Communication Objectives Flashcards
(14 cards)
What is Serial Data Transmission
Data bits are sent in a sequence, one after the other, over a single line
What is Parallel Data transmission?
Several bits are sent at the same time over a set of parallel lines
What is a problem with Parallel Data transmission?
Is only reliable over short distances
What are the advantages of serial over parallel data transmission?
Crosstalk occurs when electromagnetic interference between wires that are in proximity (such as parallel links) results in transmitting corrupted data that will need to be re-sent
Skew happens when the bits that are transmitted across parallel links travel at different speeds
Serial interfaces have fewer pins, so they are cheaper and easier to produce
What is the bit rate? What unit is it measured in?
The number of bits that are transmitted over a channel each second.
Bits per second, or bps
What is the baud rate? What unit is it measured in?
The baud rate is the number of times that a signal changes per second.
Bits per second, or bps
What is the relationship between bit rate and baud rate?
bit rate = baud rate × number of bits encoded per symbol
What is bandwidth? What unit is it measured in?
Bandwidth is the maximum rate of data transfer of a communication channel
What is latency?
Latency is the delay from the time that a signal is sent, to the time that it is received
What is synchronous transmission?
Streams of bits are transferred over a communication channel at a constant rate. The transmitter and the receiver are synchronised using a common clock signal.
What is asynchronous transmission?
There is no clock signal, so additional data (start and stop bits) is used to control the communication
How are start and stop bits used in asynchronous transmission?
A start bit is sent at the beginning of the transmission so that the receiver can prepare for the incoming data, and a stop bit marks the end of the transmission. The stop bit needs to be opposite to the start bit so that the receiver can recognise the next set of bits.
Why do you need both synchronous and asynchronous?
Synchronous transmission is ideal for high-speed, continuous data transfer, such as video streaming, while asynchronous transmission is better for sporadic data transfer, like keyboard inputs.
What is a parity bit?
An extra bit added to a string of binary code to ensure that the total number of 1-bits in the string is even
