All that the example does is load the plivo.php functions, assign some variables and then echo those variables into a sentence without using any plivo functions. It is a nice rudimentary demonstration of PHP's $_REQUEST super global, the echo function and the require_once function, but it does not demonstrate ANY plivo code whatsoever.

all files require plivo.php which is missing.
These examples are worthless

Line 5 missing a semicolon!

click-to-call example param "TO" is being submitted twice on $params and answer_url string,

make sure to change answer_url "To" variable to 'callTo" instead and on second script in order for this example to work...

I use plivo for linked two telephone numbers by callback function.
But code preview in example:
https://www.plivo.com/docs/getting-started/making-outbound-calls/

";
// print_r ($response);
// echo "

I have try to work with this file and is very confusing.

1. Why are 2 files in one instead of of 2 separate files, ex: phone_ivr.php, phone_tree.php?
   If they are 2 files, please can you separate them.
2. Why you are you changing the REQUEST_METHOD?
   For GET you have POST and for POST you have GET.
3. Also, why is the file called phone_ivr.php do the phone part need to be the actual phone number that will be using the service?

I sign up for PLIVO service and I have spend crazy hours trying to make this thing work, and is useless. This is a very poor example.

All the examples reference the following line to load the plivo library
require 'vendor/autoload.php';

Which SDK is this using? It doesn't seem to match the plivo-php repo?