31. Broadband long-distance communications were originally made possible by the advent of—
    

1. 1. Telegraph cables
      

   
   
   

   2. Repeater amplifiers
      

   
   
   

   3. HF radio
      

   
   
   

   4. Geostationary satellites

   
   
   

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   NA

   Correct Option: B

   NA

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32. Switching systems—
    

1. 1. Improve the efficiency of data transfer
      

   
   
   

   2. Are not used in data systems
      

   
   
   

   3. Require additional lines
      

   
   
   

   4. Are limited to small data networks

   
   
   

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   NA

   Correct Option: A

   NA

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33. The RS-232 interface—
    

1. 1. Interconnects data sets and transmission circuits
      Uses several different connectors
      

   
   
   

   2. Permits custom wiring of signal lines to the

   
   
   

   3. connector pins as desired
      

   
   
   

   4. All of the above

   
   
   

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   NA

   Correct Option: A

   NA

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34. Full duplex operation—
    

1. 1. Requires two pairs of cables
      

   
   
   

   2. Can transfer data in both directions at once
      

   
   
   

   3. Requires modems at both ends of the circuit
      

   
   
   

   4. All of the above

   
   
   

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   NA

   Correct Option: D

   NA

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35. A forward error-correcting code corrects errors by—
    

1. 1. Requiring partial retransmission of the signal
      

   
   
   

   2. Requiring retransmission of the entire signal
      

   
   
   

   3. Requiring no part of the signal to be retransmitted
      

   
   
   

   4. Using parity to correct the errors in all cases

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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