Serial Input Parallel Output
In such types of operations, the data is entered serially and taken out in parallel fashion.
Data is loaded bit by bit. The outputs are disabled as long as the data is loading.
As soon as the data loading gets completed, all the flip-flops contain their required data, the outputs are enabled so that all the loaded data is made available over all the output lines at the same time.
4 clock cycles are required to load a four bit word. Hence the speed of operation of SIPO mode is same as that of SISO mode.