Emergency call system, function

P82.95-3013-79

P82.95-2961-79

Function requirements, emergency call system, general

 Circuit 30

 Transport mode is inactive.

 Each vehicle-related service is authorized separately.

 The communication module of the emergency call system control unit 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")

 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 code 527 (COMAND APS with single DVD drive (with navigation)) or vehicles as of 02.03.2015)

 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-diagnosis

 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 additional subfunction is described in the separate document entitled "Additional telematics services, function".

 The Internet connection is not controlled through the emergency call system control unit, but rather through the audio equipment.

Self-diagnosis

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-diagnosis (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 sends the message "Circuit 15R" 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-diagnosis, 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-diagnosis, light-emitting diodes light up for approx. 10 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 controls the LEDs in the emergency system button, the MB info button and the breakdown assistance button via direct lines.

Status indication in instrument cluster

The status of the emergency call system is displayed in the form of a text message on the instrument cluster in the event of an active service or a fault in the 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 service of the emergency call system is indicated by a text message or a pop-up window (with confirmation prompt) on the Audio/COMAND display.

The display of the message or the pop-up window is sent by the emergency call system control unit via the following route:

Diagnostic CAN 

Front SAM control unit with fuse and relay module 

Interior CAN 

Audio equipment 

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 triggered: Manual or automatic emergency call, MB-Info call, breakdown assistance, 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 hands-free system microphone is used for voice commands; it is integrated into the inside rear view mirror (A67). The signals of the hands-free system microphone are relayed via a direct line to the audio equipment. The audio unit then loops through the signals from the hands-free system microphone and forwards them 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 hands-free system 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.

The center instrument panel speaker is actuated by the emergency call system control unit for voice output. For all other applications (e.g. audio mode), the speaker system is muted by a mute signal from the emergency call system control unit over a direct line to the sound system amplifier control unit (with CODE 810 (Sound system)) or to the audio equipment (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 only be terminated by the Service Center or by pressing the accept/terminate phone call button in the "Hang up" subfield for at least 15 s.

As of 10.05.2013, the accept/terminate phone call button sends the signal vial the following route:

Steering wheel electronics 

Steering LIN 

Steering column tube module control unit 

Chassis CAN 1 

Front SAM control unit with fuse and relay module 

Chassis CAN 2 

Instrument cluster 

Interior CAN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

Up to 09.05.2013, the accept/terminate phone call button sends the signal vial the following route:

Steering wheel electronics 

Steering LIN 

Steering column tube module control unit 

Chassis CAN 

Instrument cluster 

Interior CAN 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

Position finding

For position finding, the emergency call system control unit uses the satellite supported global navigation system (GPS) positioning system. 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 via the global positioning system antenna splitter for the following vehicles:

 With CODE 512 (COMAND APS with DVD changer)

 With CODE 527 (COMAND APS with single DVD drive (with navigation))

 Vehicles as of 02.03.2015

The GPS signals are used by the emergency call control unit to calculate the current vehicle position (receiver). 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 needs wheel speed and yaw rate signals from one of the following components:

 Electronic Stability Program control unit (except CODE 233 (DISTRONIC PLUS))

 Premium Electronic Stability Program control unit (with CODE 233 (DISTRONIC PLUS))

The Electronic Stability Program control unit or the Premium Electronic Stability Program control unit sends the signals via the following route:

Chassis CAN (up to 09.05.2013) or chassis CAN 1 (as of 10.05.2013) 

Front SAM control unit with fuse and relay module 

Diagnostic CAN 

Emergency call system control unit

 Error during 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 emergency call system control unit also (redundantly) receives the crash information, including crash level, via the following route:

Chassis CAN (up to 09.05.2013) or chassis CAN 1 (as of 10.05.2013) 

Front SAM control unit with fuse and relay module 

Diagnostic CAN

 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 system 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 emergency call system control unit reads in the emergency call system button signals via a direct line.

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 emergency call system control unit receives the crash signal (redundant) and the crash level via the following route:

Supplemental restraint system control unit 

Chassis CAN (up to 09.05.2013) or chassis CAN 1 (as of 10.05.2013) 

Front SAM control unit with fuse and relay module 

Diagnostic CAN

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 communications module integrated in the emergency call system control unit transmits and receives the mobile phone signals directly 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.

 Model 207 as of 3/2/15
as of model year 2016 up to model year 2017
with code 348 (Emergency call/assistant system)
Model 207 up to 3/1/15
as of model year 2013 up to model year 2016
with code 348 (Emergency call/assistant system)
with code 512 (COMAND APS with DVD changer)
Model 207 up to 3/1/15
as of model year 2013 up to model year 2016
with code 348 (Emergency call/assistant system)
with code 527 (COMAND APS with single DVD drive (with navigation))
With a manual or an automatic emergency call, the Service Center can transfer the map data to the vehicle if required. The data is made available to the navigation module of the audio equipment. Data transfer to the audio equipment is described in the documented titled, "Additional telematics services".

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 if one of the four services with the highest priority is activated by SMS 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 data recording for remote diagnosis has its own data channel and it can be conducted in addition to any 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:

 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.