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After the siren test, the e-mails start rolling in

In Switzerland, there are around 5,000 sirens that alert the population in the event of a disaster. Of these, 3,200 are provided by the company Kockum Sonics AG. We paid them a visit on testing day and found out what happens after the sirens have been tested and why it might not be necessary for much longer.

Evelyne Owa

February 8, 2023 . 4 minutes read

There’s nothing to show that the building houses members of the Swiss civil-defense agency. The gray, flat-roofed building in a residential part of Dübendorf is utterly unassuming. To the right of the door are two small signs with company names. One of them reads Kockum Sonics. Pascal Loretz and Nina Delnon greet us with firm handshakes and warm smiles. He’s the CEO, she’s the project manager. It’s Wednesday afternoon, just before the annual siren test throughout Switzerland.

Kockum Sonics CEO Pascal Loretz develops various IoT solutions for the manufacturing industry, as well as civil defense alarm systems.

A busy time for the siren experts

For the ten-employee SME, everything on this day revolves around the 3,200 fixed sirens it has produced for cantons and municipalities and for whose maintenance it’s now responsible. The sirens are activated if large sections of the Swiss population are in danger and need to be alerted as quickly as possible – for example, in the event of natural disasters or a nuclear threat.

A key date in the calendar: The Swiss siren test takes place every year on the first Wednesday of February.

A key date in the calendar: The Swiss siren test takes place every year on the first Wednesday of February.

Before, during and after the siren test, staff from cantons, municipalities and civil-defense organizations contact Kockum Sonics. They report technical issues, arrange siren-test training for their service personnel or ask for sound measurements if they suspect that there are new buildings in their areas not reached by the sirens.

Special requests and fault reports

Pascal Loretz takes us to the siren, which is located in the test laboratory at Kockum Sonics AG. It’s about three meters high and made of trapezoidal, gray cast-metal elements. Most Kockum Sonics civil-defense sirens look like this, explains Pascal Loretz. But there are also exceptions. «We had to provide a golden siren for the Rolex building in Geneva,» says the CEO and laughs. The control box is on the wall next to the siren. It houses the button for manually triggering the alarm. «Fixed sirens can also be set remotely,» says Loretz.

In the test laboratory at Kockum Sonics, everything is digitally connected and remote-controlled. CEO Loretz’s vision is to connect all civil defense sirens with the IoT.

The first sirens start sounding outside. They begin quietly, before rising in volume, then getting quieter again, ascending and descending in pitch. The Dübendorf sirens appear to be working perfectly. This isn’t the case everywhere. «After the siren test, we start to get fault and failure notifications. Last year, we got around 100,» says Nina Delnon. Sometimes the notifications arrive on the same day, sometimes after a few weeks. The technical team at Kockum Sonics AG is then deployed on site to resolve the problems as quickly as possible. This involves a lot of travel and good planning – sometimes without knowing the exact nature of the problem.

Smart sirens that warn of tsunamis

Sirens in the Italian region of Naples will no longer need annual testing. From June 2023, two Kockum Sonics siren systems will be installed as remote-controlled tsunami warning systems with IoT communication. Going forward, they will also be able to warn of impending eruptions by the volcano Mount Vesuvius. Assembled in Sweden and made in part with Swiss components, the sirens used in Naples are intelligently connected – the Internet of Things (IoT) has transformed them into smart products. In the future, they will communicate with seismic-monitoring systems. If there’s an immediate threat of a tsunami, the information will be sent to the sirens immediately and an alarm will automatically be triggered.

Teamwork leads to success

«This is our first IoT project with Sunrise as a partner,» says Pascal Loretz. Because, in order to enable the devices and the monitoring systems to communicate with each other, they must be connected to the Internet. This is done by means of data SIM cards, which are integrated into the sirens, as well as an IoT management platform for managing the SIM cards. Both are from Sunrise. The project team also includes IT specialists from Celphone, who are responsible for connecting the sirens, as well as specialists from Swissphone, who provide the alarm platform.

A classic creative workplace: This is where the technicians from Kockum Sonics develop their solutions, together with their IoT project partners.


The smart city trade fair with Sunrise Business

Sunrise and Kockum Sonics will be attending SmartSuisse together. The strategy congress with the smart-city theme will take place on March 28–29, 2023, at the Congress Center in Basel. CEO Pascal Loretz and IoT expert Patrik Jud will give a presentation on the IoT siren project with Sunrise on March 28 at 14:00.


The IoT Starter Services make it easy to start using the Internet of Things for so-called «retro-fit projects» – such as those from Kockum Sonics – as well as for newly developed IoT devices. Business customers can choose from five different data packages and simply order them via the web shop, allowing them to enter the test phase with their prototypes just a few days later.

«The tsunami project with Kockum Sonics is typical of an IoT project,» says expert Patrik Jud, who advises Sunrise business customers on the Internet of Things. «The IoT brings together customers and specialists from different disciplines.» Thanks to straightforward data-roaming solutions, there are no barriers to collaborating with partners in other European countries.

«When it comes to civil defense, IoT sirens would be desirable»
Pascal Loretz, CEO Kockum Sonics AG

Constant monitoring – not just once a year

What’s the situation in Switzerland when it comes to smart sirens? Would IoT make sense here as well? «When it comes to civil defense, IoT sirens would be desirable,» says Pascal Loretz. «You’d always know whether the sirens were working, not just on the day of testing.» «It would be easy to upgrade the old sirens,» adds Patrik Jud. Thanks to the IoT, disruptions are continuously notified, analyzed and rectified. Depending on the issue, problems could be fixed directly via remote access. And thanks to the ongoing collection of data from all sirens, disruptions could be fixed in advance or even avoided altogether, resulting in cost savings. In terms of costs, Nina Delnon is delighted: «Our first IoT project has demonstrated that smart solutions are cheaper than we thought. We were pleasantly surprised.»

The digital control unit for the sirens is already IoT-ready and enables remote maintenance of thousands of systems, nation-wide software upgrades or real-time monitoring.

Data SIM cards

Data SIM cards are not just for IoT use but are also beneficial for private use. With We Connect surf, your laptop or tablet is always connected to the Internet, whether you’re at home or on the go. For CHF 12.50 per month, you get unlimited 5G data in Switzerland; 500 MB for roaming in Europe is also included.

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