Emergency Call (eCall)

Emergency Call (eCall)

Emergency Call (eCall) is a mandatory safety feature for intelligent vehicles that automatically or manually prompts the vehicle to dial a unified emergency services number in the event of a severe road accident, transmitting critical data such as the accident location and vehicle details to a Public Safety Answering Point (PSAP) to reduce emergency response times. According to European Union estimates, the full roll-out of eCall across Europe could save up to 2,500 lives annually.

Working Principle and Data Content

The core workflow of the eCall system operates via two parallel communication channels: a voice channel and a data transmission channel. Once triggered, the in-vehicle unit automatically dials a unified emergency number (such as 112 in the EU or 122 in China) and, whilst establishing the voice link, transmits a Minimum Set of Data (MSD) to the nearest PSAP via an in-band modem or an IMS-based packet-switched domain. The MSD contains essential information, including the vehicle's precise location (latitude/longitude), Vehicle Identification Number (VIN), time of the accident, direction of travel, and vehicle type, allowing emergency responders to quickly pinpoint the crash site and prepare rescue measures beforehand.

The system can be activated either automatically or manually. Automatic triggering is typically initiated by airbag deployment signals, accelerometer sensors registering a collision deceleration exceeding 4g, or vehicle rollover events. Manual triggering is carried out by the driver or passengers pressing the in-cabin SOS button.

International Regulations and Mandatory Timetable

The eCall system has already entered the mandatory regulatory phase across multiple global markets and is currently undergoing a major technological transition from legacy circuit-switched (CS) networks to Next Generation eCall (NG-eCall), which is built on 4G/5G and IMS architecture.

In the European Union, Regulation (EU) 2024/1180 mandates the fitment of eCall systems on all new M1 (passenger cars) and N1 (light commercial vehicles) models. Key regulatory milestones stipulate that from 1 January 2026, new type-approval applications for conventional CS-eCall systems will no longer be accepted; from 1 January 2027, all new type approvals must fully migrate to NG-eCall solutions, though existing models certified prior to this date may remain on sale. In terms of technical standards, EN 17184:2024 specifies the functional requirements, EN 17240:2024 outlines the test methods, and the strict requirement for NG-eCall IMS call setup latency is capped at no more than 3 seconds.

China gazetted its mandatory national standard GB 45672-2025 "Accident Emergency Call System for Vehicles" (AECS) in 2025, which will take full effect on 1 July 2027, making eCall systems compulsory on all newly manufactured Category M1/N1 vehicles. The standard expressly requires location data to operate on a BeiDou-priority or BeiDou single-mode basis, with onboard units required to support full-band connectivity across 4G networks at minimum.

Technological Upgrades of Next Generation eCall (NG-eCall)

Core advancements of NG-eCall include: shifting from reliance on legacy 2G/3G circuit-switched networks to packet-switched technology underpinned by 4G/5G and IMS, keeping pace with telecommunication infrastructure evolution; exceeding the conventional 140-byte MSD payload limit to support dynamic telematics data such as video feeds, crash severity metrics, and high-voltage battery status; enhancing positioning accuracy via the fusion of GNSS and onboard vehicle sensors to achieve dynamic errors of ≤3 metres; and offering dual-mode fallback capabilities to traditional CS-eCall whenever 4G/5G coverage is unavailable.

Safety Assurance and Privacy Compliance

In the event of vehicle power loss following an accident, the eCall system relies on a backup battery to maintain at least 10 minutes of voice call operation. The system is activated strictly during emergencies and does not track vehicle movements continuously, fully complying with relevant data protection and privacy regulations.