Description And Operation: Description
The Alarm Siren Unit (ASU) module communicates with the Body Control Module (BCM) via the Local Interface Network (LIN) serial data bus.
The BCM controls the activation of the siren and supplies the configuration of the parameters that are used by the ASU to operate correctly (e.g. sound levels, number of alarm cycles per execution, etc.).
In the other direction, the ASU sends the BCM the information on its status.
The LIN data bus is also used to send and receive the messages regarding the "Heart Beat" function, which monitors the integrity of the connections between the BCM and the siren module. A small battery, which is used if the heart beat is missing, is integrated in the ASU.
The alarm siren module cannot be repaired or adjusted and, if ineffective or damaged, it must be replaced.