Introduction

The LIN protocol as proposed is an automotive focused low speed universal asynchronous receiver transmitter (UART) based network. Some of the key characteristics of the LIN protocol are signal-based communication, schedule table-based frame transfer, commander/responder communication with error detection, node configuration and diagnostic service transportation.

The LIN protocol is for low-cost automotive control applications as, for example, door module and air conditioning systems. It serves as a communication infrastructure for low-speed control applications in vehicles by providing:

— signal-based communication to exchange information between applications in different nodes;
— bit rate support from 1 kbit/s to 20 kbit/s;
— deterministic schedule-table-based frame communication;
— network management that wakes up and puts the LIN cluster into sleep state in a controlled manner;
— status management that provides error handling and error signalling;
— transport layer that allows large amount of data to be transported (such as diagnostic services);
— specification of how to handle diagnostic services;
— electrical physical layer specifications;
— node description language describing properties of responder nodes;
— network description file describing behaviour of communication;
— application programming interface.

The ISO 17987 series is based on the open systems interconnection (OSI) basic reference model as specified in ISO/IEC 7498‑1 which structures communication systems into seven layers.

The OSI model structures data communication into seven layers called (top down) application layer (layer 7), presentation layer, session layer, transport layer, network layer, data link layer and physical layer (layer 1). A subset of these layers is used in the ISO 17987 series.

The ISO 17987 series distinguishes between the services provided by a layer to the layer above it and the protocol used by the layer to send a message between the peer entities of that layer. The reason for this distinction is to make the services, especially the application layer services and the transport layer services, reusable also for other types of networks than LIN. In this way, the protocol is hidden from the service user and it is possible to change the protocol if special system requirements demand it.

The ISO 17987 series provides all documents and references required to support the implementation of the requirements related to the following.

— ISO 17987‑1 (this document): provides an overview of the ISO 17987 series and structure along with the use case definitions and a common set of resources (definitions, references) for use by all subsequent parts.
— ISO 17987‑2 : specifies the requirements related to the transport protocol and the network layer requirements to transport the PDU of a message between LIN nodes.
— ISO 17987‑3 : specifies the requirements for implementations of the LIN protocol on the logical level of abstraction. Hardware-related properties are hidden in the defined constraints.
— ISO 17987‑4 : specifies the requirements for implementations of active hardware components which are necessary to interconnect the protocol implementation.
— ISO/TR 17987‑5 : specifies the LIN application programming interface (API) and the node configuration and identification services. The node configuration and identification services are specified in the API and define how a responder node is configured and how a responder node uses the identification service.
— ISO 17987‑6 : specifies tests to check the conformance of the LIN protocol implementation according to ISO 17987‑2 and ISO 17987‑3. This comprises tests for the data link layer, the network layer and the transport layer.
— ISO 17987‑7 : specifies tests to check the conformance of the LIN electrical physical layer implementation (logical level of abstraction) according to ISO 17987‑4.

BS ISO 17987-1:2025

Road vehicles. Local Interconnect Network (LIN) - General information and use case definition

Current

Published:

31 May 2025