61. Which of the following communication modes support two-way traffic but in only one direction at a time?
A. simplex B. half duplex
C. three-quarters duplex D. all of the above
62. Which of the following might be used by a company to satisfy its growing communications needs?
A. front end processor B. multiplexer
C. controller D. concentrator
E. all of the above
63. What is the number of separate protocol layers at the serial interface gateway specified by the X.25 standard?
A. 4 B. 2
C. 6 D. 3
64. The interactive transmission of data within a time sharing system may be best suited to
A. simplex lines B. half-duplex lines
C. full duplex lines D. biflex-lines
65. Which of the following statement is incorrect?
A. The difference between synchronous and asynchronous transmission is the clocking derived from the data in synchronous transmission.
B. Half duplex line is a communication line in which data can move in two directions, but not at the same time.
C. Teleprocessing combines telecommunications and DP techniques in online activities
D. Batch processing is the preferred processing mode for telecommunication operation.
66. Which of the following is considered a broad band communication channel?
A. coaxial cable B. fiber optics cable
C. microwave circuits D. all of above
67. Which of the following is not a transmission medium?
A. telephone lines B. coaxial cables
C. modem D. microwave systems
68. Which of the following does not allow multiple uses or devices to share one communication line?
A. duplexer B. multiplexer
C. concentrator D. controller
69. Which of the following signal is not standard RS-232-C signal?
A. VDR B. RTS
C. CTS D. DSR
70. Which of the following statement is incorrect?
A. Multiplexers are designed to accept data from several I/O devices and transmit a unified stream of data on one communication line
B. HDLC is a standard synchronous communication protocol.
C. RTS/CTS is the way the DTE indicates that it is ready to transmit data and the way the DCW indicates that it is ready to accept data
D. RTS/CTS is the way the terminal indicates ringing
71. Which of the following is an advantage to using fiber optics data transmission?
A. resistance to data theft
B. fast data transmission rate
C. low noise level
D. all of above
72. Which of the following is required to communicate between two computers?
A. communications software
C. communication hardware
D. all of above including access to transmission medium
73. The transmission signal coding method of TI carrier is called
A. Bipolar B. NRZ
C. Manchester D. Binary
74. Which data communication method is used to transmit the data over a serial communication link?
A. simplex B. half-duplex
C. full-duplex D. b and c
75. What is the minimum number of wires needed to send data over a serial communication link layer?
A. 1 B. 2
C. 4 D. 6
76. Which of the following types of channels moves data relatively slowly?
A. wide band channel B. voice band channel
C. narrow band channel D. none of the above
77. Most data communications involving telegraph lines use:
A. simplex lines B. wideband channel
C. narrowband channel D. dialed service
78. A communications device that combines transmissions from several I/O devices into one line is a
A. concentrator B. modifier
C. multiplexer D. full-duplex line
79. How much power (roughly) a light emitting diode can couple into an optical fiber?
A. 100microwatts B. 440microwatts
C. 100picowatts D. 10miliwatts
80. The synchronous modems are more costly than the asynchronous modems because
A. they produce large volume of data
B. they contain clock recovery circuits
C. they transmit the data with stop and start bits
D. they operate with a larger bandwidth
81. Which of the following statement is correct?
A. terminal section of a synchronous modem contains the scrambler
B. receiver section of a synchronous modem contains the scrambler
C. transmission section of a synchronous modem contains the scrambler
D. control section of a synchronous modem contains the scrambler
82. In a synchronous modem, the digital-to-analog converter transmits signal to the
A. equalizer B. modulator
C. demodulator D. terminal
83. Which of the following communications lines is best suited to interactive processing applications?
A. narrow band channel C. simplex lines
C. full duplex lines D. mixed band channels
84. A remote batch-processing operation in which data is solely input to a central computer would require
A. telegraph line B. simplex lines
C. mixed bad channel D. all of above
85. A band is always equivalent to
A. a byte B. a bit
C. 100 bits D. none of above
86. The loss in signal power as light travels down the fiber is called
A. attenuation B. prorogation
C. scattering D. interruption
87. Avalanche photodiode receivers can detect bits of transmitted data by receiving
A. 100photons B. 200 photons
C. 2000photons D. 300 photons
88. Communication circuits that transmit data in both directions but not at the same time are operating in
A. a simplex mode B. a half duplex mode
C. a full duplex mode D. an asynchronous mode
89. Mechanism to protect private networks from outside attack is
A. Firewall B. Antivirus
C. Digital signature D. Formatting
90. Hubs are present in the network
A. To diagnose line failures, measure and manage traffic flow and simplify re configuring of LANs.
B. To interconnect the LAN with WANs.
C. To interconnect the WANs with WANs.
D. To interconnect the WANs with LANs.