user42808: I have a GSM A6 module, like this one.
I'm going to use an Arduino Nano as a bridge to communicate with it, I have an external power source (since I read that this module can consume up to 2A at its maximum consumption) (this power supply shares the GND with the module and the Arduino) and I upload the following code in the Nano:
#include <SoftwareSerial.h>

SoftwareSerial mySerial(10, 11);

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

  //Begin serial communication with Arduino and A6
  mySerial.begin(115200);

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


}

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
  }
}

I set the baud rate at 115200 of my SoftwareSerial port (connected to 10 and 11 pins on the ArduinoNano) because (even if the module says that it has auto-detect speed hability) doesn't work if I set the speed at 9600 (or any other), and I modified the SoftwareSerial library for expand the buffer from 64k to 512k (trying to solve this problem) following this page instructions (also: NICE WORK in this page!!!).
And it works ... it works relatively well, I mean:
The AT commands to test (according to the datasheet itself) are AT and ATI (in one I recieve "AT /r OK" and the last one give some usefull information like the OS and other things), and they work, only they do not show me the same answer always, I leave screenshots:


As you can see, the answers are not always exact, there is some garbage characters, and I need them to be exact, because my idea is to create a kind of alarm, in which the Arduino (One, Nano or Mega) sends and receives AT commands. I worked with the SIM900 module before and always received the same answer when I sent an AT command.
So... any help?!

user42808: Apparently the SoftwareSerial library have some limitations, so I change the baudrate communication in the moduel ussing this sentence:

AT+IPR=9600

And change the code that I upload to the Nano, changing the baudrate speed in the declaration, from:
mySerial.begin(115200);

to
mySerial.begin(9600);

And now all is well :D

42808: <p>I have a <strong>GSM A6</strong> module, like this <a href="https://es.aliexpress.com/item/A6-GPRS-Pro-Serial-GPRS-GSM-Module-Core-DIY-Developemnt-Board-Replace-SIM900-NEW/32756244758.html" rel="nofollow noreferrer">one</a>.</p>

<p>I'm going to use an <strong>Arduino Nano</strong> as a <em>bridge</em> to communicate with it, I have an external power source (since I read that this module can consume up to 2A at its maximum consumption) (this power supply shares the GND with the module and the Arduino) and I upload the following code in the <strong>Nano</strong>:</p>

<pre><code>#include &lt;SoftwareSerial.h&gt;

SoftwareSerial mySerial(10, 11);

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

  //Begin serial communication with Arduino and A6
  mySerial.begin(115200);

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


}

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
  }
}
</code></pre>

<p>I set the <strong>baud rate</strong> at <strong>115200</strong> of my SoftwareSerial port (connected to 10 and 11 pins on the ArduinoNano) because (even if the module says that it has auto-detect speed hability) doesn't work if I set the speed at <strong>9600</strong> (or <strong>any other</strong>), and I modified the SoftwareSerial library for expand the buffer from <em>64k</em> to <em>512k</em> (trying to solve this problem) following <a href="https://lastminuteengineers.com/a6-gsm-gprs-module-arduino-tutorial/" rel="nofollow noreferrer">this page</a> instructions (also: NICE WORK in this page!!!).</p>

<p>And it works ... it works relatively well, I mean:
The <strong>AT</strong> commands to test (according to <a href="https://lastminuteengineers.com/datasheets/A6-A7-A6C-GSM-Module-Datasheet.pdf" rel="nofollow noreferrer">the datasheet itself</a>) are <strong>AT</strong> and <strong>ATI</strong> (in one I recieve "<em>AT /r OK</em>" and the last one give some usefull information like the OS and other things), and they work, only they do not show me the same answer always, I leave screenshots:</p>

<p><a href="https://i.stack.imgur.com/OSmPl.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OSmPl.jpg" alt="ATI command responses"></a>
<a href="https://i.stack.imgur.com/KxQwI.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KxQwI.jpg" alt="AT command responses"></a></p>

<p>As you can see, the answers are not always <strong>exact</strong>, there is some garbage characters, and I <strong>need</strong> them to be <strong>exact</strong>, because my idea is to create a kind of alarm, in which the Arduino (One, Nano or Mega) sends and receives AT commands. I worked with the SIM900 module before and always received the same answer when I sent an AT command.</p>

<p>So... any help?!</p>
 42808: <p>Apparently the SoftwareSerial library have some limitations, so I change the baudrate communication in the moduel ussing this sentence:</p>

<blockquote>
  <p>AT+IPR=9600</p>
</blockquote>

<p>And change the code that I upload to the Nano, changing the baudrate speed in the declaration, from:</p>

<pre><code>mySerial.begin(115200);
</code></pre>

<p>to</p>

<pre><code>mySerial.begin(9600);
</code></pre>

<p>And now all is well :D</p>
