This Recommendation contains the validation (conformance) test specification for the Application Transport Mechanism@ support of VPN applications with PSS1 information flows defined in Recommendation Q.765.1 [1]. This Recommendation applies only to exchanges having implemented the ISUP'97 protocol specification for the Application Transport Mechanism and APM support of VPN applications for the exchange. It is applicable for validation testing of all types of exchanges as defined in the ISUP'97 protocol specification. This Recommendation does not deal with compatibility testing. The main text part of this Recommendation presents the requirements regarding the chosen test method@ conventions used within the ATS@ the Test Suite Structure and Test Purposes (TSS TP) for the Application Transport Mechanism@ support of VPN applications with PSS1 information flows. The annexes present the Protocol Implementation Conformance Statements (PICS)@ the Protocol Implementation eXtra Information for Testing (PIXIT)@ Protocol Conformance Test Report (PCTR) and the ATS for the Application Transport Mechanism@ support of VPN applications with PSS1 information flows the last one being available on electronic media. Annex A provides the Protocol Implementation Conformance Statement (PICS) proforma for the Application Transport Mechanism@ support of VPN applications with PSS1 information flows defined in compliance with the relevant requirements and in accordance with the guidance given in ISO/IEC 9646-7 [9]. This statement indicates which capabilities and options of a telecommunication specification have been implemented. It is necessary for evaluating the conformance of a particular implementation. The supplier of an implementation that is claimed to comply with to the reference specification for the Signalling System No. 7@ Application Transport Mechanism@ support of VPN applications with PSS1 information flows [1] is required to complete a copy of the PICS proforma provided in Annex A. Annex B provides the protocol implementation extra information for test (PIXIT) proforma needed as a preparation for testing. Annex C provides the protocol conformance test report (PCTR) proforma used for evaluating the results of the testing campaign. Annex D explains how to get hold of the actual ATS@ which is delivered in electronic form only.