2.5.7 Practice Questions
Score: 100%
Question 1: You are working with an existing fiber optic installation in your building. You want to know the length of each cable that runs through the walls. Which tool should you use?
Correct Answer
OTDR
Incorrect Answer:
Toner probe
Incorrect Answer:
Multimeter
Incorrect Answe
Smartjack
EXPLANATION
An optical time domain reflector (OTDR) sends light pulses on a cable to discover information about the cable. The results of this test can be used to: Estimate the length of a wire.
Measure the cable impedance.
Identify locations of splices and connectors on the wire. Identify shorts and open circuits, and the location of the fault.
A TDR performs the same tests on copper cables.
Use a toner probe to locate the end of a wire from a wall jack to the punch down block. Use a multimeter to measure the electrical properties of a device, such as voltage, amps, and resistance. A smart jack is a special loopback plug installed at the demarcation point for a WAN service. Technicians at the central office can send diagnostic commands to the smart plug to test connectivity between the central office and the demarc.
Question 2: You manage a network that uses 1000BaseT Ethernet. You find that one device communicates on the network at only 100 Mbps. Which tool should you use to test the drop cable and the connection to the network?
Incorrect Answer:
Toner probe
Incorrect Answer:
Multimeter
Incorrect Answer:
TDR
Incorrect Answer:
Cable tester
Correct Answer:
Certifier
EXPLANATION
A cable certifier is a multi-function tool that verifies or validates that a cable or an installation meets the requirements for a specific architecture implementation. For example, you would use a certifier to verify that a specific drop cable meets the specifications for 1000BaseT networking.
A cable tester verifies that the cable can carry a signal from one end to the other and that all wires are in their correct positions. A toner probe is two devices used to trace the end of a wire from a known endpoint into the termination point in the wiring closet. A time domain reflector (TDR) measures the length of a cable or to identify the location of a fault in the cable. A multimeter measures the electrical properties of a device, including voltage, amps, and resistance.
Question 3: You have been asked to document the wiring in your building. You would like to identify the length of each Cat5 cable to verify that it meets Ethernet standards. You need to identify the length of the cables, but most cables run through walls and ceilings, making them difficult to trace. Which tool should you use?
Incorrect Answer:
Smartjack
Incorrect Answer
Toner probe
Incorrect Answer:
OTDR
Incorrect Answer:
Butt set
Correct Answer
TDR
EXPLANATION
A TDR is a special device that sends electrical pulses on a wire in order to discover information about the cable. The TDR measures impedance discontinuities; the echo received on the same wire in response to a signal