Head Unit, Component Description - GF82.85-P-3140RRB
Model 190
With Code 506 (Audio 20 NTG 5.5 radio) Except Code 520 (Audio 20 USB) Except Code 531 (COMAND APS)
Shown On Model 190.3 (as of 01.12.2018)
Location
The head unit is located in the center console.
Tasks
The head unit has the following tasks:
- Central operating and display unit for the entertainment and communications systems integrated in the vehicle
- Integration of smartphones
- Evaluating and forwarding control signals
- Reading in of input signals as well as actuation of output media and system components
Central operating and display unit for the entertainment and communications systems integrated in the vehicle
The head unit provides the user with a structured and uniform user interface for the following system components:
- Audio (e.g. radio, Bluetooth® audio, Universal Serial Bus (USB), including integrated Media Interface for connecting iPhone® or MTP devices (Media Transfer Protocol))
- Telephony
- Internet
- Digital operator's manual
The user interface is shown on the Audio/COMAND display (A40/8).
Using the "Vehicle functions" menu, equipment-dependent contents and functions of additional systems (e.g. climate control, seat adjustments) can be shown and controlled on the Audio/COMAND display.
Integration of smartphones
The head unit enables the integration of smartphones by supporting the following integration standards:
- CarPlay (Apple) (with code 16U (CarPlay smartphone integration))
- Android Auto (Google) (with code 17U (Google Automotive Link smartphone integration))
In order to be able to use the smartphone apps, the smartphone must be connected to USB connector 2 (A90/5x2) and the integration standard selected via the "Connect" menu. If the "Automatic connection" setting has been selected, activation cannot take place via the menu.
If a smartphone is connected and the integration standard Android Auto or CarPlay is activated, the head unit is switched to a special operating mode
The radio (AM and FM) functions, vehicle settings and safety-relevant functions such as, e.g. emergency call system (with code 362 (HERMES LTE)), can still be used in any case.
If an integration standard is activated, the head unit supports the smartphone apps in the following manner:
- Volume adaptation for all audio signals
- Forwarding of control signals to smartphone
- Use of hands-free system by the smartphone
- Forwarding of audio output to the speaker system
- Mute function, e.g. with smartphone telephony
- Forwarding of position data to smartphone
- Forwarding of video signals generated by the smartphone to the Audio/COMAND display
- Forwarding of status information for displaying in the instrument cluster (A1)
The smartphone applications themselves are not shown in the instrument cluster.
("Integration mode") in which not all head unit functions can be used. The following functions of the head unit are not available if Android Auto or CarPlay is activated:
- Media player
- Telephony (with CarPlay)
With Android Auto, the following usage restrictions apply for the telephony: Calls can only be made through the connected smartphone. Telephony with code 380 (Car telephony package) is not possible.
Evaluating and forwarding control signals
The head unit receives the operation signals of the Audio/COMAND control panel (A40/9) (except code 446 (Touchpad only)) or of the Touchpad (A105) (with code 446 (Touchpad only)) via the telematics CAN (CAN A) and evaluates them.
The head unit receives the operation signals of the volume adjustment switch and head unit on switch (N72/5s1) via the telematics CAN and evaluates them.
When the DYNAMIC SELECT switch (N72/4s1) is operated, the head unit also shows the selected transmission mode on the audio/COMAND display. The head unit receives the operation signals via the telematics CAN.
Reading in of input signals as well as actuation of output media and system components
The head unit transmits and receives signals via the following connections:
- CAN
- Media Oriented System Transport (MOST)
- Direct line
- Ethernet
CAN
The head unit communicates over the telematics CAN with the following component parts:
- Audio/COMAND display:
Control signals
- Audio/COMAND control panel (A40/9) (except code 446 (Touchpad only)):
Operation signals, communication with the Drive Unit control unit (N145/1), for the operation signals of the volume adjustment switch and head unit on switch in the right lower control panel (N72/5) and the DYNAMIC SELECT switch
- Touchpad (A105):
Operation signals, with code 446 (Touchpad only), also communication with the Drive Unit control unit, for the operation signals of the volume adjustment switch and head unit on switch in the right lower control panel and of the DYNAMIC SELECT switch
- Telephone control unit (N123/9) (with code 380 (Car telephony package)):
Status of SIM card (Subscriber Identification Module) in telephone control unit
The head unit is a user interface CAN user:
- The head unit receives the signals of the head unit multifunction steering wheel button group (S163/2) and the data of the HERMES control unit (N112/9) (Display messages, connection type, field strength) from the AMG Gateway control unit via the user interface CAN.
- The head unit sends operation signals and connection requests for the HERMES control unit, for example, to the AMG Gateway control unit via the user interface CAN.
Media Oriented System Transport (MOST)
The head unit exchanges data with the Midline sound system amplifier control unit (N40/2) via MOST.
Direct line
The head unit is equipped with the following direct connections:
- Circuit 30g
- Circuit 31
- FM, AM, CL, DAB and KEYLESS GO antenna amplifier (A2/18) (input)
- FM 2 and DAB band III antenna amplifier (A2/19) (input)
- Driver hands-free system microphone (B25/26) and front passenger hands-free system microphone (B25/27) (input)
- HSVL (High Speed Video Link) line from parking system control unit (N62) (with code 220 (PARKTRONIC) or with code P44 (Parking package)) (input)
- Bluetooth® antenna (A2/91) (input and output)
- W-LAN antenna (A2/83) (input and output)
- Multimedia connection unit (A90/5) (input and output)
- Full display digital instrument cluster fan motor (M4/12), actuation and diagnosis (input and output)
- HSVL line to the Audio/COMAND display (output)
- HSVL line to the instrument cluster (output)
- Wake-up for MOST (output)
- Switch-on signal (Wake-up signal) to the telephone control unit (with code 380 (Car telephony package)) (output)
- Microphone output to HERMES control unit (with code 362 (HERMES LTE)) (output)
The speaker system will be actuated via the Midline sound system amplifier control unit.
Ethernet
The head unit is connected by Ethernet to the diagnostic connector (X11/4).
Structure
The following components are integrated into the head unit:
- Arithmetic unit
- Searchable database for audio files, including cover art and cover flow
- Bluetooth® receiver
- WLAN receiver
- 3 radio tuners for AM reception, FM phase diversity and separate FM tuner function for data services, e.g. traffic messages
- Head unit electrical fuse (A26/17f1) (15 A) on the rear panel
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