Infrastructure (1)

Question 1

Which of the following best describes the function of the network medium?

The network medium provides the physical connection between networked computers.

The network medium provides the protocol used to transmit data between end systems.

The network medium passes data between two routers.

Answer 1

The network medium provides the physical connection between networked computers.

The network medium provides the physical connection between networked computers. This connection can be made through a copper-based, fiber-optic, or wireless medium. The network medium is not a protocol, and it does pass data; it only carries signals. The network medium does not process electrical or light pulses and convert them to data; it carries only the signals generated by transceivers

Question 2

Which of the following signal types is carried by copper cable?

Fiber optic

Infrared

Electrical

Answer 2

Electrical

Copper cables use electrical signals to transmit data. Fiber optic is a cable type, not a signal type. Microwave signals can’t be transmitted over copper cable. Infrared signals are used only for wireless networks

Question 3

Identify the organizations that developed the general cable type standards for voice and data communications that are currently in use, and identify the document name.

EIA/ANSI/TWA, document 802.2

TDA/EIA/TIA, document 802.11

ANSI/TIA/EIA, document T568b

Answer 3

ANSI/TIA/EIA, document T568b

The three organizations that collectively developed the T568b document, which defines the standard for a structured cabling system for voice and data communications, are the American National Standards Institute (ANSI), the Telecommunications Industry Association (TIA), and the Electronic Industries Alliance (EIA). All of the other options are not standards organizations or cabling standards

Question 4

Which of the following cable types and connectors are used to attach a television set to a cable television (CATV) network?

A fiber-optic cable and a straight tip (ST) connector

A twisted pair cable and an RJ-45 connector

A coaxial cable and an F-type connector

Answer 4

A coaxial cable and an F-type connector

The cable type and connector used to attach a television set to a CATV network is a coaxial cable with a screw-on F-type connector. Although CATV networks typically use fiber-optic cables and ST connectors for outdoor connections, they do not use fiber for internal connections to television sets. Coaxial cables with BNC connectors are most commonly used for Thin Ethernet LANs, not CATV network connections. Twisted pair cables and RJ45 connectors are used for Ethernet LANs and telephone networks, but not CATV networks. AUI cables and vampire tap connectors are used for Thick Ethernet networks

Question 5

Which of the following cable types is used for Thick Ethernet network segments?

RG-8

RG-58

RJ-45

Answer 5

RG-8

The cable type used for Thick Ethernet segments is a coaxial cable called RG-8. RG-58 is used exclusively on Thin Ethernet segments. RJ45 is a connector type used in twisted pair cabling for data networks. RJ11 is a connector type used in twisted pair cabling for telecommunications networks

Question 6

Which of the following cable types is used for Thin Ethernet network segments?

RG-8

RG-58

RJ-45

Answer 6

RG-58

RG-58 coaxial cable is used exclusively for Thin Ethernet segments. RG-8 cable is used for Thick Ethernet segments. RJ45 is a connector type used in twisted pair cabling for data networks. RJ11 is a connector type used in twisted pair cabling for telecommunications networks

Question 7

Which of the following telecommunications components is all but obsolete and is found only in old, analog telephone installations?

66 block

110 block

Patch panel

Answer 7

66 block

A 66 block is a type of punchdown block for telephone systems that was first introduced in 1962. By the year 2000, nearly all commercial telephone installations had begun using 110 blocks instead; 110 blocks are still in use, as are patch panels and fiber distribution panels, both of which are termination points for network cable runs

Question 8

Which of the following coaxial cable types are still in general use? (Choose all correct answers.)

RG-6

RG-8

RG-58

RG-59

Answer 8

RG-6

RG-59

RG-6 and RG-59 are 75 ohm cables that are still used for cable television and similar connections. RG-8 and RG-58 are 50 ohm cables that were formerly used for Thick Ethernet and Thin Ethernet, respectively, but are no longer in general use

Question 9

Under which of the following conditions might the local building code require that a data network use plenum cable?

When multiple cables run through the same conduit

When cables run near to devices that generate electromagnetic interference (EMI)

When cables must run through heating ducts

Answer 9

When cables must run through heating ducts

A plenum space is an area of a building that provides air circulation as part of its heating or cooling system, such as a heating or air conditioning duct. Plenum cables have a sheath made of a fire retardant material that does not outgas toxic fumes should it be exposed to fire. When network cables are installed in plenum spaces, many local building codes require that installers use plenum-rated cables conforming to specific standards. Plenum cables provide no benefit when installed near other cables, or EMI sources, or when they exceed specified lengths

Question 10

Which of the following statements about the differences between fiber-optic angle-polished connectors (APCs) and ultra-polished connectors (UPCs) are true? (Choose all correct answers.)

APCs should only be joined to other APCs.

APCs generate more insertion loss that UPCs.

UPCs generate more return loss than APCs.

UPCs use a green connector boot or body.

Answer 10

APCs should only be joined to other APCs.

APCs generate more insertion loss that UPCs.

UPCs generate more return loss than APCs.

Joining an APC to a UPC creates a mismatched connection that generates an extremely high rate of insertion loss (attenuation). APCs do generate more insertion loss than UPCs and less return loss (reflection). It is APCs, not UPCs, that use green boots or bodies on the connectors

Question 11

Which of the following is not a type of fiber-optic connector?

MTRJ

ST

BNC

Answer 11

BNC

Bayonet-Neill-Concelman (BNC) is a type of connector used with coaxial cable. Subscriber connector (SC), mechanical transfer registered jack (MTRJ), and straight tip (ST) are all types of fiber-optic connectors

Question 12

Which of the following physical layer transceiver module standards is the oldest and therefore the most obsolete?

BiDi

QSFP

GBIC

Answer 12

GBIC

The Gigabit Interface Converter (GBIC) transceiver standard was first published in 1995 and defines a maximum data transfer rate of 1.25 Gbps. It was rendered all but obsolete by the Small Form-factor Pluggable (SFP) standard, introduced in 2001, which ran at the same maximum speed but was smaller in size. Subsequent variations on the standard, such as Quad Small Form-Factor Pluggable (QSFP), defined devices with faster transfer rates. Bidirectional (BiDi) transceivers were developed to eliminate the need for separate transmit and receive fibers by using multiplexing

Question 13

Which of the following cable types is typically configured in a star topology, uses eight copper conductors arranged in four pairs, and uses RJ-45 connectors?

RG-8

Twisted pair

RG-58

Answer 13

Twisted pair

There are two main types of twisted pair wiring used for data communications: unshielded twisted pair (UTP) and shielded twisted pair (STP). Both types can be used in a star topology. UTP and STP cables contain eight copper conductors twisted in four pairs. UTP and STP cables use RJ45 connectors to connect end systems to switches, patch panels, and wall plates. RG-8 and RG-58 coaxial cable can only be used in a bus topology. Fiber-optic cable can be used in a star topology, but it uses either glass or plastic conductors and doesn’t use RJ45 connectors

Question 14

Which of the following statements explains the purpose of the twists in twisted pair cabling?

The twists prevent collisions.

The twists completely eliminate crosstalk and electromagnetic interference (EMI) in adjacent wire pairs.

The twists prevent crosstalk in adjacent wire pairs and limit the effects of EMI on the signals carried over the cable.

Answer 14

The twists prevent crosstalk in adjacent wire pairs and limit the effects of EMI on the signals carried over the cable.

The twists in a twisted pair cable prevent the signals on the different wires from interfering with each other (which is called crosstalk) and also provide resistance to outside electromagnetic interference. The twists have no effect on collisions. The twists can’t completely eliminate the effects of EMI. Twists have nothing to do with the bend radius allowance for the cable

Question 15

Which of the following tools do cable installers use to add connectors such as RJ-45 and RJ-11 to twisted pair cabling?

A crimper

A splicer

A pigtail

Answer 15

A crimper

A crimper or crimping tool is a jawed device that has a set of dies in it. Installers use a crimper to squeeze the two halves of an RJ45 or RJ11 connector together, with the wires inside securing the connector to the cable. Installers use a splicing tool to splice two cable segments together. There is no tool called a pigtail or a patch

Question 16

Which of the following combinations of attributes describes the cable used for a Thin Ethernet network?

RJ-45, 50-ohm, 0.270-inch, coaxial cable with BNC connectors

RG-59, 75-ohm, 0.242-inch, coaxial cable with F connectors

RG-58, 50-ohm, 0.195-inch, coaxial cable with BNC connectors

Answer 16

RG-58, 50-ohm, 0.195-inch, coaxial cable with BNC connectors

Thin Ethernet networks use a type of 50-ohm coaxial cable called RG-58, which is 0.195 inches in diameter and uses BNC connectors. 75-ohm coaxial cable with F connectors is used for cable television networks, and RG-8 coaxial is the cable that Thick Ethernet networks use

Question 17

Which of the following connector types are typically associated with Ethernet networks? (Choose all correct answers.)

F-type

BNC

RJ-45

DB-9

N-type

Answer 17

BNC

RJ-45

N-type

Thin Ethernet networks use BNC connectors. Thick Ethernet networks use N-type connectors. All unshielded twisted pair (UTP) Ethernet networks use RJ45 connectors. F-type connectors are used with coaxial cable, typically for cable television installations. DB-9 connectors are commonly used for serial communications ports

Question 18

Which of the following connector types was typically associated with a T-connector attached to the computer?

RJ45

MTRJ

BNC

Answer 18

BNC

Thin Ethernet networks use a type of coaxial cable that runs from each computer to the next one, forming a bus topology. To connect the cable to the network computers, each network interface adapter has a T-connector attached to it, with two additional male BNC connectors, to which you connect two lengths of network cabling

Question 19

Which of the following connector types are associated with fiber-optic cables? (Choose all correct answers.)

RJ11

ST

F-type

LC

MTRJ

Answer 19

ST

LC

MTRJ

Fiber-optic cable connectors all function on the same basic principles, but there are a variety of form factors from which to choose, including straight tip (ST), local connector (LC), and mechanical transfer–registered jack (MTRJ). RJ11 is a twisted pair cable connector, and F connectors are for coaxial cable

Question 20

Which of the following types of cable, when installed, sometimes employed a device called a vampire tap?

Unshielded twisted pair

Single-mode fiber optic

Coaxial

Answer 20

Coaxial

Thick Ethernet installations used a type of coaxial cable called RG-8. To connect a node to the network, installers ran a separate cable called an attachment unit interface (AUI) cable from the computer to the RG-8 and connected it using a device called a vampire tap that pierced the sheathing to make contact with the conductors within. All of the other cable types listed use different types of connectors

Question 21

In an internal UTP cable installation, each horizontal cable run connects a wall plate in the work area to a centralized cabling nexus in a telecommunications room. Which of the following is the correct term for this cabling nexus?

Demarc

Backbone

Patch panel

Answer 21

Patch panel

The cabling nexus in a telecommunications room is called a patch panel. A telepole is a tool used for installing cables. A backbone is a network that connects other local area networks (LANs) together. A demarcation point, or demarc, is the location at which a telecommunication provider’s service meets the customer’s private network

Question 22

Which of the following statements about single-mode and multimode fiber-optic cables are true? (Choose all correct answers.)

Single-mode cables can span longer distances than multimode cables.

Single-mode cables are more resistant to electromagnetic interference than multimode cables.

Single-mode cables are more difficult to install than multimode cables.

Single-mode cables have a much larger core diameter than multimode cables.

Answer 22

Single-mode cables can span longer distances than multimode cables.

Single-mode cables are more difficult to install than multimode cables.

Single-mode cables are capable of spanning longer distances than multimode because they have a narrower core diameter, reducing signal dispersion rates. Because the core consists of fewer (typically one or two) strands, single-mode cables are less flexible than multimode and cannot bend around corners as easily, making them more difficult to install. Because they use light impulses rather than electricity, all fiber-optic cables are completely immune to electromagnetic interference

Question 23

Which of the following components are typically used only for telephone cable installations, and not for data networking? (Choose all correct answers.)

66 blocks

110 blocks

25 pair UTP cables

100 pair UTP cables

Answer 23

66 blocks

25 pair UTP cables

100 pair UTP cables

Voice telephone networks do not have performance requirements as strict as those of data networks, so they are less liable to suffer from crosstalk and other types of interference. As a result, installers often use larger UTP cables for telephone connections. UTP cables are available in configurations containing 25 wire pairs and 100 wire pairs in a single sheath, which enables installers to service multiple users with a single cable. The punchdown blocks for UTP data networks with 8P8C connectors are called 110 blocks. The older standard for punchdown blocks is the 66 block. Rarely used for data networking, 66 blocks are still found in many telephone service installations

Question 24

Which of the following statements about single-mode fiber-optic cable are true? (Choose all correct answers.)

Single-mode cables use an LED light source, whereas multimode cables use a laser.

Single-mode cables can span longer distances than multimode cables.

Single-mode cables have a smaller core filament than multimode cables.

Single-mode cables have a smaller bend radius than multimode, making them easier to install.

Answer 24

Single-mode cables can span longer distances than multimode cables.

Single-mode cables have a smaller core filament than multimode cables.

Single-mode cables have a smaller core filament and can span longer distances than multimode cables. Single-mode cables also use a laser light source, have a larger bend radius, and do not require a ground

Question 25

Which of the following tools do cable installers use to connect bulk cable runs to wall plates and patch panels?

A splicer

A pigtail

A punchdown block tool

Answer 25

A punchdown block tool

Installers use a punchdown block tool to connect the ends of bulk cable runs to jacks in wall plates and patch panels. A crimper or crimping tool is a jawed device that enables installers to squeeze the two halves of an RJ45 or RJ11 connector together, securing the connector to the cable. Installers use a splicing tool to splice two cable segments together. There is no tool called a pigtail