The Hague, 12 February 2025. Deerns has developed a solution that prevents meeting room eavesdropping without compromising functionality.
When designing meeting rooms in environments where confidentiality is essential – such as in banks, government offices and other sensitive locations – a key question is: How do you ensure maximum privacy without compromising on functionality of building systems?
During a project with stringent confidentiality requirements, an innovative concept emerged to prevent signal transmitters or speakers in meeting rooms being reversed and used as microphones. The idea was conceived in collaboration with Jac Waas, technician at Honeywell Esser. Together we further developed it into a smart and practical solution.
Working with Unica Fire & Safety, we developed a product that allows transmitters to be selectively switched off to protect privacy. They are active only when needed, such as for emergencies or public address announcements, and remain switched off when not in use. The solution offers the opportunity to retain audio signalling capability rather than switch to optical devices. Optical signals are often less conspicuous while audio messages ensure better and more rapid understanding and response to transmitted messages.
Smart circuit for safe and certified loudspeakers
The idea started with a simple circuit and a resistor, which set the transmitter to ‘non-active’. As a result, the switchboard treats the speaker as active although it is actually switched off. This ensures that the system continues standard line monitoring and can activate the speaker for use when needed, for example to transmit an emergency signal, whilst maintaining privacy by ensuring the microphone is switched off.
We worked closely with the supplier to develop the concept into a circuit diagram and prototype. This prototype underwent extensive testing and, in consultation with an accredited inspection body, was further optimised so that it can be applied in certified installations.
Loudspeakers in evacuation systems have a specific certification mark (EN 54-24), which expires as soon as they are tampered with. By separating the switch circuit from the loudspeaker, the installation remains fully certified. Moreover, this solution can be easily implemented, even in retrospect.
With further optimisations, the system has become a plug-and-play solution, making installation even easier. This smart, simple design is widely applicable, field-ready and expected to be available from early 2025.
Practical solutions through creativity and expertise
The anti-eavesdropping solution is just one example of how Deerns considers solutions beyond the obvious. With this technology, we not only offer customers a practical solution, but also set a new standard in privacy and security. By combining creative ideas with technical expertise and strong cooperation with partners, Deerns remains at the forefront of developing future-proof solutions.
