Transmission

Data is sent one bit at a time over a single wire/cable

Multiple bits of data are sent simultaneously over multiple wires

• skewing means that bits arrive at different times so data can arrive in the wrong order • crosstalk occurs which can result in data corruption • skewing and crosstalk mean the data needs to be resent • So it’s more reliable over shorter distances • uses more wires so is more expensive than serial

Between components in a computer system -In integrated circuits and within RAM

• A clock signal (shared by the sender and receiver) is used to time when signals are sent. • The signals, which are sent at regular intervals, will be received in the same order that they were sent.

• Uses start and stop bits to indicate the duration of a transmission. • The start bit is either 0/1 and the stop bit is always the opposite of the start bit. • The sender and receiver must use the same Baud rate and need only synchronise their clocks for the duration of data transmission.

The time delay that occurs during transmission

• Used within the busses during the fetch-decode-execute cycle. • Suitable for transmitting data in real-time systems as signals are sent at regular intervals

The number of signal changes that occur in a second Measured in Bd

The number of bits that are transmitted over a channel in a second

bit rate = baud rate × number of bits per signal change

The higher the bit rate, the faster the data arrives.

The range of frequencies that a communication channel can carry

They are directly proportional, the higher than bandwidth the higher the bitrate

• Usually used by PC’s - Doesn’t require a method of sharing the clock signal