PHP 5.2 Curl Fax Code Examples

I can show you how to do it with curl. You try to adjust it for PHP curl. 

curl
--header "Accept: application/json"
--header "Authorization: Bearer <token>"
-F "request=@request.json;type=application/json"
-F "attachment=@hello.txt;type=text/plain"
"https://platform.devtest.ringcentral.com/restapi/v1.0/account/~/extension/~/fax";


Content of request.json file:
{
"to": [{ "phoneNumber": <fax receiver> }]
}


Content of hello.txt:
<Whatever text you want to send.>


You can also send pdf:
-F "attachment=@test.pdf;type=application/pdf"

But how do I translate that to PHP cURL lib?... such as using curl_init(), curl-setopt(), etc?

Ya, 1.5 days were stuck reading docs and the other 1.5 days were trying to implement things fruitlessly. 

Curl to PHP: https://incarnate.github.io/curl-to-php/

Update: I find that  it doesn't support '-F' at all, so ignore this one.