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Block diagram of emergency call system |
A1/1 | Instrument cluster (KI) control unit | N70s11 | SOS button | |
A2/18 | FM/AM antenna amplifier | N70s12 | Breakdown assistance button | |
A2/47 | GPS antenna | N70s13 | MB-Info button | |
A2/51 | FM/AM antenna | N72/2 | Upper control panel (UCP [OBF]) control unit | |
A2/91 | Bluetooth® antenna | N80 | Steering column tube module (MRM) control unit | |
A2/163 | GSM HERMES antenna | N87/6 | Radio (Audio/COMAND) | |
A36 | Multimedia connection unit | N93 | Central gateway (CGW) | |
A40 | Audio/COMAND control panel | N112/9 | HERMES control unit | |
A40/2 | Right lower control panel (LCPR [UBFR]) control unit | N135 | Steering wheel electronics | |
A40/2s1 | Volume control button | S2 | Ignition lock switch | |
A40/2s2 | "ON" button | S2/3 | KEYLESS-GO start/stop button (with code FX9 (KEYLESS GO)) | |
A40/5 | Touchpad control unit | S110 | Left multifunction steering wheel button group | |
A40/8 | Audio/COMAND display control unit | S111 | Right multifunction steering wheel button group | |
B25/17 | Hands-free system microphone | X11 | Diagnostic connector | |
G1/20 | Buffer battery | CAN A | Telematics CAN | |
H4/7 | Left rear speaker | CAN D | Diagnostic CAN | |
H4/8 | Right rear speaker | CAN E | Chassis CAN | |
H4/9 | Left front speaker | CAN HMI | User interface CAN | |
H4/10 | Right front speaker | CAN V | Vehicle CAN | |
H4/27 | Center instrument panel speaker | ETHERNET | Ethernet | |
H4/33 | Left front tweeter | LIN A2 | Telephone keypad LIN | |
H4/34 | Right front tweeter | LIN B16 | Buffer battery LIN | |
H4/44 | Left rear tweeter | LIN E1 | Steering LIN | |
H4/45 | Right rear tweeter | LVDS | Low voltage differential signal | |
N2/18 | Supplemental restraint system (SRS) control unit | PWM | Pulse width modulation (signal) | |
N10/1 | Signal acquisition and actuation module (SAM) control unit | A | Mercedes-Benz | |
N30/4 | Electronic Stability Program (ESP) control unit | B | Nissan | |
N50 | Fuse and relay module control unit (SRM) | C | Default | |
N70 | Overhead control panel (OCP [DBE]) control unit | D | Option |
Function requirements, emergency call system, general
Circuit 30 ON
Transport mode not active
The communications module of the HERMES control unit is configured with the telephone number of the relevant service provider.
Emergency call system, general
The emergency call system allows a manual or automatic emergency call to be triggered. The emergency call is received by the Mercedes-Benz Service Center. The user is addressed in the language selected in the system settings of the radio (Audio/COMAND). If necessary, the Mercedes-Benz Service Center notifies the local rescue services. If the Mercedes-Benz Service Center is not staffed, the emergency call is automatically forwarded to the local rescue services.
When the HERMES control unit receives the message "Circuit 15 ON" via the diagnostics CAN, central gateway (CGW) and vehicle CAN from the SAM control unit with code FX9 (KEYLESS GO) or from the fuse and relay module (SRM) control unit, it checks the operational readiness of the emergency call system. After a successful check, the emergency call system is operational and "SOS ready" is shown on the Audio/COMAND display control unit. The following checks are carried out:
Receipt of the cyclic readiness signal from the supplemental restraint system (SRS) control unit
Connection for muting audio sources
Connection to hands-free system microphone
Connection to the HERMES GSM antenna
Connection to GPS antenna
In the event of a fault, depending on the fault type, a fault message appears on the Audio/COMAND display control unit and the fault is stored in the fault memory of the HERMES control unit. If, after switching off the ignition, the supplemental restraint system (SRS) control unit goes into sleep mode, it no longer sends a readiness signal and "SOS not ready" is shown.
The SAM control unit with code FX9 (KEYLESS GO) or the fuse and relay module (SRM) control unit sends the message "Circuit 15" via the vehicle CAN, central gateway (CGW) and diagnostics CAN to the HERMES control unit.
The emergency call system function comprises the following subfunctions:
Emergency call system status indication
Position finding
Manual or automatic emergency call
Emergency call system status indication
The status of the emergency call system is shown in the following ways:
Status indication on the Audio/COMAND display control unit
Status indication via light-emitting diode
Status indication in the instrument cluster (IC [KI]) control unit
Status indication on the Audio/COMAND display control unit
The status of the emergency call system is shown by a text message in the Audio/COMAND display control unit in the following cases:
Emergency call system operational or not operational ("SOS ready" or "SOS not ready" in telephone menu)
Emergency call has been activated ("activating" (call setup), "transmitting data" (data telegram transmission), "connected" (voice connection established))
Emergency call forwarded to local 112 rescue services (the address (with code EJ9 (COMAND Online)) and the coordinates of the vehicle position are also shown)
Call activation has failed several times ("MB emergency call processing failed. Please dial 112 on the mobile phone.")
In the event of an active emergency call, a telephone symbol, an emergency call symbol and the field strength of the HERMES control unit are also shown on the Audio/COMAND display control unit at the top right.
The HERMES control unit sends the display over the following path:
Diagnostic CAN
Central gateway (CGW)
User interface CAN
Radio (Audio/COMAND)
Low Voltage Differential Signal
Audio/COMAND display control unit
The control communication (e.g. switch on) is transmitted by the Audio/COMAND control panel via the telematics CAN to the Audio/COMAND display control unit.
Some text messages on the Audio/COMAND display control unit can be confirmed using the Audio/COMAND control panel or the touchpad control unit. The Audio/COMAND control panel sends the signals via the following route:
Telematics CAN
Radio (Audio/COMAND)
User interface CAN
Central gateway (CGW)
Diagnostic CAN
HERMES control unit
Status indication via light-emitting diode
The LED of the SOS button is used to indicate the following states:
Active service, light-emitting diode flashes.
Self-diagnosis of emergency call system, LEDs light for approx. 5 s.
Fault in emergency call system, LEDs permanently on.
Diagnosis
The HERMES control unit actuates the light-emitting diodes via the following route:
Diagnostic CAN
Central gateway (CGW)
Vehicle CAN
SAM control unit
Overhead control panel (DBE [OCP])control unit
SOS button
Status indication in the instrument cluster (IC [KI]) control unit
If the HERMES control unit fails, the instrument cluster (IC [KI]) shows "SOS nonfunctional". The failure of the HERMES control unit is reported over the following path:
Diagnostic CAN
Central gateway (CGW)
User interface CAN
Instrument cluster (IC [KI]) control unit
Position finding
In vehicles with code EA1 (Audio 20 CD radio) and code EV5 (Preinstallation for Garmin MAP PILOT) or with code EJ9 (COMAND Online), the HERMES control unit takes over the position finding signals from the radio (Audio/COMAND). The radio (Audio/COMAND) sends the signals via the following route:
User interface CAN
Central gateway (CGW)
Diagnostic CAN
HERMES control unit
In vehicles with code EJ8 (Audio 20 USB) or with code EA1 (Audio 20 CD radio) and except code EV5 (Preinstallation for Garmin MAP PILOT), the position finding is performed by the HERMES control unit. For position finding, the HERMES control unit uses the global navigation system (GPS). GPS is available worldwide. GPS position finding is irretrievable after vehicle transport (e.g. by train or ferry or after towing). Recalculation of the GPS position (following an interruption in satellite reception) can take several minutes. At the same time as the GPS position finding the HERMES control unit conducts a permanent basic position finding, that enables the position of the vehicle to be determined even when the GPS reception fails.
The position finding function consists of the following component functions:
GPS position finding
Basic position finding
GPS position finding
In vehicles with code EA1 (Audio 20 CD radio) and code EV5 (Preinstallation for Garmin MAP PILOT) or with code EJ9 (COMAND Online), the radio (Audio/COMAND) receives the GPS signals from the GPS antenna.
In vehicles with code EJ8 (Audio 20 USB) or with code EA1 (Audio 20 CD radio) and except code EV5 (Preinstallation for Garmin MAP PILOT), the HERMES control unit receives the GPS signals from the GPS antenna.
Additional function requirement for basic position finding
Circuit 15 ON
Basic position finding
The HERMES control unit requires the following signals for basic position finding:
Wheel speed and yaw rate signals from the Electronic Stability Program (ESP) control unit
Steering wheel angle sensor signal
The Electronic Stability Program (ESP) control unit sends the wheel speed and yaw rate signals via the following route:
Vehicle CAN
Central gateway (CGW)
Diagnostic CAN
HERMES control unit
The steering wheel angle sensor integrated into the steering column tube module (MRM) control unit sends the signal via the following route:
Chassis CAN
Central gateway (CGW)
Diagnostic CAN
HERMES control unit
The HERMES control unit uses the data to calculate the instantaneous position of the vehicle (longitude, latitude and direction of travel).
Position finding errors, rolling backwards with "circuit 15 OFF" (ignition switched off) or transport of the vehicle falsify the basic position finding. In both cases, this deviation is automatically corrected on receipt of GPS data.
Manual or automatic emergency call
In an emergency situation, a service receptionist from the Mercedes-Benz Service Center can obtain an overview of the condition inside the vehicle with the aid of the data received from the HERMES control unit (voice connection and data telegram) and initiate appropriate help measures. An emergency call be initiated manually or automatically. These emergency calls are made for the following reasons:
Automatic alerting of the rescue services after an accident
Alerting rescue services by pushing a button (own emergency situation, observed accident)
Reduction in rescue times through fast emergency notification with details on exact location involved
The automatic emergency call has priority over a manually triggered emergency call. If an automatic emergency call is triggered during a manual emergency call, the manual emergency call is interrupted. If a manual emergency call is triggered during an automatic emergency call, it is ignored. However, a data telegram containing updated position data is sent to the Mercedes-Benz Service Center, and the existing connection is maintained.
The manual or automatic emergency call function consists of the following subfunctions:
Triggering of an automatic emergency call
Triggering of a manual emergency call
Voice connection between vehicle and Service Center
Additional function requirements for triggering an automatic emergency call
Circuit 15 ON
Triggering of an automatic emergency call
In the event of an accident with deployment of the restraint systems (not the PRE-SAFE® system) an automatic emergency call (eCall) is immediately sent. An emergency call is sent out regardless of the severity of the accident.
The HERMES control unit receives the crash information via a direct line as a digital crash signal from the supplemental restraint system (SRS) control unit.
The supplemental restraint system (SRS) control unit also (redundantly) sends the crash information, including crash level, via the following route:
Vehicle CAN
Central gateway (CGW)
Diagnostic CAN
HERMES control unit
The supplemental restraint system (SRS) control unit cyclically sends a readiness signal via the same route as the crash information. The HERMES control unit thereby monitors communication with the supplemental restraint system (SRS) control unit and the proper function of the crash detection.