Communication Flashcards
What is the difference between Serial and Parallel Transmission.
Serial transmits one after another
Parallel transmits all at the same time
When is Serial Transmission used
for all long haul communication
for most computer networks
When is Parallel Transmission used
short range, high speed connections
Inside a computer
e.g. printers, RAM
Advantages of Serial over Parallel
Cheaper
Travels longer distances
Little data corruption
Cant suffer from SKEW
Advantages of Parallel over Serial
Simpler hardware
higher speed of transmission
What is SKEW
Where all the bits don’t arrive at the same time so the data becomes screwed
Only happens in Parallel transmission
What are the 2 different types of Serial Transmission
Synchronous
Asynchronous
What is synchronous transmission
Data is transferred at regular intervals
These are synchronised by a clock
Useful for real time data
Enables whole blocks of data to be sent in timed sequences
Much faster
What is Asynchronous transmission
Data is transferred one character at time
A start bit, stop bit and parity bit sent with each character
Generally for lower speed transmission (internet)
Data is sent in packets containing a character that include start,stop,parity bits
What is bandwidth
Range of frequencies that can be transmitted across a network connection
What is bit rate
The number of bits that are transferred between devices per second
What is baseband
The simplest form of data transmission, at each signal change just one bit is transmitted
What is baud rate
Number of times a signal in a communications channel changes state in a second
Equation for calculating bit rate
baud rate * number of bits per signal
What is Latency
The delay between an action being started and its effect being noticed
