The parallel transmission defines a transmission structure that shares multiple data bits at a similar time over separate media. In general, parallel transmission can be used with a wired channel that uses multiple, separate wires.
The figure given below shows the concept and shows why engineers use the term parallel to characterize the wiring.
The figure omits two important elements. First, in addition to the parallel wires that each hold data, a parallel interface generally includes other wires that enable the sender and receiver to coordinate. Second, to create installation and troubleshooting simply, the wires for a parallel transmission system are located in a single physical cable. Thus, one expects to view a single, large cable connecting a sender and receiver rather than a set of independent physical wires.
The advantages of parallel transmission are as follows −
High speed − It can transmit N bits at the same time. A parallel interface can work N times quicker than an equivalent serial interface.
Match to underlying hardware − Internally, computer and transmission hardware use parallel circuits. Thus, a parallel interface matches the internal hardware well.
Data is sent much faster as parallel transmission can increase the transfer speed by a factor of n over the serial transmission.
A huge amount of data is to be transmitted over connection lines.
Parallel transmission can send information from computer to printer. The printer is linked to the parallel port of the computer and a parallel cable that has multiple wires can link the printer to the computer. It is a very fast data transmission mode.
Transmission of n communication lines is required to transmit the data stream and for this n number of wires must be required.
This is expensive so it is usually limited to shorter distances.