1 - Theory of Computer Science / Data Transmission

Exam Questions - Data Transmission

Example Question 1

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4

Question 4 requires you to tick true or false for five statements relating to serial Half-Duplex transmission.

It is important to think about both parts of the transmission - Serial AND Half Duplex.

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Example Question 2

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7

(a)
Question 7 (a) requires you to draw arrows between three pairs of computers. The arrows should demonstrate Simplex, Half Simplex and Duplex transmission.

Your arrows for this question should look like this:

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(b) Part B asks you to give one example use for Simplex and Duplex transmission. There are many possible answers for this question. 

Any of the following answers would gain 1 mark each:

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Simplex
  1. Microphone to computer
  2. Sensor to computer
  3. Computer to printer
  4. Computer to speaker
  5. Computer to monitor
  6. Webcam to computer
  7. Sending data to a device
Duplex
  1. Telephone call
  2. Voice over IP
  3. Computer to printer (Only award once)
  4. Instant messaging
  5. Broadband connections
  6. Video conferencing
  7. Computer to modem

Example Question 3

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6

(a) Question 6 (a) gives you three descriptions of data transmission.  You need to read each description carefully whilst paying attention to the direction that data can travel and the number of wires it uses.

Hint -
If it has several wires = It is parallel
If it has one wire = It is serial

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(b) Part (b) asks you to give reasons why serial connection would be used instead of Parallel when connecting devices to a computer.
Here you are essentially describing the pros of serial over parallel.

Any of the following points would gain you a mark (Max 2 marks)

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  1. A single wire means that there is less chance of interference (Cross talk)
  2. Single wire reduces cost
  3. More reliable over longer distances (No skew)
  4. Bits will be synchronized after transmission (No skew)

Example Question 4

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3.

(a) Question 3 requires you to draw lines from a technical term to the matching description.  Some of these terms are data transmission related and others are to do with error detection.  This question is a good example of how the two topics may be combined into one question.  Again, with this question you should be careful as the technical term includes the wire type AND the direction.

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Example Question 5

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3

(a)
(i) This question requires a written description of serial transmission.  Remember that you need to give 2 points as it is worth 2 marks

Any 2 of the following points would get a mark each

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  1. One bit sent at a time // Bits sent sequentially
  2. Over a single wire
  3. Synchronous or asynchronous

(ii) This question requires a written description of Parallel transmission.  Remember that you need to give 2 points as it is worth 2 marks

Any 2 of the following points would get a mark each

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  1. Several bits sent at a time
  2. Using many / multiple wires
  3. Synchronous

(b)
Question b asks you to suggest which is the best type of data transmission method for a printer 1 km away from its office.  Here they are looking for you to refer to the cable type - Serial or Parallel

Answer (Worth 1 mark)
Serial

Next you must give two reasons for your choice. Each of the following points are worth 1 mark.

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  1. Serial data transmission is more reliable over long distances
  2. Less likely for the data to be skewed or out of synchronization
  3. Less interference as only one wire
  4. It is cheaper connection as only one wire is needed
  5. A fast connection is not required as a printer is limited by the printing speed.

Example Question 6

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7

(a) Question 7 part (a) asks for a description of parallel data transmission. The question is 2 marks so 2 points should be given.

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  • Uses several / multiple wires
  • Transmits multiple bits at a time

(b) Part B ask you for one benefit and one drawback of parallel data transmission over serial transmission over a short distance.

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Benefit
  • Quicker / faster data transfer
Drawback
One from
  • More chance of data being skewed due to bits being sent simultaneously /out of order
  • More expensive as requires more wires
  • More chance of interference as more wires are used (can create cross talk)

(c) Part (c) asks for one example where parallel transmission is used.

Each of the following marks would be worth 1 mark

Answers
  • Used in Integrated circuits
  • Used in RAM
  • Used in connections to peripherals e.g. printer