Communication

Question 1

What is baud Rate

Answer 1

Number of times a signal changes per second

Question 2

What is bit rate

Answer 2

Number of bits transmitted over a channel per second

Question 3

Difference between bit rate and baud rate

Answer 3

Bit rate is baud rate multiplied by the number of bits per signal

Question 4

What is bandwidth

Answer 4

Maximum rate of data transfer of a communication channel

Question 5

Relationship between bit rate and bandwidth

Answer 5

They are directly proportional

The greater the amount of data that can be transmitted over a channel, the more bits that can be transferred per second

Question 6

What is latency

Answer 6

The delay from the time that a signal is sent, to the time its received

Question 7

What is a protocol

Answer 7

A set of rules that determine the communication between devices

Question 8

Specify the details of the communication in the protocols

Answer 8

• types of transmission (sync or a-sync)
• types of interfaces (serial or parallel)
• the transmission channel (wired or wireless)
• speed of transmission (bit or baud rate)
• error checking techniques
• format of transmitted data

Question 9

What is synchronous transmission

Answer 9

Streams of bits are transferred over a channel at a constant rate.

Transmitter and receiver are synchronised using a common clock signal

Question 10

What is asynchronous transmission

Answer 10

There is no clock signal, so start and stop bits are used to control communication

Data transmitted when available rather than specific intervals

Question 11

Difference between sync vs a-sync

Answer 11

• a-sync uses a start and stop bit to mark beginning and end of transmission, stop signal typically longer than 1 bit so receiver has time to reset
• sync uses clock signal, no need for start and stop bit, commonly used with parallel transmission

Question 12

What is serial transmission

Answer 12

Data bits are sent in a sequence over a single wire

Question 13

What is parallel transmission

Answer 13

Several bits are sent at the same time over their own dedicated wires.

Only reliable over short distances

Question 14

Advantages of serial over parallel transmission

Answer 14

• Parallel experiences skew and crosstalk over longer distances
• Parallel is only efficient over shorter distances and with a lower bitrate
• cheaper as less wires are used

Question 15

What is crosstalk

Answer 15

Occurs when electromagnetic interference between wires that are close

Results in transmitting corrupted data that will need to be re-sent

Question 16

What is skew

Answer 16

Happens when bits that are transmitted across parallel links travel at different speeds

In sync transmission, this results in data falling out of sync with clock signal, leading it to not be read correctly