Transports and Interfaces: Siebel Enterprise Application Integration > EAI DLL and EAI File Transports >

About EAI DLL Transport

You use the EAI DLL Transport when you want to call a function that exists in an external DLL. You must know the exported function in the DLL that you want to invoke. You specify the EAI DLL Transport as one of the business services in your workflow.

NOTE:  The EAI DLL Transport only accepts String type as input or output to the external DLL. The external function also must return String type.