Communication Methods

3.3.6

Lesson Outcomes By the end of this lesson you should

– Define both serial and parallel transmission methods and describe where they are used.

– Consider the effect of distance on the transmission of data.

– Define baud, bit rate, bandwidth and latency – Differentiate between baud and bit rate. – Consider the relationship between bit rate and

bandwidth.

Serial vs Parallel• What is meant by serial and parallel

transmission?– Serial data transmission is when single bits

are sent one after another along a single wire– Parallel data transmission is the transmitting

of single bits along several wires simultaneously

Key Learning

Point

Define both serial and parallel transmission methods and describe where they are used.

Serial vs Parallel

Advantages Disadvantage Advantages Disadvantage

Is it best used for short or long distance data transmission? Why?

Serial Parallel

Key Terms• These are key terms that you need to

know.– Baud– Bit rate– Bandwidth– Latency

Key Learning

Point

Define baud, bit rate, bandwidth and latency

Baud• The term baud rate refers to the rate at

which the signal changes. The unit of measure, 1 baud is equivalent to one signal change per second.

1/baud = seconds between signals

Key Learning

Point

Define baud, bit rate, bandwidth and latency

Bit Rate• The bit rate is the number of bits

transmitted each second. When a single signal is sent at a time, the baud rate and bit rate are the same.

Bit rate = Bits per signal * Baud rate

Key Learning

Point

Define baud, bit rate, bandwidth and latency

Bandwidth• Bandwidth is the measurement (Hz) of the

speed at which data is transmitted over a transmission medium. The greater the bandwidth, the faster the data transmission.

Bit Rate = Baud Rate * Number of bits per signal

Key Learning

Point

Define baud, bit rate, bandwidth and latency

Latency• Latency is the time delay between the moment a

message/command is sent and the moment a response is returned.

Key Learning

Point

Define baud, bit rate, bandwidth and latency

Your First Task• On a post it note you should answer this

question;– Describe the differences between baud and

bit rate. – Describe the relationship between bandwidth

and bit rate.

Your Main Task• On Jogle 3.3.6 you will find under topic 2 a

worksheet to be completed.• Add detail to you answers to show your

complete understanding.

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is when single bits are sent one after

another along a single wire

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is the transmitting of single bits along

several wires simultaneously

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is the rate of change of signals on a wire

or a line

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is the time delay between the moment a

message/command is sent and the moment a response is returned

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is an automated process of negotiation

that dynamically sets parameters of a communications channel established between two entities before normal communication over the channel begins

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is a transmission medium used for a

network over short distances

Test Your Key Terms• On your whiteboard write the key term that

this is describing…– This is when the arrival of data cannot be

predicted by the receiver; so a start bit is used to signal the arrival of data and to synchronise the transmitter and receiver temporarily.

Exam Time• Have a go at the exam questions.

Remember the key exam tips– 1 minute per mark– State/define does not require long detailed

answers– Describe/explain does require long detailed

answers