GF82.85-P-2030CAC Audio Mode, Function
GF82.85-P-2030CAC Audio Mode, Function
MODEL 207.3 /4
- with CODE (512) COMAND APS with DVD changer
- with CODE (526) COMAND with single DVD drive (without navigation)
- with CODE (527) COMAND APS with single DVD drive (with navigation)
- except CODE (498) Japan version
- with CODE (528) COMAND with DVD changer
Function requirements, audio mode, general
^ Circuit 30g ON
General information on the audio mode
Audio functions are operated using the following components:
- Left multifunction steering wheel button group (S110)
- Right multifunction steering wheel button group (S111)
- Audio/COMAND control panel (A40/9)
- Operating panels of the COMAND controller unit (A40/3)
- Voice control system (VCS) function (with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS with DVD changer)
With the Aux audio source (via the AUX electrical connector (X39/45), without code (518) Media Interface) the actual operation is performed on the connected device itself. It is however possible to select "Standard" or "Boost" in the "Volume" menu. The input level can be increased by selecting "Boost".
In vehicles as of 1.7.2011, audio files can also be played back over a Universal Serial Bus (USB) stick connected via the USB electrical connector (X115).
In vehicles with code (810) Sound system, the audio signals are output by the COMAND controller unit via Media Oriented System Transport (MOST) to the sound system amplifier control unit (N40/3) and from there via direct lines to the following speakers:
- Left door tweeter (H4/1h1)
- Left door bass speaker (H4/1h2)
- Right door tweeter (H4/2h1)
- Right door bass speaker (H4/2h2)
- Left rear tweeter (H4/3h1)
- Left rear bass speaker (H4/3h2)
- Right rear tweeter (H4/4h1)
- Right rear bass speaker (H4/4h2)
- Center instrument panel speaker (H4/27)
- Rear shelf bass speaker (H4/29)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)
On vehicles without code (810) Sound system, the audio signals are output over direct lines by the COMAND controller unit to the following speakers:
- Left door tweeter
- Left door bass speaker
- Right door tweeter
- Right door bass speaker
- Left rear tweeter
- Left rear bass speaker
- Right rear tweeter
- Right rear bass speaker
The Audio mode consists of the following function sequences which can be activated with the menu item Audio:
^ Function sequence for radio mode function (FM/AM)
^ Function sequence for DVD/CD audio and video
^ Function sequence for Bluetooth(R) audio (as of 1.6.2010)
^ "Music Register", general (with code (527) COMAND APS with single DVD drive (with navigation) or with code (512) COMAND APS with DVD changer)
Function sequence for radio mode (FM/AM)
The antennas in the rear window (model 207.3) receive audio signals for the FM and AM (MW, LW, SW) radio frequency bands.
On vehicles with code (494) USA version, the AM frequency range receives MW frequency range signals only.
The following useful signals relevant for the radio reception are modulated onto these signals:
- Music signals
- Speech signals
- Data signals (e.g. traffic information)
Model 207.3
The FM signals are sent from the antenna structures on the rear window over direct lines to the FM, AM and CL antenna amplifier (A2/18) and are routed to the FM rear window antenna amplifier (A2/19).
The AM signals are transmitted from the antenna structures on the rear window over direct lines to the FM, AM and CL antenna amplifier.
Model 207.4:
The FM signals are sent from the antenna structures in the windshield over direct lines to the FM, AM and CL antenna amplifier (A2/55) and to the TV 3, FM2 and DAB band III antenna amplifier (A2/54).
Reception of the AM signals takes place in model 207.4 via the AM soft top antenna (A2/111) with a closed soft top and via the rear side paneling AM antenna with an open soft top.
The AM signals are sent on via the AM amplifier with selection switch (A104/2) by means of a direct line to the FM, AM and CL [ZV] antenna amplifier. The AM signals from the AM soft top antenna are also amplified by the AM amplifier (A104/1).
The antenna amplifiers filter the frequencies of the radio frequency bands out of the received signals and amplify them. The amplified signals are then sent via coaxial lines to the tuner integrated in the COMAND controller unit and demodulated.
The demodulated audio signals on vehicles with code (810) Sound system are sent by the COMAND controller unit via MOST to the sound system amplifier control unit, where they undergo final amplification.
The radio mode function sequence consists of the following subfunction sequences:
^ Function sequence for AM reception (MW, LW, SW)
^ Function sequence for FM reception
^ Function sequence for Radio Broadcast Data System (RBDS) reception (with code (494) USA version) or Radio Data System (RDS) reception
^ Function sequence for Radio text+ (as of 1.6.2010)
^ Function sequence for high-definition (HD) radio mode (with code (494) USA version)
Function sequence for AM reception (MW, LW, SW)
For the MW and LW 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).
On vehicles with code (494) USA version, the AM frequency range receives MW signals only.
Function sequence for FM reception
For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM).
These signals are demodulated by the FM tuner integrated into the COMAND controller unit. In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible).
There is also an additional reception-dependent switch-over by the COMAND controller unit between the FM, AM and CL antenna amplifier and the FM rear window antenna amplifier (model 207.3) or the TV 3, FM2 and DAB band III antenna amplifier (model 207.4).
Function sequence for RBDS reception (with code (494) USA version) or RDS reception
Apart from the normal radio program, many radio stations (FM) transmit additional digital information such as station names, program type (e.g. pop, culture, etc.) and traffic program identification.
This information is evaluated by the COMAND controller unit and shown on the Audio/COMAND display (A40/8), when the following preconditions are complied with:
- An RDS or RBDS station is set.
- The RDS or RBDS function has been activated.
Function sequence for Radio text+ (as of 1.6.2010)
During FM radio operation, additional information on the program can be shown on the Audio/COMAND display. For this, the "Info" softkey in the function bar must be pressed.
Function sequence for HD radio mode (with code (494) USA version)
The HD radio function is implemented in the COMAND controller unit. The high definition tuner integrated into the COMAND controller unit is a combined AM/FM/weather band receiver with HD radio function. It demodulates the analog AM and FM signals using the two integrated double tuners and decodes the digital AM and FM signals using the integrated HD radio decoder chips.
The Weather band function enables the reception of US Weather band signals and reception of digital carriers of the analog AM/FM programs that are also broadcast by the stations.
The HD radio function improves the audio quality using digital technology:
- FM (96 kbit/s):
- CD sound quality (no multipath interference)
- AM (36 kbit/s):
- FM sound quality (stereo)
The stations also broadcast other audio channels and data with the digital carriers. This supplements the program with up to 2 additional audio channels per frequency (e.g. foreign language program from National Public Radio "NPR") and supplemental information (e.g. track and artist) can be received.
Additional transmission of digital carriers is designated as "On Channel", the digital station is tuned to the same frequency as the analog station.
The digital transmission process in the FM and AM band is known as "in-band".
In contrast to the satellite digital audio radio (satellite radio) (SDAR) function (with code (536) SIRIUS satellite radio) regional stations and programs are received by the HD radio function and no fees will be charged.
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.
As of 1.6.2010, the artist name will also be shown on the Audio/COMAND display if the inserted disk provides the information.
Data exchange between the COMAND controller unit and Audio/ COMAND display is performed via telematics CAN (CAN A). The video signals are sent via a low voltage differential signal (LVDS) line.
Function sequence for Bluetooth(R) audio (as of 1.6.2010)
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: First a check is performed as to whether an authorized telephone is inserted in the mobile phone cradle (A34/15) (with code (386) Comfort telephony). If this is the case, the COMAND controller unit connects to the telephone and assumes the comfort telephony status.
If a mobile phone cradle (with code (386) Comfort telephony) is present but no telephone is inserted, a prompt appears after 2 min as to whether a switchover to basic telephony is desired. With "No", the system remains in the comfort telephony status.
If no mobile phone cradle is present or no telephone inserted, 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 it is changed to the Bluetooth(R) audio application, "No Bluetooth audio device connected" is shown on the Audio/COMAND display if the corresponding audio sources are shown in the device list.
With the comfort telephony status, the connected device is always treated as if it only supports HFP.
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 (A1).
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
"Music Register", general (with code (527) COMAND APS with single DVD drive (with navigation) or with code (512) COMAND APS with DVD changer)
The hard disk integrated into the COMAND controller unit can be used to save files (in MP3 format) from the following data media and they can be called up again as and when required.
- CD, DVD
- Secure Digital (SD) card (as of 1.7.2011)
- Personal Computer Memory Card International Association (PCMCIA) card (up to 30.6.2011)
- USB stick, connected via the USB electrical connector (as of 1.7.2011)
