D2 Pt1
What is an option for a broadband cable network to maximize the use of its optical fiber resources?
Leasing spare fibers
Which of the following best describes basic service provided by the cable company?
Local-origination channels
Which fiber-optic cable type provides the most stable transport characteristics and additional protection from stresses caused by macrobends and microbends?
Loose-tube cable
The NESC provides guidelines concerning which portion of the fiber-optic cable network?
Minimum safety clearances between different conductors of overhead and underground electric supply and communication lines
What is a common solution when congestion from modem activity and traffic becomes unacceptable in a hybrid fiber/coax network?
Node splitting, the subdividing of serving areas into two or more smaller serving areas
what does the amplification process in an avalanche photodiode (APD) introduce into the electrical output of an optical detector?
Noise
Which element of a PON consists of a downstream (forward path) optical transmitter, an upstream (return path) receiver, and a multiplexer/demultiplexer?
OLT
What is true of offline UPS systems?
Offline UPS systems route incoming power directly to connected devices and switch to a battery backup during a power interruption
Which component of an optical modulation system contains an optical detector and demodulator?
Optical receiver
Which of the following is a passive device that performs the bi-directional functions of optical splitting and optical combining?
Optical splitter
What product based on the DOCSIS defines the protocols for IP telephony over HFC networks?
PacketCable
Which of these items should be identified on a route map so that the design can provide (or not provide) special network access?
Parks
What about RFoG made broadband cable operators envision using it to make a seamless transition from the legacy HFC architecture over to a GPON or EPON?
RFoG can operate in parallel with GPON and EPON, independent of the PON communications protocols and data rates
In an optical network, what is reflectance?
Reflectance is the reflected light from a single Fresnel reflection event
Which of the following is the ratio of electrical output power from the detector to the optical input power, expressed by amperes or volts per watt of optical input power?
Responsivity
What is a consideration for using ribbon fiber?
Ribbon fiber requires different tools and and equipment to perform splicing
Which of the following is true about the SONET transmission standard?
SONET defines Optical Carrier (OC) data rates and interface standards that enable international communications carriers to interconnect existing fiber-optic transmission networks
When installing fiber-optic cable over coaxial cable, what should be done at the coaxial cable expansion loops?
Secure the fiber-optic cable to the strand across the coaxial cable expansion loops using plastic cable ties or support straps
Which fiber-optic cable design category typically uses some star topology variation?
Signal distribution
Which of the following is true in a DOCSIS 3.1 CMTS?
The CMTS transmits data downstream using OFDM and QAM carriers
When delivering high-speed internet service, the cable modem tunes to the downstream carrier and communicates with which of the following?
The Cable Modem Termination System (CMTS)
What is the one main function of the FDH?
The FDH provides effective fiber management by grouping splitters into local serving areas.
What is an advantage of a digital return system?
The amount of fiber required in the network can be greatly reduced by using DWDM digital return transmitters in hub-to-headend architectures
What are the two accepted methods for pulling the fiber-optic cable off the cable reel as part of an aerial installation?
The back-pull method and the drive-off method.
What should you be looking for when analyzing the network design maps to troubleshoot a problem?
The device common to those customers affected before traveling to make signal status checks
How can a distribution amplifier be identified in the network or on a network design map?
The distribution amplifier has multiple downstream outputs
What two critical elements align the optical fibers in a connection?
The ferrules and the mating adapter
When opening a distribution amplifier station housing, why is it usually unnecessary to loosen the bolts at the bottom of the housing?
The housing lid is usually attached to the base of the housing with hinges
Why are laser diodes most effective when coupled to single-mode fiber?
The laser diode has a small spectral width, efficient coupling, and fast modulation speeds
How can a less-experienced technician identify what non-standard symbols on the network design maps represent?
The legend at the bottom of the network design map that defines the map symbols, cable types, and amplifier data
The number of rectifiers used in a DC power plant design depends on what?
The load that is placed on the system
How does a centralized server VOD architecture simplify server management compared to distributed server architecture?
The number of servers needed for video content storage is smaller than in the distributed server architecture
What occurs in the wavelength division multiplexing (WDM) process?
The optical output from multiple lasers operating at different wavelengths is combined and transported over a single, common optical fiber
What is the RF distribution tap value indicated on the tap face plate by a sticker or number stamped into the housing?
The signal loss between the downstream input port and tap ports
What is involved when monitoring the status of optical nodes?
The use of a node transponder that continuously monitors many several critical functions
How is the cable jetting method of installing fiber-optic cable in conduit different from other methods?
There is no need for a pulling rope in the conduit before the cable is installed
What characteristics about upstream signals from cable modems and set-top boxes (STB) make them impractical for verifying and aligning a distribution amplifier return section?
They are of short duration and originate from various locations
What is true of online UPS systems?
They are recommended for commercial applications such as data centers and telecommunications operations
How do technicians know the specific type of SMF used in a particular project?
They have read the project's specification records
Which of the following is true about optical nodes?
They maintain four main sections: the optical receiver, radio frequency (RF) amplifier module, the reverse optical transmitter, and the Direct Current (DC) power supply
Why is -48 VAC within a positive ground used by the telecommunications industry?
This reverse polarity is a means of mitigating electrolytic corrosion on the outside plant
How does a distribution amplifier in a fiber node receive the downstream radio frequency (RF) signals?
Through a coaxial cable that is connected to the downstream optical receiver
What test instrument sends out a test signal and displays any reflections caused by impedance mismatches in the cable that are characteristic of cable faults?
Time Domain Reflectometer (TDR)
What option is available on most optical nodes for connecting to the power supply?
To connect the power cable from the power supply directly to the power port of the node
Why do many optical nodes accept two independent power supplies?
To create redundant powering of the node
When troubleshooting an outage in an optical network, why would a technician want to refer to the network's as-built documentation?
To help determine specific cable lengths
What is the core objective of the DOCSIS provisioning of EPON, or DPoE, access architecture?
To make the EPON elements appear and operate as DOCSIS elements to the existing DOCSIS-based back office provisioning operations
Why are backup AC generators included in many commercial AC UPS and DC power systems?
To provide AC power during a prolonged utility power interruption
Why is there a diplex filter at each downstream output port in a distribution amplifier?
To separate the downstream radio frequency (RF) from the upstream RF signals
Why was the zero-dispersion point in SMF moved to 1550 nm?
To take advantage of SMF's low intrinsic absorption and lower attenuation at 1550 nm
What is the basic amplifier application that increases the amplitude of the radio frequency (RF) signal to compensate for the signal loss of cable and passive devices preceding the amplifier called?
Unity gain
What is the ideal way for a broadband cable network designer to plan the replacement of coaxial cable with fiber-optic cable to shorten amplifier cascades?
Use the existing coaxial network infrastructure
What is unique about WDM-PON?
WDM-PON deployed in a greenfield system allows each subscriber to get their own designated wavelength
What do diameter differences between spliced fibers look like on an OTDR?
What do diameter differences between spliced fibers look like on an OTDR?
In the tree-and-branch architecture, how is the downstream signal from the trunk fed to the distribution branches?
Within each trunk amplifier, a portion of the downstream is fed to a bridger amplifier to boost the signal before being split and routed to the distribution branches
What is installed in the input stage of a distribution amplifier for a flat frequency response into the input amplifier when the input signal has negative tilt?
a cable equalizer with positive slope
how is the AC voltage separated from the RF signal in a distribution amplifier?
by a capacitor which passes the AC and blocks the RF and an RF choke which offers a low resistance path to the AC and effectively blocks the RF
List the six methods by which signals arrive at the cable system headend
direct feed, satellite, over-the-air, terrestrial microwave, local origination and PSTN
What type of LED has relatively narrow spectral widths, high output power levels, and performs at high modulation rates?
edge-emitting LED
The process of combining digital services in the headend is called
multiplexing
What term describes the frequency spectrum into an amplifier having higher amplitude at low frequencies than the high frequencies?
negative tilt
What is the main factor in determining the sensitivity of an optical receiver?
noise
What is used to select which distribution amplifier secondary downstream output ports are active and whether they have equal or unequal output levels?
plug-in modules or jumpers
Which diode is the most commonly used in optical receivers because it is inexpensive and can be operated from a standard power supply?
positive-intrinsic-negative (PIN) diode
What provides the cable network's interface to the internet?
the cable modem termination system (CMTS)
what value of interstage equalizer should be installed if the associated amplifier tombstone field is blank and the amplifier output slope is 7 dB
the default factory value
when configuring the upstream return in a distribution amplifier with multiple upstream ports, the amplitude levels for which port should be adjusted first?
the distribution amplifier upstream port with the most attenuation in its upstream path
what is one drawback of using F-P lasers in HSD networks?
the emission of a number of discrete wavelengths or side modes
when configuring the input stage of a distribution amplifier, what element values can vary from those in the amplifier tombstone, depending on the input amplitude measurements?
the input equalizer and attenuator pad values
which standards organization is considered to be the creator of the world's most recognized communications standards, known as recommendations
the international telecommunication union (ITU)
why is the term "gain control" applied to amplifier gain and controls inaccurate?
the only way to vary the output of any amplifier is to adjust the amplitude level of the signal going into the amplifier
In which component in a fiber-optics communication system do changes to the intensity of the optical signal occur?
the optical transmitter
Describe an application for a distribution amplifier in an HFC network?
to maintain downstream amplitude levels to addresses farthest from the fiber-node?
In a distribution amplifier, why is the frequency response at the input of the second output stage sloped?
to reduce intermodulation distortion levels caused by amplifying high amplitude input levels
Many of the potential drawbacks from early coaxial tree-and-branch distribution can be overcome by
utilizing an HFC or PON architecture
what is the expected DC voltage on most HFC network equipment?
+ 24 VDC, +/- 0.5V
In an HFC fiber-optic node, common voltages produced by DC power supplies are +5, +12, and ______.
+24 VDC
For a 1-G EPON NGA architecture with a downstream speed of 10Gbps, what are the two upstream data rates that are supported?
1 Gbps and 10 Gbps
Which wavelength range does the EPON use for its upstream wavelengths?
1260 to 1360 nm
How many meters of slack cable is typically used in an aerial installation?
15-25 meters
What is the maximum data rate the XG-PON (10 Gigabit Asymmetric Passive Optical Network) access architecture supports in the upstream?
2.5 Gbps
What is the minimum clearance in the middle of a cable span between the power's secondary conductor and the fiber-optic cable belonging to a broadband operator?
30 inches
In terms of bandwidth, how wide is a video signal in a U.S. cable system?
6 MHz
What is one example of a stipulation in a franchise agreement that would affect network design?
A 100% fiber-optic network
What can be attached to the pulling line to prevent the fiber-optic cable from twisting during installation?
A break-away swivel
Shorts in the coaxial cable and excessive amounts of current can damage the distribution amplifier. Several devices can be used to protect the distribution amplifier from these problems. Which device shorts to ground when an overvoltage situation occurs?
A fast transfer electric crowbar (FTEC)
What is spliced into the hardline coaxial cable to combine the AC power with the transported RF signal in an HFC network
A power inserter
What is MPEG?
A universally accepted digital television (DTV) standard, first released in 1992
Which of the following statements about local ad insertion is true?
A video server usually performs local ad insertion
Which type of diode requires a higher voltage power supply and more complex circuitry than PIN diodes?
APD
Which PON access architecture type replaced the APON?
BPON
Which statement about pigtails used for optical fiber terminations is true?
Before splicing, pigtails should be labeled to correspond with the correct color code and patch panel designation
What is required for checking the physical network integrity when maintaining the coaxial cable network?
Being observant and performing some minor tasks while engaged in regularly scheduled activities
What is the wavelength allocation for video distribution, or RF overlay, in broadband passive optical network (BPON) access systems?
Between 1550 and 1560 nm
How often does the Federal Communications Commission (FCC) require cable operators to perform proof-of-performance (POP) measurements on the signals in the headend and at specified test locations throughout the network?
Bi-annually
What is the purpose for distribution amplifiers in an HFC network?
Boost the downstream signals before being divided and circulated throughout neighborhoods in the coaxial cable portion of the network
How should surface particulates usually be removed from optical connectors?
By using a combination, wet-to-dry method
Lesson 9 Question 10 CHECK
CHECK
Lesson 9 Question 8 CHECK
CHECK
Lesson 9 Question 9 CHECK
CHECK
Which of the following statements about forward error correction (FEC) is true?
CHECK
What is the purpose of grounding to earth?
CHECK - (1) To protect against the adverse effects of lightening; (2) assist in the reduction of static; and (3) bring a zero-voltage reference to system components.
Light is guided along the core of a fiber because of this difference between the core and cladding
CHECK - (I'm pretty sure it's just "refractive index") The difference in refractive indexes, between cladding, and core,causes light to be reflected off the cladding and back into the core along the optical fiber.
What minimum amount of slack must be provided for splicing fiber-optic cable in underground installations?
CHECK - 15 meters on inbound and outbound span.
In networks transporting data rates higher than ______. F-P lasers are considered inadequate.
CHECK - 2.5 Gbps
What is a prerequisite before performing a fusion splice of optical fibers?
CHECK - A controlled environment such as a splicing van, trailer or tent and a stable work surface that is large enough to accommodate the fusion splicer, tools, and the splice closure.
What is required of a mechanical splice used for acceptance testing?
CHECK - A mechanical splice used for acceptance testing should be simple to use and reusable.
What is the difference between the FTTN and FTTC topologies?
CHECK - An FTTC is allowed a smaller number of RF amplifiers between the optical fiber and the customer premises.
What can be used as a pulling line in a conduit that is missing a pulling line?
CHECK - An unused cable that is already installed in the conduit.
How are optical splitters used in the forward path?
CHECK - As passive branching devices that divide an optical signal across multiple output fibers.
Where would you expect Fresnel reflections to occur in a fiber-optic network?
CHECK - At connections and mechanical splices where the signal source is entering or exiting the cable.
What is the proper way to handle fiber once it is spliced?
CHECK - At the heat-shrink protective sleeve that has a steel bar inside it.
Why are Velcro straps preferred over standard plastic tie wraps when bundling pigtails for storage in a splice panel?
CHECK - Because Velcro straps are removable and can hold the pigtails together without placing undue strain on the optical fibers
What are two critical factors for a successful installation of fiber-optic cable?
CHECK - Cable pulling tension and bend radius.
What is one reason broadband cable operators install fiber-optic cable in stages instead of changing the infrastructure all at once?
CHECK - Changing the infrastructure all at once would cause too many service disruptions.
What is an example of transport media in a telecommunications network?
CHECK - Coaxial cable.
Which type of optical detection involves a photodiode that converts the light waves to an electrical signal that varies in proportion to intensity changes in the light waves?
CHECK - Direct
Coarse wavelength division multiplexing (CWDM) applications were expanded to include use in what band, where a large OH absorption loss occurred with older single-mode fibers (SMF)?
CHECK - E-band
Besides protection, what else must the coating on an optical fiber do?
CHECK - Function over a wide temperature range, be compatible with cable gels, adhere to the glass cladding over the lifetime of the cable, and be mechanically strippable for splicing operations.
What is one element used in the transmission and reception of dense wavelength division multiplexing (DWDM)?
CHECK - High-quality, temperature cooled distributed feedback lasers.
Which type of PON topology places the optical splitters at the headend and then routes them to each customer premises?
CHECK - Home run
What should be installed to prevent the buildup of lethal amounts of static electricity on long lengths of aerial fiber-optic cable?
CHECK - Install grounding clamps, which connect the cable exterior and metallic messengers to a good solid ground at each pole site.
What is an ONU/ONT?
CHECK - It is a device that converts light from fiber to RF (Radio frequency) for coaxial distribution into the home.
What is true about using a premade fiber-optic pigtail for splicing to patch panels or terminal equipment?
CHECK - It is faster and more reliable than installing connectors in the field.
What are the characteristics of ITU-T G.657 BIF?
CHECK - It is flexible for installation in small spaces and has a small bend radius of 7.5mm or 10mm.
What is digital modulation?
CHECK - It is the interruption of light waves in a coded sequence.
In what type of installation is wide wavelength division multiplexing (WWDM) used?
CHECK - It is used in passive optical networks.
What is the purpose of a fiber demarcation box?
CHECK - It provides a safe place to splice, split, distribute, store, and cross-connect fiber optics.
What is the purpose of the MST?
CHECK - It provides access to connect fiber-optic cable drops from the customer premises to the network.
What is the purpose of the SDU?
CHECK - It provides surge protection, a test jack, circuit protection, wiring management, and fiber termination.
What is the main benefit of deploying WDM technology?
CHECK - It will increase the capacity of the existing fiber networks tenfold without adding any more fiber.
What step should be performed at the beginning of every fusion splicing operation?
CHECK - Make a number of test splices to set up the fusion splicer and to verify the instrument's settings and calibration for both the environment and the type of fiber to be spliced.
What are the primary causes of intrinsic loss in SMF?
CHECK - Material absorption and Rayleigh scattering
Chromatic dispersion is a combination of which two dispersions?
CHECK - Material and waveguide dispersion.
How much cost savings can be achieved by eliminating pulling lines using cable jetting over conventional pulling techniques?
CHECK - More than 40%
Which PON element uses patch panels?
CHECK - Optical distribution network (ODN)
Which component of a digital optical network is used to receive digital modulation light waves and convert them to an electrical signal?
CHECK - Optical transponder???
What is the best approach to repairing an aerial fiber-optic drop cable for FTTx applications?
CHECK - Replace the entire section of fiber drop cable.
What is used in OSP fiber-optic cable to protect and isolate the optical fibers from stress?
CHECK - Strength members and buffer tubes.
What type of SMF is ideal for FTTH installations?
CHECK - The ITU-T G.657 Bend Insensitive Fiber (BIF)
What is a safety concern when an aerial fiber-optic cable is installed between poles, even though there are no high-voltage power lines?
CHECK - The buildup of lethal amounts of static electricity on the fiber-optic cable that can discharge through a person on a ladder or some other conductor connected to the ground.
If tight-buffered distribution fiber-optic cable is installed between the master splice panel in an OEE and a rack-mounted fiber-optic distribution panel, where in the facility must the distribution panel be located?
CHECK - The distribution panel can be located anywhere in the facility since the distribution cable complies with indoor code requirements for riser or plenum installations.
What are the three categories of the fiber-optic cable used to identify the location of the fiber in the network?
CHECK - The fiber-optic cable in a PON is placed in one of three categories, trunk, branch, and drop, to identify the cable's location in the network
Which type of fusion splicer is ideal for FTTx splicing?
CHECK - The fixed V-Groove splicer.
In underground installations, what are two recommended techniques that prevent the pulling tension through the conduit from exceeding the pulling tension specification of the fiber-optic cable?
CHECK - The midpoint pull and the intermediate pull.
Which fusion splicer alignment method uses a camera to align the optical fibers before splicing?
CHECK - The profile alignment system (PAS) method.
When installing aerial fiber-optic cable employing the back-pull method, the trailer should be positioned in line with the strand. What should be the height distance from the ground to the set-up chute?
CHECK - The trailer should be positioned in line with the strand and at least twice the distance from the pole as the height from the ground to the set-up chute.
What is the purpose of the ground block?
CHECK - To protect fragile electronics like TVs and STBs from damaging lightning strikes and power surges.
In a PON, which category of fiber-optic cable is routed from the headend into the ODN?
CHECK - Trunk
When defining the optical transport region of SMF, specifying which of the following is more accurate, technically correct, and critical to use?
CHECK - When defining the optical transport region of a single-mode fiber, MFD is more accurate, technically correct, and critical to use than the core diameter.
When preparing fiber-optic cable for connection to a patch panel, how much buffer tube and fiber slack should be provided?
CHECK - When preparing fiber-optic cable for connection to a patch panel, how much buffer tube and fiber slack should be provided?
When is it necessary to use the intermediate pull technique to install fiber-optic cable in conduit?
CHECK - When the cable route has multiple 90 degree bends throughout.
The main elements of the optical transmitter are the electrical interface, data encoder/modulator, laser, and ______.
CHECK - an optical interface
Which type of optical amplifier produces no measurable distortion to the modulated light wave?
CHECK - erbium-doped fiber amplifiers (EDFA)
Which type of optical coupler provides the least amount of insertion loss?
CHECK - fused
The quality and attenuation value of a mechanical splice of optical fibers depends on which tool during the preparation process?
CHECK - the cleaving tool.
What process must happen before digital modulation can occur in an optical transmitter?
CHECK - the data must be encoded
Typically, what is the first step when adjusting an optical receiver?
CHECK - turn on the optical receiver
Which of the following is true regarding the optical signal-to-noise (SNR) in a transmission line?
CHECK! - It is defined as the ratio of signal power to noise power???
What is the best way to set up the RF power levels for a QAM carrier?
CHECK!!
When working on a ladder, which of the following is a best practice?
CHECK!! - Avoid The top two rungs of any ladder.
Which of the following describes how the signal is being transported through the network without following the physical path requirements of the peripherals?
CHECK!!!
Why do most broadband cable networks use analog modulation downstream instead of digital modulation?
CHECK!!!
Which of the following are true regarding splice closures?
CHECK!!! - Splice closures are used to protect optical fibers and splices against a full range of environmental changes in aerial installations or blow ground in vaults.
Long lengths of fiber-optic cable can consistently be pulled or blown into the flexible conduit at fast rates due to which of the following?
CHECK!!!!! - There is no need for a pulling rope in the conduit before the cable is installed.
What group established the data-over-cable service-interface-specification (DOCSIS)?
CableLabs
Broadband cable operators provide customers with HSD connections to the Internet through their HFC networks using what standard?
DOCSIS
What are the main elements of an optical receiver?
Demodulator, electrical interface, optical detector, optical interface
Which type of map contains node information?
Design map
When activating a fiber-optic network, which acceptance-testing stage includes adjusting attenuation levels for the first time?
During equipment activation
Which type of PON architecture was formed to develop a cost-effective, high-bandwidth, easy-to-provision solution for connecting businesses, schools, libraries, and customer local area networks to the public Internet
EPON
What is one of the requirements that have been identified for NGA network architectures?
Expanded troubleshooting capability
Which of the following acts as a patch panel, splice panel, and house optical splitter, but is located in a pedestal, has lower fiber counts and is easier to install?
FAT
Which topology allows a smaller number of radio frequency (RF) amplifiers between the optical fiber and the customer premises?
FTTC
What information should always be included in fiber-optic network documentation?
Fiber assignments
In a PON FTTx network, which OSP device contains fiber test points that will minimize service disruption to customers?
Fiber distribution hub
What type of fiber-to-the-x (FTTx) topology does a passive optical network (PON) use to make a point-to-multipoint (P2MP) fiber-oprtic cable connection between the broadband cable headend and the customer premises?
Fiber-to-the-home (FTTH)
Where does a distribution amplifier module receive the direct current (DC) required for operation?
From a DC power supply module that converts the alternating current AC voltage to DC voltage
What technologies are defined in DOCSIS 4.0 to help sustain the HFC network infrastructure for several more years?
Full Duplex DOCIS (FDX) and Extended Spectrum DOCSIS (ESD)
Which optical splitter package is similar in appearance and size to a standard fusion splice protector
Fused biconical taper (FBT)
What parameter is critical in an OTDR when testing a PON with significant splitter losses?
High dynamic range
Which type of fiber topology used in a PON places the PON splitters at the headend while providing one designated fiber for every customer premise?
Home-run
What are the concerns for RFoG and FTTx systems?
How and who will provide AC power to the ONT at the customer premises
When would a mid-entry splice in a fiber-optic network be used?
In a self-healing ring network that requires only two fibers to feed an optical fiber drop
When determining whether the optical power into an optical receiver is within the acceptable dynamic range, if the optical power is too high, but the loss budget agrees with the design, what should be done to optimize the optical power?
Install an optical attenuator
Which of the following is true of a centralized power node?
It can provide sufficient power for the fiber-optic node, including outside plant (OSP) amplifiers and customer premises network interface devices (NID) for telephony service
What is the function of an optical node?
It converts light energy to RF
What is the current standardized OD of the cladding of SMF?
It is 125 micrometers, with an accuracy of +/- 1 micrometer
What does a thermal control circuit in a distribution amplifier do?
It maintains the amplifier output levels as the input levels vary with temperature changes
What are the advantages of loose buffer tube fiber?
It offers the best protection for the fibers under high pulling tension and moisture with its fiber-coated gel