Computer Science Data Transmission

Simplex

• Transmission possible in two directions simultaneously

• Transmission possible in one direction only

• Transmission in two directions, but not at the same time

Duplex

• Transmission possible in one direction only

• Transmission possible in two directions simultaneously

• Data is sent one bit at a time over a single wire or channel

Serial Transmission

• Several bits of data (usually 1 byte) are sent down several wires or channels at the same time

• Transmission possible in two directions simultaneously

• Data is sent one bit at a time over a single wire or channel

Parallel full duplex

• Several bits of data sent down several wires or channels at the same time, in one direction only

• Several bits of data sent down several wires or channels at the same time, in both directions simultaneously

• Data is sent one bit at a time over a single wire or channel, in one direction only

Serial duplex

• Several bits of data sent down several wires or channels at the same time, in one direction only

• Several bits of data sent down several wires or channels at the same time, in both directions simultaneously

• Data is sent one bit at a time over a single wire or channel, in both directions simultaneously

Half Duplex

• Transmission in two directions, but not at the same time

• Transmission possible in one direction only

• Transmission possible in two directions simultaneously

Drawbacks of serial transmission

• Too fast

• Slower than parallel

• Expensive cables

• Synchronisation issues

Drawbacks of parallel transmission

• Slow

• Expensive cables

• Not suitable for long distances due to synchronisation issues

• Fast