Use an Input transformation in a mapplet when you want the mapplet to receive input from a source in a mapping. When you use the mapplet in a mapping, the Input transformation provides input ports so you can pass data through the mapplet. Each port in the Input transformation connected to another transformation in the mapplet becomes a mapplet input port. Input transformations can receive data from a single active source. Unconnected ports do not display in the Mapping Designer.
You can connect an Input transformation to multiple transformations in a mapplet. However, you cannot connect a single port in the Input transformation to multiple transformations in the mapplet.