Sequentially dial phone numbers using Twilio and Twilio's PHP helper library

sequential_dialing.php

<?php
// Require the bundled autoload file - the path may need to change
// based on where you downloaded and unzipped the SDK
require __DIR__ . '/twilio-php-master/Twilio/autoload.php';

// Use Twilio\TwiML to build TwiML instructions through PHP
use Twilio\Twiml;

// Instantiate a TwiML object.
$response = new Twiml();

// Fill this array with phone numbers to be called. List them in order of importance.
// The included phone numbers are fake example numbers so be sure to change them.
$callToArr = (1 => '+15554441212', 2 => '+16667778989');


if (isset($_REQUEST['index'])) {
    $index = $_REQUEST['index'];
} else {
    $index = 1;
}

if ($index <= count($callToArr)){
    $next = $index + 1;
    $dial = $response->dial(['timeout' => 15,'action' => '/sequential_dialing.php?index='.$next], );
    $dial->number($callToArr[$index]);
}