FINALTERM EXAMINATION
Spring 2010
CS601- Data Communication
Shared by Usman Baig
Time: 90 min
Question No: 1 ( M a r k s: 1 ) .
When data are transmitted from device A to device B, the header from A’s layer 4 is read by B’s __________ layer.
► physical
► transport
► application
► none of the given
Question No: 2 ( M a r k s: 1 ) .
A periodic signal completes one cycle in 0.001 s. What is the frequency?
► 1 Hz
► 100 Hz
► 1 KHz
► 1 MHz
Question No: 3 ( M a r k s: 1 ) .
Zero crossing bandwidth is also called as equivalent noise bandwidth.
► True
► False
Question No: 4 ( M a r k s: 1 ) .
Amplitude in ASK is more resistive to EMI and Noise.
► True
► False
Question No: 5 ( M a r k s: 1 ) .
If FCC regulations are followed, the carrier frequencies of adjacent AM radio stations are ____________ apart.
► 5 KHz
► 10 KHz
► 200 KHz
► 530 KHz
Question No: 6 ( M a r k s: 1 ) .
There are _________________ types of serial transmission:
► 1
► 2
► 3
► 4
Question No: 7 ( M a r k s: 1 ) .
Synchronous transmission have _____________.
► a start bit
► a stop bit
► ga
ps between bytes
► none of the given
Question No: 8 ( M a r k s: 1 ) .
Which of the following is an example of ITU-T modem standards:
► T-series
► X-series
► N-series
► V-series
Question No: 9 ( M a r k s: 1 ) .
The maximum data rate in the uploading direction is still ____________.
► 26.6 Kbps
► 33.6 Kbps
► 36.6 Kbps
► 46.6 Kbps
Question No: 10 ( M a r k s: 1 ) .
Category 5 UTP cable is used for data transmission of upto__________.
► 100 Mbps
► 200 Mbps
► 250 Mbps
► 400 Mbps
Question No: 11 ( M a r k s: 1 ) .
All of popular Fiber optic connectors are ___________ shaped.
► Conical
► Barrel
► Circular
► Rectangular
Question No: 12 ( M a r k s: 1 ) .
The VLF and LF bands use _________ propagation for communications.
► Ground
► Sky
► Line of sight
► Space
Question No: 13 ( M a r k s: 1 ) .
Multiplexing is the set of techniques that allows simultaneous TX of multiple signals across ___________ data link
► Single
► Multi
► Single and Multi
► none of the given
Question No: 14 ( M a r k s: 1 ) .
Need for Addressing makes Asynchronous TDM inefficient for bit or byte ___________.
► Interleaving
► Addition
► Substraction
► None of the given
Question No: 15 ( M a r k s: 1 ) .
_________ takes data from one high speed line and breaks it into portions.
► Multiplexing
► Inverse multiplexing
► Inverse subtraction
► Inverse addition
Question No: 16 ( M a r k s: 1 ) .
A traditional telephone line has a bandwidth of __________.
► 2000Hz
► 4000 Hz
► 2000 MHz
► 4000 MHz
Question No: 17 ( M a r k s: 1 ) .
If the ASCII character H is sent and the character I is received, what type of error is this?
► Single-bit
► Multiple-bit
► Burst
► Recoverable
Question No: 18 ( M a r k s: 1 ) .
At the CRC generator, __________ added to the data unit after the division process
► 0s are
► 1s are
► The polynomial
► The CRC remainder is
Question No: 19 ( M a r k s: 1 ) .
Error control in the data link layer is based on ________________
► automatic repeat request
► automatic repeat acknowledgment
► automatic send acknowledgment
Question No: 20 ( M a r k s: 1 ) .
In line discipline the initiator first transmits a frame called an ________
► Enquiry
► Acknowledgment
► NAK
► Request
Question No: 21 ( M a r k s: 1 ) .
Primary device uses ____________ to receive transmission from the secondary devices.
► ACK
► ENQ
► POLL
Question No: 22 ( M a r k s: 1 ) .
Flow control is needed to prevent ___________.
► Bit errors
► Overflow of the sender buffer
► Overflow of the receiver buffer
► Collision between sender and receiver
Question No: 23 ( M a r k s: 1 ) .
For stop-and-wait ARQ, for N data packets sent, ___________ acknowledgments are needed.
► N
► 2N
► N-1
► N+1
Question No: 24 ( M a r k s: 1 ) .
In Y-MODEM Multiple files can be sent simultaneously
► True
► False
Question No: 25 ( M a r k s: 1 ) .
HDLC is an acronym for ______________.
► High-duplex line communication
► High-level data link control
► Half-duplex digital link combination
► Host double-level circuit
Question No: 26 ( M a r k s: 1 ) .
Token Bus has no commercial application in data communications
► True
► False
Question No: 27 ( M a r k s: 1 ) .
The BNC-T connector is a T-shaped device with _______ ports
► Three
► Two
► Four
► Five
Question No: 28 ( M a r k s: 1 ) .
Each station in the Token Ring regenerates the frame.
► True
► False
Question No: 29 ( M a r k s: 1 ) .
Repeater works on __________ layer.
► Data Link
► Physical
► Network
► Application
Question No: 30 ( M a r k s: 1 ) .
Trunks are transmission media such as _________ that handle the telephone to the nearest end office.
► Satellite links
► Twisted-pair & Fiber-optic
► Twisted-pair
► Fiber-optic
Question No: 31 ( M a r k s: 2 )
What kind of error is undetectable by the checksum? [2]
Error detection method used by the higher layers like VRC,LRC,CRC,checksum is also based on the concept of redundancy
Question No: 32 ( M a r k s: 2 )
What are properties of signals?
Question No: 33 ( M a r k s: 2 )
Whether in Asynchronous or Synchronous TDM, addressing is used?
Question No: 34 ( M a r k s: 2 )
What is the basic purpose of Router?
Question No: 35 ( M a r k s: 3 )
Why we need a Null Modem?
Question No: 36 ( M a r k s: 3 )
Count LRC for the following bits?
10011010 10100101 1101 0110
Question No: 37 ( M a r k s: 3 )
what are the categories of multiplexing?
There are three catogaries of multiplxing
FDM
TDM
Have a two other catagories
Synchronous and asyrounce
WDM
Question No: 38 ( M a r k s: 3 )
What are the three purposes of control frames at data link layer?
Question No: 39 ( M a r k s: 5 )
Compare line decipline methods ENQ/ACK and Poll/ Select?
=>ENQ/ACK coordinates which device may start a transmission and whether or not the intended recipient is ready and enabled.
=> Using ENQ/ACK, a session can be initiated by either station on a link as long as both are of equal rank.
=> In both half-duplex and full-duplex transmission, the initiating device establishes the session.
=> In half duplex, the initiator then sends its data while the responder waits. The responder may take over the link when the initiator is finished or has requested a response.
=> In full duplex, both devices can transmit simultaneously once the session has been established.
POLL/SELECT:
=> The poll/select method of line discipline works with topologies where one device is designated as a primary station and the other devices are secondary stations.
=> Multipoint systems must coordinate several nodes, not just two.
=> The question to be determined in these cases, therefore, is more than just, are you ready? It is also, which of the several nodes has the right to use the channel?
=> Using ENQ/ACK, a session can be initiated by either station on a link as long as both are of equal rank.
=> In both half-duplex and full-duplex transmission, the initiating device establishes the session.
=> In half duplex, the initiator then sends its data while the responder waits. The responder may take over the link when the initiator is finished or has requested a response.
=> In full duplex, both devices can transmit simultaneously once the session has been established.
POLL/SELECT:
=> The poll/select method of line discipline works with topologies where one device is designated as a primary station and the other devices are secondary stations.
=> Multipoint systems must coordinate several nodes, not just two.
=> The question to be determined in these cases, therefore, is more than just, are you ready? It is also, which of the several nodes has the right to use the channel?
Question No: 40 ( M a r k s: 5 )
what is the difference between character oriented and bit oriented protocols?
