RNS 850 Radio Navigation System

RNS 850 Radio Navigation System

The optical MOST BUS performs the system data exchange. Participating systems:

• Radio

• Telephone

• Navigation unit

• Voice control

• Audio drives

• Sound system

• Data bus on board diagnostic interface

The connection to the other data bus systems in the vehicle is provided by the Data bus on board diagnostic interface (J533).

• In the case of the minimum equipment level, a complete system configuration is comprised of the combination of Information electronics control module 1 (J794) , the Front information display control head (J685) , the radio and the Data bus on board diagnostic interface (J533). Combination with other components is optional.

• The radio navigation system RNS 850 is available with and without telephone equipment.

Components:

As a result of the networking of the individual vehicle systems, numerous control modules contribute to the function of the audio output in the MOST system.

These control modules communicate with each other via the different bus versions. To ensure communication using several bus versions, the data bus on board diagnostic interface processes the data and sends it to the corresponding control module.

Audio Playback Components:

The following components are part of the audio play back.

1 At least one of the following audio sources

• DVD Changer (R161)

• Information electronics control module 1 (J794)

• Radio

2 Digital sound system control module (J525) / or radio

3 Speaker

Audio Playback Function:

The digital audio signal can be produced by different control modules depending on the vehicle equipment level and the actively selected audio source.

For example, if the DVD changer is the selected audio source, it will read the audio signal coming from the CD.

This digital audio signal is sent via the MOST bus to the Digital sound system control module (J525) or the radio.

In the digital sound system control module or radio, the digital audio signal is converted to an analog signal, filtered, equalized, amplified. The signal is output via the individual channels to the speakers.

The type of output to the individual channels depends on the current sound settings. The number of channels differs from sound package to sound package.

Dynamic Noise Compensation Function:

The dynamic noise compensation uses the following value in order to control the volume.

• Driving speed

• Blower speed

• Noise measurement via a microphone in the roof module

• Volume compensation in the radio navigation system RNS 850

The ABS control module receives a speed signal from the ABS speed sensors. It evaluates the signal and then sends it to the instrument cluster/chassis CAN.

The Climatronic control module sends the information for controlling the fresh air blower to the comfort CAN bus.

The Data bus on board diagnostic interface (J533) reads out these signals. It then sends them via the optical MOST bus to the digital sound system control module or the radio.

Noises are recorded by the Interior microphone (R74) , which is installed in the roof console and is connected directly to the digital sound system control module or the radio.

The degree of noise compensation can be adjusted. The information electronics control module 1 evaluates the input and then sends it to the digital sound system control module or the radio via the optical bus.

Using these values, the digital sound system control module or the radio then adjusts the volume inside the vehicle.

Soft music is made louder as the vehicle speed increases, or loud music will be made softer.

This adaptation is always performed on the basis of the volume set by the customer. The volume is never lower than the customer setting.