This serves to inform the receiver when data is available. In addition, another line may be used by the receiver to inform the sender that the data has been used, and its ready for the next data. The sender, upon getting the DU signal, removes the data and sends the next data element in the same manner. This exchange of signals such as DA and DU between the sender and the receiver is called a handshake . Parallel transmission is obviously faster than serial, because more than one bit is sent at a time.
Parallel transmission is good only for short links, and examples are found in all computers.
The address, data and control buses which interface the processor to other peripherals inside the computer are all parallel buses. Serial Each bit is sent over a single wire, one after the after. In asynchronous, each character is synchronized using a start and stop signal. In synchronous, each group or block of characters is synchronized using a synchronize flag. In the following sections, serial transmission will be further investigated.