In Talend, connections are the ones to determines the data process, data output, or the logical sequence of work. Talend provides various types of connections like the 'Rowthat' which deals with an actual data flow. There are also varieties of Row connections that are supported in Talend, Main, Lookup, Filter,.Rejects, ErrorRejects and many others.
Another type of connection is Iterate that performs a loop on files in a directory.
Another is Trigger that is used to create dependency like the Subjob Trigger, OnSubjobOK, OnSubjobError, Run if and others.
The link is also a Talend connection that is used to transfer the table schema information