The electronic gong acts as an acoustic signal generator for the hour signal tone 1 (T1), the temperature warning tone 2 (T2), a warning signal tone 3 (T3) and the code signal tone 1 with tone 2. The signal lines for gong activation of tone 1 - tone 3 are used by the instrument cluster, however, they can be interrupted by the park distance signal tone 4 (T4). Tones T4 and T5 can be activated via further inputs at the gong, dependent on the vehicle equipment level. These acoustic functions cannot be triggered by the instrument cluster electronics (IKE ) but rather they are a functional part of other vehicle components.
The hour signal T1 reminds the user of radio news broadcasts or traffic announcements with three short "beeps" (1 kHz).
In the case of the temperature warning T2, one single gong (1 kHz) is triggered which warns the driver of low outside temperatures (ice hazard).
Warning signal T3 warns the user by means of a long tone (1 kHz), followed by the gong sounding. It acts as the acoustic signal for the light check module (LCM). The light check module (LCM) informs the instrument cluster that the acoustic signal has been triggered by an I-bus telegram (instrument bus).
The short code signal is triggered by the tone T1 and T2 (750 Hz). It indicates to the user that the programmed speed limit has been exceeded or it draws attention to a code function still active when starting.