USR IOT USR-GM3 User manual

USR-GM3/GM3s User Manual www.usr iot . c o m
Jinan USR IOT Technology Limited 1 / 55 [e-mail]
USR-GM3/GM3s
USR-GM3/GM3s
USR-GM3/GM3s
USR-GM3/GM3s User
User
User
User Guide
Guide
Guide
Guide
(USR-GM3/GM3s )
File version: Ver1. 08
USR-GM3/GM3s is highly-integrated UART to GSM/GPRS module, Users can easily make
communication between serial device and cellphone and network device with it.
This module is different from the common modules on the market, it is the smallest GPRS DTU,
plug-and-play device. USR-GM3s will be with SIM card inside, more easier to use, it just need
power supply.

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Content
USR-GM3/GM3s User Guide ......................................................................................................................................... 1
Quick Start ......................................................................................................................................................................... 3
1.1. Testing environment ......................................................................................................................................... 3
1.2. Transmission ..................................................................................................................................................... 4
2. Introduction ................................................................................................................................................................... 6
2.1. Short Description .............................................................................................................................................. 6
2.2. Characteristic .................................................................................................................................................... 6
2.3. Features ............................................................................................................................................................. 6
2.4. Application Field ................................................................................................................................................ 7
3. Hardware ....................................................................................................................................................................... 8
3.1. Pin Description .................................................................................................................................................. 8
3.1.1. Outside View .......................................................................................................................................... 8
3.1.2. Pin Assignment （ Top ）....................................................................................................................... 8
3.1.3. PCB Layout ............................................................................................................................................ 8
3.1.4. Pin Description ....................................................................................................................................... 9
3.1.5. Outside Antenna .................................................................................................................................. 11
3.2. Hardware B lock D iagram .............................................................................................................................. 11
4. Module Functions ...................................................................................................................................................... 11
4.1. Work Mode ...................................................................................................................................................... 12
4.1.1. Switching Work Mode ......................................................................................................................... 12
4.1.2. Network transmission ......................................................................................................................... 12
4.1.3. HTTPD Function ................................................................................................................................. 20
4.1.4. SMS Message Transmission ............................................................................................................. 23
4.2. Register Package ........................................................................................................................................... 27
4.2.1. Description ........................................................................................................................................... 28
4.2.2. Usage .................................................................................................................................................... 28
4.3. Heart Beat Package ....................................................................................................................................... 29
4.3.1. Description ........................................................................................................................................... 30
4.3.2. Usage .................................................................................................................................................... 30
4.4. UART ................................................................................................................................................................ 31
4.4.1. RS485 ................................................................................................................................................... 32
4.4.2. Similar RFC2217 ................................................................................................................................. 32
5. Parameters Setting .................................................................................................................................................... 33
5.1. Operating AT command ................................................................................................................................. 34
5.2. AT Command Format ..................................................................................................................................... 35
5.3. AT Command Set ........................................................................................................................................... 37
Appendix A: Contact ...................................................................................................................................................... 54
Appendix B: Disclaimer ................................................................................................................................................. 55
Appendix C: Update History ......................................................................................................................................... 55

USR-GM3/GM3s User Manual www.usr iot . c o m
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Quick
Quick
Quick
Quick Start
Start
Start
Start
This chapter is a quick start guide for using USR-GM3/GM3s module. If it is the first time to
use USR-GM3/GM3s for you, you should read this chapter carefully, and then follow the tips,
try to do some tests by yourself. It will help you to know about USR-GM3/GM3s generally. If
you have experience of using USR-GM3/GM3s, please escape this chapter.
In this chapter, you will be told how to make communication between serial device and TCP
server. Under default setting, GM3 module works in network transmission mode, it connects
to our TCP test server, address is test.usr.cn, port is 2317. The server will respond what it
receives.
All the software used in this document can be obtained from our website www.usriot.com
www.usriot.com
www.usriot.com
www.usriot.com .
You can also access USR customer support center: http://h.usriot.com
http://h.usriot.com
http://h.usriot.com
http://h.usriot.com .
1.1.
1.1.
1.1.
1.1. Testing
Testing
Testing
Testing environment
environment
environment
environment
The voltage of module is TTL 3.3V, so you should not connect it with computer serial port
directly, an adapter is necessary.
NOTE:
NOTE:
NOTE:
NOTE:
1.
1.
1.
1. If
If
If
If it
it
it
it is
is
is
is the
the
the
the first
first
first
first time
time
time
time to
to
to
to use
use
use
use our
our
our
our module
module
module
module for
for
for
for you,
you,
you,
you, please
please
please
please use
use
use
use our
our
our
our EV
EV
EV
EV K(Evaluation
K(Evaluation
K(Evaluation
K(Evaluation Kit)
Kit)
Kit)
Kit) ,
,
,
, it
it
it
it
may
may
may
may save
save
save
save you
you
you
you lot
lot
lot
lot of
of
of
of trouble
trouble
trouble
trouble and
and
and
and time.
time.
time.
time.
2.
2.
2.
2. keep
keep
keep
keep default
default
default
default setting
setting
setting
setting in
in
in
in this
this
this
this test.
test.
test.
test.

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1.2.
1.2.
1.2.
1.2. Transmission
Transmission
Transmission
Transmission
1. Put SIM card into the socket on EV K , connect COM1 to PC ’ s serial port with cable.
2. Open test software ” USR-TCP232-Test ” , set right serial port number and baud rate, and
open it. As the following figure.
3. Power up the EV K with DC 5V adapter, then the POWER led will be on, several seconds
later, the WORK led will twinkle, and then GPRS LINKA led will be on.

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Meaning of led:
POWER
“ on ” means normal power supply, “ off ” means power supply failure.
WORK
“ blink ” means running correctly, “ off ” means not running.
GPRS
“ on ” means attached, “ off ” means attach failure.
LINKA
“ on ” means socket A has connected to server, “ off ” means not connect.
LINKB
“ on ” means socket B has connected to server, “ off ” means not connect.
DATA
“ blink ” means transmission, “ off ” means no transmission.
4. Wait for LINKA led on, send data to module via serial port. For example, if you send
“ www.usr.cn ” , at the same time, the DATA led will be on for a while. Then, you will get
“ www.usr.cn ” in the receiving window from our test server.

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2.
2.
2.
2. Introduction
Introduction
Introduction
Introduction
2.1.
2.1.
2.1.
2.1. Short
Short
Short
Short Description
Description
Description
Description
USR-GM3/GM3s is new listing at 2015, it is one embedded GSM module. USR-GM3/GM3s
is designed for embedded system, it is so small and convenient that you can integrate it to
your system easily.
2.2.
2.2.
2.2.
2.2. Characteristic
Characteristic
Characteristic
Characteristic
Small and completed function GPRS DTU, transmission between serial and GPRS
Support GSM850/900,DCS1800/1900
Support GSM/GPRS/EDGE , support 2G/3G/4G SIM card, but based on 2G network
Support 2 sockets, Support TCP and UDP
4KB cache for each of sockets, user can choose to cache data or not
Support register package and heart beat package
Support setting parameters via SMS message
Support 4 work modes: SMS message transmission mode, network transmission mode
and HTTPD mode
Support basic and extend AT command sets
Support similar RFC2217
Support flow control: RTS/CTS
Support RS485
2.3.
2.3.
2.3.
2.3. Features
Features
Features
Features
Baud rate: 2400, 4800, 9600, 14400, 19200, 28800, 33600, 38400, 57600 115200,
230400, 460800, 921600.
Operating voltage: 3.40V~4.20V
Operating current: average 55mA~80mA, maximum 750mA
Operating temperature: - 25 ~+85 ° C
Storage temperature: -40~+125 ° C
Storage humidity: 5%~95%RH
Max TX power : GSM900 class4(2W)
，
DCS1800 class1(1W)

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2.4.
2.4.
2.4.
2.4. Application
Application
Application
Application Field
Field
Field
Field
In power industry, USR-GM3/GM3s can embedded in the electric meter, power application
terminals and other equipment to realize of reactive power
compensation monitoring, distribution monitoring, meter collection and copy,
street lamp controlling and other applications, to achieve smart city.
In Heating field, USR-GM3/GM3s can be embedded in m-BUS concentrator to achieve the
integration of the concentrator and wireless communication.
In water industry, USR-GM3/GM3s is also plays a significant role in system of water set co
py, water resource management and remote monitoring, wireless communication of water
pipe network monitoring.
In Environmental protection , USR-GM3/GM3s module can be integrated into the on-line
monitoring system of flue gas on-line monitoring (CEMS), water quality online monitoring.
In the field of equipment maintenance ( Equipment maintenance field),USR-GM3/GM3s use
in the system of equipment remote monitoring, such as elevator monitoring, air conditioning
monitoring.
Other GPRS communication applications .

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3.
3.
3.
3. Hardware
Hardware
Hardware
Hardware
3.1.
3.1.
3.1.
3.1. Pin
Pin
Pin
Pin Description
Description
Description
Description
3.1.1.
3.1.1.
3.1.1.
3.1.1. Outside
Outside
Outside
Outside View
View
View
View
3.1.2.
3.1.2.
3.1.2.
3.1.2. Pin
Pin
Pin
Pin Assignment
Assignment
Assignment
Assignment （Top
Top
Top
Top ）

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3.1.3.
3.1.3.
3.1.3.
3.1.3. PCB
PCB
PCB
PCB Layout
Layout
Layout
Layout

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3.1.4.
3.1.4.
3.1.4.
3.1.4. Pin
Pin
Pin
Pin Description
Description
Description
Description
Note: ‘ P ’ for power, ‘ I ’ for input, ‘ O ’ for output, ‘ N ’ for not connect
Pin
Pin
Pin
Pin Name
Name
Name
Name Type
Type
Type
Type Description
Description
Description
Description
1 VCC P
Power supply ，3. 4 V to 4.2V
2 VCC P
Power supply ，3. 4 V to 4.2V
3 GND P Power ground
4 GND P Power ground
5 Reload I Pull-down 1s restore default setting, >3s restore factory setting
6 NC N Keep no connecting
7 RS485 O Control RS485 RX/TX
8 NC N Keep no connecting
9 Reset I Restart , pull-down 1s for restart
10 GPRS O GPRS status, high for attached, low for not attached
11 LINKA O Socket A status, high for connected, low for not connected
12 LINKB O Socket B status, high for connected, low for not connected
13 DATA O Data status, high for transmission, low for not transmission
14 WORK O Running status, high for normal, low for failure
15 SHUT I Shut down, pull - down for shut module
16 NC N Keep no connecting
17 GND P Power ground
18 SPEAKER- O Speaker negative terminal
19 SPEAKER+ O Speaker positive terminal
20 MIC- I Microphone negative terminal
21 MIC+ I Microphone positive terminal
22 VSIM P Power supply for SIM card
23 SIM_CLK O Clock line for SIM
24 SIM_DAT I/O Data line for SIM
25 SIM_RST O Reset line for SIM
26 NC N Keep no connecting
27 HST _ TXD O Upgrade from uart
28 HST _ RXD I Upgrade from uart
29 V_PAD P 2.8V output
30 NC N Keep no connecting
31 NC N Keep no connecting
32 NC N Keep no connecting
33 NC N Keep no connecting

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34 NC N Keep no connecting
35 TXD1 O TX line for uart1
36 RXD1 I RX line for uart1
37 CTS1 O CTS line for uart1
38 RTS1 I RTS line for uart1
39 GND P Power ground
40 GND P Power ground
41 RF O RF output
42 GND P Power ground
3.1.5.
3.1.5.
3.1.5.
3.1.5. Outside
Outside
Outside
Outside Antenna
Antenna
Antenna
Antenna
1. The line of Antenna should be short to make the insert loss lower and routed as RF
line strictly to keep 50ohm matching.
2. It ’ s better to put the antenna pad on the edge of the PCB .
3.2.
3.2.
3.2.
3.2. Hardware
Hardware
Hardware
Hardware B
B
B
B lock
lock
lock
lock D
D
D
D iagram
iagram
iagram
iagram
The interface module provides includes: power input, output, on/off control, reset to restart
control, control, restore the factory Settings, working module, analog audio input, output, UART,
SIM, RF antenna.

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4.
4.
4.
4. Module
Module
Module
Module Functions
Functions
Functions
Functions
4.1.
4.1.
4.1.
4.1. Work
Work
Work
Work Mode
Mode
Mode
Mode
USR-GM3/GM3s module can work in 3 modes
SMS message transmission mode
network transmission mode

HTTPD mode
4.1.1.
4.1.1.
4.1.1.
4.1.1. Switching
Switching
Switching
Switching Work
Work
Work
Work Mode
Mode
Mode
Mode
Choose by button you want to work mode
And then select save all parameters
Can save the default parameters for the user, click on the restart after effective working
mode.
Note: if you can't find the above tool buttons please refer to the picture's position on the
drive, you can see the hidden button

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4.1.2.
4.1.2.
4.1.2.
4.1.2. Network
Network
Network
Network transmission
transmission
transmission
transmission
4.1.2.1.
4.1.2.1.
4.1.2.1.
4.1.2.1. Description
Description
Description
Description
Under this mode, customer ’ s serial device can send data to TCP or UDP server via this
module, Module can also receive data from server, and transmit the data to customer ’ s
serial device.
Customers don ’ t need to know the detail of communication, just need some simple setting.
GM3 support 2 sockets, socket A and socket B, they are standalone with each other. GM3
only supports TCP Client and UDP Client.
4.1.2.2.
4.1.2.2.
4.1.2.2.
4.1.2.2. Application
Application
Application
Application Scenarios
Scenarios
Scenarios
Scenarios
If user want to make communication between serial devices and devices on the network,
but in the place where serial device stays using router to connect to network is not
convenient for user. But signal from base station is available, so GM3 module can build a
bridge between serial device and devices on the network .
4.1.2.3.
4.1.2.3.
4.1.2.3.
4.1.2.3. Usage
Usage
Usage
Usage
Note: All the AT commands terminate with carriage return(0x0D), we ignore it here.
About how to use AT commands, please refer to chapter 5.
We have one software for customers to use , customers can get it from our
website: http://www.usriot.com/Download/248.html.
http://www.usriot.com/Download/248.html.
http://www.usriot.com/Download/248.html.
http://www.usriot.com/Download/248.html.
And we have one software for customers to do serial and network tests, customers can get
it from our website: http://www.usriot.com/Product/78.html
http://www.usriot.com/Product/78.html
http://www.usriot.com/Product/78.html
http://www.usriot.com/Product/78.html .
TCP/UDP
data
Serial dataGM3
TCP/UDP
data
Internet
PC
Serial device

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1. Set TCP server software, log in remote server via remote desktop connection.
Then open network test software, set the parameters as the bellowing.

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2. Set Module Parameters
1) Set work mode as network transmission
2) Enable socket A
3) Set socket A as TCP client, server address is test.usr.cn(domain), server port is 10000 .
3. Restart GM3, wait the connection of socket A has been established, send data to
module via serial port, then you will get data at network server software. And send data
to module via network, then the data will be got at module serial port.

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4.1.2.4.
4.1.2.4.
4.1.2.4.
4.1.2.4. Special
Special
Special
Special Type
Type
Type
Type Of
Of
Of
Of Sending
Sending
Sending
Sending Command
Command
Command
Command
Besides under “ AT command mode ” , customers can also send At commands under network
transmission mode via serial or network. This kind of commands is different from common ones,
customers should add command password and # at the front of common command string,.
Note: every command string should terminate with carriage return. Here we use [0D].

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4.1.2.4.1.
4.1.2.4.1.
4.1.2.4.1.
4.1.2.4.1. Serial
Serial
Serial
Serial AT
AT
AT
AT Command
Command
Command
Command
1. Set work mode as network transmission.
2. Enable serial command function.
3. Query command password.
After setting successful, restart GM3, then send “ usr.cn#AT+VER ” via serial.
Then GM3 will respond the firmware version.

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4.1.2.4.2.
4.1.2.4.2.
4.1.2.4.2.
4.1.2.4.2. Network
Network
Network
Network AT
AT
AT
AT command
command
command
command
1. Enable network command function.
2. Query command password.
Besides, customers need to configure socket A or socket B for network connection, refer to

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chapter 4.1. 2. 3. After setting successful, restart GM3. When connection is establishing,
send “ usr.cn#AT+VER ” from network.