Emergency Call System, Basic Function - GF82.95-P-9900A
MODEL ALL (CAR)
with CODE 362 (HERMES LTE)
Overview
This document contains information on:
- Function of the emergency call system
- Connecting
- Data transfer
- Voice connection
- Position finding
General
The telematics services control unit controls the emergency call system via a mobile radio connection to the Service Center. The emergency call system allows a manual or automatic emergency call to be triggered. A voice connection is established to the Mercedes- Benz Emergency Call Center or to a public emergency call center. To enable the emergency call center to locate and identify the vehicle quickly, the telematics services control unit also transmits a data telegram.
Function requirement
- Circuit 15 on (only automatic emergency call)
Function of the emergency call system
When the ignition is switched on, the telematics services control unit checks the readiness of the emergency call system. In the process, it checks the following facts:
- Reception of the cyclic readiness signal ("lifesign") from the SRS
- Intact connection for the muting of audio sources
- Intact connection to the hands-free system microphone
- Intact connection to the emergency call system antenna(s)
- Intact connection to the GPS antenna
If the test is successful, the emergency call system is then ready for operation.
In the event of a fault, a fault message appears on the media display, depending on the fault type. The telematics services control unit also logs the fault in the fault memory.
If, after the ignition is switched off, the Supplemental Restraint System control unit switches to the sleep mode, it no longer sends a readiness signal. The media display then shows a message to indicate that the emergency call system is not completely operational. If there are no faults in the system, the message disappears when the ignition is switched on.
Automatic emergency call: If the restraint systems are triggered in an accident, the telematics services control unit immediately makes an automatic emergency call. The severity of the accident is immaterial.
The SRS sends the crash information to the telematics services control unit.
An autonomous emergency braking maneuver by the collision warning system also triggers an automatic emergency call if it brakes the vehicle to a standstill.
while the connection is being established for the automatic emergency call, the two buttons on the multifunction steering wheel for making/accepting and rejecting/terminating a phone call are disabled. This prevents any unintentional termination of the emergency call.
Manual emergency call: If the user operates the SOS button, the manual emergency call is triggered. To prevent unintentional operation, the button is fitted with a cover.
If the telematics services control unit triggers an automatic emergency call during a manual emergency call, the telematics services control unit transmits a data telegram with updated information to the emergency call center. The current connection of the manual emergency call remains intact and the service receptionist can see that an automatic emergency call has been triggered.
Connecting
When the emergency call has been triggered, the telematics services control unit establishes a connection to the Mercedes-Benz emergency call center via the emergency call system antenna(s). In doing so, the telematics services control unit mutes the audio sources and interrupts any existing telephone connections.
If the Mercedes-Benz emergency call center cannot be reached, the telematics services control unit automatically forwards the emergency call to the local rescue services 112. In some countries, the emergency call is automatically forwarded to the local rescue services for legal reasons.
Data transfer
As soon as the connection has been established, the telematics services control unit automatically transmits a data telegram to the Mercedes-Benz emergency call center. The telematics services control unit transmits the following data:
- Current position of the vehicle
- Route (a few 100 meters before the accident)
- Direction of travel
- Vehicle identification number
- Type of drive in vehicle
- Estimated number of people in vehicle
- "Mercedes me connect" present or not
- Manually or automatically triggered emergency call
- Time of the accident
- Language setting in multimedia system
Voice connection
After the data telegram has been sent to the Mercedes-Benz emergency call center, the user can speak to a service receptionist via the voice connection. If possible, the Mercedes-Benz emergency call center takes the call in the language that is set in the multimedia system.
During the emergency call, the hands-free system is not available for telephone calls.
If necessary, the Mercedes-Benz emergency call center notifies the local rescue services.
Position finding
The GPS antenna receives the signals for position finding and transmits them to the telematics services control unit. The telematics services control unit then evaluates the signals.
In parallel with the GPS position finding, the telematics services control unit constantly carries out basic position finding. This makes it possible to locate the position of the vehicle even when GPS reception fails. To do this, the telematics services control unit receives wheel speed and yaw rate signals from the ESP® and signals of the steering wheel angle sensor from the steering column tube module control unit.
In addition, position data from the navigation system, if available, are used for position determination.
Rolling backward with the ignition switched off or vehicle transportation will falsify the basic position finding. In both cases, the telematics services control unit corrects the deviation on receipt of GPS data. Recalculation of the GPS position (following an interruption in satellite reception) can take several minutes.
| Further basic functions | |||
|---|---|---|---|
| Collision warning system, basic function | Vehicles with code 239 (DISTRONIC PLUS), code 23P (Driving Assistance Package), code 258 (COLLISION PREVENTION ASSIST PLUS) or with code P20 (Driving Assistance Plus Package) | GF54.70-P-9900A | |
| Multimedia system control, basic function | GF82.85-P-9904A | ||
| Control units | |||
| Telematics services control unit, basic function | GF82.85-P-9892A |