IEC 61158-6-2:2010(E) specifies the protocol of the Type 2 fieldbus application layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545). It defines the protocol provided to define the wire-representation of the service primitives defined in IEC 61158-5 2:2010, and the externally visible behavior associated with their transfer. This second edition cancels and replaces the first edition published in 2007 and constitutes a technical revision. The main changes with respect to the previous edition are: - Clause 2 and Bibliography: update of normative and bibliographic references; - subclause 3.4: update of abbreviations; - subclause 4.1.2.1: update list of service request/response PDUs (Time Sync and Parameter ASEs/objects); - subclause 4.1.8.6: update of Time Sync ASE/object; - new subclause 4.1.8.7: new Parameter ASE/object; - subclause 4.1.10.2: update/add object and services codes for Time Sync and Parameter ASEs; - new subclause 11.7: new QoS specification.