Sorry please ignore the previous comment the code I use to do the communication is 

<code> void setup() { // Initialize serial communication with the computer Serial.begin(9600); // Adjust baud rate as needed // Initialize serial communication with the SIM7600CE module Serial1.begin(9600); // Adjust baud rate as needed // Wait for the SIM7600CE module to initialize delay(5000); // Send an AT command to the SIM7600CE module Serial1.println("AT"); } void loop() { // Check if data is available from the SIM7600CE module if (Serial1.available()) { // Read the response from the SIM7600CE module String response = Serial1.readString(); // Print the response to the serial monitor Serial.println("Response from SIM7600CE module: " + response); } // Check if data is available from the computer if (Serial.available()) { // Read the data from the computer char command = Serial.read(); // Send the data to the SIM7600CE module Serial1.print(command); } } </code>