pick up
noise floor, signal-to-noise ratio (SNR)
What must be done to transmit low frequency signals at higher frequencies
modulation
How do LEDs differ from lasers
LEDs incoherent & Lasers coherent
What do synncronous transmission do with charactors
blocks many charactors together
When is turn around complete
post deployment inspections complete, maintenance actions documented, supply actions documented and items requesitoned
What do FM sidebands need to be significant
at least 1% of total power
What standard uses much of the same pins as RS-232
RS-530
What is the STP bendign radius with a sheath
6 inches
Max speed of CAT4
20 Mbps
RS-422 10 Mbps length
40 feet
What is material dispersion
different velocities for separate wavelenghts
Wht does the backbone provide
interconnectivity between buildings
What are APDs suitable for
high-speed, long-distance
What principal does fiber optics work on
total internal reflection
What does the surface emitter have
etched will in GaAs
What is the PN junction
depletion region
Minimum RS-232 pins
2, 3, 7
What is the bending radius of STP without a sheath
3 inches
In RS-232, if connecting two computers what must cross
2 & 3, 4 & 5, 6 & 20
What is the advantage of SSBSC
1/2 bandwidth required
What is the purpose of RS-232C
provide compatability between various communication devices
When does the employment phase end
when the end-ex order is received
When does the communications network end
When the communications end-ex order is received
What varies frequencies of signals
FM
How does the FM oscillator deviate
Deviates above carrier frequency during positive half cycle of the modulating signal
Why was RS-530 developed
Due to the disadvantages of RS-449
In FM, the rate of deviation is proportional to what
frequency of the modulting signal
When does fiber require shielding
When constructed with metallic sheild
What is the pull tension for unshielded UTP
25 lbs
What is the makeup of a patch cord
one connector at each end
What is the life of the cabling systems that EA come up with
10 years
What are the 3 fiber lightsources
LED semiconductor laser diode, non-semiconductor laser diode
What part of DSBSC carries info
amplitude & phase
What is modal dispersion
different paths of light in various modes
What does LRC check
entire horizonal line for parity
When is CRC most effective
When blocks are greater then 512
what is dark current
small current with no light
What are the two ways to connect equpment to transmit serial
single-ended (unbalanced) & differential (balanced)
What material is used for semiconductor photodiodes
silicon
What is numberical aperture
fiber's light gathering capability
What is STP backbone made out of
22 or 24 AWG
What is the fiber optics light range
750 to 1500
What is used to exctract info from the DSBSC
heterodyne detector
1 sideband, no carrier
SSBSC
Max speed of CAT5
100 Mbps
RS-232 clear to send pin
5
What is the UTP benging radius
1 inch
What does the AEFC ensure
ensures AEFs maintainted at peak readiness
What are broadcast facility records for
records and drawings pertaining to broadcast system facilities
What standard is for balanced cirucits
RS-422
What is attenuation in fiber described in
dB/km
What are the line driver volts for RS-422 and RS-423
4.0 to 12.0 volts peak-to-peak
What is the RS-422 transition region
-2.0 to +2.0 volts
What is the DTE
source and destination of data
What are the 4 steps in projects
Inventory, familarization, review, document findings
RS-423 100 Kpbs length
300 feet
What does Snell's Law state
if light enters junction of two media at different refractive indices beyond the critical angle, the light is totally internally reflected
How can Fresnel losses be reduced
by using index-matching fluids
What is RG-58 known as
thinnet
What is the DCE
device which transfers data to end point
What does uniform quantizing do
define conded amplitude values as steps of equual amplitude range
What does non-uniform quantizing do
provide more coded amplitude levels at low signals levels with fewer at high signal levels
What is done in the review phase
identify and solve any potential problems
What are UTCs for
systematic planning of force packages
What is the UTC for comm & info
6K
What is the ATM transmission unit
one charactor in length
To recover intel from DSBEC, you must reinsert carrier frequency at what
exact frequency & phase modulation
What is the ATM parity bit for
determines if transmission good or bad
What is 98% effective when used together
VRC & LRC
RS-232 56Kbps length
50 feet
How is dispersion measured
ns/km
What does responsivity respond on
wavelength of light
What is briefed to personnel
security measures, local conditions, purpose of deployment, estimated duration
What does band limiting do
calculates highest and lowest freqencies
RS-422 10Mbps length
4,000 feet
What is optical pwoer expressed in
microwatts & milliwatts
What is the refractive index
ratio of speed the light in a vacuum to its speed in a medium
how often are EIA standards reviewed
5 years
In FM, the amount of oscillator frequency change relationed with the signal
directly proportional ot the amplitude of teh modulating signal
What are reasons for deployements
war, national emergency, natural disaster, practice, readiness inspection
What are the twon important factors of light propagation
refractive index & angle which the light strikes the junction of the material
What does the system engineering phase include
completion of cable sheets, planning system cannibalization, obtaining necessary freuqncy assignments, cre assignment sheets, technical control config, circuit engineering
When is the frag order used
used for each tactical operation
What is the Nyquist sampling theorem
taking samples at twice the highest frequency in the band-limited signal
In fiber, attenduation comes from what two things
absorption and Rayleigh scattering
RG-58 max length
185 meters
Two types of photodetectors
positive intrinstic negative (PIN) & avalanche photodiode (APD)
In PM, the carrier phase shifts at what
the rate of the modulating signal
What is the makeup of breakout cables
connector at one end, multifiber cables at other
what is the maximum distance of horizonal cables
90 meters
What is MEFPAK
AF system for UTC package management
What are the two designs of LEDs
edge-emitter & surface emitter
what are the results of overbending fiber
microbending & macrobending
What are the steps to pulse code modulation
band limiting, sampling, quantizing, encoding
What interconnects backbone media to horizontal media
mechanical terminators, patch cords, jumper cables
What prevents direct contact of securing devices to cable's outer sheath
cable shims
PPM affects what
position
How effective is CRC
99%
How does light bend away from the normal
passes from a higher-index material to a lower one
What varies amplitude of the carrier
AM
In AM, what needs 2x bandwidth to transmit
DSBEC
Disadvantage of DSBEC
wastes power
What is forward error control
recieving end corrects errors
FM produces how many sidebands
infinite
Fiber Optics immune to what
EMI
What does AEFC maintain
lessons learned library from previous deployments
What is ATM
High-bandwidth technology with speeds at 600 Mbps or more
Makeup of Pigtail
connector at one end and spliced at other end
What does sampling do
converts continuous signal into discreet signal
What is light
elecromagnetic radiation in the wavelength range
What does quantizing do
finite values replaces infinite values
8 PSK produces how many bits
3 bits
one-millionith of a meter is
micron
FCC establishes limits on what
modulating signal
what are post deoployment converence actions
discuss equipment and circuit problems
How many AEFs are there
10
What determines the frequency of the wave
Energy posessed by the photon
In FM, what is amount of deviation proportional to
amplitude of the modulating signal
Max RG-58 length from horizontal to DTE
15 meters
RS-232 logic 0 volts
+5 to +15 volts
RG-58 pulling tension
25 lbs
Why divide backbone and horizontal cabling structures
Keeps LAN/WAN managable
How many pair grouping in UTP
25 pairs
What is pull tension on shielded UTP
450 lbs
Purpose of AEFs
meet steady-state rotational reqrirements for forward deployed forces
1 carrier and 2 sidebands
DSBEC
RS-232 logic 1 volts
-5 to -15 volts
function of RS-232 start bit
indicates beginning of serial character
What topology distributes backbone and horizontal fiber optic cable
star
How many cross-connects are allowed from MC to horizonatal interface in TC
2
What is the single-mode fibers backbone length
60 km
What is a trigger point
When more forces are required then the AF maintains
VRC checks for what
odd or even parity
LED stands for what
light emmiting diode
Non-uniform quantizing and companding decreases the length of the code from
11 to 7