The acoustic alarm of the antitheft alarm system (DWA) as well as the acoustic feedback for arming/disarming (coded) are triggered via an alarm.
The siren is designed as an emergency siren so that an acoustic alarm can be triggered independent of the vehicle electrical system.
When the antitheft alarm system is armed, the siren is activated by the ZKE general module via the STDWA line and deactivated when the system is disarmed (the same line also activates and deactivates the tilt alarm sensor and interior protection). The siren is informed of the alarm triggering status by the general module via the SIREN line.
When the siren is armed, an alarm may still be triggered if the siren is disconnected from the vehicle electrical system or the vehicle battery is disconnected.
The alarm is triggered for 30 seconds. The alarm is interrupted immediately when the DWA is disarmed.
An alarm triggered by tampering with the emergency current siren is not stored in the alarm counter as the general module cannot register the alarm being triggered.
The siren contains the entire electronics as well as a rechargeable battery necessary for triggering an alarm so that it is independent of the vehicle electrical system. The rechargeable battery is charged via the vehicle battery.
The acoustic feedback provided when arming and disarming the antitheft alarm system are coding variants in the ZKE general module. During acoustic feedback, the siren is operated at reduced volume.
Acoustic feedback takes place as follows:
A differentiation is made between two basic versions of the siren for USA and EUR operation. The EUR variant can be used for both continuous tone as well as for intermittent tone (depending on the coding of the general module). When an alarm is triggered, the general module informs the siren of the coded mode of operation. This is stored in the siren so that the specified operating mode is retained even if the siren itself is triggered. When the general module is recoded, the mode stored in the siren is also changed the next time the alarm is triggered.