IEC 61158-6-19:2010(E) specifies the protocol of the Type 19 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 61158-5-19:2010, 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: - increasing the number of supported devices (511 instead of 254); - introducing a communication version identification; - adding a mechanism for remote address allocation; - introducing enhanced parameter addressing (32 bit instead of 16 bit); - restructuring control and status word; - improving the redundancy and hotplug features; - improving the error handling; adding a multiplexing protocol (SMP: Type 19 Messaging Protocol).