Voice Output, Function

Block diagram of COMAND voice output,
illustrated with the following equipment:

- Sound system (code 810)

The marked elements are the components which are essentially used for voice output.

The navigation guidance is supported significantly by voice output.

Originally the voice data is stored as single word segments on the CD-ROM. This data is automatically transmitted from the CD-ROM to the navigation processor (A40/3n2) where it is stored. The navigation processor (A40/3n2) connects these segments to form complete instructions or information and generates corresponding AF signals. If required the AF signals generated in this manner are transmitted internally to the COMAND audio signal processing stage, amplified and output on the vehicle loudspeakers.


NOTE: If the vehicle is equipped with a sound system (code 81O), the voice signals are transferred as analog signals from the COMAND audio signal processing circuit to the sound system amplifier (N40/3) where they are amplified and then output on the vehicle loudspeakers (see block diagram).


NOTE: Several driving recommendations in short sequence are consolidated into one single voice output.

Manual voice data loading from CD-ROM
COMAND is equipped with various languages. They can be selected with the "System settings" menu. The data for voice output is transferred from the CD-ROM to the navigation processor where it is stored in a non-volatile memory.


NOTE: Loading a language requires several seconds and changes the voice output as well as the menu texts.
After an interruption in the power supply the language is automatically reloaded.


NOTE: Avoid extreme vibration (e.g. poor road conditions) while loading a language from the CD-ROM. Otherwise the voice output may be choppy. In such cases it is necessary to reload the language.

Voice output superimposed with another audio source
When voice output and another audio source (CD, CC, radio) are active simultaneously, the one signal is superimposed on the other.

Voice output volume
The volume for the voice output can be changed during voice output. A defined distance (can be adjusted in "Settings" menu) is maintained automatically between the volume of the current audio source and the volume of the voice output.

Example:
During voice output, the volume is reduced so that the specified difference in volume between the voice output and audio signal would not be maintained. COMAND then reduces the level of the audio signal until the specified volume difference is again maintained. The volume for the audio signal is then increased after completion of the voice output to the level present before the voice output.

Moreover, the volume for the voice output cannot be reduced to less than a certain minimum level.

Voice output mute circuit
The navigation voice output can be switched to mute with the mute button (button with loudspeaker crossed out symbol) during voice output. The mute feature applies only for the current voice output.

If an audio source (CD, radio,..) is audible at the same time as voice output from the navigation module, the voice output from the navigation module is muted the first time the mute button is pressed and the entire output is muted when it is pressed a second time.