Recommendation ITU-T Z.166 specifies the control interfaces for TTCN-3 test system implementations. The TTCN-3 control interfaces (TCI) 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 of [ETSI ES 201 873-6 V4.6.1]). The interface definition uses the CORBA Interface Definition Language (IDL) to specify the TCI completely. Clauses 8@ 9@ and 9.7 of [ETSI ES 201 873-6 V4.6.1] present language mappings for this abstract specification to the target languages Java?@ ANSI C@ and C++.