title: Open com port in php
body: <p>I have a usb 3G modem Huawei E1550 and Windows XP.
  I want to send sms with this modem trhow php.</p>
  
  <p>I use this function to open a modem com port:</p>
  
  <pre><code>$fp = fopen ("COM3:", "wb+");
  if (!$fp) {
      echo "Not open";
  } else {
      echo "Open";
  }
  </code></pre>
  
  <p>And every time I get a error:</p>
  
  <blockquote>
    <p>Warning: fopen(COM3:) [function.fopen]: failed to open stream: Invalid argument in D:\Apache\htdocs\z91.ru\audio\test.php on line 3</p>
  </blockquote>