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InDTU332G Industrial Cellular Modem
Reliable Serial to GSM/GPRS Communication

The InDTU332G cellular modem provides wireless data communications between field serial devices and the central control system to enable remote control of industrial field sites.

Featuring rugged design, high reliability and easy-to-use features, the InDTU332G is ideal for M2M and IoT applications including distribution automation, smart metering, water & wastewater, heating, street light monitoring and etc. It will be available with LTE CAT M1 and NB-IoT soon. 

Overview Applications Specifications Documentation Part Numbers
Industrial Design


Industrial-grade chip of ultra-low power consumption, adaptable to various power supply modes 

Wide operating temperature: -40°C~70°C

Wide voltage input: 5~35VDC 

Solid housing, IP30 protection 

Compact-sized, easy to fit and integrate 

CE, FCC certified

Highly-reliable Wireless Communications

Self-recovery: embedded watchdog, self recover from faults, ensuring normal operation of the device

● Link redundancy: SMS and GPRS link mutual backup to ensure continuous data transmission

● Link detection: multi-layer link detection mechanisms including PPP layer heartbeat, ICMP detection, TCP Keepalive and application layer heartbeat, keeping wireless connection "always on"

Easy and Flexible to Manage

Support configuration software login via local serial port

Support RTOOL remote configuration over TCP/IP

Support remote batch management via InHand Device Manager cloud

 Support SMS configuration (coming soon)

Rich Functions for Intelligent Solutions

● Modbus RTU/Modbus TCP protocol conversion for industrial SCADA systems and field devices 

Support IEC101/IEC104 conversion (coming soon)

● Support transparent TCP/UDP protocol

● Support InHand DC protocol

● Support user-defined TCP/UDP hearbeat and login data 

● Support multi-center, 1-5 centers

InDTU332G Specifications
Network Connection
Internet Access



Network Type

Quad-Band GSM 850/900/1800/1900 MHz

Network Protocol

Network Protocol

Ping, DNS, transparent TCP/UDP, InHand DC TCP/DC

UDP, user-defined login/heartbeat data packet

Protocol Conversion

Modbus RTU/TCP protocol conversion

Network Security

Multi-level Authorization

User levels: administrator, maintenance staff

Certification Security

Support login security certification


Reliable Upgrade

Patent upgrade mechanism, ensures reliable upgrade

Link Connection Detection

Send heartbeat packet detection, auto connect once disconnected

Embedded Watchdog

Device operation self-detection technology, and self-recovery from operation faults

Network Management

Configuration Method

Support configuration via local serial port, support RTool, Device Manager "Device Cloud" platform remote configuration

Configuration Backup

Support import and export of configuration files

Upgrade Method

Patent upgrade mechanism, upgrade firmware through local serial port or remotely


Support local and remote viewing of logs, facilitate engineers to check device operating status


Data activation, SMS activation, timed on/off

Network Management

Support InHand Device Manager remote central management


Serial Port

2 x Logic serial ports:
Serial port 1: RS-232/485 (Optional)
Serial port 2: RS-232

RS-232 signal: TXD, RXD, GND
RS-485 signal: 485+, 485-, GND

8 PIN industrial terminal, 3.81mm pitch

SIM Card Slot

1.8V/3V, drawer-type slot x 1


50Ω / SMA x 1

Mechanical Properties








ABS engineering plastics

Power Supply

Power Input


Power Interface

Pluggable industrial terminal connection

Polarity Reverse Protection


Overload Protection



Operating Temp.

-40 ~ 70℃

Storage Temp.

-40 ~ 85℃

Ambient Humidity

5 ~ 95% (non-condensing)

LED Indicators



EMC Index


EN61000-4-2, level 3


EN61000-4-5, level 3

Shock Wave ImmunityEN61000-4-12, Level 3



Part Numbers    



Quad-Band GSM 850/900/1800/1900 MHz                  



Quad-Band GSM 850/900/1800/1900 MHz                        

Models available with LTE CAT M1 and NB-IoT coming soon.
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