Recommendation ITU-T Z.166 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. This Recommendation defines the interfaces as a set of operations independent of a target language.

The interfaces are defined to be compatible with the TTCN-3 standards (see clause 2 of ETSI ES 201 873-6 V4.5.1). 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 V4.5.1 present language mappings for this abstract specification to the target languages Java and ANSI C.

This revision of the Recommendation contains amendments, clarifications, corrigenda and editorial corrections.