Chapter 5: Network Cabling

Suppose you're assisting with a cable installation using fiber-optic cabling that will support Gigabit Ethernet. You're approved to install segments up to 4000 m in length. What kind of cable are you using?

1000 Base-LX SMF

What is a twist ratio, and why is it important?

The more twists per foot in a pair of wires, the more resistant the pair will be to crosstalk or noise.

What kind of cable uses BNC connectors? Which connector is likely to be used by cable TV?

Coaxial cable, F-connector

What type of fiber cable problem is caused when pairing a 50-micron core cable with a 62.5-micron core cable?

Fiber type mismatch

Which fiber connector contains two strands of fiber in each ferrule?

MTRJ

Which kind of crosstalk occurs between wire pairs near the source of the signal?

NEXT

What characteristic of optical transmissions is primarily responsible for the distance limitations of fiber-optic cabling?

Optical loss is the degradation of the light signal after it travels a certain distance away from its source ( just as the light of a flashlight dims after a certain number of feet)

Why is SMF more efficient over long distances than MMF?

SMF consists of a narrow core of 8 to 10 microns in diameter. Laser-generated light travels a single path over the core, reflecting very little. Because it reflects little, the light does not disperse as the signal travels along the fiber.

Which kind of multiplexing assigns slots to nodes according to priority and need?

STDM (statistical time division multiplexing)

Which fiber transceiver is the same size as SFP transceivers, but can support network speeds over 10 Gbps?

The SFP+ is the same module size as SFP; theoretical maximum transmission speed is 16 Gbps.

How is latency measured, and in what unit?

The delay from which data leaves the source to when it arrives at the receiver, then back. It's measured in RTT (round trip time) in milliseconds.

Which part of a toner and probe kit emits an audible tone when it detects electrical activity on a wire pair?

Tone locator (or probe)

Suppose you're creating patch cables to be used in a government office. What color wire goes in the first pin?

White/green

What is the difference between short circuits and open circuits?

A short circuit is an unwanted connection, such as when exposed wires touch each other. An open circuit is one where needed connections are missing, such as when a wire breaks.

Why do APC ferrules create less back reflection than UPC ferrules?

APC (Angle Polished Connector) uses a polished surface like an UPC (Ultra Polished Connecter) but the tips are angled at 8 degrees which causes any light reflection at the ends to be reflected any direction back but into the signal, which UPC and other straight connections tend to do more of as they are reconnected again and again.

Which transmission characteristic is never fully achieved?

Bandwidth

What kind of tool can measure the distance to the location of damage in a cable?

Cable Performance Tester can measure the distance to a connectivity device, termination point, or damage in a cable.

Which of these categories of twisted- pair cable can support Gigabit Ethernet?

Cat 5e, Cat 6a, Cat 7

What is the earliest twisted-pair cabling standard that meets the minimum requirements for 10GBase-T transmissions?

Cat 6a

What fiber is used in fiber-optic cabling to protect the inner core and prevent the cable from stretching?

kevlar