NCTI MT2 - MT3

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; 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.

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, fiber-to-the-x (FTTx) systems?

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

The 10G-EPON access architecture supports two data rates in the upstream: what are they?

1 Gbps and 10 Gbps.

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 (F-P) lasers are considered inadequate.

2.5 Gbps.

What is the maximum data rates the XG-PON1 (10G-PON) access architecture supports in the upstream?

2.5 Gbps.

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

A 100% fiber-optic network.

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 a 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.

Which of the following statements is true when using troubleshooting equipment to test fiber-optic plant?

An optical power meter is used to measure the strength of light signals anywhere in a fiber system where a connection can be made.

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.

What documentation changes should occur as changes are introduced to a fiber-optic network?

Documentation must be updated to reflect the new configuration and performance data.

When activating a fiber-optic network, which acceptance-testing stage includes adjusting attenuation levels for the first time?

During equipment activation.

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 are potential sources of problems in aerial installations?

Falling branches, pole attachment problems, and improper sag and loading considerations.

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

Fiber assignments.

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 protocol and data rates.

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.

Which category of fiber-optic cable design typically uses some variation of the star topology?

Signal distribution.

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.

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.

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.

What step should be performed at the beginning of every fusion splicing operation?

Make a number of test splices 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.

Improper use of nylon tie wraps can induce what problem?

Microbends.

During installation of fiber-optic cable, what does damage to the cable jacket cause?

Moisture migration into the cable.

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 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-to-multipoint (P2MP) topology?

P2P topologies are more stable than P2MP topologies.

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

Parks.

What topology do most fiber-to-the-user (FTTx) networks use which requires greater fiber color code management in its documentation?

Point-to-multipoint (P2MP).

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.

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 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.

What is the best way to prevent problems in outside fiber-optic splice enclosures?

The outer jacket and the internal cable structures must be secured individually to protect the closure and splice trays from the effects of expansion and contraction.

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.

Which of the following statements is true regarding optimum performance in the fiber-optic network?

The role of maintenance is to proactively maintain network tolerances and recognize, locate, and remedy potential problems.

A fiber-optic network maintenance plan should be developed with which of the following in mind?

The task of compiling the physical document must become the responsibility of an identifiable position or organization.

Which of the following statements is true regarding the troubleshooting process?

The troubleshooting process should include steps that identify, analyze, and locate the problem as well as diagnose its source, repair the problem, and test to ensure the problem is resolved.

What is true of online uninterruptible power supply (UPS) systems?

They are recommended for commercial applications such as data centers and telecommunications operations.

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.

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 (1 inch) of jacket and any armor that is present, from 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 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 fiber debris or fiber chips onto clean hands.

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.

when 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.

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

Turn on the optical receiver.

What is the ideal way for a broadband cable network designer to plan the replacement 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.

Why do many optical nodes accept two independent power supplies?

For redundant powering of the node.

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

Fused.

Which type of passive optical network (PON) access architecture replaced asynchronous PON (APON)?

Gigabit-capable PON (GPON).

How are optical splices secured in a splice tray?

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

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

The data must be encoded.

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.

Which type of fusion splicer is ideal for fiber-to-the-x (FTTx) splicing?

The fixed V-groove splicer.

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.

The number of rectifiers used in a DC power plant design

is dependent upon the load placed on the system.