Resolving the eCall Callback Issue

eCall is estimated to have the potential to save up to 2,500 lives annually. But one legacy issue remains: ensuring a callback service is possible.

New to eCall? Check out our special focus page here for a brief overview.

eCall, an initiative to bring swift assistance to drivers involved in a collision anywhere in Europe, has been a mandatory requirement in all new-type passenger vehicles sold in the EU since April 2018. As attention turns to implementing the next generation of eCall based on packet-switched networks, one significant outstanding issue remains to be fully resolved. That is to ensure that all Public Safety Answering Points (PSAPs) can make a callback to the vehicle in the event that a call is dropped or further information is required from the occupant(s) of the vehicle.

How does eCall work?

When a crash takes place, an in-vehicle system (IVS) with sensors is activated and automatically calls the pan-European emergency number 112 using the public switched telephone network. A voice connection is established with the relevant PSAP and a minimum set of data (MSD), including Global Navigation Satellite System (GNSS) coordinates and direction of travel, is sent in the same voice channel to the PSAP. This is, for all intents and purposes, a mobile originated emergency call. The IVS is fitted with a SIM and has a telephone number.

If you are not familiar with eCall, check out this short video describing how it works. The European Commission estimates that eCall can speed up emergency response times by 40% in urban areas and 50% in rural areas and reduce the number of fatalities by at least 4% and severe injuries by 6%. Estimates suggest that between 2018 and 2021, over 60 million eCall-enabled vehicles were registered in the EU representing an approximate 25% penetration rate in the overall fleet. EENA has seen a corresponding increase in the number of eCalls received by European PSAPs during that period and it continues to rise.

If an eCall should drop for any reason such as, for example, patchy mobile coverage, the PSAP call taker should be able to make a callback to the vehicle. However, evidence has shown that this does not always work. A significant contributing factor to the callback problem is that some of the telephone numbers used by eCall devices are not provisioned on all fixed and mobile networks in Europe. This is an issue that was anticipated by the Electronic Communications Committee (ECC) in its 2017 recommendation on numbering for eCall.

Why is callback a problem for eCall but not for other services?

Fixed and mobile telephony services use numbers from a national numbering plan. When you purchase a SIM, you are assigned a telephone number and you are able to be contacted on that number consistently. These numbers are effectively guaranteed to be provisioned on all fixed and mobile network which means that they can be dialled. National numbers are also used for eCall but international numbering ranges have emerged as the preferred option. International numbering ranges are managed by the International Telecommunications Union (ITU) and 15-digit numbering ranges beginning +882 and +883 are widely used for eCall. The use of international numbers is preferred as international carriers and car manufacturers/IVS manufacturers can enter bilateral agreements for eCall connectivity at a global or regional level. International numbering resources are commonly used for machine-to-machine type services. Figure 1 illustrates the different actors involved in an initial eCall and an eCall callback to a +882/+883 ITU global number.

Figure 1: Actors involved in eCall and eCall callback (Source: ITU)

An eCall is originated and terminated nationally and only involves network operators in one jurisdiction to complete the call. However, callback is more complex, involves more actors and there are several potential bottlenecks which could contribute to the problem:

  • – The enterprise telephone system used in the PSAP is not configured correctly to process incoming Calling Line Identity (CLI) for very long numbers (e.g. 15-digit numbers) and only a truncated CLI is presented to the PSAP operator. A callback is then not possible as the CLI is incorrect.
  • – Outgoing calls to unfamiliar numbers are often barred on the enterprise telephone system’s routing configuration.
  • – The numbers in question are not configured on the PSAP service provider’s network. i.e. the network operator providing a telephone service to the PSAP.
  • – No CLI was presented to the PSAP because the initial eCall came from a device in “Limited-Service State” (LSS). LSS can occur when mobile network coverage is poor and access to any available network can be facilitated for the sole purpose of making an emergency call. For example, when your device displays a message saying “Emergency Calls Only” it is most likely in LSS.

It should also be noted that this will remain an issue after the transition to next generation eCall as telephone numbers will continue to be used.

In 2019, the ECC and Orange France carried out a survey of European PSAPs where they were asked to make a test call to a +882/+883 number and confirm that they could make the call and listen to a recorded message. The survey received 22 responses and around half of the respondents could not make the call. The survey served as an awareness-raising exercise and the issue has since been resolved in many countries through local discussions and agreements. To further raise awareness, the ITU published information on the matter in its Operational Bulletin in September 2019 and in an ITU Circular in May 2020. The ITU also published an article on the subject in March 2020. Earlier this year, EENA worked with some European Operators and PSAPs in Germany to resolve eCall callback issues using test calls to  international numbering resources. Once awareness was raised, resolving the problem was straightforward.

In this regard, it is important that the entire European network operator community is aware of the numbering ranges being used for eCall. To facilitate this, the ECC has since established an online notification procedure for operators and service providers planning to use certain numbering ranges for eCall. The list of all notified numbering ranges used for eCall is published and accessible to all other operators on the ECC’s website. Other operators can then take steps to provision these numbers.

Network operators and service providers are also encouraged to apply appropriate tariffs at wholesale and retail level for calls to these numbers. Call costs, while not a technical barrier to callback, may present an economic barrier. PSAPs rely on public funding and should not have to pay high call charges for calling back vehicles while trying to assist citizens in life-and-death situations.

On average, there were 44 road deaths per million inhabitants in the EU in 2021. According to official statistical data on eCall, the service is estimated to have the potential to save up to 2,500 lives annually, while also reducing the severity of injuries by 10% to 15%. Getting an immediate alert in the event of an accident and knowing the exact location of the crash site cuts emergency services’ response time by 50% in rural and 40% in urban areas. Sometimes, a callback is necessary and could be the crucial element in saving a life or reducing the severity of an injury.

Play your part

The need for raising awareness of this issue continues. It is incumbent upon all actors in the eCall supply chain to ensure that eCall callback works. Please take note of the ECC’s notification procedures and notified numbering lists and play your part in facilitating seamless eCall callback.

As we transition to next generation eCall, this is one legacy issue that can be resolved through cooperation. Please contact me at [email protected] if you need more information.

The opinions expressed are those of the author and do not necessarily represent the views of EENA. Articles do not represent an endorsement by EENA of any organisation.

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