IEC 61158-6-9:2014 defines the protocol provided to define the wire-representation of the service primitives defined in IEC 61158-5-9, and define the externally visible behavior associated with their transfer. This standard specifies the protocol of the Type 9 fieldbus application layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545). This third edition cancels and replaces the second edition published in 2010 and constitutes a technical revision. The main changes are: - Correct Time-difference valid range; - Correct Table 3 state transition; - Include Transparent timeliness class in BNU AREP formal model.