This standard defines an interconnect bus for (but not limited to) microcontrollers and devices with limited reprogrammability. This bus provides a multi-drop bit-serial communication protocol that will allow the interconnection of distributed, independently manufactured devices. The protocol is optimized for instrumentation, distributed data acquisition systems, control devices, and test and measurement. The purpose of Section 1 is to serve as the foundation for the standard. It contains the overall definition of the bus network as well as a reference model for protocol sections. Protocol descriptions are contained in later sections of this document. This section contains the basis for those descriptions, such as the primitives employed to describe interactions between layers in the protocol reference model. An important part of this section is a description of what is meant by conformance to IEEE Std 1118-1990This standard defines an interconnect bus for (but not limited to) microcontrollers and devices with limited reprogrammability. This bus provides a multi-drop bit-serial communication protocol that will allow the interconnection of distributed, independently manufactured devices. The protocol is optimized for instrumentation, distributed data acquisition systems, control devices, and test and measurement. The purpose of Section 1 is to serve as the foundation for the standard. It contains the overall definition of the bus network as well as a reference model for protocol sections. Protocol descriptions are contained in later sections of this document. This section contains the basis for those descriptions, such as the primitives employed to describe interactions between layers in the protocol reference model. An important part of this section is a description of what is meant by conformance to IEEE Std 1118-1990