Overview

The 4G LTE UART / USB  modem, 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 Quectel. This Modem based on QUECTEL module, will automatically fallback to  3G UMTS/HSPA+ and  2G mode in the absence of 4G Network , which will enable you to use it across the entire country including remote villages where 4G/3G towers are less populated . Since this modem supports GNSS ,customer can make use of Geo Location identification using  (GPS, GLONASS) Satellite networks.

What's On Board

Modem Basic Specifications

Outer Dimension of the Board

Connectors onboard

Pin Functions

Jumpers Onboard

Network Connection Status/Activity LED Indicator

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 Connector marked "MAIN" on the modem. #2
3. Connect GPS Antenna to the connector marked K1.
4. Install Required Quectel USB Driver software from the download link provided.(Device Manager view, before and after installations of USB Driver as below) 

   Before Installing Quectel USB Driver

   After Installing Quectel USB Driver

5. Connect Micro-B USB cable to the modem (K6) from Computer.
6. Connect DC Power supply to the connector K1.(Ensure Polarity)
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, N.MODE LED (Yellow) will turn ON  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 3 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. 
    

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 K5 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 K1.(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, N.MODE LED (Yellow) will turn ON  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 3 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. AT+QURCCFG="URCPORT","UART1"<CR><LF>
    For redirecting the modem replies to the UART1 Port as well.
11. ATE0<CR><LF>
    To Turn OFF the Echo send by modem , we can issue "ATE0" followed by CR and LF.
12. 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. 
    

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 K5 to the Arduino board using provided RMC Cable as per below image.
5. Connect DC Power supply to the connector K1.(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, N.MODE LED (Yellow) will turn ON  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 3 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.
   
   ​ #include &lt;SoftwareSerial.h&gt;; SoftwareSerial mySerial(2, 3); // Assign pins for RX, TX void setup() { mySerial.begin(115200); // set the baud rate as 115200 } void loop() { mySerial.print("AT\r\n"); // Transmit AT to the module delay(500); // wait for a 500ms delay mySerial.print("ATE0\r\n"); // Echo Off delay(500); // wait for a 500ms delay while(1); // Loop for ever }

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   ​ #include <SoftwareSerial.h>;   SoftwareSerial mySerial(2, 3);                               // Assign pins for RX, TX   void setup() {   mySerial.begin(115200);                                    // set the baud rate as 115200 }   void loop() {   mySerial.print("AT\r\n");                                  // Transmit AT to the module             delay(500);                                                // wait for a 500ms delay   mySerial.print("ATE0\r\n");                                // Echo Off                                                         delay(500);                                                // wait for a 500ms delay                                                       while(1);                                                  // Loop for ever   }

    

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 J4 and keep it open.
2. Ensure Jumper J3 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 K5 to the Arduino board using provided RMC Cable as per below image.
7. Connect DC Power supply to the connector K1.(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, N.MODE LED (Yellow) will turn ON  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 3 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.
    
    ​ #include &lt;SoftwareSerial.h&gt;; SoftwareSerial mySerial(2, 3); // Assign pins for RX, TX #define GSM_PWR_KEY 5 #define GSM_STATUS_PIN 4 #define POWER_ON_OFF_PIN 6 void setup() { pinMode(GSM_PWR_KEY,OUTPUT); // Pin Setting as output digitalWrite(POWER_ON_OFF_PIN,HIGH); // Pnsure the Port Pin Register value pinMode(POWER_ON_OFF_PIN,OUTPUT); // Pin Setting as output pinMode(GSM_STATUS_PIN,INPUT); // Pin Setting as input digitalWrite(POWER_ON_OFF_PIN,LOW); // Power ON the Modem delay(500); digitalWrite(GSM_PWR_KEY,HIGH); // Start the Modem delay(2000); digitalWrite(GSM_PWR_KEY,LOW); while(digitalRead(GSM_STATUS_PIN) != 0) // Wait till modem is ready {} mySerial.begin(115200); // set the baud rate mySerial.print("AT\r\n"); // Transmit AT to the module delay(500); // wait for a 500ms delay mySerial.print("ATE0\r\n"); // Echo Off delay(500); // wait for a 500ms delay } void loop() { mySerial.print("AT\r\n"); // Transmit AT to the module delay(500); // wait for a 500ms delay mySerial.print("ATE0\r\n"); // Echo Off delay(500); // wait for a 500ms delay while(1); // Loop for ever }

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    ​ #include <SoftwareSerial.h>;   SoftwareSerial mySerial(2, 3);                               // Assign pins for RX, TX   #define GSM_PWR_KEY       5 #define GSM_STATUS_PIN    4 #define POWER_ON_OFF_PIN   6   void setup() {   pinMode(GSM_PWR_KEY,OUTPUT);                               // Pin Setting as output   digitalWrite(POWER_ON_OFF_PIN,HIGH);                       // Pnsure the Port Pin Register value   pinMode(POWER_ON_OFF_PIN,OUTPUT);                          // Pin Setting as output   pinMode(GSM_STATUS_PIN,INPUT);                             // Pin Setting as input     digitalWrite(POWER_ON_OFF_PIN,LOW);                        // Power ON the Modem   delay(500);   digitalWrite(GSM_PWR_KEY,HIGH);                            // Start the Modem   delay(2000);   digitalWrite(GSM_PWR_KEY,LOW);                                  while(digitalRead(GSM_STATUS_PIN) != 0)                    // Wait till modem is ready   {}     mySerial.begin(115200);                                    // set the baud rate   mySerial.print("AT\r\n");                                  // Transmit AT to the module             delay(500);                                                // wait for a 500ms delay   mySerial.print("ATE0\r\n");                                // Echo Off                               delay(500);                                                // wait for a 500ms delay   }   void loop() {   mySerial.print("AT\r\n");                                  // Transmit AT to the module             delay(500);                                                // wait for a 500ms delay   mySerial.print("ATE0\r\n");                                // Echo Off                                                         delay(500);                                                // wait for a 500ms delay                                                       while(1);                                                  // Loop for ever   }

     

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.
   

Sending SMS using ARDUINO via UART 

• Arduino Code using Software Serial port download 
  #include &lt;SoftwareSerial.h&gt;; SoftwareSerial mySerial(2, 3); // Assign pins for RX, TX void setup() { mySerial.begin(115200); // set the baud rate mySerial.print("AT\r\n"); // Transmit AT to the module delay(500); // wait for a 500ms delay mySerial.print("ATE0\r\n"); // Echo Off delay(500); // wait for a 500ms delay mySerial.print("AT+CMGF=1\r\n"); // Switch to text mode delay(500); // wait for a 500ms delay } void loop() { mySerial.print("AT+CMGS=\"9349160503\"\r\n"); // Send SMS to a cell number delay(500); // wait for a 500ms delay mySerial.print("Test MSG"); delay(500); mySerial.write(0X1A); // Ctrl-Z indicates end of SMS delay(500); // wait for a 500ms delay while(1); }

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  #include <SoftwareSerial.h>;   SoftwareSerial mySerial(2, 3);                               // Assign pins for RX, TX   void setup() {   mySerial.begin(115200);                                    // set the baud rate   mySerial.print("AT\r\n");                                  // Transmit AT to the module             delay(500);                                                // wait for a 500ms delay   mySerial.print("ATE0\r\n");                                // Echo Off                               delay(500);                                                // wait for a 500ms delay   mySerial.print("AT+CMGF=1\r\n");                           // Switch to text mode                   delay(500);                                                // wait for a 500ms delay     }   void loop() {                                 mySerial.print("AT+CMGS=\"9349160503\"\r\n");              // Send SMS to a cell number             delay(500);                                                // wait for a 500ms delay   mySerial.print("Test MSG");   delay(500);           mySerial.write(0X1A);                                      // Ctrl-Z indicates end of SMS       delay(500);                                                // wait for a 500ms delay   while(1);     }

   

• 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 Quectel EC20/EC25 4G LTE 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+QURCCFG="URCPORT","UART1"<CR><LF>
  For redirecting the modem replies to the UART1 Port as well.
• 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 Quectel EC20/EC25 4G LTE 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+QGPS=1<CR><LF> 
  Turn ON the GPS Function .
  Answer Expected : OK
• AT+QGPSLOC?<CR><LF> 
  Initially we have to wait atleast 30 Seconds and issue this command to read the GPS location details
  Answer Expected : GPS Data starting  with "+QGPSLOC:"
• AT+QGPSEND<CR><LF> 
  Turn OFF the GPS Function before exiting.
  Answer Expected : OK
•