Preview

02 - Synchronous and asynchronous transmission

 1. Why is parallel communication considered to be asynchronous?

  Because there is a central clock that controls the timings of wire connections

  Because it is thicker than a serial cable

  Because there is no central clock that controls the timings of data sent on different wires

  Actually, it is not considered to be asynchronous

 2. Parallel communication is generally considered synchronous.

  TRUE

  FALSE

 3. Asynchronous and synchronous transmission are methods of transferring data.

  FALSE

  TRUE

 4. In Asynchronous transmission the control signals are embedded in it in order to ________________________________.

  control the output signals and voltage

  stabilise the data

  synchronise the transmission

  sort the bits

 5. In Asynchronous transmission the transmitter's and receiver's clocks are not kept synchronised and only become synchronised __________________________________________-

  None of these options are valid answers

  before the data is sent

  at the time of the tranmission of data

  when all transmissions have ceased

 6. ____________________________bits are used as markers to indicate where the message starts and ends.

  serial and parallel

  indicator and parallel

  bus and address

  Start and stop

 7. All messages have _________________bits added to them before sending.
Note: it is these bits that are used to synchronise the data transfer between the two devices

  bus and address

  start and stop

  serial and parallel

  indicator and parallel

 8. In Asynchronous transmission both devices must _________________________________________or else they will be out of sync.

  receive and send signals at different rates (not the same rate)

  receive and send signals at the same rate

  connect to WI-FI or ethernet at the same rate

  send the same number of bits using the same number of wires

 9. Start and stop bits are useful because they ensure the sending and receiving of signals at the same rate.

  FALSE

  TRUE

 10. If there is a central clock that controls the timing of the data sent on different wires, it suggests _______________ transmission.

  serial

  synchronous

  parallel

  asynchronous

 11. This figure represents asynchronous data being transmitted using odd parity in the direction of the arrow. What is the name and purpose of bit A?
synchronous_async_examquestion1.png

  None of these options are valid answers

  It is called the START BIT and its purpose is to synchronise the recipient's device

  It is called the START BIT and its purpose is to synchronise receiver

  It is called the PARITY BIT and its purpose is to desynchronise the recipient's device

 12. Referring to the question above: what is the name and purpose of bit B?

  It is called the START BIT and its purpose is to synchronise the recipient's device

  It is called the PARITY BIT and its purpose is to parity check// check for errors in transmission

  It is called the START BIT and its purpose is to synchronise receiver

  It is called the STOP BIT and its purpose is to allow receiver to process received bits (indicate end of data)

 13. Referring to the question above: what is the name and purpose of bit C?

  It is called the START BIT and its purpose is to synchronise the recipient's device

  It is called the PARITY BIT and its purpose is to parity check// check for errors in transmission

  It is called the STOP BIT and its purpose is to allow receiver to process received bits (indicate end of data)

  It is called the START BIT and its purpose is to synchronise receiver

 14. What type of transmission is being described in the following statements?
// Receiver and transmitter (clocks) do not need to be/are not (exactly) synchronised 

// transmission of data without use of external clock signal 

// receiver and transmitter clock only synchronised at start of/for length of transmission

 // data sent as soon as available rather than waiting for clock pulse/ synchronisation symbol;

  Erroneous

  Receiving

  synchronous

  asynchronous

 15. Fill in the blanks for this description of Asynchronous transmission.
Data is _________________________________________________________
Sender and receiver are only synchronized when data is being sent
The start bit synchronises the receiver

  transmitted on several different baud wires at the same time (parallel but not restricted by clock times)

  transmitted intermittently (rather than as a steady stream)

  transmitted as a steady stream (rather than transmitted intermittently)

  transmitted one bit at a time in a serial manner