The primary purpose of conformance testing is to increase the probability that different implementations are able to interwork. This supplement provides guidelines on the conformance testing for Recommendations of the T.170-series using DAVIC specifications, as the conformance testing information contained in the DAVIC specifications is not sufficient in all cases. This supplement relies on the testing architecture and terminology based on ISO/IEC 9646 conformance testing. Besides conformance testing, which cannot guarantee interworking, interoperability testing is necessary where a product's capability of working with others to achieve a common task is checked. Interoperability testing is outside the scope of this supplement.