Chapter 4

Question 1

____________ is not a function of a data link protocol.

  Media access control 
  Message delineation 
  Amplitude shift keying 
  Indicating when a message starts and stops 
  Error control

Answer 1

Amplitude shift keying

Question 2

_____________ is an effective way to prevent impulse noise, cross talk, and intermodulation noise.

  Shielding wires 
  Adding fluorescent lights 
  Adding repeaters to a circuit 
  Adding amplifiers to a circuit 
  Shorting a circuit

Answer 2

Shielding wires

Question 3

Stop-and-wait ARQ uses ___________ type of data flow.

  full simplex 
  half complex 
  full duplex 
  half duplex 
  full complex

Answer 3

half duplex

Question 4

Polling is the process of permitting all clients to transmit or receive at any time.

t or f

Answer 4

False

Question 5

If a signal with a frequency of 500 MHz combines with a another signal of 1500 MHz and they form a new signal of 2000 MHz; this is an example of:

  intermodulation noise 
  attenuation 
  echo 
  white noise 
  cross-talk

Answer 5

intermodulation noise

Question 6

With contention:

a) computers wait until the circuit is free before they send data
b) the server or front end processor works consecutively through a list of clients to determine who should have access to the media
c) the front end processor must wait for a response from the polled client or terminal
d) one computer starts the poll and passes it to the next computer on the multipoint circuit
e) there is never a chance for “collision,” or two computers trying to send data at the same time

Answer 6

a) computers wait until the circuit is free before they send data

Question 7

Which of the following is true about the data link protocol, SDLC:

a) It is a client-server protocol developed by Compaq in 1996.
b) It transmits each character independently of one another and includes start and stop bits for each character sent.
c) It uses a special bit pattern called a flag at the beginning and end of every frame (or packet).
d) It uses a contention media access control protocol and is used in most LANs today.
e) It does not have any error detection capabilities.

Answer 7

It uses a special bit pattern called a flag at the beginning and end of every frame (or packet).

Question 8

_____________ is an effective way to prevent attenuation.

  Shielding wires 
  Adding fluorescent lights 
  Adding repeaters or amplifiers to a circuit 
  Changing multiplexing techniques 
  Shorting a circuit

Answer 8

Adding repeaters or amplifiers to a circuit

Question 9

Synchronous transmission:

a) cannot be used on multipoint circuits
b) is used to send one character at a time
c) uses start bits before each character to be sent
d) uses stop bits after each character to be sent
e) is used to transmit a “frame” or “packet” of data at a time

Answer 9

e) is used to transmit a “frame” or “packet” of data at a time

Question 10

Asynchronous transmission:

a) is used to transmit each character simultaneously with all other characters
b) has a pre-determined, fixed time between sending characters
c) is typically used on multipoint half duplex circuits
d) uses a continuous series of start bits as an idle signal
e) each character is transmitted independently of all other characters

Answer 10

e) each character is transmitted independently of all other characters