ESP8266 NodeMCU vs Sim800L Module

Hi Blynk Community,
I have some problems with my project.
I used ESP8266 NodeMCU to connect with Sim800L Module to access internet and connect with Blynk. However, I have a problem. I know, NodeMCU can use wifi, but I want to use it for some areas with WiFi. Can someone help me?
This is the code I used:

   #define BLYNK_PRINT Serial


 #include <TinyGsmClient.h>
#include <BlynkSimpleSIM800.h>

char auth[] = "YourAuthToken";

// Your GPRS credentials
// Leave empty, if missing user or pass
char apn[]  = "v-internet";
char user[] = "mms";
char pass[] = "mms";

#include <SoftwareSerial.h>
SoftwareSerial SerialAT(3, 1); // RX, TX

TinyGsm modem(SerialAT);

void setup()
  // Debug console


  // Set GSM module baud rate

  // Restart takes quite some time
  // To skip it, call init() instead of restart()
  Serial.println("Initializing modem...");
 // modem.restart();

  // Unlock your SIM card with a PIN

  Blynk.begin(auth, modem, apn, user, pass);

void loop()


and the problem I have:

GPIOs 1 & 3 are the Serial Tx and Rx pins on the NodeMCU. You can’t use these for your SoftwareSerial connection, as they are being used internally by the NodeMCU.


I’ve tried with GPIOs 13& 15, but it’s not working…

Is this the correct baud rate for your SIM800? Can you communicate with it using AT commands at this baud rate?

When your code compiles is it using the SoftwareSerial library from your ESP core?
What version of the ESP core are you using?


You can try the example ESP8266_GSM in ESP8266_GSM library

More info in;