A bus is a system for data transfer between several participants via a common transfer path. During data transfer between two participants, all others must remain silent so as not to jam each other.
A serial bus can be defined as a transmission path (shared channel) over which the participants transmit their data serially in other words bit after bit, sequentially in time and using a common medium, for example, ethernet uses a serial bus architecture. In contrast, in parallel bus systems, the individual bits which form a character are transmitted simultaneously by a certain number of data lines. This results in increased costs for cable and connectors; the transmission time is shorter than with a serial bus.

• Modern computer buses can use both parallel and bit serial connections.