transfer.php

<?php

require_once 'path/to/tropo.class.php';

// Create a new instance of the Tropo object.
$tropo = new Tropo();

// Create a say object and give it the URL of an audio file.
$say = new Say("http://mp3server.com/someringtone.mp3");

// Create a new On object to handle the ring event.
$on = new On('ring', null, $say);

// Create a new transfer
$tropo->transfer("+15407894563", array("timeout" => 60, "ringRepeat" => 5, "on" => $on));

// Hangup when done.
$tropo->hangup();

// Render JSON for Tropo to consume.
$tropo->renderJSON();

/*
 * Rendered JSON.
 * 
 * {
    "tropo": [
        {
            "transfer": {
                "to": "+15407894563",
                "ringRepeat": 5,
                "timeout": 60,
                "on": {
                    "event": "ring",
                    "say": {
                        "value": "http://mp3server.com/someringtone.mp3"
                    }
                }
            }
        },
        {
            "hangup": "null"
        }
    ]
}
 * 
 */

?>