The National Early Warning and Notification System in the Slovak Republic

The National Early Warning and Notification System in the Slovak Republic

SEHIS is a modern and complex public warning and notification system in Slovakia, based on the MDSA21 technology developed by the Telegrafia company. Currently, the system contains over 600 interconnected electronic sirens, controlled from 30 warning centres.


Situation Before System Implementation

According to the opinion of the Civil Protection Department of the Slovak Ministry of Interior, our client, the main disadvantage of the previous system was the absence of central control at the national level. The whole warning and notification system was heavily human-dependent, and many of its functions needed personal intervention for activation and deactivation. Upon the delivery of a voice message or emergency call, the sirens in the old system could be activated only manually from individual district control centres, and the communications channels had no backup. Besides, there was no message recording for further analysis purposes (and as a result, there was no information about who, where and when activated the sirens).

However, the critical element of the whole system was the obsolete motor sirens, supplied from a single 380 V power source with no back-up. In case of a power failure (e.g. caused by floods), the sirens became inoperable.

Furthermore, the sirens were controlled only by a single one-way communications channel, with no backup provided, which meant that they only received commands, but the system operators had no feedback on the siren condition or status, or information whether the sirens are operational. The last disadvantage was that the motor sirens in the old system reproduced only two possible tones (constant or wavering).

national warning system

Major Business Objectives

Based on the previous analysis, our customer defined the following basic requirements for the warning solution: 

  • The new system built on sophisticated digital technologies (unlike the old one containing analogue devices)
  • Two-way communication between control centres and sirens (providing the information about the readiness of the sirens, feedback on their status, and allowing silent siren tests)
  • The notification system capable of delivering the information on the type of alarm to the public (voice input and output, and live-voice announcements)
  • Power backup for at least 72 hours in case of a power supply failure
  • The replacement of the old hard-wired line control of sirens with radio control
  • The overall system backup, the duality of technology
electronic siren

Solution Description

What makes the SEHIS system so exceptional is its integrity, allowing the interconnection of individual and separated smaller subsystems into one fully functional national unit. SEHIS is built on the MDSA21 technology, which is complex modern equipment developed for public mass warning and notification, having the following functions:

  • Telemetric control, real-time monitoring and testing of warning devices (electronic sirens)
  • Individual or group notification based on an input from the monitoring system and/or from a warning module
  • Effective communication established between control centres
  • Recording of radio communications and phone calls
  • Monitoring and management of technological processes

The whole system technology is dual: two separate data backup systems, two separate control units, and two separate communications channels. A radiotelemetric system and RDS (Radio Data System) were proposed as two communications channels in SEHIS,  compliant with the customer requirements. In case one channel fails, the communication is automatically directed to the other one.

The new generation of modern Pavian electronic sirens was used as the constituent elements of the warning system, developed by the Telegrafia company and fully satisfying the most challenging criteria. The sirens can communicate with control centres and provide all relevant information on their status and operability. They come up in a bold design and are made of high-quality anticorrosive material. Thanks to low energy consumption and pulse amplification, the sirens are capable of 72-hour operation without power supply. They have excellent acoustic characteristics (300 W to 3000 W) and advantages of traditional loudspeakers, i.e. the capability to reproduce any kind of sound. This is useful for alarm identification; therefore, the sirens can also reproduce live voice to inform the public of the type of alarm and provide further instructions if necessary. They are modular and can serve as monitoring stations as well, monitoring,  for example, chemicals in the air and sending data to the relevant authorities.

The whole warning and notification system is an open system with predefined interfaces for the connection of additional means of communications. The process of its implementation is divided into several phases, and up to now, the following phases have been completed:

  • The warning system designed, including siren types, their arrangement and communications protocols
  • Data transmission and security ensured
  • The infrastructure of warning and notification centres built
  • The siren installation process started
  • The phase of connecting the individual autonomous systems into the centralised national system entered (dam monitoring systems, large industrial plants and others)
city warning system

Benefits for the end user

  • The fully automated system functions with very little manual human intervention
  • The possibility of any siren control from any control point in the system (control centres or manual remote control)
  • More than 72-hour backed-up operation in case of a 230V power supply failure
  • Multi-channel control system with defined priorities (the replacement of one communications channel with another prioritised channel to prevent communication breakdown)
  • Two-way communications between the siren and control centre (real-time siren status information)
  • Optional alarm signals, customised notification messages, and live-voice announcements
  • Automatic data recording and storage
civil protection

The top quality of the SEHIS system and its technological solution was confirmed by Ing. Ján Repa, Director of the Civil Protection Department of the Section of the Crisis Management and Civil Protection o the Ministry of Interior of the Slovak Republic:

 ”The SEHIS system has stood the test of time – it is truly a complex and modern system which has met all of our requirements. Its successful operation has been proved in Slovakia, but not only. It is gradually being implemented in many other neighbouring countries.”

The article was written by

Zuzana Jacova

Zuzana works at Telegrafia at the marketing department. Her main responsibility is to keep an eye on Google Ads and Facebook. Online marketing is changing all the time, giving her the chance to expand her knowledge constantly and put it into real practice. After work, she relaxes best by going to the gym and watching good films.

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