Talend SAP RFC Server is a standalone server that acts as a gateway between Talend Studio and an SAP server. It receives SAP IDocs or SAP BW Data Source objects from the SAP server and makes them available for processing by the tSAPIDocReceiver component or the tSAPDataSourceReceiver component and other components in Talend Jobs. For more information about these components, see Talend Components Reference Guide.
Talend SAP RFC Server is built on an embedded Apache Active MQ. It publishes IDocs or Data Source objects in JMS (Java Message Service) topics or replicates them to JMS queues for batch processing. The tSAPIDocReceiver component or the tSAPDataSourceReceiver component can then subscribe to these JMS topics or read from the JMS queues.
Note that the SAP server needs to be configured to operate with Talend SAP RFC Server. For more information, see the Knowledge Base article https://help.talend.com/pages/viewpage.action?pageId=268960615.