Hi,

If your SIM800L GSM module is not connecting to the network, there could be several reasons for this issue. Let’s troubleshoot step by step:

1. Power Supply and Wiring:
   • Ensure that you provide sufficient power to the SIM800L module. It requires 3A current during network search.
   • Connect the GND (ground) pin before the VCC (power) pin. Disconnection in the wrong order can lead to damage.
   • Use a capacitor between the GND and VCC pins of the SIM800L, placed as close as possible to the module.
   • Keep the wires short to minimize interference.
2. Basic Connection:
   • Connect your SIM800L to an Arduino Uno with the following connections:
     • GND → GND
     • VCC → 5V (Arduino)
     • Tx → Rx
     • RST → 3.3V
     • Rx → Tx (Use a voltage divider to drop the voltage to 2.8V, as the module works best with this voltage.)
3. Software Configuration:
   • Use the following code snippet to initialize the SIM800L:

     #include 
     
     // Create software serial object to communicate with SIM800L
     SoftwareSerial mySerial(10, 11); // SIM800L Tx & Rx connected to Arduino pins 11 & 10
     
     void setup() {
         // Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
         Serial.begin(9600);
         // Begin serial communication with SIM800L
         mySerial.begin(9600);
         Serial.println("Initializing...");
         delay(1000);
         mySerial.println("AT"); // Handshake test
         mySerial.println("AT+CSQ"); // Signal quality test
         mySerial.println("AT+CCID"); // Read SIM information
         mySerial.println("AT+CFUN=0"); // Turn off radio
         delay(5000);
         mySerial.println("AT+CFUN=1"); // Turn on radio
         delay(1000);
         mySerial.println("AT+CREG?"); // Check network registration
     }
     
     void loop() {
         // Update serial communication
         updateSerial();
     }
     
     void updateSerial() {
         delay(500);
         while (Serial.available()) {
             // Handle incoming data from SIM800L
         }
     }
     

   • Adjust the code according to your specific requirements.
4. Network Registration:
   • Use the following AT commands to check network registration:
     • AT+COPS?: Tells you which network operator your SIM is registered with.
     • AT+CREG?: Checks the registration status (0 or 1 means registered).
     • If not registered, perform network registration using AT+CREG=1.
5. SIM Card Considerations:
   • Ensure you use a compatible SIM card with the SIM800L.
   • Insert the SIM card correctly.
   • Enable PIN protection on your SIM card.
   • Set the correct APN for your cellular network.
6. Signal Strength:
   • Move to a location with a strong cellular signal.

Remember to follow these steps carefully, and hopefully, your SIM800L will successfully connect to the network!