Industrial 3G Modem with RS-232 and USB interface


Industrial 3G Modem with RS-232 and USB interface


  1. Industrial design, making it a reliable cellular solution for data collection and transmission.
  2. Reliable GSM/GPRS/EDGE/WCDMA/HSPA network connectivity, providing fast and cost-effective long-range wireless applications.
  3. Designed for Data, SMS and Voice Applications.
  4. Support TCP Server, TCP Client, UDP Client Connection stack.
  5. Support Standard AT Commands.
  6. A Digital Input Channel for Resetting the System.
  7. LED Indicators for 2G/3G and Power Indication.
  8. High Reliability in Harsh Environment.
  9. RS-232 Port Supports 9600 bps to 115200 bps.
  10. USB 2.0 high speed.
  11. USB Driver for Windows, LinPAC (Linux 2.6).
  12. Mount Easily on DIN-Rail.


The GTM-203M-3GWA is an industrial Quad-band 3G WCDMA cellular modem with RS-232 and USB interfaces working on frequencies of Quad-band WCDMA 850/900/1900/2100 MHz, and Quad-band GSM 850/900/1800/1900 MHz. The GTM-203M-3GWA enables internet connection over 3G, when 3G service is available.

It automatically selects 3G or GPRS continue to work. Moreover, the GTM-203M-3GWA has the integrated TCP, UDP/IP stack so that even simple controllers with serial communication ports can be connected to the modem without the need for special driver implementation. With the features of GTM-203M-3GWA, the systems can be SMS and 3G/GPRS connection applications with various PLC and PC.


  • Remote Data Monitor and Control.
  • Water, gas and oil flow metering and schedule.
  • Power station monitoring and control.
  • Oil field, weather forecast, environmental protection, street lamp monitoring and control.
  • Fleet management.
  • Vending machine.
  • Vehicle logistics and diagnostics controlling.


  • ANT-421-05
LED Indicators
Status 1 x Power
1 x 3G/GSM
2G System
Data Transmission Rate GPRS
Downlink transfer: Max. 85.6 kbps; Uplink transfer: Max. 42.8kbps
Frequency Band 850/900/1800/1900 MHz
Coding Schemes CS 1, CS 2, CS 3, CS 4
Downlink transfer: Max. 9.6 kbps; Uplink transfer: Max. 9.6kbps
GPRS Multi-slot GPRS class 12; GPRS station class B
Power Class Class 4 (2 W @ 850/900 MHz)
Class 1 (1 W @ 1800/1900 MHz)
SMS Format Sending: UCS2/7bits
Receiving: UCS2/7bits
3G System
Data Transmission Rate HSPA
Downlink transfer: Max. 7.2 Mbps; Uplink transfer: Max 5.76 Mbps
HSDPA Max. 7.2 Mb/s
WCDMA Max. 384 kb/s Download/Upload link
Frequency Band WCDMA 850/900/1900/2100 MHz
Power Class Class 3 (250mW @ WCDMA/HSPA)
SMS Mode MT, MO, CB, Text and PDU mode
Reset Input
Type Isolated, 3750 Vrms
ON Voltage Level +3.5 VDC ~ +30 VDC
OFF Voltage Level +1 VDC max.S41
Input Impedance 3 kΩ, 0.25W
COM Ports
Ports 1 x RS-232 (RxD, TxD, GND)
Baud Rate 9600 bps ~ 115200 bps (default:115200 bps)
Specification USB 2.0 (high speed)
Driver Windows XP/Vista/7/8/Server 2012
Casing Metal
Dimensions (mm) 28 x 78.5 x 100 (W x L x H)
Installation DIN-Rail
Operating Temperature -25℃ to 70℃
Storage Temperature -40℃ to 80℃
Humidity 5~90% RH, non-condensing
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