Three transfer objects are available in the SAP system plug-in for connecting with RFC, BAPI and IDoc.
A RFC is used to call-up a function in an SAP system. Import and export parameters of different types can be used (simple, structures, tables). The call-ups are carried out synchronously.
BAPIs are standard interfaces of the SAP system and allow access to methods of business objects. Similar to RFCs, functions are addressed and their parameters (simple, structures, tables) made available. The call is also made synchronously.
The IDoc data format is used for asynchronous data transfer. IDocs are structured documents used to send and receive transaction-based data to and from the SAP system.