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OTP-C4G-VD Voice remote monitoring DIY Module

4G GSM Listening device

This is a voice remote monitoring DIY module equipped with a SIM card that supports 4G+2G networks. It is designed for use in Europe, the Middle East, Africa, Korea, Thailand, New Zealand, Australia, South America, and North America. The module does not have a voice recording function, but it allows live monitoring of any sound around the device through a phone.

Key Features:

  1. Voice-Activated Start Voice Monitoring: When the system detects any sound, the device automatically dials the master number (your phone number), enabling you to remotely listen to voices or conversations.
  2. SMS Alarm/Phone Call Alarm: The device sends SMS alerts or makes phone calls to notify you of specific events. You can also turn the alerts on or off using SMS commands.
  3. Noise Reduction: The module features HD sound monitoring and takes advantage of the full 4G network, ensuring high-quality audio.
  4. DIY Small Module & Long Battery Life: The module is compact and can be placed anywhere. It is powered by a rechargeable 1200mAh battery, providing approximately one week of standby time.
  5. Long-Distance Voice Monitoring: The module supports long-distance voice monitoring, with a range of up to 20 meters.

Command List:


How to Rest>>>

1, Quickly click the device button 7 times

2, You will see the Red Indicator keeping on and goes blinking, quick blinking

3, Waiting for Red Indicator off, then restart the device and configuration it by SMS again


Video guide:


>>>Set Master Phone Number

Customer’s phone: Admin call me

Device’s reply: Call me success!Setting call no1: to 079*******

>>>Delete Call Number

Customer: del 079******

Device: del "079******" success



>>>Pass word setting


Customer: Password 123456

Device: Password set to 123456 success

(the password with more than 6 digits)

  >>>Alarm Mode

 Customer: Call on

Device: Call on success


Customer: Call off

Device: Call off success


Customer:message on

Device:message on success


Customer:message off

Device:message off success

  >>>Sound Sensitivity (H: High sensitive, M: Middle, L: Least sensitive, Default: L)

 Customer: Voxsens L

Device: Voxsens set L success


Version A: Europe, Middle East, Africa, Korea, Thailand

LTE-FDD: B1/B3/B5/B7/B8/B20

GSM: 900/1800MHz

Version B: Australia/New Zealand/South America

LTE-FDD: B1/B2/B3/B4/B5/B7/B8/B28/B66

GSM: 850/900/1800/1900MHz

Version C: Global Network Support

LTE-FDD: B1/B2/B3/B4/B5/B7/B8/B12/B13/B18/B19/B20/B25/B26/B28/B66/

LTE-TDD B38/B39/B40/B41

GSM/GPRS/EDGE: 850/900/1800/1900 MHz

Package List:

1* Main Device 4G

1* SIM Card Kits

1* English User Manual

1* Box