Basic Particle Photon sketch to send a message to Dweet.io using GET. Written specifically for the SIM7600E-H, but may work well on other similar modules.

DweetSIM7600_for_Photon.ino

/*
 * Basic sketch to send a message to Dweet.io using GET
 * This sketch is written specifically for the SIM7600E-H
 * This specific version is for Particle Photon.
 * 
 * Connect the R pin on the module to pin 19 on the Photon
 * Connect the T pin on the module to pin 18 on the Photon
 * 
 * Also enter your own deviceName below (replace "8675840")
 * and you can then go and see the result at
 * http://dweet.io/get/latest/dweet/for/8675840
 * 
 * You will also have to change the PIN and APN for this
 * to work with YOUR telcom provider.
 * 
 * Written by https://github.com/jenschr
 */

String deviceName = "8675840";

int counter = 0;

// Declare metod with defaults here. Implementation is further down
void sendAndReadResponse( String command, int extraWaitInMillisecondsForResponse = 200 );

void setup()
{
  pinMode(D7, OUTPUT);
  
  // Set your Serial monitor speed to this
  Serial.begin(115200);
  // The SIM7600 module is using 115200 baud by default
  Serial1.begin(115200);
  // Wait for SIM to come online
  Serial.println("Wait 8 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 7 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 6 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 5 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 4 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 3 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 2 boring seconds for the green LED to turn on");
  delay(1000);
  Serial.println("Wait 1 boring second for the green LED to turn on");
  delay(1000);
  

  // Change speed from 115200 to 19200 to prevent errors
  //Serial1.println("AT+IPR=19200");
  //delay(1000);
  //Serial1.begin(19200);
  //delay(1000);

  // Setup the module - start by just saying "hi" with an AT
  sendAndReadResponse("AT");
  // Enter the PIN for your SIM card in the command below (unless it's 1234)
  //sendAndReadResponse("AT+CPIN=1234");
  sendAndReadResponse("AT+CFUN=1");
  sendAndReadResponse("AT+CGACT=1,1");
  // Last parameter here ('internet') is your telco's APN. Google it unless you know it?
  sendAndReadResponse("AT+CGDCONT=1,\"IP\",\"internet\"");
  sendAndReadResponse("AT+CGPS=1");
  sendAndReadResponse("AT+CGREG?");
  sendAndReadResponse("AT+NETOPEN");
  sendAndReadResponse("AT+IPADDR");

  // Send request to Dweet.io
  sendAndReadResponse("AT+CHTTPACT=\"dweet.io\",80");
  Serial1.print("GET http://dweet.io/dweet/for/");
  Serial1.print(deviceName);
  Serial1.println("?temperature=55.5&humidity=77.7&bananas=TheBestThing HTTP/1.1\n");
  Serial1.println("Host: dweet.io\n");
  Serial1.println("User-Agent: mozilly\n");
  Serial1.println("Content-Length: 0\n");
  Serial1.print(char(26)); delay(20);
  Serial1.print(char(26));
}

void sendAndReadResponse( String command, int extraWaitInMillisecondsForResponse )
{
  // Send the command
  Serial.print( "Sending: " );
  Serial.println( command );
  Serial1.println( command );

  // Setup a timeout
  int requestStartTime = millis();
  int millisecondsSinceRequestStarted = 0;
  bool wegotResponse = false;

  // Wait until we get a response (or timeout)
  while ( !wegotResponse || millisecondsSinceRequestStarted < 2000 )
  {
    millisecondsSinceRequestStarted = millis() - requestStartTime;
    if ( Serial1.available() > 0 )
    {
      wegotResponse = true;
    }
    Particle.process();
  }

  // Print out the results
  if ( millisecondsSinceRequestStarted < 2000 )
  {
    Serial.print("\nCommand: '");
    Serial.print(command);
    Serial.println(" timed out?\n");
  }
  else if (Serial1.available() > 0)
  {
    Serial.print("<\n");
    
    // wait a little longer so we get the whole response
    delay(extraWaitInMillisecondsForResponse);

    // Print out the response to Serial monitor
    while ( Serial1.available() )
    {
      char ch = Serial1.read();
      if ( ch ) {
        Serial.print(ch);
      }
    }
    Serial.println("\n>");
  }
}

// In the main loop, you can keep entering AT commands from your Serial Monitor
void loop()
{
  /* send everything received from the SIM7600
     to usb serial & vice versa */
  if (Serial.available() > 0) {
    Serial.print(">");
    delay(100);
    while ( Serial.available() ) {
      char ch = Serial.read();
      Serial.print(ch);
      Serial1.print(ch);
    }
  }
  if (Serial1.available() > 0) {
    Serial.print(":");
    delay(10);
    while ( Serial1.available() ) {
      char ch = Serial1.read();
      if ( ch ) {
        Serial.print(ch);
      }
    }
  }

  // blink the LED, just to show we are alive
  if ( counter % 1000 == 0 ) {
    digitalWrite( D7, !digitalRead(D7) );
  }
  counter++;
}