USR-GM3 Low Power GSM GPRS Module

USR-GM3 is highly-integrated Low Power GSM GPRS Module, used for data transparent transmission.

  • SMD Type
  • Operation temperature Range of -25° ~85°
  • Quad-Band GSM/GPRS 850/900/1800/1900MHz

Introduction of Low Power Gsm Modules

The Low Power Gsm Modules, used for data transparent transmission. USR-GM3 is highly-integrated UART to GSM/GPRS module. Users can easily make communication with it among serial device, cellphone and network device. USR-GM3 is an embedded GSM module. It is designed for embedded system, and it is so small and convenient that you can integrate it to your system easily.

Features of Low Power Gsm Modules

  • Small and completed function GPRS DTU, transmission between serial and GPRS
  • Support GSM850/900,DCS1800/1900
  • Support GSM/GPRS and 2G/3G/4G card, but don’t support 3G/4G network
  • Support 2 sockets, Support TCP and UDP
  • 4KB cache for each of sockets, user can choose to cache data or not
  • Support register packet and heartbeat packet
  • Support setting parameters via SMS message
  • Support 3 work modes: SMS transmission mode, network transmission mode and HTTPD mode
  • Support basic and extend AT command sets
  • Support class RFC2217, can dynamically modify serial parameter of module via network
  • Support flow control: RTS/CTS
  • Support RS485

Function of Low Power Gsm Modules

Structure of Low Power Gsm Modules

Unique Features of Low Power Gsm Modules

When USR-GM3 module works as TCP CLIENT, and after TCP connection is established, module will automatically send scheduled register packet to help TCP Server identify the TCP connection. Register packet includes IMEI code, ICCID code and user-defined register data.

USR-GM3 GPRS module can send heartbeat packet to network server and serial device in network transmission mode. GPRS module maintains the normal connection with server by keeping sending serial heartbeat packet. Serial heartbeat packet is mainly applied to sensors which can not actively send data to server. And serial heartbeat packet can realize real-time monitoring of sensor device.

LBS base station location can get location information of USR-GM3 by mobile network.

Socket b function is suitable for such requirements as sending data to two servers, data backup and remote abnormality diagnosis.

USR-GM3 connects with FTP server to remotely upgrade user’s devices such as charging pile, instruments and remote POS machine. Only custom firmware has this function.

Application Field of Low Power Gsm Modules

Agricultural IOT Environment Monitoring Solution

Charging Pile Data Real-time Transmission Solution

City Bus Real-time Data Acquisition Solution

Remote POS Online Payment Solution

Image of Low Power Gsm Modules



14.4 Kbps ~ 57.6 Kbps

Standard Frequency Range

GPRS Multi-slot Class GPRS Class 10
GPRS Terminal Device Class
Class B

GPRS Coding Schemes CS1 ~ CS4
Max Launch Power
GSM900 class4 (2W), DCS1800 class1 (1W)

GSM standard AT instruction set / USR extension AT instruction set / data transmission / SMS transmission

Network Protocol

Network Link Count 2
Network Buffer Send: 4K bytes, receive: 4K bytes
Port Number 1
Interface Standard
TTL: SMT 2.8 ~ 3.6 V
Data Bits
5, 6, 7, 8
Stop Bit 1, 2
Check Bit None, Even, Odd
Baud Rate2400 bps ~ 921600 bps
Flow Control CTS/RTS
BufferReceive and send 4K bytes respectively
Device Interface

SIM Card 1.8V / 3V
Speech Interface 1 channel MIC input, 1 channel SPEAK output
Virtual Serial(USR-VCOM) Windows 2000 or higher (32 bit/64 bit)
Configuration Serial AT command, SMS AT command, network AT command
Basic Parameter
Size 27.9 x 24 x 3 mm
Operating Temp. -25 ~ 85°C
Storage Temp. -40 ~ 125°C, 5 ~ 95% RH(no condensation)
Input Voltage DC 3.4 ~ 4.2V, recommend: 3.8V
Working Current Average: 55 ~ 90mA; Max: 750mA
Warranty2 years

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