Telco Engineering1

1. What is the frequency limit of copper wire?

A. approximately 0.5 MHz

B. approximately 1.0 MHz

C. approximately 40 GHz

D. None of the above

2. Approximately what is the frequency limit of the optical fiber?

A. 20 MHz

B. 1 MHz

C. 100 MHz

D. 40 GHz

3. A single fiber can handle as many voice channel as

A. A pair of copper conductors

B. a 1500-pair cable

C. approximately 40 GHz

D. a 1000-pair cable

4. An incident ray can be defined as

A. A light ray reflected from a flat surface

B. A light ray directed toward a surface

C. A diffused light ray

D. A light ray that happens periodically

5. The term dispersion describes the process of

A. Separating light into its component frequencies

B. Reflecting light from a smooth surface

C. The process by which light is absorbed by an uneven rough surface

D. Light scattering

6. Which of the following terms describes the reason that light is refracted at different angles?

A. Photon energy changes with wavelength

B. Light is refracted as a function of surface smoothness

C. The angle is determined partly by a and b

D. The angle is determined by the index of the materials

7. The term critical angle describes

A. The point at which light is refracted

B. The point at which light becomes invisible

C. The point at which light has gone from the refractive mode to the reflective mode

D. The point at which light has crossed the boundary layers from one index to another

8. The cladding which surrounds the fiber core

A. Is used to reduce optical interference

B. Is used to protect the fiber

C. Acts to help guide the light in the core

D. Ensures that the refractive index remains constant

9. The reflective index number is

A. A number which compares the transparency of a material with that of air

B. A number assigned by the manufacturer to the fiber in question

C. A number which determines the core diameter

D. A term for describing core elasticity

10. The terms single mode and multimode are best describes as

A. The number of fibers placed into a fiber-optic cable

B. The number of voice channels each fiber can support

C. The number of wavelengths each fiber can support

D. The index number

11. The higher the index number

A. The higher the speed of light

B. The lower the speed of light

C. Has no effect on the speed of light

D. The shorter the wavelength propagation

12. The three major groups in the optical system are

A. The components, the data rate and response time

B. The source, the link, and the receiver

C. The transmitter, the cable, and the receiver

D. The source, the link, and the detector

13. As light is coupled in a multipoint reflective device, the power is reduced by

A. 1.5 dB

B. 0.1 dB

C. 0.5 dB

D. 0.001 dB

14. When connector losses, splice losses, and coupler losses are added, what is the final limiting factor?

A. Source power

B. Fiber attenuation

C. Connector and splice losses

D. Detector sensitivity

15. The term responsivity as it applies to a light detector is best described as

A. The time required for the signal to go from 10 to A. The time required for the signal to go from 10 to 90 percent of maximum amplitude

B. The ratio of the diode output current to optical input power

C. The ratio of output current to output power

D. The ratio of output current to input current

16. Loss comparisons between fusion splices and mechanical splices are

A. 1:10

B. 10:1

C. 20:1

D. 1:20

17. The mechanical splice is best suited for

A. Quicker installation under ideal conditions

B. Minimum attenuation losses

C. Field service conditions

D. Situations in which cost of equipment is not a factor

18. EMD is best describe by which statement?

A. 70 percent of the core diameter and 70% of the fiber NA should be filled with light

B. 70 percent of the fiber diameter and 70% of the cone of acceptance should be filled with light

C. 70 percent of input light should be measured at the output

D. 70 percent of the unwanted wavelengths should be attenuated by the fiber

19. Which of the following cables will have the highest launch power capability?

A. 50/125/0.2

B. 85/125/0.275

C. 62.5/125/0.275

D. 100/140/0.3

20. The term power budgeting refers to

A. The cost of cables, connectors, equipment, and installation

B. The loss of power due to defective components

C. The total power available minus the attenuation losses

D. The comparative costs of fiber and copper installations

21. FDDI stands for:

A. Fiber Digital Data Interface

B. Fiber Distributed Data Interface

C. Fiber Distribution Delay Interface

D. Frequency-Division Data Interface

22. FITL stands for:

A. Fiber In The Loop

B. Fiber Input Timing Loss

C. Frequency Input to The Loop

D. Fiber Input Timing Loop

23. FTTC stands for:

A. Fiber Transmission Timing Constraint

B. Fiber Transmission Technology Committee

C. Fiber Telephone Transmission Cable

D. Fiber To The Curb

24. SONET stands for:

A. Simple Optical Network

B. Standard Optical Network

C. Synchronous Optical Network

D. None of the above

25. DWDM stands for:

A. Digital Wavelength-Division Modulation

B. Dense Wavelength-Division Modulation

C. Double Wavelength-Division Modulation

D. Dense Wavelength-Division Multiplexing

26. A Soliton is a:

A. Defect in the glass

B. Type of particle

C. Type of pulse

D. Type of optical network

27. Adding bits to synchronize one digital signal to another is called:

A. Bit stuffing

B. bit-synch

C. SDH

D. WDM

28. Power above the minimum required by an optical receiver is called:

A. Gain margin

B. System margin

C. Excess gain

D. overdrive

29. Typically, repeaters are not required for fiber-optic cable lengths up to:

A. 1000 miles

B. 100 miles

C. 100 km

D. 10 km

30. In SONET, OC-1 stands for:

A. Optical Carrier level one

B. Optical Coupler unidirectional

C. Optical Channel one

D. Optical Cable type 1

31. In SONET, STS stands for:

A. Synchronous Transport Signal

B. Synchronous Transport System

C. Synchronous Transmission Signal

D. Synchronous Transmission System

32. A commonly used fiber-based system for LANs is:

A. FDDI

B. high-speed Ethernet

C. gigabit Ethernet

D. All of the above

33. The use of solitons on fiber-optic cables is:

A. common

B. experimental

C. obsolete

D. Not possible

34. OTDR stands for:

A. Optical Time-Delay Response

B. Optical Timing Delay Requirement

C. Optical Time-Domain Reflectometer

D. Optical Time-Division Relay

35. Using fiber-optic cable in a telephone system except for the connection to the subscriber's phone is called:

A. FDDI

B. FTTC

C. FITL

D. SONET

36. As the meridional ray is propagated along the optic fiber it:

A. Travels in a sort of spiral shape

B. Stays in the center of the fiber

C. Passes repeatedly through the center of the core

D. Is reflected off the inside surface of the primary buffer.

A fiber has an index of refraction of 1.6 for the core and 1.4 for the cladding.

37. Find the critical angle.

A. 16 deg

B. 61 deg

C. 34.8 deg

D. 70 deg

38. Find the refraction angle for in incident of 30 deg.

A. 16 deg

B. 61 deg

C. 34.8 deg

D. 70 deg

39. Find the refraction angle for in incident of 70 deg.

A. 16 deg

B. 61 deg

C. 34.8 deg

D. 70 deg

43. A single-mode fiber has a numerical aperture of 0.15. What is the maximum core diameter it could have for use with infrared light with a wavelength of 820 nm?

A. 2.1 um

B. 2.1 mm

C. 4.2 um

D. 4.2 mm

An optical communication link extends for 40 km. The laser-diode emitter has an output power of 1.5 mW, and the receiver requires a signal strength of – 25 dBm for a satisfactory signal-to-noise ratio. The fiber is available in lengths of 2.5 km and can be spliced with a loss of 0.25 dB per spliced. The fiber has a loss of 0.3 dB/km. The total of all the connection losses at the two ends is 4 dB.

44. Find the laser output power in dBm.

A. 7.16 dBm

B. 2.24 dBm

C. 1.5 dBm

D. 1.76 dBm

46. Find the total loss due to attenuation rating of 0.3dB/km.

A. 10 dB

B. 54 dB

C. 23 dB

D. 12 dB

48. DTMF stands for:

A. Digital Telephony Multiple Frequency

B. Dial Tone Master Frequency

C. Dual-Tone Multi frequency

D. Digital Trunk Master Frequency

49. PSTN stands for:

A. Public Switched Telephone Network

B. Private Switched Telephone Network

C. Primary Service Telephone Network

D. Primary Service Telephone Numbers

50. POTS stands for:

A. Private Office Telephone System

B. Primary Office Telephone Service

C. Primary Operational Test System

D. Plain Old Telephone Service

51. LATA stands for:

A. Local Access and Transport Area

B. Local Access Telephone Area

C. Local Area Telephone Access

D. Local Area Transport Access

52. A LATA is a:

A. A local calling area

B. A type of digital local network

C. A way of accessing a tandem office

D. A way of accessing a central office

53. Central offices are connected by:

A. Local loops

B. Trunk lines

C. Both a and b

D. None of the above

54. Local loops terminate at:

A. A tandem office

B. A toll station

C. A central office

D. An interexchange office

55. Call blocking:

A. Cannot occur in the public telephone network

B. Occurs on the local loop when there is an electrical power failure

C. Occurs only on long-distance cables

D. Occurs when the central office capacity is exceeded

56. In telephony, POP stands for:

A. Post Office Protocol

B. Point Of Presence

C. Power-On Protocol

D. None of the above

57. The cable used for local loops is mainly:

A. twisted-pair copper wire

B. Shielded twisted-pair copper wire

C. Coaxial cable

D. fiber-optic

58. FITL stands for:

A. Framing Information for Toll Loops

B. Fiber In the Toll Loop

C. Framing In The Loop

D. Fiber-In-The-Loop

59. Loading coils were used to:

A. Increase the speed of the local loop for digital data

B. Reduce the attenuation of voice signals

C. Reduce crosstalk

D. provide C-type conditioning to a local loop

60. DC current flows through a telephone:

A. When it is on hook

B. When it is off hook

C. As long as it is attached to a local loop

D. Only when it is ringing

61. The range of DC current that flows through a telephone is:

A. 20 uA to 80 uA

B. 200 uA to 800 uA

C. 2 mA to 8 mA

D. 20 mA to 80 mA

62. The separation of control functions from signal switching is known as:

A. step-by-step switching control

B. Crossbar control

C. Common control

D. ESS

63. The typical voltage across a telephone when on-hook is:

A. 48 volts DC

B. 48 volts, 20 hertz AC

C. 90 volts DC

D. 90 volts, 20 hertz AC

64. The typical voltage needed to "ring" a telephone is:

A. 48 volts DC

B. 48 volts, 20 hertz AC

C. 90 volts DC

D. 90 volts, 20 hertz AC

65. The bandwidth of voice-grade signals on a telephone system is restricted in order to:

A. Allow lines to be "conditioned"

B. prevent "singing"

C. Allow signals to be multiplexed

D. All of the above

67. Signal loss is designed into a telephone system to:

A. Eliminate reflections

B. Prevent oscillation

C. Improve signal-to-noise ratio

D. Reduce power consumption

70. Basic FDM groups can be combined into:

A. supergroups

B. mastergroups

C. jumbogroups

D. All of the above

72. PABX stands for:

A. Power Amplification Before Transmission

B. Private Automatic Branch Exchange

C. Public Automated Branch Exchange

D. Public Access Branch Exchange

73. SLIC stands for:

A. Single-Line Interface Circuit

B. Standard Line Interface Card

C. Subscriber Line Interface Card

D. Standard Local Interface Circuit

75. Find the traffic in Erlang if there are 40 calls with an average duration of 3 minutes.

A. 2 E

B. 1 E

C. 3 E

D. 5 E

76. Find the traffic in Cmin if there are 40 calls with an average duration of 3 minutes.

A. 230 Cmin

B. 120 Cmin

C. 60 Cmin

D. 2 Cmin

77. Find the traffic in CCs if there are 40 calls with an average duration of 3 minutes.

A. 3600 CCs

B. 120 CCs

C. 72 CCs

D. 72000 CCs

78. Find the traffic in E if there are 72,000 calls with an average duration of 1 second.

A. 2 E

B. 1 E

C. 3 E

D. 5 E

A telephone system has 1000 calls with an average duration of 3min.

79. Find the traffic in Cmin.

A. 50 Cmin

B. 3000 Cmin

C. 30 Cmin

D. 1800 Cmin

Telco Engineering1

More Quizzes