Saturday, August 14, 2010

CS601 Final Paper 2010

FINALTERM  EXAMINATION
Spring 2010
CS601- Data Communication
Ref No: 1576598
Time: 90 min
Marks: 60











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Question No: 1      ( Marks: 1 ) - Please choose one
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      ( Marks: 1 ) - Please choose one

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      ( Marks: 1 ) - Please choose one
 

Zero crossing bandwidth is also called as equivalent noise bandwidth.

       True

       False



Question No: 4      ( Marks: 1 ) - Please choose one
 

Amplitude in ASK is more resistive to EMI and Noise.

       True

       False



Question No: 5      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

There are _________________ types of serial transmission:

       1

       2

       3

       4



Question No: 7      ( Marks: 1 ) - Please choose one
 

Synchronous transmission have _____________.

       a start bit

       a stop bit

       ga
ps between bytes
       none of the given



Question No: 8      ( Marks: 1 ) - Please choose one
 

Which of the following is an example of ITU-T modem standards:

       T-series

       X-series

       N-series

       V-series



Question No: 9      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

Category 5 UTP cable is used for data transmission of upto__________.

       100 Mbps

       200 Mbps

       250 Mbps

       400 Mbps



Question No: 11      ( Marks: 1 ) - Please choose one
 

All of popular Fiber optic connectors are ___________ shaped.

       Conical

       Barrel

       Circular

       Rectangular



Question No: 12      ( Marks: 1 ) - Please choose one
 

The VLF and LF bands use _________ propagation for communications.

       Ground

       Sky

       Line of sight

       Space



Question No: 13      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

Need for Addressing makes Asynchronous TDM inefficient for bit or byte ___________.

       Interleaving

       Addition

       Substraction

       None of the given



Question No: 15      ( Marks: 1 ) - Please choose one
 

_________ takes data from one high speed line and breaks it into portions.

       Multiplexing

       Inverse multiplexing

       Inverse subtraction

       Inverse addition



Question No: 16      ( Marks: 1 ) - Please choose one
 

A traditional telephone line has a bandwidth of __________.

       2000Hz

       4000 Hz

       2000 MHz

       4000 MHz



Question No: 17      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

Error control in the data link layer is based on ________________

       automatic repeat request

       automatic repeat acknowledgment

       automatic send acknowledgment



Question No: 20      ( Marks: 1 ) - Please choose one
 

In line discipline the initiator first transmits a frame called an ________

       Enquiry

       Acknowledgment

       NAK

       Request



Question No: 21      ( Marks: 1 ) - Please choose one
 

Primary device uses ____________ to receive transmission from the secondary devices.

       ACK

       ENQ

       POLL



Question No: 22      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

For stop-and-wait ARQ, for N data packets sent, ___________ acknowledgments are needed.


       N

       2N

       N-1

       N+1



Question No: 24      ( Marks: 1 ) - Please choose one
 

In Y-MODEM Multiple files can be sent simultaneously

       True

       False



Question No: 25      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 1 ) - Please choose one
 

Token Bus has no commercial application in data communications

       True

       False



Question No: 27      ( Marks: 1 ) - Please choose one
 

The BNC-T connector is a T-shaped device with _______ ports

       Three

       Two

       Four

       Five



Question No: 28      ( Marks: 1 ) - Please choose one
 

Each station in the Token Ring regenerates the frame.

       True

       False



Question No: 29      ( Marks: 1 ) - Please choose one
 

Repeater works on __________     layer.

       Data Link

       Physical

       Network

       Application



Question No: 30      ( Marks: 1 ) - Please choose one
 

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      ( Marks: 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      ( Marks: 2 )
 

What are properties of signals?


Question No: 33      ( Marks: 2 )
 

Whether in Asynchronous or Synchronous TDM, addressing is used?


Question No: 34      ( Marks: 2 )
 

What is the basic purpose of Router?


Question No: 35      ( Marks: 3 )
 

Why we need a Null Modem?


Question No: 36      ( Marks: 3 )
 

Count LRC for the following bits?
10011010  10100101   1101 0110


Question No: 37      ( Marks: 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      ( Marks: 3 )
 

What are the three purposes of control frames at data link layer?


Question No: 39      ( Marks: 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?





Question No: 40      ( Marks: 5 )
 

what is the difference between character oriented and bit oriented protocols?

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