Over the course of time, numerous functions have migrated into the automobile, which have contributed to making car driving increasingly more convenient. Car drivers are largely unaware that modern convenience functions require many different sensors and actuators. As can be seen from the figure “Conventional Networking”, for a long time it was usual practice to connect the growing number of sensors and actuators directly to a central ECU.

As the resulting situation posed the problems of continually increasing costs, space requirements and weight of ‘electronification’ while reliability was decreasing, developers quickly recognized the benefits of networking sensors and actuators via a serial bus system. This was also necessary because growing individualization required many different wire harness and connector variants, which in turn made their production, installation and maintenance significantly more difficult.

Right from the start, the CAN bus was never even considered for the cost-sensitive sub-bus or sensor/actuator field (also referred to as Class A), and so in the mid-1990s many automotive OEMs and suppliers began to develop suitable solutions that could address sub-bus requirements. Many of these solutions gradually disappeared from the scene, except for one: LIN (Local Interconnect Network).

A key reason for this was the founding of the LIN Consortium, under whose guidance well-known automotive OEMs and suppliers, as well as semiconductor and tool producers, came together to create an OEM-independent standard for communication in the sensor/actuator field.

With the definition of a simple and cost-effective physical layer, a lean communication protocol, and a methodology for automated development of LIN nodes or LIN networks (LIN Work Flow), the LIN Consortium created the necessary preconditions for implementing simple and cost-effective bus nodes.

Meanwhile, LIN has become established as a sub-bus, and LIN can be found in nearly every vehicle today, typically in convenience applications such as controls for the climate control system, seats, doors and mirrors. The figure “LIN Networking” shows a typical use of LIN in the automobile. All sensors and actuators are equipped with a LIN bus interface and are connected to the LIN bus and the “Central ECU” (in the example: Door ECU). In the process, the door ECU assumes the role of a CAN-LIN gateway.