EAO Schweiz AG / Wed 23.03.2022

New Series 57 Multi-Tone Warning Indicator.

Audible warning and LED status indication combined in a single compact device.

Olten, Switzerland, November 2021 – EAO has expanded its globally recognised Series 57 to include another innovative product in the form of the multi-tone warning indicator. Safety has absolute priority when it comes to opening and closing doors in public transportation. This also has an impact on accessibility issues – whether for facilitating passenger entry on trains, trams, bus or for public use emergency call and call-for-aid systems. Users can depend on both the audible and the visual warnings provided by the Series 57 multi-tone warning indicators (MTWI).

Typical applications

  • Passenger access to trains, trams, bus
  • Emergency call and call-for-aid systems
  • Access control systems
The Series 57 MTWI uniquely combines two rail industry established HMI functions into one singular compact device – the Series 56 multi-tone sound module and the Series 57 warning indicator. This provides additional advantages and enhances safety in public transportation, especially for people with visual impairments. Passengers are intuitively warned about potential dangers thanks to the loud, audible warning signal and the LED status indicator visible from any angle.


  • Audible and visual warning in a single device
  • A single cable for space and cost savings in mounting
  • Modern, timeless design of Series 57
  • Long service life and attractive total cost of ownership
  • Intense 180° illumination
When the train door is opened, green LEDs steadily illuminate or flash (must be controlled externally). At the same time, the door opening audio signal will sound to provide an additional acoustic warning. As soon as the door closes, the red LEDs illuminate (or flash) and the “door closing” signal can be heard clearly. Choices in LED colours and combinations are available and can be tailored to meet the specific application requirements (e.g. TSI PRM). Additionally, for emergency call system announcements, a passive speaker module variation is available that can be connected to an external signal source and amplifier.

Read more on www.eao.com/57-mtwi
  • Swissrail Industry Association
  • Taubenstrasse 32
  • CH-3011 Bern

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