GF82.85-P-2030FQJ Audio Mode, Function

GF82.85-P-2030FQJ Audio Mode, Function
MODEL 218
- with CODE (527) COMAND APS with single DVD drive (with navigation system)
- with CODE (498) Japan version

Function requirements, general
^ Circuit 30g ON
Audio functions are selected using the following controls:
- Left multifunction steering wheel button group (S110)
- Right multifunction steering wheel button group (S111)
- Audio/COMAND control panel (A40/9)
- Buttons on audio unit
- Voice control system (VCS [SBS])
The audio mode function consists of the following subfunctions:
^ Audio output function sequence
^ Function sequence for volume/tone settings
^ Function sequence for radio mode (FM/AM)
^ Function sequence for DVD/CD audio and video
^ Function sequence for Music Register
^ Video mode function sequence
^ Function sequence for media interface
^ Function sequence for Bluetooth(R) audio

Audio output function sequence
Audio output on vehicles with code (810) Sound system occurs through the sound system amplifier control unit (N40/3), which is actuated by the audio equipment via the Media Oriented System Transport (MOST). The sound system amplifier control unit actuates the following speakers via two direct lines each:
- Center instrument panel speaker (H4/27)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)
- Left front door sound system bass speaker (H4/64)
- Right front door sound system bass speaker (H4/65)
- Left front door sound system tweeter (H4/68)
- Right front door sound system tweeter (H4/69)
- Left rear door sound system tweeter (H4/70)
- Right rear door sound system tweeter (H4/71)
- Left front door sound system midrange speaker (H4/72)
- Right front door sound system midrange speaker (H4/73)
- Left rear door sound system midrange speaker (H4/80)
- Right rear door sound system midrange speaker (H4/81)
For the bass speaker (H4/17), the audio signal is transmitted via MOST from the audio equipment to the sound system amplifier control unit and from there using direct lines to the bass speaker via the rear bass speaker amplifier (N40/9).
On vehicles without code (810) Sound system, the audio signals are output by the audio equipment to the following speakers via direct lines:
- Left front door speaker (H4/1)
- Left front door tweeter (H4/1h1)
- Right front door speaker (H4/2)
- Right front door tweeter (H4/2h1)
- Left rear door speaker (H4/3)
- Left rear door tweeter (H4/3h1)
- Right rear door speaker (H4/4)
- Right rear door tweeter (H4/4h1)
In the following, the repetitive list of speakers will no longer be used; instead, the term "speaker system" will be used.

Function sequence for volume/tone settings
All volume and tone settings are performed using the COMAND controller unit. This is performed either by the user or automatically by the COMAND control unit.
The volume and tone settings are shown on the Audio/COMAND display (A40/8). Predefined settings can be selected and reset to the manufacturer default setting via the system settings.
With the "AUX" audio source, "Standard" and "Boost" can be selected in the "Volume" menu. The input level can be increased by selecting "Boost".
For vehicles with code (810) Sound system, the COMAND controller unit is not only equipped with the general tone settings (treble, bass and balance) but also with the "Logic7(R)" tone setting (surround sound).
The audio signals are output over the speaker system.
The volume and tone setting partial function is subdivided into the following subfunctions:
^ Function sequence for manual volume/sound settings
^ Function sequence for speed-dependent volume control (SDV [GAL])

Function sequence for manual volume/sound settings
The manual volume/tone setting function is subdivided into the following subfunctions:
^ Function sequence for volume settings via right multifunction steering wheel button group
^ Function sequence for volume settings via COMAND control unit
^ Function sequence for sound settings via audio/COMAND control panel

Function sequence for volume settings via right multifunction steering wheel button group
Pressing the "+" and "-" button for setting specific functions and volume control (S111s1) enables the volume for the desired audio function to be increased or reduced.
The control signals are forwarded TO THE COMAND control unit over the following path:
- Buttons + and - for setting specific functions and volume control
- Steering wheel electronics (N135)
- Steering LIN (LIN E1)
- Steering column tube module control unit (N80)
- Chassis CAN (CAN E)
- Instrument cluster (A1)
- Interior CAN (CAN B)
- COMAND control unit
After evaluating the control signals, the requested settings in vehicles with code (810) Sound system are forwarded via MOST to the sound system amplifier control unit.
On vehicles without code (810) Sound system, the selected settings are processed and amplified internally
The audio output via the speaker system is interrupted by actuating the mute button (S111s6).

Function sequence for volume settings via COMAND control unit
Operating the rotary switch on the COMAND control unit enables the volume to be raised or lowered for the desired audio function. The control signals are processed in the COMAND controller unit.
The desired settings in vehicles with code (810) Sound system are forwarded via MOST to the sound system amplifier control unit where they are processed and amplified. On vehicles without code (810) Sound system, the selected settings are processed and amplified internally
The audio output via the speaker system is interrupted by actuating the "MUTE" button on the COMAND control unit.

Function sequence for sound settings via audio/COMAND control panel
The user can set the corresponding sound by selecting the "Sound" menu on the audio/COMAND control panel.
The control signals from the Audio/COMAND control panel are forwarded over the telematics CAN (CAN A) to the COMAND controller unit.
The desired settings are relayed on vehicles with code (810) Sound system via MOST to the sound system amplifier control unit where they are then processed.
In vehicles without code (810) Sound system, the selected settings are processed internally.

Function sequence for speed-dependent volume control
The volume is adapted to the noise level in the vehicle interior with the aid of the speed-dependent volume control defined by the vehicle speed. To do this, the instrument cluster sends the vehicle speed via interior CAN to the COMAND controller unit (without code (810) Sound system) or via MOST to the sound system amplifier control unit (with code (810) Sound system).
The COMAND controller unit or the sound system amplifier control unit increases the output level according to the vehicle speed or decreases it.
In vehicles with code (810) Sound system, the SDV [GAL] is additionally optimized by using the sound system microphone (B25/6).
The sound system amplifier control unit reads in the signals of the sound system microphone, evaluates the signals, and adjusts the volume of the output audio signals to the interior or driving noises.

Function sequence for radio mode (FM/AM)
The antennas receive signals for the FM and AM (MW) radio frequency bands. The following useful signals relevant for the radio reception are modulated onto these signals:
- Music signals
- Speech signals
- Data signals (e.g. traffic information)
The COMAND controller unit receives the FM1/2 and AM signals via the following route:
- AM/FM1 signals:
- Rear window antenna
- FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18)
- COMAND controller unit
- FM2 signals:
- Rear window antenna
- FM 2 and DAB antenna amplifier (A2/19)
- COMAND controller unit
The radio mode function sequence consists of the following subfunctions:
^ Function sequence for AM tuner (MW)
^ Function sequence for FM double tuner with multipath reception (FM)

Function sequence for AM tuner (MW)
For the MW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM). These signals are demodulated by the AM tuner integrated into the COMAND controller unit. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible).

Function sequence for FM double tuner with multipath reception (FM)
For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM).
These signals are demodulated by the FM double tuner integrated into the COMAND controller unit. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible). The COMAND controller unit also enables reception- specific switchover between the FM 1, AM, CL [ZV], and KEYLESS-GO antenna amplifier and the FM 2 and DAB antenna amplifier.
The Vehicle Information and Communication System (VICS) signals are demodulated by a separate FM tuner. VICS provides current traffic information that can be made available to the navigation system.

Function sequence for DVD/CD audio and video
The DVD/CD audio and video function can be used to play audio CDs or audio DVDs (including MP3 format) as well as video DVDs.
User guidance for controlling DVD/CD functionality and displaying supplemental information is carried out via the Audio/COMAND display.
Data exchange between the COMAND controller unit and the Audio/ COMAND display takes place via telematics CAN. The video signals are sent via a low voltage differential signal (LVDS) line.
The audio signals are output over the speaker system.

Function sequence for Music Register
The hard disk integrated into the COMAND controller unit can be used to save files (in MP3 format) and they can be called up again as and when required. Because of legal specifications it is not possible to copy MP3 files from an external source into the Music Register. Instead of this, in the "Disc" menu one can use "REC" to store music tracks from an audio CD as an MP3 file on the COMAND controller unit's hard disk ("rip"). The MP3 files in the Music Register are not imported, but actually created by the COMAND controller unit itself.

Video mode function sequence
The DVD drive of the COMAND controller unit supports playback of video DVDs. In the process, the video image is shown on the Audio/ COMAND display after the "DVD Video" menu has been activated in the "VIDEO" menu.
The video signals are transmitted via a separate video line to the COMAND controller unit. The COMAND controller unit transmits the image data via an LVDS line to the Audio/COMAND display.
The audio signals are output over the speaker system.
The video mode function can be selected with the following controls:
- Audio/COMAND control panel
- Buttons on COMAND controller unit
The video DVD function is only available when the vehicle is stationary (v < 5 km/h). When the vehicle is moving, only acoustic playback remains active and - for safety reasons - a warning is shown on the Audio/COMAND display.

Function sequence for media interface
The media interface allows the following portable devices to be connected to the COMAND controller unit via the media interface electrical connector (X18/70) (a universal device interface) using an adapter cable:
- Auxiliary (AUX) devices (Class 1)
- e.g. video camcorder
- Media Transfer Protocol devices (class 2)
- e.g. "iPod", digital audio player or other universal serial bus (USB) devices via the Media Transfer Protocol
- USB devices (class 3)
- e.g. USB memory sticks, mobile hard disks (mass storage devices)
Adapter cables in angled and straight design are available as accessories for the three adaptation options.
On vehicles as of 1.7.11 the USB memory sticks must be connected to the USB electrical connection (X115) in the center console's stowage compartment under the armrest: If you try to connect a USB memory stick using an adapter cable to the media interface electrical connection, the following message appears on the Audio/COMAND display: "Note: Please connect the device to the other USB port".
With the "AUX" audio source, "Standard" or "Boost" can be selected in the "Volume" menu. The input level can be increased by selecting "Boost". Further operation of the AUX devices takes place in the AUX device itself.
For USB and Media Transfer Protocol devices, the menu navigation and graphical display of the menu navigation are implemented on the Audio/COMAND display and are dependent on the particular portable terminal connected. The connected portable terminals are controlled using one of the following controls:
- Buttons on the COMAND controller unit
- Audio/COMAND control panel
- Left multifunction steering wheel button group and right multifunction steering wheel button group
The user can select the "Media interface" menu item as well as the relevant submenu item to have the audio data or video data displayed on the Audio/COMAND display.
The control signals of the multifunction steering wheel button groups are forwarded to the COMAND controller unit in the following manner:
- Left multifunction steering wheel button group and right multifunction steering wheel button group
- Steering wheel electronics
- Steering LIN
- Steering column module control unit
- Chassis CAN
- Instrument cluster
- Interior CAN
- COMAND control unit
After evaluation of the control signals in the COMAND controller unit, they are then sent to the connected portable device as follows:
- MOST
- Media interface control unit (N125/1)
- Media interface electrical connector
- Media interface adapter cable
- Portable device
The media interface control unit is supplied with voltage via two direct lines (circuit 31g and circuit 30g). If a portable USB or Media Transfer Protocol terminal is connected, this is detected by the media interface control unit as follows:
- Media interface adapter cable
- Media interface electrical connector
- Media interface control unit
The audio signals are transmitted from the connected portable device to the COMAND controller unit via the following route:
- Adapter cable
- Media interface electrical connector
- Media interface control unit
- MOST
Video signals and data are sent via a Y - brightness (luminance)/C - color information (chrominance) line to the COMAND controller unit.
The video signals are then processed internally and sent via an LVDS line to the Audio/COMAND display.

Function sequence for Bluetooth(R) audio
Via the Bluetooth antenna (A2/91), the COMAND controller unit can receive Bluetooth(R) audio signals from external devices. Bluetooth(R) audio is divided into the following subfunctions:
^ Search for devices and authorization
^ Connection and reconnection
^ Meta data and display of information

Search for devices and authorization
The same options exist for the authorization of a Bluetooth(R) audio source as are available for telephony:
- Search via the device list or
- External authorization
The device lists are set up the same for Bluetooth(R) audio and telephony. In the respective list, only those devices that support the corresponding Bluetooth(R) profile of the respective function are found or displayed during a search. During telephony, the hands-free profile (HFP) is used. With Bluetooth(R) audio, the Audio/Video Remote Control Profile (AVRCP) and Advanced Audio Distribution Profile (A2DP) are used. If a device supports both functions, it is shown in both lists following authorization.

Connection and reconnection
An authorized device can be connected by means of selection in the corresponding list. If a device is connected that supports both HFP and AVRCP/A2DP, all profiles are connected. That means that the device is now a telephone and at the same time a source for Bluetooth(R) audio.
On most devices, it is necessary to start the player on the telephone so that it can then be controlled via the COMAND controller unit.
When starting, the COMAND controller unit proceeds with the following strategy:
The COMAND controller unit searches for the last two telephones. If one of these devices is found, the COMAND controller unit connects to this device. If this device also supports AVRCP/A2DP, these profiles are also connected. If a device is connected that only supports HFP and a change to the Bluetooth(R) audio application occurs, "No Bluetooth audio device connected" is shown on the COMAND controller unit if corresponding audio sources are shown in the device list.
If no Bluetooth(R) audio source is shown in the device list, "No Bluetooth audio device authorized" is shown on the Audio/COMAND display and the selection option "Connect last device" is not shown in the menu.
If a Bluetooth(R) audio source is shown in the device list, the last Bluetooth(R) audio source used can be connected via "Connect last device". However, the connection to the current telephone is interrupted here.
The search process with "Connect last device" can only be interrupted by changing to telephony. Otherwise, the search is continued in the background.
If a device is connected that only supports AVRCP/A2DP and a change to telephony is then made, the connection to the device is disconnected and the COMAND controller unit begins the search for the last two telephones.

Meta data and display of information
The display of information for Bluetooth(R) audio depends on the respective device used. If this supports AVRCP 1.0, "Audio streaming" is exclusively shown on the Audio/COMAND display and in the instrument cluster.
As of AVRCP 1.3, the track, album and artist are shown. In addition, the currently played time of the track can also be conveyed.
Furthermore, there is the option of changing between the normal track sequence and shuffle.
It is possible to jump to the next or the previous track using the left multifunction steering wheel button group.
Notes on supported devices for Bluetooth(R) audio can be found under: http://www.mercedes-benz.com/connect