Chapter 3 - Networking Topologies, Connectors, and Wiring Standards Flashcards
Why would a network administrator use plenum-rated cable during an installation?
B, C. Plenum-rated means that the cable’s coating doesn’t begin burning until a much higher temperature of heat, doesn’t release as many toxic fumes as PVC when it does burn, and is rated for use in air plenums that carry breathable air, usually as nonenclosed fresh-air return pathways that share space with cabling.
Which of the following Ethernet unshielded twisted-pair cabling types is/are commonly used?
D. UTP is commonly used in twisted-pair Ethernet like 10BaseT, 100BaseTX, 1000BaseTX, and so on.
In which of the following categories is UTP cable not rated?
D. Unshielded twisted-pair has standards from Category 2 through 8 for use on Ethernet networks. There is no Category 9 defined.
What type of connector does UTP cable typically use?
C. UTP usually connects with RJ-45. You use a crimper to attach an RJ connector to a cable.
Which of the following provides the longest cable run distance?
A. Single-mode fiber allows for the maximum cable run distances.
You need to crimp on a connector using an RJ-45 connector. Which pin-out configuration would you use to connect a host into a switch?
B. You would use a straight-through cable to connect a host to a switch, and the typical pin-out is called T568A.
Why is fiber-optic cable immune to electromagnetic interference (EMI) and radio frequency interference (RFI)?
C. Fiber-optic cable transmits digital signals using light impulses rather than electricity; therefore, it is immune to EMI and RFI.
What type of cable transmits lights from end to end?
B. Remember that fiber-optic cable transmits a digital signal using light impulses. Light is carried on either a glass or a plastic core.
What is the main difference between single-mode fiber (SMF) and multimode fiber (MMF)?
B. The difference between single-mode fibers and multimode fibers is in the number of light rays (and thus the number of signals) they can carry. Generally speaking, multimode fiber is used for shorter-distance applications and single-mode fiber for longer distances.
What type of cable should be used if you need to make a cable run longer than 100 meters?
C. Standards limit UTP to a mere 100 meters. Different fiber-optic types have different maximum lengths, but fiber-optic is the only cable type that can extend well beyond 100 meters.
Which of the following are fiber-optic connectors?
B, D, E. There are many different types of fiber-optic connectors. SC, ST, LC, and MT-RJ are some of the more typical connectors in use today.
You need to connect two devices on a network and they need to send voice traffic. Which of the following cables will you use?
B. To connect two devices for voice on a vertical connect, the minimum cable you can use is Category 5.
How many hosts on a half-duplex segment can talk at one time?
B. In half-duplex communication, a device can either send communication or receive communication, but it cannot do both at the same time.
On which type of cable does EMI have the least effect?
B. Fiber-optic cable transmits only light (not electricity like UTP), so EMI has zero effect on it.
How many devices can be connected to a full-duplex segment?
C. Full-duplex communication requires a point-to-point configuration because the collision-avoidance circuit is disabled.
How many wires are used in a 100BaseTX UTP transmission?
B. 100BaseTX utilizes only pins 1, 2, 3, and 6.
A crossover cable is used to connect all of the following except
D. All devices that are pinned the same for transmit and receive require a crossover cable to communicate directly.
How is a T1 crossover cable wired?
A. A T1 cable uses pairs 1 and 2, so connecting two T1 CSU/DSU devices back-to-back requires a crossover cable that swaps these pairs. Specifically, pins 1, 2, 4, and 5 are connected to 4, 5, 1, and 2, respectively.
The purpose of the demarcation point is to separate the customer from whom?
D. The demarcation point, or demarc, is the point at which the operational control or ownership changes from your company to a service provider. This is often at the MDF in relation to telephone connections and the CSU/DSU in regard to WAN connections.
You need to make a T568B cable for a Fast Ethernet link. How many pairs will you use?
B. Fast Ethernet is 100BaseTX and this type of cable uses two pairs of wires.
Media types : Copper UTP STP Coaxial Fiber Single-mode Multimode
Copper : RJ-45 RJ-11 BNC DB-9 DB-25 F-type
Fiber : LC ST SC APC UPC MTRJ
Transceivers : SFP GBIC SFP+ QSFP
Characteristics of fiber transceivers:
Bidirectional
Duplex
Termination points : 66 block 110 block Patch panel Fiber distribution panel
Copper termination standards: TIA/EIA 568a TIA/EIA 568b Crossover Straight-through
Coaxial cable, referred to as coax, contains a center conductor made of copper that’s surrounded by a plastic jacket with a braided shield over it. A plastic such as polyvinyl chloride (PVC) or fluoroethylenepropylene (FEP, commonly known as Teflon) covers this metal shield.
The Teflon-type covering is frequently referred to as a plenum-rated coating, and it’s definitely expensive but often mandated by local or municipal fire code when cable is hidden in walls and ceilings.
The difference between plenum and non-plenum cable comes down to how each is constructed and where you can use it. Many large multistory buildings are designed to circulate air through the spaces between the ceiling of one story and the floor of the next; this space between floors is referred to as the plenum.
