How to make live voice phone call using Twilio instead of just playing an MP3 when call is answered?

Question

To call phone number from notebook through Twilio I created ASP.NET-MVC 5.2 application.

I can call a number and answer the phone but I don't know how to achieve live voice(to be able to talk) connection instead of just playing music.

I created an action method inside HomeController:

  public ActionResult Call(string to) {
            client = new TwilioRestClient(Settings.AccountSid, Settings.AuthToken); 

            var result = client.InitiateOutboundCall(Settings.TwilioNumber, to, "http://twimlets.com/message?Message%5B0%5D=http://demo.kevinwhinnery.com/audio/zelda.mp3"); //it causes to play zelda theme when call is answered by callee

            if (result.RestException != null) {
                return new System.Web.Mvc.HttpStatusCodeResult(500, result.RestException.Message);
            }

            return Content("Call enroute!");
        }

 public ActionResult Index() {
            return View();
        }

This action method is invoked by Ajax call.

When I hit the button from Views\Home\Index.csthml:

    <form>
        <p>Enter your mobile phone number:</p>
        <input id="to" type="text"
               placeholder="ex: +16518675309" />
        <button>Send me a message</button>
    </form>

The script below is invoked which passes the phone number from <input id="to"> to the action method public ActionResult Call(string to) in the HomeController:

$('form button').on('click', function(e) {
    e.preventDefault();

    // expect just a string of text back from the server 
    var url = '/call'; 
    $.ajax(url, { //invokes call action method
        method:'POST',
        dataType:'text',
        data:{
            to:$('#to').val()//passes the number argument to the action method
        },
        success: function(data) {
            showFlash(data);
        },
        error: function(jqxhr) {
            alert('There was an error sending a request to the server');
        }
    })
});

This starts phone call to the specified number i.e. 48123456789 where 48 is the country code. When the call is answered by the callee, the zelda theme is played.( http://twimlets.com/message?Message%5B0%5D=http://demo.kevinwhinnery.com/audio/zelda.mp3 )

Instead of that I would like to talk through notebook(it has internal microphone) to the person I've called and let this person talk back. In few words I would like to have live voice.

Question: How to achieve live voice phone call using Twilio in ASP.NET-MVC 5.x?

Settings.AccountSid and Settings.AuthToken are my credentials:

 public static class Settings
    {
        public static string AccountSid { get { return "A###############0"; } }
        public static string AuthToken { get { return "e###############0"; } }
        public static string TwilioNumber { get { return "4########1"; } }
    }

Answer 1

Twilio evangelist here.

If you want to place a phone call from your browser you'll need to look at using Twilio Client for JavaScript:

https://www.twilio.com/docs/quickstart/csharp/client

That will let you place a VoIP call from the browser into Twilio. Once the call reaches Twilio you can then bridge that call with another Twilio Client, SIP endpoint or PSTN phone:

https://www.twilio.com/docs/quickstart/csharp/client/outgoing-calls

Hope that helps.

Answer 2

The way to do this would be to use the Dial Twiml https://www.twilio.com/docs/api/twiml/dial Dial can take one of several options; either a phone number, a SIP URL or a Twilio Client identifier. An example of dial is the CallMe twimlet available at https://www.twilio.com/labs/twimlets/callme and would look something like the following

<Response>
    <Dial>
        <Number>+44.........</Number>
    </Dial>
</Response>

If you've already got a softphone installed on your notebook then you could dial that. If you've got Skype you could use your Skype phone number for example.

If you don't have a softphone installed, you could always use Twilio client https://www.twilio.com/client and have that running inside your web browser.