Chapter 2 : Communication and internet technologies Flashcards
What is Simplex data transmission? And give an example
It is where data is transferred only one way (This is Unidirectional) (Radio)
What is Half-Duplex data transmission? And give an example
It is where data is able to be transferred both ways but can only go one way at a time (This is Bidirectional) (Walkie Talkie)
What is Full Duplex data transmission? And give an example
It is where data is able to be transferred both ways at the same time (This is Bidirectional) (Phone call)
What is Serial data transmission?
It is where data is sent over a single wire, 1 bit at a time (can be Simplex, Half-Duplex or Full Duplex)
Where is Serial data transmission used and why?
It is used over long distances as there isn’t a problem with data arriving out of synchronisation
What is Parallel data transmission?
It is where data is sent as several bits of data over several wires where each wire is used to send a bit
Where is Parallel data transmission used and why?
It is used over short distances as it is very fast but it isn’t used over long distances as the bits can become skewed and unsynchronised
What is Asynchronous data transmission?
Is when data is transmitted in an agreed bit pattern and are sent with control bits to mark out the groups of data
Advantages and Disadvantages of Asynchronous data transmission
A. You don’t need the computers to be in sync
D. Bits are wasted as control bits
What is Synchronous data transmission?
Is when data is transmitted in a continuous stream with timing signals so that both computers are in sync
Advantages and Disadvantages of Synchronous data transmission
A. It is faster
A. Doesn’t need control bits
D. It needs the computers to be in Sync
What does USB stand for?
Universal Serial Bus
What kind of data transmission does USB use (Asynchronous or Synchronous)?
Asynchronous
How does a computer know if a USB device has been plugged in?
A small change in the voltage level on the data signal wires in the cable
What does a computer do if it doesn’t recognise a device?
The computer will look for the driver which matches the device and if this is not available then it will prompt the user to download it