The present document specifies the control interfaces for TTCN-3 test system implementations. The TTCN-3 Control Interfaces provide a standardized adaptation for management@ test component handling and encoding/decoding of a test system to a particular test platform. The present document defines the interfaces as a set of operations independent of a target language. The interfaces are defined to be compatible with the TTCN-3 standard (see clause 2). The interface definition uses the CORBA Interface Definition Language (IDL) to specify the TCI completely. Clauses 8@ 9@ 10@ 11 and 12 present language mappings for this abstract specification to the target languages Java?@ ANSI C@ C++@ XML and C#. A summary of the IDL-based interface specification is provided in annex A.