Module 5: Cabling
What is a twist ratio, and why is it important?
A twist ratio is the number of twists per meter or foot. The more twists per foot in a pair of wires, the more resistant the pair will be to crosstalk or noise.
What kind of tool can measure the distance to the location of damage in a cable?
Cable tester.
What fiber is used in fiber-optic cabling to protect the inner core and prevent the cable from stretching?
Kevlar.
Which kind of multiplexing assigns slots to nodes according to priority and need? a. WDM (wavelength division multiplexing) b. STDM (statistical time division multiplexing) c. TDM (time division multiplexing) d. CWDM (coarse wavelength division multiplexing)
b. STDM
What is the difference between short circuits and open circuits?
A short circuit is an unwanted connection, ex. exposed wires touching. An open circuit is one where necessary connections are missing, ex. wire breakages.
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 mode of fiber cable are you using?
Single mode fiber cabling.
How is latency measured, and in what unit?
Latency is determined by calculating a packet's RTT (round-trip delay). RTT is measured in milliseconds.
What characteristic of optical transmission is primarily responsible for the distance limitations of fiber-optic cabling?
Optical loss.
Which fiber transceiver is the same size as SFP (small form-factor pluggable) transceivers, but can support network speeds over 10 Gbps?
SPF+.
Why is SMF (single-mode fiber) more efficient over long distances than MMF (multi-mode fiber)?
The core of SMF is narrower than MMF and reflects very little light. The light does not disperse as much along the fiber.
Why do APC (angled physical contact) ferrules create less back reflection than UPC ferrules?
The end faces of APC ferrules are placed at an angle to each other, so the reflection is sent back in a different direction than the source of the signal.
Which fiber connector contains two strands of fiber in each ferrule? a. MT-RJ b. SC c. ST d. LC
a. MT-RJ
Suppose you're creating patch cables to be used in a government office. What color wire goes in the first pin? a. White/orange b. White/green c. Brown d. Blue
b. White/green
Which of these categories of twisted-pair cable can support Gigabit Ethernet? a. Cat 5, cat 6, cat 7 b. Cat 5e, cat 6, cat 3 c. Cat 5e, cat 6a, cat 7 d. Cat 6, cat 7a, cat 5
c. Cat 5e, cat 6a, cat 7
Which cable is best suited for ultra-high-speed connections between a router and a switch on the same rack? a. RG-6 coaxial cable b. Cat 5e twisted-pair cable c. Cat 6 twisted-pair cable d. Passive twinaxial cable
c. Cat 6 twisted-pair cable
What is the earliest twisted-pair cabling standard that meets the minimum requirements for 10GBASE-T transmissions at 100 meters? a. Cat 5e b. Cat 6 c. Cat 6a d. Cat 7
c. Cat 6a
What type of fiber-cable problem is caused when pairing a 50-micron core cable with a 62.5-micron core cable? a. Dirty connectors b. Wavelength mismatch c. Fiber type mismatch d. TX/RX reverse
c. Fiber type mismatch
Which kind of crosstalk occurs between wire pairs near the source of the signal? a. Alien 👽 b. TX/RX (transmitted/received signal) reverse c. FEXT (far-end crosstalk) d. NEXT (near-end crosstalk)
d. NEXT
Which part of a toner and probe kit emits an audible tone when it detects electrical activity on a wire pair? a. TDR (time-domain reflectometer) b. Tone generator c. Tone locator d. Toner
c. Tone locator
Which transmission characteristic is never fully achieved? a. Latency b. Throughput c. Bit rate d. Bandwidth
d. Bandwidth
