The built-in receiver in the Bowl II acoustic safe, in standby mode, constantly compares the level of the background electromagnetic field with a pre-set threshold level of the electromagnetic field in the device. If an incoming call is received on a mobile phone placed inside the device or if it is unauthorized activated for information transmission, the electromagnetic field intensity near the phone increases sharply. If the threshold level is exceeded, an acoustic noise generator is automatically activated in the acoustic safe, its speaker located inside in close proximity to the mobile phone’s microphone.
The level of acoustic noise at the microphone input is such that it reliably ensures the jamming of the mobile phone’s acoustic channel. This same acoustic noise also serves as a signal to the phone’s owner that their mobile phone is active. After the incoming call ends or the session of unauthorized activation of the mobile phone is completed, the electromagnetic field intensity near the phone drops below the threshold level, and the Bowl II returns to standby mode.
Additionally, the device implements the ability to protect confidential speech information from its unauthorized transmission via DECT wireless communication technology. The device’s operating principle in the DECT range is similar to that in the cellular ranges.
Technical Specifications
| Specification | Details |
|---|---|
| Monitored Ranges | GSM (2G) – 900/1800 MHz UMTS (3G) – 900/2100 MHz LTE (4G) – 800/1800/2500 MHz DECT – 1880/1900 MHz |
| Noise Level at the Mobile Phone Microphone Location | not less than 100 dB |
| Effective Noise Signal Spectrum | 250 – 4000 Hz |
| Device Power Supply | from built-in battery, power adapter |
| Continuous Operation Time from Fully Charged Battery | not less than 40 hours |