Serial
Several bits of data are sent at one time
Data is sent one bit at a time
Data is sent in only one direction
Parallel
Date is sent in only one direction
Data is transmitted in both directions (not at the same time)
Several bits of data are sent at once
Half-Duplex
data is Transmitted in a continuous stream, and is accompanied by timing signals
Data is transmitted in an agreed bit pattern, bits are grouped together and sent with control
Full-Duplex
Data is transmitted in both directions simultaneously
several bits of data are sent at the same time
Simplex
data is transmitted in both directions
Asynchronous
Data is transmitted in a continuous stream, the data is accompanied by timing signals
Synvhronous
Data is not transmitted
