user74141: Am using SIM7600X 4G HAT with Arduino Uno
I follow to manual to Power up the module and it works well, The NET light flashing.

But when I connect to Arduino Uno and use DigitalPin 2 write (High -> Delay500ms -> Low) for "power on pulse" it doesn't work, The NET light still not flashing.

My code:
#include <Waveshare_SIM7600.h>
// Pin definition
int POWERKEY = 2;

char phone_number[] = "XXX";      //Store the phone number you want to call

void setup() {
  Serial.begin(9600);
  sim7600.PowerOn(POWERKEY);
  sim7600.PhoneCall(phone_number);
}
  
void loop() {

}

code from Waveshare (Waveshare_SIM7600.h):
/**************************Power on Sim7x00**************************/
void Sim7x00::PowerOn(int PowerKey = powerkey){
   uint8_t answer = 0;

  Serial.begin(9600);

  // checks if the module is started
  answer = sendATcommand("AT", "OK", 2000);
  if (answer == 0)
  {
    Serial.print("Starting up...\n");
    
    pinMode(PowerKey, OUTPUT);
    // power on pulse
    digitalWrite(PowerKey, HIGH);
    delay(500);
    digitalWrite(PowerKey, LOW);
    
    // Stuck in below loop because Send AT command and no response ///////
    // Becuase NET light not flashing (not connect) //////////////////////

    // waits for an answer from the module
    while (answer == 0) {     // Send AT every two seconds and wait for the answer
      answer = sendATcommand("AT", "OK", 2000);
      delay(1000);
    }

  }

  delay(5000);

  while ((sendATcommand("AT+CREG?", "+CREG: 0,1", 500) || sendATcommand("AT+CREG?", "+CREG: 0,5", 500)) == 0)
    delay(500);
}


user74141: The GSM module requires a 5V 2A source and my Arduino Uno cant draw for it, my solution is to use a power bank that can draw 5V 2A for powering the GSM module and jump PWR pin to GND (manual said) the NET led start flashing and module can working but TX, RX pin still there for comm.

74141: <p>Am using SIM7600X 4G HAT with Arduino Uno</p>
<p>I follow to manual to Power up the module and it works well, The NET light flashing.
<a href="https://i.stack.imgur.com/LfO3O.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LfO3O.png" alt="enter image description here" /></a></p>
<p>But when I connect to Arduino Uno and use DigitalPin 2 write (High -&gt; Delay500ms -&gt; Low) for &quot;power on pulse&quot; it doesn't work, The NET light still not flashing.
<a href="https://i.stack.imgur.com/GmI5L.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GmI5L.jpg" alt="enter image description here" /></a></p>
<p>My code:</p>
<pre><code>#include &lt;Waveshare_SIM7600.h&gt;
// Pin definition
int POWERKEY = 2;

char phone_number[] = &quot;XXX&quot;;      //Store the phone number you want to call

void setup() {
  Serial.begin(9600);
  sim7600.PowerOn(POWERKEY);
  sim7600.PhoneCall(phone_number);
}
  
void loop() {

}
</code></pre>
<p>code from Waveshare (Waveshare_SIM7600.h):</p>
<pre><code>/**************************Power on Sim7x00**************************/
void Sim7x00::PowerOn(int PowerKey = powerkey){
   uint8_t answer = 0;

  Serial.begin(9600);

  // checks if the module is started
  answer = sendATcommand(&quot;AT&quot;, &quot;OK&quot;, 2000);
  if (answer == 0)
  {
    Serial.print(&quot;Starting up...\n&quot;);
    
    pinMode(PowerKey, OUTPUT);
    // power on pulse
    digitalWrite(PowerKey, HIGH);
    delay(500);
    digitalWrite(PowerKey, LOW);
    
    // Stuck in below loop because Send AT command and no response ///////
    // Becuase NET light not flashing (not connect) //////////////////////

    // waits for an answer from the module
    while (answer == 0) {     // Send AT every two seconds and wait for the answer
      answer = sendATcommand(&quot;AT&quot;, &quot;OK&quot;, 2000);
      delay(1000);
    }

  }

  delay(5000);

  while ((sendATcommand(&quot;AT+CREG?&quot;, &quot;+CREG: 0,1&quot;, 500) || sendATcommand(&quot;AT+CREG?&quot;, &quot;+CREG: 0,5&quot;, 500)) == 0)
    delay(500);
}
</code></pre>
 74141: <p>The GSM module requires a 5V 2A source and my Arduino Uno cant draw for it, my solution is to use a power bank that can draw 5V 2A for powering the GSM module and jump PWR pin to GND (manual said) the NET led start flashing and module can working but TX, RX pin still there for comm.</p>
