user13435: Is possible the communication between several Arduinos to one serial port in the PC ?
If I have ARD_A, ARD_B,... ARD_Z running with some code like this
void setup()
{
    Serial.begin(9600);
}

void loop()
{
    while (Serial.available() > 0)
    {
       String stringID = Serial.read()
       int nFound = stringID.indexOf("@ARD_01"); 
                    // ---> Id is unique for each arduino
       if ( nFound > 0 )
          Serial.print("this is @ARD_01 responding sending some data");
     }
}

And in the pc there is an exe sending a string:
"@ARD_01 I want your data" 
   process the data
"@ARD_02 I want your data" 
   process the data
"@ARD_03 I want your data" 
   process the data


user4143: Not directly, no.  A PC's serial port - either a "real" one or a USB one, can only communicate with one device.
The Arduino, though, is a USB device, so you can just plug them all into a USB hub or a bunch of hubs - each one will get its own COM port.  Managing all those COM ports can be kind of tricky though, especially when you have a lot of devices.
Another option, one that is more widely used when you want to communicate with a lot of slave devices from one master device is to use a multidrop network.  RS-485 is the most popular of these.  It allows you to connect many slave devices to one set of serial wires and the master sends instructions to a slave, and the slave may respond with data and information on request.
RS-485 requires special hardware to interface normal TTL level RS-232 (UART) ports to the bus.
You can read more about RS-485 here: https://en.wikipedia.org/wiki/RS-485

13435: <p>Is possible the communication between several Arduinos to one serial port in the PC ?</p>



<p>If I have ARD_A, ARD_B,... ARD_Z running with some code like this</p>

<pre class="lang-C++ prettyprint-override"><code>void setup()
{
    Serial.begin(9600);
}

void loop()
{
    while (Serial.available() &gt; 0)
    {
       String stringID = Serial.read()
       int nFound = stringID.indexOf("@ARD_01"); 
                    // ---&gt; Id is unique for each arduino
       if ( nFound &gt; 0 )
          Serial.print("this is @ARD_01 responding sending some data");
     }
}
</code></pre>

<p>And in the pc there is an exe sending a string:</p>

<pre class="lang-C++ prettyprint-override"><code>"@ARD_01 I want your data" 
   process the data
"@ARD_02 I want your data" 
   process the data
"@ARD_03 I want your data" 
   process the data
</code></pre>
 4143: <p>Not directly, no.  A PC's serial port - either a "real" one or a USB one, can only communicate with one device.</p>

<p>The Arduino, though, is a USB device, so you can just plug them all into a USB hub or a bunch of hubs - each one will get its own COM port.  Managing all those COM ports can be kind of tricky though, especially when you have a lot of devices.</p>

<p>Another option, one that is more widely used when you want to communicate with a lot of <em>slave</em> devices from one <em>master</em> device is to use a <em>multidrop</em> network.  RS-485 is the most popular of these.  It allows you to connect many slave devices to one set of serial wires and the master sends instructions to a slave, and the slave may respond with data and information on request.</p>

<p>RS-485 requires special hardware to interface normal TTL level RS-232 (UART) ports to the bus.</p>

<p>You can read more about RS-485 here: <a href="https://en.wikipedia.org/wiki/RS-485" rel="nofollow">https://en.wikipedia.org/wiki/RS-485</a></p>
