Fiber Install and Activation

What is the purpose of grounding to earth?

(1) To protect against the adverse effects of lightning, (2) assist in the reduction of static, and (3) bring a zero-voltage reference to system components.

The 10G0EPON access architecture supports two data rates in the upstream. What are they?

1 Gbps and 10 Gbps

What is one of the requirements that have been identified for next-generation access network architectures?

10 Gbps downstream data rate capacity.

What is the minimum amount of slack that must be provided for splicing fiber-optic 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 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

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

What is one example of a stipulation in a franchise agreement that would affect network design?

A 100% fiber-optic network

What is channel bonding?

A 3.0 revision to DOCSIS that significantly increases upstream and downstream transport data rates.

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

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.

Where would you expect to install a mid-entry splice in a fiber-optic cable network?

A location where select number of optical fibers need to be spliced, and the remaining buffer tubes and fibers remain untouched.

What is required of mechanical splices used for acceptance testing?

A mechanical splice used for acceptance testing should be simple to use and reusable.

What is MPEG?

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-the-curb (FTTC) topologies?

An FTTC is allowed a smaller number of RF amplifiers between the optical fiber and the customer premises.

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.

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.

What are the amplitude levels into an optical transmitter different between analog television and 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.

What is the wavelength allocation for video distribution (RF overlay) in broadband PON (BPON) access systems?

Between 1,550 and 1,560 nm

What is the purpose of buffer tubes in fiber-optic cable?

Buffer tubes protect and separate the optical fiber in smaller bundles.

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.

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

In a 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 FFoG and fiber-to-the-x systems

Consideration of how and who will provide AC power to the optical network terminal (ONT)at the customer premises.

What function does the detector in an optical receiver perform?

Conversion of an optical carrier to an electrical signal, and demodulation of the modulated optical carrier.

What are the main elements of an optical transmitter?

Data encoder,modulator,electrical interface, laser,optical interface.

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

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 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

Which type of optical amplifier produces no measurable distortion to the modulated light wave?

Erbium-doped fiber amplifiers (EDFA)

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?

Ethernet PON (EPON)

What information should always be included in fiber-optic network documentation?

Fiber assignments

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.

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 bi-conical taper (FBT)

Which type of optical coupler provides the least amount of insertion loss?

Fused.

What do diameter differences between spliced fibers look line on an optical time domain reflectometer?

Gain in one direction and high loss in the opposite direction.

Which type of 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.

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 combining devices that stream an optical signal across two common fibers.

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 optizize 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

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 services

What is the current standardized outside diameter of the cladding of single-mode fiber?

It is 125 µm, with an accuracy of ±1 µm.

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.

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.

Why are laser diodes most effective when coupled to singlemode fiber?

Its 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.

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.

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 instruments's setting and calibration for both the environment and the type of fiber to be spliced.

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 can achieve how much of a cost savings over conventional pulling techniques?

More than 40%

What does the amplification process in an avalanche photodiode (APD) introduce into the electrical output of an optical detector?

Noise

What are the factors that contribute to an optical receiver's sensitivity?

Noise, responsivity, response time, linear response, back reflection, optical detector.

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 PON consists of a downstream (forward path),optical transmitter, an upstream(return path) receiver, and a multiplexer/demultiplexer?

Optical line terminal (OLT)

Which component of an optical modulation system contains an optical detector and demodulator?

Optical receiver

Which component of a digital optical network is used to receive digital modulation light waves and convert them to an electrical signal?

Optical tranponder

What is a benefit of using a point to point topology instead of a point-to-multipoint topology?

P2P topologies are more stable than P2MP topologies.

Which of these items should be identified on a route map?

Parks

Which layer of a SONET maps the signals into a synchronous payload envelope(SPE)?

Path

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 RFoG that made broadband cable operators envision using it to make seamless transition from the legacy HFC architecture over to a GPON or EPON?

RFoG can operate in parallel with GPON or EPON, operating 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 refection event

Internet protocol telephony systems in broadband cable networks

Require a call management server, media gateway, signaling gateway, billing system, and CMTS.

How are optical splices secured in a splice tray?

Retaining clips hold optical splices in place in a splice tray.

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 SONET transmission standard?

SONET is the North American standard used for telephony applications.

Which type of network topology allows troubleshooting a problem or switching around the problem to be accomplished easily from the central hub?

STAR

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.

What information can be derived from recording the sequentaial marking information printed on a fiber-optic cable jacket in the "as-built" documentation?

Slack and splice locations.

In what applications is a splice closure used?

Splice closures are used to protect optical fibers and splices against a full range of environmental changes in aerial installations or below ground in vaults.

What is the purpose of splice trays inside splice closures?

Splice trays are designed to provide protection for mechanical splices, fusion splice protectors, and optical splitters as well as provide storage for the required fiber slack.

What is used in outside plant fiber-optic cable to protect and isolate the optcial fibers from stress?

Strength members and buffer tubes.

In regard to providing high-speed data service,

The CMTS can provide a data transfer rate up to 38 Mbps, using 256-QAM in a single 6Mhz channel.

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 a lower fiber counts than the FDH.

What type of single-mode fiber is intended for fiber-to-the-home installations?

The ITU-T G.657 bend-insensitive fiber (BIF)

Which standards organization is considered to be the creator of the worlds' most recognized communications standards, known as "recommendations"?

The International Telecommunications Union (ITU)

What are the two accepted methods for pulling fiber-optic cable off the cable reels as part of an aerial installation?

The back-pull method and the drive-off method.

How should the buffer tubes be secured in the closure?

The buffer tubes should be secured with tie wraps to allow slight movement without pulling or stressing the optical fibers.

What is a 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.

What is one process that has to happen before digital modulation can occur in an optical transmitter?

The data must be encoded

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.

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.

What is a 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 splicing?

The fixed V-groove splicer.

What is one advantage and one disadvantage of single-mode fiber with a large mode field diameter?

The larger the MFD, the easier it is to splice and connectrorize the fiber, although it becomes more sensitive to bending losses.

What is a characteristic of light in a laser beam?

The laser beam consists of a limited range of wavelengths (monochromatic), with all light waves in phase (coherent light).

In underground installations, what are the 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 architecture

The number of servers needed for video content storage is smaller than in the distributed server architecture.

What is true of the following types of UPS?

The offline type routes incoming power directly to connected devices and switches to battery backup during a power interruption.

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.

In which component in a fiber-optics communication system do changes to the intensity of the optical signal occur?

The optical transmitter

Which fusion splicer alignment method uses a camera to align the optical fibers before splicing?

The profile alignment system (PAS) method.

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.

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 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.

How is the high air speed blowing method (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.

What is true of online 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 with a positive ground used by the telecommunications industry?

This reverse polarity is a means of mitigating electrolytic corrosion on the outside plant.

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.

When preparing a fiber-optic cable for splicing, what is the purpose of removing approximately 2.5 cm of jacket and any armor that is present, for the end of the cable?

To access the cable's rip cord and to check the cutting depth of the knife or ringing tool.

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.

When splicing fiber-optic cable, why is it a good safety practice to clean off fiber strippers and other hand tools after each use?

To prevent the accidental transfer of the fiber debris to fiber chips onto clean hands.

Why are backup AC generators included in many commercial AC UPS and DC power systems?

To provide AC power in the event of a prolonged utility power interruption.

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 1550 nm in single-mode fiber

Whe preparing a splice closure, what should be done with the fiberglass rod strength member that runs down the center of loose-tube fiber-optic cable?

Trim the strength member back for convenience, but leave it long enough to be tightly clamped to a strain-relief lug in the closure.

In a passive optical network (PON), which category of fiber-optic cable is routed from the headend into the distribution network (ODN)?

Trunk

Typically, what is the first step to take when adjusting an optical receiver?

Turn on the optical receiver.

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.

What does water do to the glass core of an optical fiber?

Water causes the glass core of the optical fiber to become opaque, which degrades the signal as it's transported through the fiber.

When is it necessary to use the intermediate pull technique to install fiber-optic cable in conduit?

When the cable route has multiple 90 degree bends throughout.