Communication methods

Bit rate

the speed at which data is transmitted serially, measured in bits per second

Baud rate

the rate at which the signal changes

Baseband

only two voltage levels are most commonly used, one to represent zero, and the other to represent one

Bandwidth

the range of frequencies that a transmission medium can carry

Latency

the time delay between the moment transmission of the first byte/packet of a communication starts and when it is received

Parity

a system of error-checking in which an extra bit is added to a byte of data before transmission to check if an error is likely to have occurred

Even parity

the total number of ‘1 bits in every byte, including the parity bit itself, must be an even number

Odd parity

the total number of ‘1 bits in every byte, including the parity bit itself, must be an odd number

Protocol

a set of rules relating to communication between devices

Advantages of serial over parallel transmission

• Lower associated costs (smaller and less complex connectors)

• Less likely to be affected by crosstalk

• Much more reliable over greater distances

• Lack of interference at higher frequencies (higher frequency → higher net data transfer rate)

Where is parallel communication used?

• Integrated circuits

• Within RAM

What is the main advantage associated with asynchronous transmission?

There doesn’t need to be a way of sharing the clock signal

What is the requirement for pieces of equipment to be linked together?

They must be using the same protocol