<?php

  $filename = "/dev/ttyUSB1";



    if (!$handle = fopen($filename, 'r+'))

    {

      echo "The device isn't detected";

      exit;

    }

    else

    {

      if (fwrite($handle, "AT") === FALSE)

      {

        echo "Command is sent";
        $reply = fread ($filename);
        echo $reply;

        exit;

      }

    }



?>