NCTI STUDY GUIDE
Why might a technician who is troubleshooting an outage in an optical network want to refer to the network's as-built documentation?
It will help the technician determine specific cable lengths.
Which answer best describes network topology?
It's a sub-layer of network architecture that describes the physical and logical configuration of connected elements between the signal source and the network termination elements.
5-4. Why are laser diodes most effective when coupled to singlemode fiber?
It's high coupled power, directionality, and speed.
What is a design option for a broadband cable network to maximize the use of its optical fiber resources?
Leasing spare fibers.
When preparing fiber-optic cable for connection to a patch panel, how much buffer tube and fiber slack should be provided?
Leave enough slack in the buffer tubes to allow the splice trays to reach the splicing equipment and enough fiber slack to store on individual trays for later additions, moves, and changes.
Which of the following statements about local ad insertion is true?
Local ad insertion is performed usually by a video server.
1-9. Which of the following best describes basic service provided by the cable company?
Local origination channels
Which type of fiber-optic cable provides the most stable transport characteristics and additional protection from stresses caused by macrobends and microbends?
Loose-tube cable.
What are some advantages of using flexible conduit?
Low coefficient of friction (COF) and the capability to bend around corners and obstructions with minimal splices.
9-9. What step should be performed at the beginning of every fusion splicing operation?
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.
7-3. What are the primary causes of intrinsic loss in single-mode fiber?
Material absorption and Rayleigh scattering.
Chromatic dispersion is a combination of which two dispersions?
Material and waveguide dispersion.
. The National Electrical Safety Code (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 communications lines.
Eliminating pulling lines using high air speed blowing (HASB) can achieve how much of a cost savings over conventional pulling techniques?
More than 40%.
1-5. Process of combining digital services in the headend is called.
Multiplexing
4-7. What term describes the frequency spectrum into an amplifier having higher amplitude at low frequencies than the high frequencies?
Negative tilt
2-3. What is a common solution when congestion from modem activity and traffic becomes unacceptable in a hybrid fiber/coax (HFC) network?
Node splitting, the subdividing of serving areas into two or more smaller serving areas.
5-5. What are the factors that constribute to an optical receiver's sensitivity?
Noise, responsivity, response time, linear response, back reflection, and optical detector material.
5-7. What does the amplification process in an avalanche photodiode (APD) introduce into the electrical output of an optical detector?
Noise.
5-9. What happens if the optical signal exceeds the maximum specified input power into a photodetector?
Nonlinear operation resulting in distortion, data errors, and signal loss.
. Which element of a passive optical network (PON) uses patch panels?
Optical distribution network (ODN)
Which element of a passive optical network (PON) consists of a downstream (forward path) optical transmitter, an upstream (return path) receiver, and a multiplexer/demultiplexer?
Optical line terminal (OLT
Which element of a passive optical network (PON) uses a Bragg grating filter?
Optical line terminal (OLT).
Which component of an optical modulation system contains an optical detector and a demodulator?
Optical receiver
Which of these components is used in a passive optical network (PON)?
Optical splitters
Which component of a digital optical network is used to receive digital modulation light waves and convert them to an electrical signal?
Optical transponder
What is a benefit of using a point-to-point (P2P) topology instead of a point-tomultipoint (P2MP) topology?
P2P topologies are more stable than P2MP topologies
What product based on the Data Over Cable Service Interface Specification (DOCSIS) defines the protocols for Internet protocol (IP) telephony over hybrid fiber/ coax (HFC) networks?
PacketCable.
Which of these items should be identified on a route map?
Parks.
Which layer of a synchronous optical network (SONET) maps the signals into a synchronous payload envelope (SPE)?
Path.
3-3. What is used to select which distribution amplifier secondary downstream output ports are active and wether they have equal or unequal output levels
Plug-in modules or jumpers
Which statement about pigtails used for optical fiber terminations is true?
Prior to splicing, pigtails should be labeled to correspond with the correct color code and patch panel designation.
What is it about radio frequency over glass (RFoG) that made broadband cable operators envision using it to make a seamless transition from the legacy hybrid fiber/coax (HFC) architecture over to a gigabit-capable passive optical network (GPON) or Ethernet passive optical network (EPON)?
RFoG can operate in parallel with GPON and EPON, operating independent of the PON communications protocols and data rates.
What is it about radio frequency over glass (RFoG) that made broadband cable operators envision using it to make a seamless transition from the legacy hybrid fiber/coax (HFC) architecture over to a gigabit-capable passive optical network (GPON) or Ethernet passive optical network (EPON)?
RFoG can operate in parallel with GPON or EPON, which eliminates the need for any downtime during the transition
5. In an optical network, what is reflectance?
Reflectance is the reflected light from a single Fresnel reflection event.
8-3. What is a consideration for the use of ribbon fiber?
Ribbon fiber requires different tools and equipment to perform splicing
Which type of network topology has been focused primarily on alternative routing around cities and industrial areas?
Ring
Which of the following is true about the synchronous optical network (SONET) transmission standard?
SONET is the North American standard used for telephony applications.
11-9. 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 category of fiber-optic cable design typically uses some variation of the star topology?
Signal distribution.
13-4. Which type of network topology allows troubleshooting a problem or switching around the problem to be accomplished easily from the central hub?
Star.
What is used in outside plant fiber-optic cable to protect and isolate the optical fibers from stress?
Strength members and buffer tubes.
8-7. Since they provide the same functions, what is the primary difference between the fiber distribution hub (FDH) and fiber access terminal (FAT)?.
The FAT is typically easier to install and has lower fiber counts than the FDH.
What type of single-mode fiber is intended for fiber-to-the-home (FTTH) installations?
The ITU-T G.657 bend-insensitive fiber (BIF).
What is a safety concern when aerial fiber-optic cable is installed between poles, even though there are no high-voltage power lines?
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 ground.
1-10. 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)
In regard to providing high-speed data (HSD) service
The cable modem termination system (CMTS) can provide a data transfer rate up to 38 Mbps, using 256- QAM in a single 6 MHz channel
1-3. What provides the cable network's interface to the internet?
The cavle modem termination system (CMTS)
What is one process that has to happen before digital modulation can occur in an optical transmitter?
The data must be encoded.
4-9. 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
2-9. 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.
. The phenomenon, total internal reflection, is what enables an optical fiber to guide light. What characteristic of optical fiber causes total internal reflection?
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.
2-7. How can a distribution amplifer be identified in the network or on a network design map?
The distribution amplifier has multiple downstream output.
4-10. 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.
If tight-buffered distribution fiber-optic cable is installed between the master splice panel in an optical entrance enclosure (OEE) and a rack-mounted fiber-optic distribution panel, where in the facility must the distribution panel be located?
The distribution panel can be located anywhere in the facility since the distribution cable complies with indoor code requirements for riser or plenum installations.
5-3. What is the drawback of using Fabry-Perot (F-P) lasers in high-speed data (HSD) networks?
The emission of a number of discrete wavelengths or side modes.
What are the two critical elements that align the optical fibers in a connection
The ferrules and the mating adapter.
Which type of fusion splicer is ideal for fiber-to-the-x (FTTx) splicing?
The fixed V-groove splicer.
3-10. 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.
4-8. 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.
5-1. Which standards organization is considered to be the creator of the world's most recognized communications standard, known as recommendations?
The international telecommunication union (ITU)
What is one advantage and one disadvantage of single-mode fiber with a large mode field diameter (MFD)?
The larger the MFD, the easier it is to splice and connectorize the fiber, although it becomes more sensitive to bending losses
5-10. What is the characteristic of light in a laser beam?
The laser beam consists of a limited range of wavelrngths (monochromatic), with all light waves in phase (coherent light)
2-4. 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.
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?
The midpoint pull and the intermediate pull
In a centralized server video-on-demand (VOD) architecture,
The number of servers needed for video content storage is smaller than in the distributed server architecture.
16-4. What is true of the following types of uninterruptible power supplies (UPS)
The offline type routes incoming power directly to connected devices and switches to battery backup during a power interruption
4-4. 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
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
5-2. In which component in a fiber-optics communication system do changes to the intensity of the optical signal occur?
The optical transmitter
9-10. Which fusion splicer alignment method uses a camera to align the optical fibers before splicing?
The profile alignment system (PAS) method
9-8. The quality and attenuation value of a mechanical splice of optical fibers is dependent on which tool during the preparation process?
The quality and attenuation value of the mechanical splice of optical fibers is dependent on the quality of the cleaving tool.
2-5. 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 tap downstream input port and the tap ports.
When working on a ladder, which rungs are forbidden for standing?
The top two rungs of any ladder.
When installing aerial fiber-optic cable employing the back-pull method, how should the cable trailer be positioned in order to keep the cable from rubbing on the pole or cable reel when pulled?
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.
The frame structure of a synchronous transport signal (STS) is divided into two parts. What are they?
The transport overhead, which contains the section and line layers, and the synchronous payload envelope, which contains the path overhead and the payload data.
11-6. How is the high air speed blowing (HASB) 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
3-2. 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 uninterruptible power supply (UPS) systems?
They are recommended for commercial applications such as data centers and telecommunications operations.
Which of the following is true about optical nodes?
They contain four main sections: the optical receiver, the RF amplifier module, the reverse optical transmitter, and the DC power supply
How do technicians know the specific type of single-mode fiber used in a particular project?
They have read the project's specification records
Why is -48 VDC (volts of direct current) with a positive ground used by the telecommunications industry?
This reverse polarity is a means of mitigating electrolytic corrosion on the outside plant.
3-7. 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 is an option available on most optical nodes for connecting to the power supply?
Through a power cable that is connected from the power supply directly to the power port of the node.
2-8. 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)
4-1. Describe an application for a distribution amplifier in a hybrid fiber/coax (HFC) network?
To amplify and split the downstream signals at the optical input of the optical receiver in a fiber-node.
What is the core objective of the Data Over Cable Service Interface Specification (DOCSIS) Provisioning of Ethernet passive optical network (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.
What is the purpose of grounding to earth?
To protect against the adverse effects of lightning and assist in the reduction of static.
Why are backup AC generators included in many commercial AC uninterruptible power supply (UPS) and DC power systems?
To provide AC power in the event of a prolonged utility power interruption.
4-2. 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
3-4. Why is there a diplex 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 single-mode fiber moved to 1,550 nm?
To take advantage of the low intrinsic absorption and lower attenuation at 1,550 nm in single-mode fiber.
In a passive optical network (PON), which category of fiber-optic cable is routed from the headend into the optical distribution network (ODN)?
Trunk.
Typically, what is the first step to take when adjusting an optical receiver?
Turn on the optical receiver.
3-8. 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 ampifier called?
Unity gain.
2. Digital return path transmissions
Use dense wavelength division multiplexing (DWDM) digital return transmitters in hub-to-headend architectures
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
1-6. Many of the drawbacks from early coaxial tree-and-branch distribution can be overcome by
Utilizing an HFC or PON architecture
When is it necessary to use the intermediate pull technique to install fiber-optic cable in conduit?
When the cable route has multiple 90° bends throughout.
2-1. In the tree-and-branch architecure, 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 are the two accepted methods for pulling fiber-optic cable off the cable reel as part of an aerial installation?
he back-pull method and the drive-off method.
4-6. What is the expected DC voltage on most hybrid fiber coax (HFC) network equipment?
+24 VDC, +_ 0.5 V
17-9. The 10G-EPON access architecture supports two data rates in the upstream: what are they?
1 Gbps and 10 Gbps
What is the minimum amount of slack that must be provided for splicing fiberoptic cable in underground installations?
15 meters on both the inbound and outbound span.
How many meters of slack cable are typically used in an aerial installation?
15-25 meters.
In networks transporting data rates that are higher than _____, Fabry-Perot (FP) lasers are considered inadequate.
2.5 Gbps.
What is the maximum data rate the XG-PON1 (10G-PON) access architecture supports in the upstream?
2.5 Gbps.
11-1. 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 cable operator?
30 inches
1-4. 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 does a point-to-multipoint (P2MP) topology consist of?
A P2MP topology consists of a host element connected through a splitter or optical coupler to two or more receiving elements.
What can be attached to the pulling line to prevent the fiber-optic cable from twisting during installation?
A break-away swivel.
4-3. 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.
What are some prerequisites before performing a fusion splice of optical fibers?
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.
9-4. What is required of mechanical splices used for acceptance testing?
A mechanical splice used for acceptance testing should be simple to use and reusable
2-6. What is spliced into the hardline coaxial cable to combine the AC power with the transported RF signal in a hybrid fiber/coax (HFC) network?
A power inserter.
3-9. 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 slug.
4. What is MPEG (Moving Picture Experts Group)
A universally accepted standard for digital television, first released in 1992.
. What is the difference between the fiber-to-the-node (FTTN) and fiber-to-thecurb (FTTC) topologies?
An FTTC is allowed a smaller number of RF amplifiers between the optical fiber and the customer premises
What is the difference between the fiber-to-the-node (FTTN) and fiber-to-thecurb (FTTC) topologies?
An FTTC is allowed a smaller number of RF amplifiers between the optical fiber and the customer premises.
5-6. What is a positive-intrinsic-negative (PIN) diode?
An optical detector with current flow that is linear to the intensity of light photons, with one electron/hole pair created for every absorbed photon until saturation.
What can be used as a pulling line in a conduit that is missing a pull line?
An unused cable that is already installed in the conduit.
Where would you expect Fresnel reflections to occur in a fiber-optic network?
At connections and mechanical splices where the signal source is entering or exiting the cable.
9-5. Why are Velcro straps preferred over standard plastic tie wraps when bundling pigtails for storage in a splice panel?
Because Velcro straps are removable and can hold the pigtails together without placing undue strain on the optical fibers.
Why are the amplitude levels into an optical transmitter different between analog television and quadrature amplitude modulation (QAM) carriers?
Because analog carriers have a video sync pulse, which can be used to set amplitude. QAM carriers don't have a sync pulse; the average power of the carrier is used to adjust the QAM carrier's amplitude
18-10. Heat shrink tubing is installed over the fusion-splice to strengthen and protect it. When should the heat shrink be installed on the fiber?
Before stripping the plastic coating from the fiber
2-10. 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 (RF overlay) in broadband PON (BPON) access systems?
Between 1,550 and 1,560 nm
1-8. How often does the FCC require cable operators to perform proof-of-performace measurements on the signals in the headend and at specified test locations throughout the network?
Bi-annually
3-6. What is the purpose for distribution amplifiers in a hybrid a fiber/coax (HFC) network?
Boost the downstream signals before being divided and circulated throughout neighborhoods in the coaxial cable portion of the network.
4-5. How is the AC voltage separated from the RF signal in a distribution amplifier?
By a capacitor that passes RF but blocks the low frequency 60 hertz (Hz) AC voltage which finds a low resistance path throug the RF choke that blocks RF.
. How should surface particulates usually be removed from optical connectors?
By using a compressed-air cleaner designed for optical connectors.
What are two critical factors for a successful installation of fiber-optic cable?
Cable pulling tension and cable bend radius.
1-2. Group that established the data-over-cable-service-interface-specification (DOCSIS)
CableLabs
13-6. What is one reason why broadband cable operators install fiber-optic cable in stages instead of changing the infrastructure all at once?
Changing the infrastructure all at once would cause too many service disruptions.
What is one reason why broadband cable operators install fiber-optic cable in stages instead of changing the infrastructure all at once?
Changing the infrastructure all at once would cause too many service disruptions.
What is an example of transport media in a telecommunications network?
Coaxial cable.
16-10. In a hybrid fiber/coax (HFC) fiber optic node, what are common voltages produced by DC power supplies?
Common voltages produced by DC power supplies include +5, +12, and +24 VDC.
Which of these are concerns for radio frequency over glass (RFoG) and, fiberto-the-x (FTTx) systems?
Consideration of how and who will provide AC power to the optical network terminal (ONT) at the customer premises.
5-8. What functions does the detector in a optical receiver perform?
Conversion of an optical carrier to an electrical signal, and demodulation of the modulated optical carrier.
Broadband cable operators provide customers with high-speed data (HSD) connections to the Internet via their HFC networks using what standard?
Data Over Cable Service Interface Specification (DOCSIS).
What are the main elements of an optical transmitter?
Data encoder/modulator, electrical interface, laser, optical interface.
14-5. 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.
1-1. Six methods by which signals arrive at the cable system headend
Direct feed, satellite, over-the-air, terrestrial microwave, local origination, and PSTN
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?
Direct.
Which type of star topology used in a passive optical network (PON) places the PON splitters into fiber access terminal (FAT) located deep in the network and closer to the customer premises than the centralized split?
Distributed star
Which type of star topology used in a passive optical network (PON) places the PON splitters into fiber access terminal (FAT) located deep in the network and closer to the customer premises than the centralized split?
Distributed star.
When activating a fiber-optic network, which acceptance-testing stage includes adjusting attenuation levels for the first time?
During equipment activation.
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?
E-band.
8. Which type of optical amplifier produces no measurable distortion to the modulated light wave?
Erbium-doped fiber amplifiers (EDFA).
Which type of passive optical network (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?
Ethernet PON (EPON)
What is one of the requirements that have been identified for next-generation access network architectures?
Expanded troubleshooting capability.
What information should always be included in fiber-optic network documentation?
Fiber assignments
18-9. Which of the following describes a fiber pigtail?
Fiber-optic cable with pre-connectorized ends.
What type of fiber-to-the-x (FTTx) topology does a passive optical network (PON) use to make a point-to-multipoint (P2MP) fiber-optic cable connection between the broadband cable headend and the customer premises?
Fiber-to-the-home (FTTH).
Why do many optical nodes accept two independent power supplies?
For redundant powering of the node.
3-1. 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
2-2. What technologies are defined in DOCSIS 4.0 to help sustain the hybrid fiber/ hoax (HFC) network infrastructure for several more years?
Full Duplex DOCSIS (FDX) and Extended Spectrum DOCSIS (ESD)
Besides protection, what else must the coating on an optical fiber do?
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.
Which optical splitter package is similar in appearance and size to a standard fusion splice protector?
Fused biconical taper (FBT)
Which type of optical coupler provides the least amount of insertion loss?
Fused.
9. What do diameter differences between spliced fibers look like on an optical time domain reflectometer (OTDR)?
Gain in one direction and high loss in the opposite direction.
Which type of passive optical network (PON) access architecture replaced asynchronous PON (APON)?
Gigabit-capable PON (GPON).
What is one element used in the transmission and reception of dense wavelength division multiplexing (DWDM)?
High-quality, temperature cooled distributed feedback lasers.
9-3. 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
How are optical splitters used in the forward path?
In the forward path, optical splitters are used as passive branching devices that divide an optical signal across multiple output fibers.
What information is documented at fiber-optic slack and splice locations?
Incoming and outgoing sequential markings showing the cable's physical length.
A technician is determining whether the optical power into an optical receiver is within the acceptable dynamic range. He finds that the optical power is too high, but the loss budget agrees with the design. What should he do to optimize the optical power in this situation?
Install an optical attenuator
What should be done to prevent the buildup of lethal amounts of static electricity on long lengths of aerial fiber-optic cable?
Install grounding clamps, which connect the cable exterior and metallic messengers to a good solid ground at each pole site.
. Select the answer that best completes this sentence: In analog modulation, the _____ of the light wave changes in _____ proportion to the _____ analog signal.
Intensity; direct; incoming.
6-1. Monitoring the status of optical nodes
Involves the use of a node transponder that continuously monitors a number of critical functions
The number of rectifiers used in a DC power plant design
Is dependent upon the load placed on the system.
Which of the following is true of a centralized power node?
It can provide sufficient power for a fiber-optic node, including outside plant amplifiers and customer premises network interface devices (NID) for telephony service.
1-7. What is the function of an optical node?
It coverts light energy to RF
What is the current standardized outside diameter (OD) of the cladding of singlemode fiber?
It is 125 μm, with an accuracy of ±1 μm.
2. What is digital modulation?
It is the interruption of light waves in a coded sequence
In what type of installation is wide wavelength division multiplexing (WWDM) used?
It is used in passive optical networks
3-5. 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
