03 - Start and Stop bits in asynchronous transmiss

 1. Asynchronous transmission is a method of transferring data that has control signals embedded in it in order to synchronise the transmission.



 2. In Asynchronous transmission the transmitter's and receiver's clocks are kept synchronised right from the start and only become out of sync during transmission.



 3. Start and stop bits are used as ____________ to indicate where the message starts and where it ends.



  search indexes

  stopping conditions

 4. Before a message is sent, a _____________________ is added to the message.

  serial stop bit

  serial and parallel control bit

  start and stop bit

  parallel transmission protocol

 5. Start and stop bits are essentially used to _____________________________________________

  search for lost packets or data within the transmission media

  indicate when the message should have a full stop

  distinguish between different types of data (e.g. images or text

  synchronise the data transfer between the two devices

 6. It is not necessary for both devices to send and receive signals at the same rate, as being out of sync in asynchronous transmission is the norm.



 7. An example would be that the bit string: 00101111001 would have the stop bit 0 and a start bit of 1 added to it giving: 0 00101111001 1



 8. Start bit synchronises receiver (clock) (to transmitter/data). It also locks receiver and transmitter in phase and starts receiver's clock or _________________

  kills the receiver

  blocks the receiver for security purposes

  sets the receiver to 0 (e.g off)

  wakes receiver

 9. Stop bit allows start bit to be recognised and it allows the receiver to ____________________

  set a stop bit to 0 (e.g. off)

  block received bits

  process received bits

  find a start bit to begin the next process

 10. In Asynchronous transmission the sender and receiver are only synchronized when data is being sent