The Stealth DNG-2300
Digital white-noise generator

The OMS-2000 omni-masking speakers can also be used with the DNG-2300. Their purpose is to produce non-filterable noise in spaces like ventilation shafts, behind ceiling tiles, etc.

The DNG-2300 generator has been created to protect against listening devices which cannot be discovered by common methods. The unit protects a room by inducting non-filterable noise onto surfaces. This noise, also known as 'white' noise, is transmitted onto surfaces with the help of the TRN-2000 transducers and OMS-2000 speakers in the unit. The number of transducers and speakers is dependent on the room's configuration.

Thanks to the TRN-2000's transducers the protection level of the generator is higher than systems which only have speakers. The transducers pass most of the generated noise into the desired construction in the form of vibration while producing less audible interference. Although a slight noise may be heard inside the protected area there will be no need to raise your voice.

DNG 2300 protects from:

  • Laser and microwave surveillance systems using reflections from windows
  • Electronic stethoscopes (contact microphones)
  • Microphones built in the walls or other constructions
  • Other vibro-accousic methods of information leakage

How the eavesdropping works

Vibration-acoustic leakage is possible thanks to the ability of sound waves to penetrate walls, windows and other constructions. In some materials sound travels even better than in air. For example, water is a great conductor of sound and a heating system can be easily used for picking-up peoples' speech. This principal is used in electronic stethoscopes. They pick up vibra- tions caused by conversations on walls, windows and other constructions and transform them back into sound. These eavesdropping devices can be installed, not only in the adjacent premises, but even over a number of floors or rooms which are somehow connected to the target area - by mutual cavity or construction.

Principal of protection

The DNG-2300 can 'block' the above methods. This is carried out with the help of special transducers. It is recommended to use the REI's TRN-2000. Their parameters are optimal for many kinds of surfaces. The TRN-2000 are very efficient which means that only an insignificant part of the produced noise will be let into the air, while most of it will be 'injected' into the construction in the form of vibration. With the help of the bracket the transducers can be mounted onto practically all kinds of surfaces.