DOEACC Society 2007 Advanced Level Course In Computer Science A9-R3: DATA COMMUNICATION

PART ONE
(Answer all the questions)

1. Each ques. beneath provide a multiple option of answers. select the most improper 1 and enter in the “tear-off” ans sheet attached to the ques. paper, subsequent instructions therein. (1 x 10)

1.1 One factor in the accuracy of a reconstructed PCM signal is the
A) Signal bandwidth
B) Carrier frequency
C) Number of bits used for quantization.
D) Baud rate

1.2 Category one UTP cable is most often used in
A) Fast Ethernet Networks
B) Traditional Ethernet Networks
C) Infrared Networks
D) Telephone Networks

1.3 In 16-QAM, there are 16
A) Combinations of phase and amplitude
B) Amplitudes
C) Phases
D) bps

1.4 Guard bands increase the bandwidth for
A) FDM
B) TDM
C) CDM
D) None of the above

1.5 The physical connection ranging from an end point and a switch or ranging from 2 switches is
A) Transmission path
B) Virtual path
C) Virtual circuit
D) None of the above





1.6 Which of the subsequent is an application layer service?
A) Remote log-in
B) File transfer and access
C) Mail service
D) All of the above

1.7 The main function of transport layer is
A) Node-to-node delivery
B) Process-to-process delivery
C) Synchronization
D) Updating and maintenance of routing tables

1.8 In which kind of switching do all the packets of a message follow the identical channels of a path?
A) Data gram packet switching
B) Virtual switching packet switching
C) Message switching
D) None of the above

1.9 The shortest frame in HDLC protocol is usually the
A) Information frame
B) Supervisory frame
C) Management frame
D) None of the above

1.10 The device operating at Data link layer is
A) Bridge
B) Router
C) Repeater
D) None of the above




























2. Each statement beneath is either actual or FALSE. select the most improper 1 and ENTER in the “tear-off” sheet attached to the ques. paper, subsequent instructions therein. (1 x 10)

2.1 In FDM the users take turns in a round robin, every 1 periodically getting the entire bandwidth for a little burst of time.
2.2 The minimum bandwidth needed for QAM transmission is the identical as that needed for ASK and PSK transmission.
2.3 Fiber-optic cable is used in backbone networks, cable TV networks and fast Ethernet networks.
2.4 A multipoint connection provides a dedicated link ranging from 2 devices.

Earning:   Approval pending.