user61829: I am working on a project which utilizes three components:

Arudino Pro Mini(5v)
Breakout SIM7600 A-H from AND technologies
9V Battery (connected to RAW and GND on the Arduino board)

I am trying to communicate through the device using the pins provided on the SIM board, which unfortunately is not successful.
I am able to connect to the board directly using an usb-c cable. After installing the right drivers, I am able to communicate with the board using AT commands from my Windows PC.
However, I want to be able to send AT commands through the arduino. The set up looks like this:
I connect the following pins of arduino mini and SIM 7600A-H.

SIM 7600 TXD --> Arduino Pin 2
SIM 7600 RXD --> Arduino Pin 3
SIM 7600 Supply -->  5V
SIM 7600 GND -->  GND

The code that I am using, I tried it with every possible baud rate:
#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3); // RX, TX

void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(115200);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }


  Serial.println("Goodnight moon!");

  // set the data rate for the SoftwareSerial port
  mySerial.begin(115200);
}

void loop() { // run over and over
  if (mySerial.available()) {
    Serial.write(mySerial.read());
  }
  if (Serial.available()) {
    mySerial.write(Serial.read());
  }
}

After sending an AT command, there is no response, the module has both LED's on, indicating that it is up and running. 

user65599: Is your issue resolved? If not...
I'm using the same module and having the same problem.
Jump the resistors on the R and T pins on the module, they seem to be introducing high impedance on the line. After doing that on my module, the UART worked.
Now my problem now is the module is sending some weird characters, maybe my baud rate is not same or etc, still under investigation.

user65601: The SIM7600 UART interface works with 1.8 levels:

I'm guessing that the AND board has a level shifter from 3.3 to 1.8 to work with the 7600. Since your Arduino Por Mini is a 5V board your UART levels must be at 5V too, try adding a voltage divider to bring down the UART to 3.3V.
Also try lowering the SIM7600 baudrate, the software_serial library doesn't work good with high speeds.

61829: <p>I am working on a project which utilizes three components:</p>

<ol>
<li>Arudino Pro Mini(5v)</li>
<li>Breakout SIM7600 A-H from <a href="http://www.thebackshed.com/forum/uploads/Grogster/2018-07-24_122343_BK-SIM7600_Board_user_manual_V1.0.pdf" rel="nofollow noreferrer">AND technologies</a></li>
<li>9V Battery (connected to RAW and GND on the Arduino board)</li>
</ol>

<p>I am trying to communicate through the device using the pins provided on the SIM board, which unfortunately is not successful.</p>

<p><strong>I am able to connect to the board directly using an usb-c cable. After installing the right <a href="https://github.com/botletics/SIM7000-LTE-Shield/wiki/USB-Drivers" rel="nofollow noreferrer">drivers,</a> I am able to communicate with the board using AT commands from my Windows PC.</strong></p>

<p>However, I want to be able to send AT commands through the arduino. The set up looks like this:
I connect the following pins of arduino mini and SIM 7600A-H.</p>

<ul>
<li>SIM 7600 TXD --> Arduino Pin 2</li>
<li>SIM 7600 RXD --> Arduino Pin 3</li>
<li>SIM 7600 Supply -->  5V</li>
<li>SIM 7600 GND -->  GND</li>
</ul>

<p>The code that I am using, I tried it with every possible baud rate:</p>

<pre class="lang-cpp prettyprint-override"><code>#include &lt;SoftwareSerial.h&gt;

SoftwareSerial mySerial(2, 3); // RX, TX

void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(115200);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }


  Serial.println("Goodnight moon!");

  // set the data rate for the SoftwareSerial port
  mySerial.begin(115200);
}

void loop() { // run over and over
  if (mySerial.available()) {
    Serial.write(mySerial.read());
  }
  if (Serial.available()) {
    mySerial.write(Serial.read());
  }
}
</code></pre>

<p>After sending an AT command, there is no response, the module has both LED's on, indicating that it is up and running. </p>
 65599: <p>Is your issue resolved? If not...
I'm using the same module and having the same problem.
Jump the resistors on the R and T pins on the module, they seem to be introducing high impedance on the line. After doing that on my module, the UART worked.</p>

<p>Now my problem now is the module is sending some weird characters, maybe my baud rate is not same or etc, still under investigation.</p>
 65601: <p>The SIM7600 UART interface works with 1.8 levels:
<a href="https://i.stack.imgur.com/mwkbd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mwkbd.png" alt="enter image description here"></a></p>

<p>I'm guessing that the AND board has a level shifter from 3.3 to 1.8 to work with the 7600. Since your Arduino Por Mini is a 5V board your UART levels must be at 5V too, try adding a voltage divider to bring down the UART to 3.3V.</p>

<p>Also try lowering the SIM7600 baudrate, the software_serial library doesn't work good with high speeds.</p>
