Provides the description of the protocol (abstract syntax) and procedures for the Reliable Transfer Service Element services (ISO/IEC 9066-1). The RTSE services are furnished together with the Association Control Service Element (ACSE) services (ISO 8649) and the ACSE protocol (ISO 8650), and the presentation-service (ISO 8822). The RTSE procedures are defined in terms of a) the interactions between peer RTSE protocol machines through the use of ACSE and the presentation-service; b) the interactions between the RTSE protocol machine and its service-user. Prescribes the conformance requirements for systems implementing these procedures.