Emergency call system, function

P82.95-2963-79

Function requirements, emergency call system, general

 Circuit 30

 Transport mode not active

 Each vehicle-related service is authorized separately.

 An emergency call system control unit communication module authorized for the corresponding vehicle-related service is configured with the telephone number of the relevant service provider.

 The vehicle owner is registered and authorized at the Service Center.

Emergency call system, general

The emergency call system control unit enables the following vehicle-related services to be realized:

 Authorization ("provisioning")

 Manual or automatic emergency call

 MB information call

 Roadside assistance

 Notification in the event of antitheft alarm ("Anti Theft Notification")

 Tracking ("stolen vehicle tracking")

 Vehicle remote unlocking

 Vehicle remote locking

 Remote diagnosis ("Remote Diagnosis")

 Transmission of vehicle position ("Vehicle Locator")

 Notification of a certain speed being exceeded ("Speed Alert")

 Notification if a certain area has been reached or left ("Geo Fencing")

 Transmission of information (e.g. map data) to the vehicle ("Remote Information Feed")

 Transmission of updates to vehicle ("Remote Update")

 Visual and acoustic vehicle recognition ("Flash Lights and Sound Horn")

 Internet connection (with CODE 512 (COMAND APS with DVD changer) or with CODE 527 (COMAND APS with single DVD drive (with navigation)))

 The emergency call system control unit is not used for regular telephone calls.

The emergency call system function consists initially of the following subfunctions:

 Self-test

 Emergency call system status indication

 Telephone antenna selection

 Voice connection between vehicle and Service Center

 Position finding

 Data from the Supplemental Restraint System control unit

 Manual or automatic emergency call

 Information on prioritization of services will be provided at the end of this document.

The other subfunctions are described in separate documents:

 Additional telematics services function

 Model 172.4
as of model year 2013 up to model year 2017
with code 348 (Emergency call/assistant system)
with code 512 (COMAND APS with DVD changer)
except code 347 (Mercedes-Benz emergency call system)
Model 172.4
as of model year 2013 up to model year 2017
with code 348 (Emergency call/assistant system)
with code 527 (COMAND APS with single DVD drive (with navigation))
except code 347 (Mercedes-Benz emergency call system)
The Internet connection is not controlled via the emergency call system control unit, but via the COMAND controller unit; it is therefore not described here.

Self-test

If the emergency call system control unit receives the "Circuit 15R" message from the electronic ignition lock control unit, the emergency call system control unit performs a self-test (approx. 8 to 10 s). The light-emitting diodes of the emergency call system button, the MB-Info button and the breakdown assistance button are on for approx. 10 s.

The electronic ignition lock control unit transmits the "circuit 15R" message via the following route:

Interior CAN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

After a successful self-test, the emergency call system is operational and the light-emitting diodes go out.

 In the event of a fault, a fault message (depending on the fault type) appears on the instrument cluster, and the LEDs on the emergency call system button, the MB-Info button and the breakdown assistance button are permanently illuminated. Depending on the fault type, the fault is also stored in the emergency call system control unit's fault memory.

Emergency call system status indication

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

 Status indication through light-emitting diodes

 Status indication in instrument cluster

 Status indication on the Audio/COMAND display

 With some services, no system-specific status indication takes place in the vehicle.

Status indication through light-emitting diodes

The LEDs for the emergency call system button, the MB-Info button and the breakdown assistance button are used to display the following status:

 Emergency call system self-test, LEDs light up for approx. 5 s

 Active service, each LED flashes on and off

 Fault in emergency call system, LEDs permanently on

 System readiness of emergency call system, LEDs are off

The emergency call system control unit actuates the LEDs in the emergency call system button, the MB info button and the breakdown assistance button via the following route:

Diagnostic CAN 

Front SAM control unit with fuse and relay module 

Wiper/inside rearview mirror LIN 

Overhead control panel control unit

Status indication in instrument cluster

The status of the emergency call system is indicated in a text message in the instrument cluster in the following instances:

 Active service

 Fault in emergency call system

The emergency call system control unit sends the message via the following route:

Diagnostic CAN 

Front SAM control unit with fuse and relay module 

Interior CAN 

Instrument cluster

Status indication on the Audio/COMAND display

An active emergency call system service can be indicated by a text message or a pop-up window (with confirmation prompt) on the Audio/COMAND display.

The emergency call system control unit sends the text message or the pop-up window via the following route:

Diagnostic CAN 

Front SAM control unit with fuse and relay module 

Interior CAN 

COMAND controller unit 

LVDS line 

Audio/COMAND display

Additional function requirements for selecting the telephone antenna

 Defect in multifunction antenna or poor reception

Telephone antenna selection

Normally, the communication module integrated into the emergency call system control unit transmits and receives all mobile phone signals via the multifunction antenna. In the event of poor reception or a defective multifunction antenna, the communication module integrated into the emergency call system control unit automatically transmits and receives the mobile phone signals via the emergency call system antenna.

The emergency call system control unit monitors the multifunction antenna via a direct line, and detects the failure or poor reception. The emergency call system control unit then automatically transmits or receives the mobile phone signals for each vehicle-related service via a direct line and the emergency call system antenna.

Additional function requirements for voice connection between vehicle and Service Center

 One of the following vehicle-related services is present:

 Manual or automatic emergency call

 MB information call

 Roadside assistance

 Vehicle tracking

Voice connection between vehicle and Service Center

Regardless of the type of vehicle-related service initiated (e.g. MB-Info call), a voice connection is established to the Service Center. Following feedback from the Service Center via a special tone, a Short Message Service (SMS) message is transmitted to the Service Center. This message contains the vehicle position, customer and vehicle identification data and other vehicle data ("Initial Summary"). Then the driver can speak to a service receptionist via the existing voice connection.

The inside rearview mirror microphone is used for voice input and is integrated in the inside rearview mirror (A67). The signals from the inside rearview mirror microphone are routed over a direct line to the COMAND controller unit. In the COMAND controller unit, the signals from the inside rearview mirror microphone are only looped through and are forwarded to the communication module integrated into the emergency call system control unit. The communication module integrated into the emergency call system control unit then transmits the inside rearview mirror microphone signals to the Service Center.

The communication module of the emergency call system control unit transmits and receives the mobile phone signals via the multifunction antenna.

 In the event of a malfunction in the multifunction antenna (e.g. defective because of a rollover), the communication module integrated into the emergency call system control unit automatically transmits and receives the mobile phone signals via the emergency call system antenna.

The buildup of a voice connection to the Service Center is terminated by the communication module integrated into the emergency call system control unit after several unsuccessful dialing attempts and a corresponding message is shown in the instrument cluster as well as on the Audio/COMAND display.

For voice output, the center instrument panel speaker (with code 810 (Sound system)) or the emergency call speaker (except code 810 (Sound system)) is actuated by the emergency call system control unit.

For all other applications (e.g. audio mode), the speaker system is muted by a mute signal (mute function) from the emergency call system control unit via a direct line to the sound system amplifier control unit (with code 810 (Sound system)) or to the COMAND controller unit (except code 810 (Sound system)). Normally, the voice connection is terminated by the Service Center or by the driver.

 If there is an emergency call, the voice connection can be terminated by the Service Center or by pressing the accept/terminate phone call button (S111s3) in the "Hang up" subfield.

Position finding

For position finding, the emergency call system control unit uses the satellite supported 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). Relocating with GPS may take several minutes (in the event of initial startup of the emergency call system control unit or after interruption of satellite reception).

Basic position finding runs parallel to GPS position finding.

The position finding function consists of the following component functions:

 GPS position finding

 Basic position finding

Additional function requirement for GPS position finding

 Circuit 15R ON or activation of an authorized service

GPS position finding

The GPS receiver integrated in the emergency call system control unit receives the GPS signals either directly from the multifunction antenna, or in vehicles with code 508 (Navigation box preinstallation), with code 512 (COMAND APS with DVD changer) or with code 527 (COMAND APS with single DVD drive (with navigation)) via the Global Positioning System antenna splitter.

The emergency call system control unit calculates the current position of the vehicle (recipient) from the GPS signals. The vehicle's direction of travel is also determined using the sequence of GPS calculated locations.

Additional function requirement for basic position finding

 Circuit 15R ON

Basic position finding

For basic position finding, the emergency call system control unit requires wheel speed and yaw rate signals from the Electronic Stability Program control unit. The Electronic Stability Program control unit sends the signals via the following route:

Chassis CAN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

The current vehicle position (longitude and latitude) is then calculated in the emergency call system control unit.

 Location errors in position finding, rolling backwards with "circuit 15 OFF" (ignition switched off) or transport of the vehicle falsify the basic position finding. In both instances, the deviation is automatically corrected by the navigation processor integrated into the emergency call system control unit when it receives GPS data.

Additional function requirement for data from the 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 (E-Call) is made immediately. An emergency call is sent out regardless of the severity of the accident.

The emergency call system control unit receives the crash information via a direct line as a digital crash signal from the supplemental restraint system control unit.

The Supplemental Restraint System control unit also (redundantly) sends the crash information, including crash level, via the following route:

Chassis CAN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

 The supplemental restraint system control unit transmits a "LIFE" signal ("sign of life" for supplemental restraint system (SRS) control unit) via the same route as the crash information, incl. "crash level", every t = 500 ms. This allows the emergency call system control unit to permanently monitor communication with the supplemental restraint unit control unit and proper function of the crash recognition.

Manual or automatic emergency call

In the event that a driver is confronted with an emergency situation while in a remote location, a Service Center employee can obtain an overview of the situation inside the vehicle with the aid of the data received from the emergency call system control unit (voice connection and SMS) and initiate the appropriate action required for help. 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 of rescue workers at the press of a button (own emergency situation, observed accident)

 Reduction in rescue times through fast emergency notification with details on exact location involved

The emergency call function consists of the following subfunctions:

 Triggering of a manual emergency call

 Triggering of an automatic emergency call

 Transmission of the emergency call data and communication with the Service Center

Additional function requirements for triggering a manual emergency call

 A higher-priority vehicle-related service (automatic emergency call) is not active.

Triggering of a manual emergency call

The manual emergency call is triggered by pressing the emergency call system button marked "SOS". The emergency call system 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 signals of the emergency call system button are transmitted by the overhead control panel control unit via the following route:

Wiper/inside rearview mirror LIN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

Triggering of an automatic emergency call

The emergency call system control unit receives a crash signal from the supplemental restraint system control unit via a direct line. At the same time, the Supplemental Restraint System control unit sends the crash signal (redundantly) and the crash level via the following route:

Chassis CAN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

Transmission of the emergency call data and communication with the Service Center

After a manual or automatic emergency call has been initiated, the emergency call system control unit establishes a voice connection to the Service Center. After the Service Center replies with a special tone, the emergency call system control unit automatically transmits an SMS with the following data to the Service Center via the integrated communication module:

 Vehicle position, direction of travel and history

 Vehicle data and crash information

The communication module integrated in the emergency call system control unit transmits and receives the mobile phone signals via the multifunction antenna.

 In the event of a manual or automatic emergency call, other vehicle-related services (e.g. MB Info call) are interrupted.

 If the multifunction antenna malfunctions or the reception quality is poor, the emergency call system control unit automatically sends and receives the mobile phone signals over the emergency call system antenna.

 If connection to the Service Center cannot be established when an automatic emergency call is initiated, a voice connection is automatically set up using the emergency number whereupon the listed data then has to be communicated verbally.

 With a manual or an automatic emergency call, the Service Center can transfer the map data to the vehicle if required.

Prioritization

The emergency call system control unit can manage a voice or data connection and an SMS connection at the same time. The data connection can be used by several services simultaneously by means of transmitting data packets at staggered times. The priority management is based on the following principles:

 Services with SMS capability are executed by SMS if one of the four services with the highest priority is activated and the remaining connection resources are released for the prioritized service.

 Services without SMS capability or an Internet connection are terminated if one of the four services with the highest priority is activated and the connection resources are released for the prioritized service.

 The remote diagnosis has its own data channel, and can also be carried out for every other service.

 The four services with the highest priority are executed if no service with a higher priority is active.

Services with SMS capability are:

 Tracking ("stolen vehicle tracking")

 Vehicle remote unlocking

 Vehicle remote locking

 Notification of a certain speed being exceeded ("Speed Alert")

 Notification if a certain area has been reached or left ("Geo Fencing")

 Visual and acoustic vehicle recognition ("Flash Lights and Sound Horn")

The four services with the highest priority are listed in the following table.