使用PHP发送TCP数据

I've looked in to this a bit but still don't really understand if its possible.

I have a small webserver that sits on my private network. I want to create a php script that will connect to a telnet server on the private network and send it text every 30 seconds.

Obviously the easy part is the text and timing but connection to a TCP Port 23 and sending a string of text seems harder for some reason. What's the best way to do this?

Use PHP sockets :

<?php
while(true){
    sleep 30;
    $fp = fsockopen("www.example.com", 23, $errno, $errstr, 30);
    if (!$fp) {
        echo "$errstr ($errno)<br />
";
    } else {
        fwrite($fp, "The string you want to send");
        while (fgets($fp, 128)) {
            echo fgets($fp, 128); // If you expect an answer
        }
        fclose($fp); // To close the connection
    }
}
?>