Head Unit, Component Description - GF82.85-P-3140RFA
Model 205 up to model year 2019 with code 522 (Audio 20 radio) except code 520 (Audio 20 USB) except code 531 (COMAND® APS)
Model 253 (except 253.99) with code 522 (Audio 20 radio) except code 520 (Audio 20 USB) except code 531 (COMAND® APS)
Shown on model 205.0
Location
The head unit is centrally located in the instrument panel behind the panel at the level of the upper control panel control unit (N72/1).
Tasks
- Control unit for entertainment and communication systems integrated into vehicle
- Evaluating and forwarding control signals
- Reading in of input signals as well as actuation of output media and system components
Control unit for entertainment and communication systems integrated into vehicle
The head unit generates a structured user interface for operating the various components of the entertainment and communication system:
- Audio, e.g. radio
- Telephony (with telephone book function)
- Internet
- Navigation (with code 357 (Map navigation))
The functions of the navigation mode can be used via the voice control system.
- Emergency call (with code 347 (Mercedes-Benz emergency call system), code 350 (eCall Europe emergency call system), code 351 (Emergency call system (HERMES)))
Evaluating and forwarding control signals
The head unit receives the control signals of the following components via the telematics CAN (CAN A):
- Left lower control panel (N72/4)
- Right lower control panel (N72/5)
- Upper control panel control unit
- Off-road operating panel (S70) (model 253.9 with code 430 (Off-road package))
The head unit sends function-specific CAN signals to the relevant control units via user interface CAN (CAN HMI).
Where the "Individual" drive program is selected via the DYNAMIC SELECT switch (N72/4s11) (as of 01.06.2015) or the AGILITY SELECT switch (N72/4s1) (up to 31.05.2015) or in model 253.9 with code 430 (Off-road package) via the On-road/Off-road menu button (S70s1), the head unit also shows the additional selection options in the Audio/COMAND® display.
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 is a telematics CAN and user interface CAN subscriber:
- The following signals are among those received by the head unit via the telematics CAN:
- Operation signals from Audio/COMAND® control panel (A40/9) or touchpad (A105) (with code 448 (Touchpad))
- Control signals from the upper control panel control unit, from the left lower control panel, from the right lower control panel and from the Off-road control panel (model 253.9 with code 430 (Off-road package)) via the Audio/COMAND® operating unit
- The following signals are among those transmitted by the head unit via the telematics CAN:
- Control signals to the audio/COMAND® display
- Control signals for displays in the upper control panel control unit to the Audio/COMAND® control panel
- The following signals are among those received by the head unit via the user interface CAN:
- Control signals from instrument cluster (A1)
- Control signals for the displays in the upper control panel control unit from the electronic ignition lock control unit (N73)
- The following signals are among those sent by the head unit via the user interface CAN:
- Navigation displays to instrument cluster
- Interpreted signals from the upper control panel control unit as well as the bottom left control panel, from the bottom right control panel and from the Off-road control panel (model 253.9 with code 430 (Off-road package))
MOST
The head unit exchanges data with the following control units via MOST:
- Tuner unit (A90/4) (with code 536 (SIRIUS satellite radio), code 537 (Digital radio (DAB)) or code 865 (TV tuner))
- Sound system amplifier control unit (N40/3) (with code 810 (Sound system))
Direct line
The head unit is equipped with the following direct connections:
- Circuit 30g
- Circuit 31
- FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18) (input)
- FM 2 and DAB band III antenna amplifier (A2/108) (model 205.0/3/4, model 253) or FM 2, DAB and TV 1 antenna amplifier (A2/131) (model 205.2/3/4, model 253) (input)
- Hands-free system microphone (A67b1) (input)
- GPS antenna (A2/23), in vehicles with CODE 348 (Emergency call/assist system) via the global positioning system antenna splitter (A2/5) (input)
- Muting of the audio sources from the emergency call system control unit (N123/4) (with code 348 (Emergency call/assist system), except code 810 (Sound system)) (input)
- Muting of audio sources from the telematics services communications module (N112/1) (with code 350 (eCall Europe emergency call system) or with code 06U (Mercedes connect me basic services) and except code 810 (Sound system)) (input)
- Muting of audio sources from the HERMES control unit (N112/9) (with code 360 (HERMES UMTS) or code 362 (HERMES LTE), except code 810 (Sound system)) (input)
- Low Voltage Differential Signaling (LVDS) line from reversing camera (B84/3) (with code 218 (Reversing camera)) (input)
- LVDS line from 360° camera control unit (N148) (with CODE 501 (360° camera)) (input)
- LVDS line for video data to the Audio/COMAND® display (output)
- Bluetooth® antenna (A2/91) (input and output)
- USB electrical connections (X115) (2 connections) in stowage compartment between front seats (except code 355 (Preinstallation for navigation retrofit)) (input and output)
- USB electrical connections power supply (except code 355 (Preinstallation for navigation retrofit)) (output)
- Multimedia connection unit (A90/5) (with code 355 (Preinstallation for navigation retrofit)) (input and output)
- USB wake-up line for multimedia connection unit (with code 355 (Pre-installation for navigation retrofitting)) (output)
- Wake-up line for MOST (output)
- Audio output (speaker) (except CODE 810 (Sound system)) (output)
- Switch-on signal and power supply for mobile phone contact plate (X237/1) (with code 386 (Comfort telephony)) and cellular telephone system antenna amplifier/compensator (A28/15) (with code 386 (Comfort telephony), as of 01.06.2016 except code 379 (Telephone module with Bluetooth® (SAP profile))) (Output)
- Microphone output to emergency call system control unit (with code 348 (Emergency call/assist system)), to telematics services communications module (with code 350 (eCall Europe emergency call system) or with code 06U (Mercedes connect me basic services)) or to the HERMES control unit (with code 360 (HERMES UMTS), with code 362 (HERMES LTE)) (Output)
- Wake-up-line to the telephone and stationary heater antenna changeover switch (A2/155) (with code 386 (Comfort telephony) and code B24 (Remote control for stationary heater), as of 01.06.2016)
- Audio output to the engine sound control unit (N40/1) (with code B63 (Sporty engine sound)) (Output)
Ethernet
Via Ethernet, the head unit receives software uploads for all MOST subscribers from the diagnostic connector (X11/4) connected to the diagnostic unit.
Structure
The following components are integrated in the head unit:
- Arithmetic unit
- Single drive for CDs
- Searchable database for audio files, including cover art and cover flow
- Bluetooth® receiver
- 3 radio tuners for AM reception, FM phase diversity and separate FM tuner function for data services, e.g. traffic messages
- High definition (HD) radio tuner (with code 494 (USA version) or code 460 (Canada version))
- 4-channel audio amplifier (except CODE 810 (Sound system))
- Global navigation system (GPS) receiver
- Gyro sensor (2D)
- Traffic data recorder for TMC, TMCpro or Real Time Traffic Data (RTTD)
- Head unit electrical fuse (A26/17f1) in the combination connector at the rear panel
| Wiring diagram of head unit | PE82.85-P-2101-97FBA |