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3G Listening Device with AGC, VOX and 2 microphones
790,00  EUR  ex VAT
987,50  EUR  inc VAT
Not on stock
14 day refund
24 month warranty

This 3G listening unit is one of the most advanced on the market as it features 2 microphones (MEMS and Knowles), has automatic gain control (AGC), and can last up to 150 days in voice-activation mode, as well as 25 days in standby mode. 

The AGC permits for a clearer and more stable sound than already provided by the high-end microphones. The 3G unit has 2 of those; a MEMS and a Knowles microphone. 
One is located directly on the device's circuit board and serves for voice detection, the other one is used as an external microphone that allows for more flexibility in deploying the bug, and of course, serves as the external microphone.  

This unit was specially developed by experts and special forces in the field to be able to offer all the features like the possibility to choose between 2G and 3G, to set password protection if needed, or to set up a master number for the device. The microphones permit a 9-12 m radius, which is more than enough for indoor purposes, due to the sound quality. The AGC built into the unit will only increase this quality as well as the Real-time gain control via DTMF tones. It has 2 noise reduction filters and offers selectable audio sensitivity. 
If you are familiar with Stealth Tronic Bugs, you will know that the voice activation function can be controlled via SMS. This 3G unit permits the control and configuration of a number of functions via SMS: Voice detection, the sensitivity of VOX, battery status, ultra sleep mode, reset to factory settings, the status of the device, password settings, setting the master number, and turning off the LEDs.

The device is built to go into sleeping mode when not used, and this makes the battery last longer. It does not consume power in sleep mode. This permits up to 25 days in standby mode and up to 150 days in voice activation mode. 
This 3G unit can be connected to an electrical network and made to run on a continuous power supply. 

This is the only Bug that will work in the USA, where 2G is not available since 2020.
Find all StealthTronic products at this link.

3G Listening Unit Main Features:

  • AGC (automatic gain control) for a clearer sound
  • Real-time gain control via DTMF tones
  • The device goes in ultra sleep mode when not used, for battery saving, and a long battery life
  • You can choose between 2G and 3G
  • Voice activation mode
  • Smart VOX hanging up protocols
  • Password protection option available
  • Master number setting available
  • 2 microphones: 1x MEMS + 1x KNOWLES

3G Bug Full Specifications:

Number of microphones: 1* MEMS + 1* KNOWLES
Maximum distance from the microphone: 9-12 meters
Non-stop operation when connected to el. networks: Yes
Weight: 75g
Dimensions: 50 x 45 x 12mm
Stand-by: 25 days
Duration of automatic activation mode: 150 days
Durability during continuous interception: 12 to 18 hours
Support for bands: All
Consumption in standby: 3mA
Consumption in: VOX
VOX mode: 3mA; SLP mode: 0.5mA
Talk time consumption: 100 - 150mA
UMTS Release: 99/5 GSM Release/99/4
Supply Voltage Range: 3.3V ~ 4.3V, 3.8V type.
Operation Temperature: -40 °C ~ +85 °C
Weight Approx.: 4.3g
Control via AT commands: 3GPP TS27.007, 27.005, and other
SIM card format: Nano
Antenna: Onboard GSM/UMTS antenna
Microphone: Knowles
Selectable audio sensitivity: yes
Noise rejection filters: 2 filters
Frequency range: 300 Hz to 5 kHz
UC15-E: 900/2100MHz@UMTS / 900/1800MHz@GSM
UC15-A: 850/1900MHz@UMTS / 850/900/1800/1900MHz@GSM
UC15-T: 850/2100MHz@UMTS / 850/900/1800/1900MHz@GSM
HSDPA: Release 5 (category 6)
EDGE: Downlink only
GPRS: Multi-slot Class 12

Picture: Example of setting the VOX sensitivity and password. From user manual.

Feature focus

Sleep Mode for battery saving

The device will turn itself off - it will shut down the connection to the network and wake up in intervals to check if there are new commands. If it receives a command it will wake up and power on. If there are no commands it will power itself off again.

Real-time audio management

By using the DTMF tones, you get several options that enable you to set the microphone to the optimal mode. 
Take note, that testing this in a one-meter radius will not do much, you have to test it to the maximum distance in which the microphone can pick up sound. This is to be considered together with the signal reception, as the sound quality relies on the quality of the available signal. 

Watchdog function

No matter the quality of an electronic device, they all jam sometimes. This is why StealthTronic and experts have implemented a function that eliminates that jamming. When an issue is detected, the device will restart itself, boot itself up again, and continue to work. 

How to start up the device:

First put in the Nano SIM card and afterward the battery, and call the device in 20 sec after that.
Once set up, you can issue the SMS commands. 
Also, take note:
  • The pin code has to be removed from the Nano SIM card
  • There should be funds on the SIM card
  • Always let the device configure after activating it
  • Below is the user manual available for download, with various SMS commands that you can use on the device. 

3G Listening Device FAQs 

Can the 3G Listening Device be connected to a continuous power supply?
Yes, it can be connected to an electrical network for continuous power. This feature allows for long-term monitoring without worrying about battery life, making it ideal for situations where constant surveillance is required. The device’s design accommodates both battery and direct power supply options.

Can the 3G Listening Device be used in the USA?
Yes, this device is compatible in the USA, where 2G networks are no longer available since 2020. It supports both 2G and 3G networks, allowing for flexibility and ensuring it can operate effectively in the United States. This makes it a versatile tool for users in regions where 2G connectivity is phased out.

How can the voice activation function (VOX) be controlled?
The voice activation function can be controlled via SMS, allowing for remote configuration and activation. Users can adjust the sensitivity of the VOX, check battery status, and manage other settings through simple text commands. This feature provides convenience and flexibility in managing the device’s operations from a distance.

How do I start up the 3G Listening Device?
To start the device, insert a Nano SIM card, wait for approximately 10 seconds for it to boot up, and then wait for the unit to send replies, which may take a short amount of time. This simple setup process ensures the device is quickly ready for use. The initial boot-up sequence activates the device’s features and prepares it for operation.

How does the AGC feature enhance the 3G Listening Device’s performance?
The AGC (automatic gain control) provides a clearer and more stable sound. It automatically adjusts the microphone gain to adapt to varying noise levels, ensuring optimal audio quality. This feature, combined with the device’s high-end microphones, ensures superior sound clarity even in fluctuating acoustic environments.

Is it possible to protect the 3G Listening Device with a password?
Yes, the device offers a password protection option. This feature enhances security by preventing unauthorized access and configuration changes. Users can set and manage the password via SMS, ensuring that the device’s settings and data remain secure.

What happens if the 3G Listening Device encounters a technical issue?
The device includes a watchdog function that automatically restarts it if a problem is detected. This self-rebooting feature ensures the device continues to operate smoothly, minimizing downtime and maintaining consistent surveillance. It’s a built-in safeguard against potential device jamming or failures.

What is the battery life of the 3G Listening Device in voice activation mode?
The battery can last up to 150 days in voice activation mode. This extended battery life is due to the device’s ultra sleep mode, which conserves power when the device is not actively being used. The device is designed to consume no power in sleep mode, significantly extending its operational period without needing a recharge.

What is the maximum sound pickup radius of the microphones?
The microphones can pick up sounds within a 9-12 meter radius. This range is sufficient for most indoor environments, ensuring that conversations and sounds are captured with clarity. The device’s advanced microphones and AGC feature contribute to its effective sound pickup capabilities.

What types of microphones are used in the 3G Listening Device?
The device features two types of microphones: a MEMS microphone located on the circuit board and a Knowles microphone as an external option. The MEMS microphone is primarily for voice detection, while the Knowles microphone allows for flexible deployment and enhanced audio capture. This dual-microphone setup ensures comprehensive sound coverage and quality.


The quality of the mobile signal in the place of installation strongly affects the quality of interception.
SIM Card not included, however, all (SIM card) operators are compatible with the device. 
For more information on the setup of the device, take a look at the PDF available for download below. 
24 Months Warranty

>>Download detailed specifications (PDF)<<


Disclaimer: Items on the website are not be used for the purpose of illegal surveillance of unsuspecting subjects. The items are to be used only in compliance with all the local laws and regulations under the threat of penalty.

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