An emergency call is a signal transmitted to a control center or emergency call center in an emergency to help those affected in an emergency situation. In Europe, the emergency number for emergency calls is 112.
- Emergency calls can be made from the home by people in need of help and care; in this case, they are referred to as home emergency calls. In addition, there is the automatic emergency call from a motor vehicle, in the event of an accident. In addition, there is the mobile emergency call, which is not bound to a specific location and is triggered on a mobile device. The communication channels for these examples are the classic telephone network, the IP network and mobile networks. connection is established between the emergency call device and the emergency call center. This connection is used to transmit personal and location data from the emergency victim. Status reports can be transmitted via the simultaneously switched voice connection. In the case of car accidents and mobile emergency calls, position accuracy is crucial in order to reach the accident victim as quickly as possible. Position accuracy is calculated by measuring the time of flight between several signals. Depending on the mobile network, the corresponding methods are called Enhanced Observed Time Difference( E-OTD) and Observed Time Difference of Arrival (OTDOA).
- In addition, there is the Emergency Telecommunications( EMTEL) technology from the European Telecommunications Standards Institute( ETSI) and the Emergency Call System( eCall) from the European Union( EU). Positioning methods for locating mobile subscribers include Automatic Location Identification( ALI), which automatically transmits the complete address of the person concerned to the emergency call center when an emergency call is made, and Advanced Mobile Location( AML) for precise mobile positioning.
- Another technology used to trigger an emergency call on mobile devices is the ManDown sensor( MD) or overturn sensor. With this circuit, an emergency call is triggered when the mobile device exceeds a predefined tilt angle. Also known as the dead man's sensor, this emergency call technology is triggered when the mobile device has a certain tilt angle for a certain period of time. To prevent this emergency call from being falsely triggered, the user is alerted to the potential emergency call by a prior alarm tone. The ManDown technology is used in work areas that involve a high risk of danger. For example, the risk of gas leakage. The emergency call can be triggered by setting several operating parameters such as the tilt angle, the duration of the tilt and the Zeispanne in which the mobile device is not moved.