In data communication via networks, the data is transmitted serially synchronously or asynchronously and the clock signal is derived from the digital signal. If the synchronization takes place bit by bit, it is referred to as bit synchronization.
When computerscommunicate over short distances, for example with peripheral devices, the data is transmitted in parallel, bytewise in byte synchronization. If byte data is to be transmitted over longer distances, then the data that is present in parallel at the computer interface must be converted into serial data signals. This is done by parallel-serial converters, for example shift registers. The data is then transmitted byte-serially. If the data is required again in parallel form after serial transmission, serial-parallel converters are available for this purpose.