A7672S 4G LTE / 2G / GPRS / GNSS* /GPS* Modem (USB / UART)

 

Overview

 

This A7672S Based 4G LTE /2G / GPRS /GNSS* / GPS* Modem with UART / USB communication options, is a high quality commercial and industrial grade product from rhydoLABZ, which is professionally designed with impedance matching RF PCB designs and, is built with IoT/M2M-optimized Multi-Band LTE module from SIMCOM. This Modem will automatically fallback to 2G mode in the absence of 4G Network , which will enable you to use it across the entire country including remote villages where 4G towers are less populated . Since this modem supports GNSS* ,customer can make use of Geo Location identification using  (GPS, GLONASS) Satellite networks.

Note: This SIMCOM A7672S UART /USB modem support VoLTE , which will enable you to use JIO sim card on it.
Made in INDIA: The Modem is manufactured in fully automatic SMT production line at our own factory in INDIA. It is not a student grade low quality product or low cost china make products available in the market. It is designed and manufactured for industrial and commercial use .

 

* There are two versions of this modem are available with us. One with GNSS(GPS ) option and other without GNSS . So while placing order select proper version .

 

What's On Board

 

  1. LED Indicators
  2. K8 RMC Connector for Power
  3. K11 Serial Comm. RMC Connector
  4. K9 Serial Comm. Status & Control RMC Connector
  5. Modem Status & Control Pins RMC Connector
  6. Micro SIM  Socket
  7. USB Micro B Connector for Communication
  8. Audio Connector Option
  9. Audio Headphone Jack (3mm)
  10. Debug /Log Output Pins Connector Option
  11. UFL Connector for GPS Antenna
  12. UFL Connector for Main 4G LTE Antenna
  13. Main 4G LTE Antenna SMA Connector
  14. LDO 3Amp Voltage Regulator

 

  1. J5 PCB Jumper
  2. GNSS / GPS LDO Voltage Regulator IC
  3. J4 PCB Jumper
  4. J3 PCB Jumper
  5. J1 PCB Jumper
  6. J6 PCB jumper

 

 

Modem Basic Specifications

 

Communication Module * SIMCOM A7672S-FASE or  A7672S-LASE Module
Communication Network Supported 4G LTE, 2G, GPRS 
GNSS (GPS) Support * Included (External Active Antenna included) *
VoLTE Supported  Yes
Power Supply  5V – 13V DC
Current Requirement 300mA Normally (Peak up to 2Amp)
Modem Interfaces Serial UART , USB 
SIM Card Micro SIM (PUSH-PULL Type)
Normal Operation Temperature -40°C ~85°C
Serial UART Baud rate Supported  From 300bps to 3686400bps ( 115200bps is Default)

 

Outer Dimension of the Board

 

 

Connectors onboard

 

Connector Name Connector Details
K1* UFL Connector for GPS External Antenna (Active or Passive) *
K2 UFL Connector for 4G LTE Main Antenna 
K3 Micro SIM Card Slot
K4 Modem Control & Status Interface
K5 Debug Pins
K6 USB Communication Interface
K7 N/A
K8 Power Supply Input
K9 UART Communication Hardware Handshaking Pins for Advanced user
K10 Audio Pins (Mic & Ear Phone)
K11 UART Serial Communication Interface 
K12 Headphone Jack

 

 

 

Pin Functions

 

Connector PIN  Name I/O Functions
K8
K8 1 VCC Power Positive Power Input (5V-12V) DC Voltage
2 GND Power Negative Power Input (Ground)
K11
K11 1 V-INT Power Pin should be provided with required interfacing Voltage level. (Min 2.5V – Max 5V). Suppose user wants to interface modem with external 5V Microcontroller, then this pin should be supplied with 5V, incase of user want to interface with 3.3V Microcontroller , pin must be supplied with 3V3 , so on…
2 RXD D.Input UART Receive input PIN (Voltage level depends on V-INT Pin)
3 TXD D.Output UART Transmit output PIN (Voltage level depends on V-INT Pin)
4 GND Power Ground Return path for communication interface.
K4
K4
 
1 ON/OFF D.Input This PIN used to turn ON  or turn OFF modem power by Disabling EN pin of the internal Voltage Regulator IC. User can select either Automatic Mode or Manual mode powering option by Jumper J3. By default the PCB jumper J3 is Open and the Modem is in Automatic Powering mode. ie. once powered, Modem turned ON itself. If user wants to control the powering of the Modem manually , then the jumper should be Short and to turn ON the modem, user has to pull down  ON/OFF input. if unused, keep it Short.
2 PKEY D.Input Used to start and stop the modem by External microcontroller. Modem can start /stop automatically on powering or manually using this pin. A PCB jumper (J4) is provided to select this options. By default this jumper is shorted to start the Modem automatically on powering. User can remove the soldered jumper (J4) and control the modem using this pin.
In manual mode, Modem can be started by applying a HIGH level pulse having a width of more than 1 Second on this Pin and later can be stopped by applying again High level pulse having a width of more than 1 Second.if unused, keep it open.
3 RST D.Input Modem can be reset by applying HIGH level pulse having a width of minimum 500 milli second. if unused, keep it open.
4 N/C    
5 STS D.Output It is Modem status output. It is internally pulled up to V-INT voltage level using 10k Resistor. if unused, keep it open.
6 N.LIGHT D.Output It is GSM Modules NET-STATUS pin, voltage level inverted by a internal transistor. Indicate network activity status. Collector of this transistor is connected to internal LED (N-LED) and directly shared with this pin to connect external circuitry or LED through a current limiting resistor. if unused, keep it open.
K10
K10
 
1 MIC- A.Input Mic Input Negative Pin
2 MIC+ A.Input Mic Input Positive Pin
3 EAR- A.Output Earphone Output Negative Pin
4 EAR+ A.Output Earphone Output Positive Pin
K9
K9
 
1 DTR D.Input Data terminal ready, sleep mode control pin of the GSM Module , routed after voltage level conversion. Maximum input voltage HIGH level should be same as V-INT pin voltage. if unused, keep it open.
2 RI D.Output Ring indicator Pin of the GSM Module, routed after voltage level conversion. Maximum output voltage HIGH level will be same as V-INT pin voltage. if unused, keep it open.

 
3 DCD D.Output DCD (Data carrier detection) pin of the GSM Module,routed after voltage level conversion.Maximum output voltage HIGH level will be same as V-INT pin voltage. if unused, keep it open.
4 CTS D.Output CTS (Clear to send ) pin of the GSM Module,routed after voltage level conversion.Maximum output voltage HIGH level will be same as V-INT pin voltage. if unused, keep it open.
5 RTS D.Input RTS (Request to send) pin of the GSM Module,routed after voltage level conversion.Maximum input voltage HIGH level should be same as V-INT pin voltage. if unused, keep it open.

 

#1: This pin is directly connected to the GSM Module, not used any voltage level conversion or current limiting in between and input/output voltage HIGH level is 1.8V. Care must be taken while using this pin to avoid damage to the GSM Module. If unused, keep it open

 

Jumpers Onboard

 

Jumper  Type Default Function
J1 PCB Jumper Short Used to connect and disconnect 3V3 DC Voltage to GPS antenna connectors. For GPS active antenna this jumper should be shorted and for passive patch antenna it should be kept open.
J5 PCB Jumper Open Jumper 3 is used to select manual or automatic power controlling of the modem. By default it is open and in automatic mode ON Mode,which enable the modem to turn ON instantly upon applying the power to VCC pin. Even in this Automatic ON mode , you can control the Modem VBAT power by ON/OFF Pin on K4 connector. 

 

In order to turn ON/OFF modem manually by external microcontroller/circuit keep this jumper short. If the jumper is shorted , modem power will be OFF , until the your microcontroller boots ,starts your application  and pulling down the pin ON/OFF of K4 connector.

J3 PCB Jumper Short It is used to ground the PKEY pin of the A7672 module permanently, which wil enable automatic starting of the modem on powering. If user would like to control the modem by manually ,either by provided SMD Tactile switch SW1 or by host microcontroller via GPIO pin, this jumper should be kept open. 
J4 PCB Jumper Open Used to put the gsm module in USB Boot mode.
J6 PCB Jumper Shorted to 3V3 Jumper option to select GPS voltage source . Can select either 2V8 from Module internal Regulator or 3V3 from external LDO Regulator. 

 

 

Network Connection Status/Activity LED Indicator

 

Name Logic Level Changes Status

NET(NETLIGHT) (4G LTE Mode)

OFF Power OFF / Sleep
800ms ON ,800ms OFF Network Registered
200ms ON , 200ms OFF Data transfer is ongoing
Always ON Searching Network
PWR (Power ON LED) Always high Power LED will ON once the MODEM Power Turned ON.  
STS (Status)  Always high Once modem starts this LED will be ON

 

 

 

Getting  Started


 

Test the Modem out of box using MODEM USB port.
  1. Insert Micro SIM card to SIM card holder provided on bottom of the Board. Please ensure the direction of SIM Notch is same as the image shown nearby.
  2. Connect Provided LTE Antenna to the SMA/UFL Connector marked "MAIN" on the modem. #2
  3. Connect GPS Antenna* to the connector marked K1.
  4. Connect Micro-B USB cable to the modem (K6) from Computer.
  5. Connect DC Power supply to the connector K8.(Ensure Polarity)
  6. When the modem is successfully powered-up, the PWR LED (Red) on the modem will be ON, the STS LED(GREEN) will light after 1-2 seconds and the NET LED(BLUE) will blink every second. After the Modem registers in the network (takes between 10-60 seconds), this LED will blink in step of 800 milli seconds.
  7. Open Serial Monitor Software and select respective COM Port (AT Port) and other settings on Computer as below. #3
    Default Setting are Baud rate :115200, Data bits:8 , Stop bit:1 and Parity:None
  8. ​AT<CR><LF>
    Now type and send simple attention command, "AT" followed by Carriage Return("/r") and New line ("/n") Character by expecting "OK" from the modem.
    Some of the Serial Monitor software will automatically append this Carriage Return/New line Character automatically or you have to add it asap.
    Once you got "OK" from the modem, all set and we can proceed with other commands…
  9. ATE0<CR><LF>
    To Turn OFF the Echo send by modem , we can issue "ATE0" followed by CR and LF.
  10. AT+CREG​?<CR><LF>
    Now we have to check whether the Modem is registered successfully with the SIM Provider Network by sending AT+CREG? followed by CR and LF. 
#2: Never use modem without connecting Main Antenna. This may damage the 4G Module.
#3: User can use any available Serial Port Software like DOCKLIGHT, REAL TERM, HYPER TERMINAL or QCOM from Quectel (included in the downloadable Driver zip file)

 

 

Test the Modem using USB to Serial Converter board.
  1. Insert Micro SIM card to SIM card holder provided on bottom of the Board. Please ensure the direction of SIM Notch is same as the image shown nearby.
  2. Connect Provided LTE Antenna to the SMA Connector marked "MAIN" on the modem. #2
  3. Connect GPS Antenna to the connector marked K1.
  4. Connect UART Connector K11 to the USB to Serial Converter board using provided RMC Connector Cable as per below image.
  5. Connect the USB Converter to the Computer and Install the required USB Driver for the Converter board ( if not installed)
  6. Connect DC Power supply to the connector K8.(Ensure Polarity).
    You may be able to power the modem from USB to Serial Converter board's VCC Out pin also. But this entirely depends on the Computer's USB port capability.(Not guaranteed and Recommended)
  7. When the modem is successfully powered-up, the PWR LED (Red) on the modem will be ON, the STS LED(GREEN) will light after 1-2 seconds and the NET LED(BLUE) will blink every second. After the Modem registers in the network (takes between 10-60 seconds), this LED will blink in step of 800 milli seconds.
  8. Open Serial Monitor Software and select respective COM Port (AT Port) and other settings on Computer as below. #3
    Default Setting are Baud rate :115200, Data bits:8 , Stop bit:1 and Parity:None
  9. ​AT<CR><LF>
    Now type and send simple attention command, "AT" followed by Carriage Return("/r") and New line ("/n") Character by expecting "OK" from the modem.
    Some of the Serial Monitor software will automatically append this Carriage Return/New line Character automatically or you have to add it asap.
    Once you got "OK" from the modem, all set and we can proceed with other commands…
  10. ATE0<CR><LF>
    To Turn OFF the Echo send by modem , we can issue "ATE0" followed by CR and LF.
  11. AT+CREG​?<CR><LF>
    Now we have to check whether the Modem is registered successfully with the SIM Provider Network by sending AT+CREG? followed by CR and LF. 
#2: Never use modem without connecting Main Antenna. This may damage the 4G Module.
#3: User can use any available Serial Port Software like DOCKLIGHT, REAL TERM, HYPER TERMINAL or QCOM from Quectel (included in the dowloadable Driver zip file)

 

 

Test the Modem using Arduino UNO Board. (Basic/Simple 4 wire Connection)
  1. Insert Micro SIM card to SIM card holder provided on bottom of the Board. Please ensure the direction of SIM Notch is same as the image shown nearby.
  2. Connect Provided LTE Antenna to the SMA Connector marked "MAIN" on the modem. #1
  3. Connect GPS Antenna to the connector marked K1.
  4. Connect UART Connector K11 to the Arduino board using provided RMC Cable as per below image.
  5. Connect DC Power supply to the connector K8.(Ensure Polarity).
    You may be able to power the modem from ARDUINO Board VCC pin (5V-12V) also. But this entirely depends on your power supply/Arduino Board Voltage Regulator capability.(Not guaranteed by us)
  6. When the modem is successfully powered-up, the PWR LED (Red) on the modem will be ON, the STS LED(GREEN) will light after 1-2 seconds and the NET LED(BLUE) will blink every second. After the Modem registers in the network (takes between 10-60 seconds), this LED will blink in step of 800 milli seconds.
  7. Load the sample code provided to Arduino board and check the response on Arduino Serial Port Monitor window.
    Default Setting are Baud rate :115200, Data bits:8 , Stop bit:1 and Parity:None
  8. Once you got "OK" from the modem, all set and you can proceed with your required commands…
  9. ATE0<CR><LF>
    To Turn OFF the Echo send by modem , we can issue "ATE0" followed by CR and LF.

     

     

     

 

Test the Modem using Arduino UNO Board. (Advanced Mode)


Users those who wishes to control the modem Power, Start/Stop modem manually  or check the status of the modem periodically by hardware can opt the this advanced mode circuit connections as below .others can use above simple connection method.

  1. Remove the short on jumper J3 and keep it open.
  2. Ensure Jumper J5 shorted . 
  3. Insert Micro SIM card to SIM card holder provided on bottom of the Board. Please ensure the direction of SIM Notch is same as the image shown nearby.
  4. Connect Provided LTE Antenna to the SMA Connector marked "MAIN" on the modem. #1
  5. Connect GPS Antenna to the connector marked K1.
  6. Connect UART Connector K11 to the Arduino board using provided RMC Cable as per below image.
  7. Connect DC Power supply to the connector K8.(Ensure Polarity).
    You may be able to power the modem from ARDUINO Board VCC pin (5V-12V) also. But this entirely depends on your power supply/Arduino Board Voltage Regulator capability.(Not guaranteed by us)
  8. When the modem is successfully powered-up, the PWR LED (Red) on the modem will be ON, the STS LED(GREEN) will light after 1-2 seconds and the NET LED(BLUE) will blink every second. After the Modem registers in the network (takes between 10-60 seconds), this LED will blink in step of 800 milli seconds.
  9. Load the sample code provided to Arduino board and check the response on Arduino Serial Port Monitor window.
    Default Setting are Baud rate :115200, Data bits:8 , Stop bit:1 and Parity:None
  10. Once you got "OK" from the modem, all set and you can proceed with your required commands…
  11. ATE0<CR><LF>
    To Turn OFF the Echo send by modem , we can issue "ATE0" followed by CR and LF.

     

     

     

 

 

Examples


 

Sending SMS using USB From Computer 
  1. Connect Modem to Computer using either on board USB Port or using External USB to Serial converter board.
  2. Open Serial port software and enter the below command to send SMS.

     

    • AT<CR><LF> 
      Attention Command,  this signifies that our Modem is working properly. 
      Answer Expected : OK

    • ATE0<CR><LF> 
      This Command is being sent to stop the echo.
      Answer Expected : OK

    • AT+CREG?<CR><LF> 
      It is being used to check whether the SIM got registered with the Network.
      Answer Expected : +CREG: 0,1  or +CREG: 0,5

    • AT+CMGF=1<CR><LF> 
      Configuring Text mode for sending SMS
      Answer Expected : OK

    • AT+CMGS="Mobile Number"<CR><LF> 
      Set the destination mobile number enclosed in the DOUBLE QUOTES.
      Answer Expected : >

    • "Hi, How are you?"<SUB>
      Here we enter our message body followed by CONTROL-Z (<SUB>) 
      Answer Expected : SMS confirmation starting with "+CMGS"

  3. SerialMonitor Software Command/Response View for Sending SMS.
    SerialMonitor Software Command/Response View for Sending SMS.

 

Sending SMS using ARDUINO via UART 
  • Arduino Code using Software Serial port download 

     

     

  • Since Arduino UNO is sharing its serial port with USB IC via 1K Ohm series resistor , you may face difficulty to use normal serial port along with this modem. So above arduino codes are based on  Software serial interface . 
  • Arduino PIN 2 and PIN3 are used as RX and TX respectively for interfacing with Modem TX and RX.
     
Reading SMS using Modem 
  • AT<CR><LF> 
    Attention Command,  this signifies that our Modem is working properly. 
    Answer Expected : OK
  • ATE0<CR><LF> 
    This Command is being sent to stop the echo.
    Answer Expected : OK
  • AT+CREG?<CR><LF> 
    It is being used to check whether the SIM got registered with the Network.
    Answer Expected : +CREG: 0,1  or +CREG: 0,5
  • AT+CMGF=1<CR><LF> 
    Configuring Text mode for SMS
    Answer Expected : OK
  • AT+CNMI=2,1,0,0,0<CR><LF>
    Configure Modem to notify on incoming SMS reciept. Modem will inform the SMS reciept by "+CMTI:<Message index Number> "
  • AT+CMGR=<Message index Number>
    Now Read SMS using <Message index Number> received.
     

 

 

How to get GPS Location using simcom A7672S 4G LTE Modem
  • AT<CR><LF> 
    Attention Command,  this signifies that our Modem is working properly. 
    Answer Expected : OK
  • AT_CGNSSPWR=1<CR><LF>
    should be executed to let GNSS module power on firstly and have to wait till getting the confirmation . may take 10-30Seconds.
    Answer Expected : "OK" and "+CGNSSPWR: READY!" afetr few seconds
  • AT+CGPSCOLD<CR><LF> 
    COLD start GNSS, When first used;
    Answer Expected : OK
  • AT+CGNSSTST=1<CR><LF> 
    Answer Expected : OK
  • AT+AGPS<CR><LF> 
    Activating Assisted GPS function for better accuracy.
    Answer Expected : OK
  • AT+CGPSINFO<CR><LF> 
    Get GPS fixed position information , After 1 minute , GPS location information will be recived .
    Answer Expected : OK

 

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