Emergency call system, function

P82.95-3028-79

Function requirements, emergency call system, general

 Circuit 30

 Transport mode not active

 A mobile phone or a telephone module with Bluetooth® (SAP) (with code 379 (Telephone module with Bluetooth® (SAP))) is connected via Bluetooth® to the head unit.

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 spoken to in the language that is selected in the system settings of the head unit. If necessary, the Mercedes-Benz Service Center notifies the local rescue services.

If the head unit receives the "Circuit 15R" message from the electronic ignition lock control unit via user interface CAN, the head unit checks the operational readiness of the emergency call system. The following checks are carried out:

 Receipt of cyclic readiness signal ("sign of life") from the Supplemental Restraint System control unit

 Operating capability of the SOS button

 Availability of a mobile phone or telephone module with Bluetooth® (SAP profile) connected to the head unit via Bluetooth®

The LED of the SOS button illuminates for approx. 5 s. After successful checking, the emergency call system is operational and the LED goes off. At the same time, "SOS ready" is displayed in the telephone menu on the audio/COMAND display.

 In the event of a fault, depending on the type of fault a fault message appears on the audio/COMAND display and the LED of the SOS button is permanently actuated. Depending on the type of fault, the fault is also stored in the fault memory of the head unit.

The emergency call system function comprises the following subfunctions:

 Emergency call system status indication

 Voice connection between vehicle and Mercedes-Benz Service Center

 Data from the supplemental restraint system control unit

 Manual or automatic emergency call

 An automatically triggered emergency call has priority via a manually triggered emergency call.

Emergency call system status indication

The status of the emergency call system is shown in the following ways:

 Status indication via light-emitting diode

 Status indication on the Audio/COMAND display

Status indication via light-emitting diode

The LED of the SOS button is used to indicate the following states:

 Self-diagnosis of emergency call system, LED lights up for approx. 5 s.

 Emergency call has been triggered, LED flashes.

 Fault in emergency call system, LED on permanently.

 Emergency call system ready for operation, LED is off.

The head unit actuates the LED of the SOS button via the following route:

User interface CAN 

Electronic ignition lock control unit 

Interior CAN 

Front SAM control unit 

Roof LIN 

Overhead control panel control unit

Status indication on the Audio/COMAND display

The status of the emergency call system is indicated by a text message on the audio/COMAND display in the following cases:

 Emergency call system is operational.

("SOS ready" in "Telephone" menu)

 Emergency call is triggered.

("activating" (call setup), "transmitting data" (data telegram transmission), "connected" (voice connection established))

 Fault in emergency call system

The head unit transmits the text messages over an LVDS line to the Audio/COMAND display.

Additional function requirements for voice connection between vehicle and Mercedes-Benz Service Center

 Manual or automatic emergency call triggered.

Voice connection between vehicle and Mercedes-Benz Service Center

Once the emergency call has been triggered, a voice connection with the Mercedes-Benz Service Center is established. The head unit mutes the audio sources and interrupts any telephone call that may be in progress. After a data telegram has been transmitted to the Mercedes-Benz Service Center, the user can speak to a service receptionist via the voice connection. The Mercedes-Benz Service Center carries out the call in the language that was selected in the system settings of the head unit and transmitted in the data telegram.

The hands-free system microphone, which is integrated into the inside rear-view mirror (A67), is used for voice commands. The signals from the hands-free system microphone are sent to the head unit via a direct line. The volume for the voice output can be adjusted using the volume control button. The signal is sent by the right lower control panel (for automatic transmission) or from the left lower control panel (for manual transmission) via lower control panel LIN to the Audio/COMAND control panel and from there via telematics CAN to the head unit. For voice output, the head unit in vehicles with CODE 810 (Sound system) forwards the signals received from the Mercedes-Benz Service Center via the MOST to the sound system amplifier control unit. In vehicles except CODE 810 (Sound system), the head unit outputs the received signals via the speaker system.

 The setup of a voice connection to the Mercedes-Benz Service Center is aborted after several unsuccessful dialing attempts, and a corresponding message appears on the audio/COMAND display.
In a normal case, the voice connection is terminated by the Mercedes-Benz Service Center or the user.

The head unit transmits the signals of the hands-free system microphone to one of the following components via the Bluetooth® antenna:

 Telephone module with Bluetooth® (SAP profile) (with code 379 (Telephone module with Bluetooth® (SAP profile)))

 Mobile phone (except code 379 (Telephone module with Bluetooth® (SAP)))

In vehicles with code 379 (Telephone module with Bluetooth® (SAP)), the telephone module with Bluetooth® (SAP) transmits the signals via the following route:

Mobile phone contact plate 

Telephone antenna splitter 

Left telephone antenna or right telephone antenna 

Mercedes-Benz Service Center

In vehicles except code 379 (Telephone module with Bluetooth® (SAP)) and with code 386 (Comfort telephony), the mobile phone transmits the signals via the following route:

Mobile phone contact plate 

Cellular telephone system antenna amplifier/compensator 

Telephone antenna splitter 

Left telephone antenna or right telephone antenna 

Mercedes-Benz Service Center

On vehicles except code 379 (Telephone module with Bluetooth® (SAP)) and except code 386 (Comfort telephony), the mobile phone sends the signals directly to the mobile telephone network.

 Model 205
with code 347 (Mercedes-Benz emergency call system)
with code 386 (Comfort telephony)
except code 348 (Emergency call/assistant system)
except code 351 (eCall emergency call system)
except code 379 (Telephone module with Bluetooth® (SAP profile))
In the event of left or right telephone antenna failure (e.g. defect due to a rollover), the antenna of the mobile phone is used.

Additional function requirements for data from supplemental restraint system control unit

 Circuit 15R ON

Data from the supplemental restraint system control unit

In the event of an accident with airbag deployment, an automatic emergency call is immediately sent out. An emergency call is sent out regardless of the severity of the accident. The head unit receives the crash information, including the crash level, from the supplemental restraint system control unit via the user interface CAN.

 The supplemental restraint system control unit transmits a readiness signal cyclically (e. g. every 500  ms) via the same route as crash information. In this way the head unit monitors the communication with the supplemental restraint system control unit and the correct operation of the crash detection.

Additional function requirements for triggering an automatic emergency call

 Ignition ON (circuit 15R) (with ignition OFF, "Ecall not ready" appears on the display)

Manual or automatic emergency call

In an emergency situation, a service receptionist from the Mercedes-Benz Service Center can obtain an overview of the status inside the vehicle with the aid of the data received from the emergency call system 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 manual or automatic emergency call function consists of the following subfunctions:

 Function sequence for activating an automatic emergency call

 Function sequence for activating a manual emergency call

 Function sequence for transmission of emergency call data and communication with the Mercedes-Benz Service Center

Function sequence for activating an automatic emergency call

In the event of an accident with airbag deployment, an automatic emergency call is immediately sent out. An emergency call is sent out regardless of the severity of the accident. The head unit receives the crash information, including the crash level, from the supplemental restraint system control unit via the user interface CAN. An automatic emergency call is also triggered (redundant) if the head unit receives the "central locking emergency opening" signal and at the same time the cyclic readiness signal ("sign of life") from the supplemental restraint system control unit is not received.

The front SAM control unit transmits the "Central locking emergency opening" signal via the following route:

Interior CAN 

Electronic ignition lock control unit 

User interface CAN 

Head unit

 The supplemental restraint system control unit transmits a readiness signal cyclically (e. g. every 500  ms) via the same route as crash information. In this way the head unit monitors the communication with the supplemental restraint system control unit and the correct operation of the crash detection.

Additional function requirements for triggering a manual emergency call

 No automatic emergency call is active.

 A manual emergency call can also be made with ignition OFF.

Function sequence for activating a manual emergency call

A manual emergency call can be triggered in two different ways:

 Press SOS button

 Select emergency call address book entry

Press SOS button

The manual emergency call is triggered by pressing the SOS button marked "SOS". The SOS button is covered up with a locking flap. Pressing the protective lid unlocks the lid and it automatically opens with the aid of a spring mechanism.

The signal of the SOS button is transmitted via the following route:

Overhead control panel control unit 

Roof LIN 

Front SAM control unit 

Interior CAN 

Electronic ignition lock control unit 

User interface CAN 

Head unit

Select emergency call address book entry

If the head unit is switched off, it can be switched on using the "ON" button in the right lower control panel (with automatic transmission) or in the left lower control panel (with manual transmission). The telephone function can be activated at the upper control panel control unit. In both cases, the control signals are forwarded via the following route:

LCP LIN 

Audio/COMAND control panel 

Telematics CAN 

Head unit

The address book of the head unit can be opened in the "Telephone" menu. The emergency call address book entry ("Mercedes-Benz Emergency Call") is in first position.

The reserved emergency call address book entry is selected using one of the following operating options:

 Audio/COMAND controller of the Audio/COMAND control panel

 Touchpad (with CODE 522 (Audio 20 radio) or with CODE 531 (COMAND APS))

 Left multifunction steering wheel button group and right multifunction steering wheel button group

 Voice control system (with CODE 531 (COMAND APS))

The control signals from the Audio/COMAND controller are sent by the Audio/COMAND control panel via telematics CAN to the head unit.

The touchpad (with CODE 522 (Audio 20 radio) or with CODE 531 (COMAND APS)) transmits the control signals via the telematics CAN to the head unit.

The control signals of the left multifunction steering wheel button group and the right multifunction steering wheel button group are forwarded as follows:

Steering wheel electronics 

Steering LIN 

Steering column tube module control unit 

Chassis FlexRay 

Electronic ignition lock control unit 

User interface CAN 

Instrument cluster 

User interface CAN 

Head unit

The voice commands of the voice control system (with CODE 531 (COMAND APS)) are converted into electrical signals by the hands-free system microphone and forwarded to the head unit.

Function sequence for transmission of emergency call data and communication with the Mercedes-Benz Service Center

Once a manual or automatic emergency call has been triggered, the head unit sets up a voice connection with the Mercedes-Benz Service Center. Audio sources are muted, and existing telephone connections are interrupted.

The status of the connection setup is indicated by the following messages on the audio/COMAND display:

 "Activating" (setting up the call)

 "Transmitting data" (transmission of emergency call data (data telegram))

 "Connected" (voice connection established)

As soon as a connection to the mobile phone and the mobile telephone network has been established, the head unit automatically transmits two SMS using message access profile (MAP) to the Mercedes-Benz Service Center. The text messages contain the following information:

 Time stamp

 GPS position (global navigation system) of the vehicle

 Language

 Vehicle identification number

 MB Contact status (ON or OFF)

Once the text messages have been transmitted, the voice connection is set up. The head unit first transmits a shortened data telegram using the dual tone multiple frequency (DTMF) via the voice connection. Then the user is contacted by a service receptionist from the Mercedes-Benz Service Center.

 The user can end the emergency call by pressing the accept/terminate phone call button (S111s3) on the multifunction steering wheel in the corresponding subfield.
During an automatic emergency call, the accept/terminate phone call button on the multifunction steering wheel is temporarily disabled while the connection is being set up in order to avoid unintentional termination. Pressing the accept/terminate phone call button 2 times briefly in succession can interrupt the automatic emergency call.

Prioritization

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 (SMS or DTMF) containing updated position data is sent to the Mercedes-Benz Service Center, and the existing connection is maintained.