Serial communication between nodemcu and Arduino

int val = 0;
int incoming = 0;
int incoming1 = 0;

void setup()
{
  Serial.begin(115200);  //Begin Serial to talk to the Serial Monitor   

  Serial.println("Serial Monitor Connected"); 
  Serial.parseInt();     //clear any garbage in the buffer.  
}

void loop()
{


  //     From the Rx Arduino
  incoming1 = Serial.available();  
  while(incoming1 != 0)           //While there is something to be read
  {
    val = Serial.parseInt();    //Get new value
    Serial.print("Receiving...  ");    
    Serial.println(val);        //Print new value to the Serial Monitor
    incoming1 = Serial.available();
  }
}

int val = 0;
int incoming = 0;
unsigned int i;
byte Send_buf[] = {0x01,0x03,0x00,0x00,0x00,0x0a,0xFD};




void setup()
{
  Serial.begin(115200);

}

void loop()
{
  incoming = Serial.available();
  while (incoming != 0)                 //While there is something to be read
  {
  Serial.write(Send_buf[0]);
   
  }
 
  
  //delay(200);
}

01 03 00 00 00 0A FD instead of 
01 03 00 00 00 00 00 FD

#include "SoftwareSerial.h"

const byte rxPin = 13;
const byte txPin = 15;

SoftwareSerial mySerial (rxPin, txPin); 

void setup() 
{
  mySerial.begin(115200);
  Serial.begin(115200);
  Serial.print("Started");
}

void loop() 
{
  if(mySerial.available())
  {
    String incomingMessage = mySerial.readString();
    Serial.println(incomingMessage);
  }
}

#include "SoftwareSerial.h"

const byte rxPin = 2;
const byte txPin = 3;

SoftwareSerial mySerial (rxPin, txPin); 

void setup() 
{
  mySerial.begin(115200);
  Serial.begin(115200);
  Serial.print("Started");
}

void loop() 
{
  if(mySerial.available())
  {
    String incomingMessage = mySerial.readString();
    Serial.println(incomingMessage);
  }
}

Serial.println("this implements TX0 at GPIO1 and RX0 at GPIO3"); 
Serial1.println("this implements TX1 at GPIO15 and RX1 at GPIO13");