To automatically turn on sim800A using code without pressing the power button for 3 seconds

[ab29]

Everytime when I plug the adapter to sim800a I need to press the power button for some time to switch it on. Is there any way to automatically switch it on using code or any connections.
Please help me, there is a similar discussion in another thread, but I didn't get it since the module is different.
Solution for other module

[b707]

@ab29

but I didn't get it since the module is different.

please show link to your module

[ab29]

I don't have the link and this is how it looks

[ab29]

and I am reading this type of output through serial monitor any reasons on this?
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[ab29]

#include <SoftwareSerial.h>

//Create software serial object to communicate with SIM800L
SoftwareSerial mySerial(D1, D0); //SIM800L Tx & Rx is connected to Arduino #3 & #2

void setup()
{
  //Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
  Serial.begin(9600);
  
  //Begin serial communication with Arduino and SIM800L
  mySerial.begin(9600);

  Serial.println("Initializing..."); 
  delay(1000);

  mySerial.println("AT"); //Once the handshake test is successful, it will back to OK
  updateSerial();
  
  mySerial.println("AT+CMGF=1"); // Configuring TEXT mode
  updateSerial();
  mySerial.println("AT+CNMI=1,2,0,0,0"); // Decides how newly arrived SMS messages should be handled
  updateSerial();
}

void loop()
{
  updateSerial();
}

void updateSerial()
{
  delay(500);
  while (Serial.available()) 
  {
    mySerial.write(Serial.read());//Forward what Serial received to Software Serial Port
  }
  while(mySerial.available()) 
  {
    Serial.write(mySerial.read());//Forward what Software Serial received to Serial Port
  }
}

[b707]

You can't use pins 0 & 1 for SoftwareSerial because it used for Serial, please choose the different ones

@ab29

SoftwareSerial mySerial(D1, D0);

[ab29]

It's for Nodemcu and what else pin can I use rest except 1 and 2?

[b707]

Sorry, I thought you use Arduino Uno/Nano

As about the power - I didn't find a PWRKEY pin on your modem board. But you can to solder a wire to the hole near the Power button (see image)

and control turning on the modem using the arduino pin.

According to datasheet, the procedure to turn on the modem is:

PWRKEY should be pulled low at
least 1.2 second and then released to
power on/down the module