Building an auto dialer system using DTMF response to transfer to agent

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DTMFAutoDialer.zip

This article is a brief introduction about DTMF autodialer solutions in relation with Ozeki VoIP SIP SDK. After reading through this page you will be fully familiar with all the essential terms concerning DTMF-based autodialing technology and what you will need for creating your own solution using Ozeki VoIP SIP SDK.

Prerequisites:

Introduction

The DTMF signaling in a VoIP call can be used for a lot of purposes. You can use it, for example, for user authentication or IVR (interactive voice response) tree navigation.

In a call center the IVR navigation can be the base of a call routing process. When the user gets to a point in an IVR tree when there is no other option to choose the call center server can transfer the call to an agent. This call transfer is made automatically therefore needs an autodialer system.

The call transfer process can be made according to the location of the caller in the IVR tree, for example is the customer has chosen that their problem is with service "A" then the call center can redirect the call to an expert of that service.

In most call center applications there are also a special keypress that redirects the call to a human operator any time. This is usually the # key.

Ozeki VoIP SIP SDK provides all the background support that is needed for DTMF signal handling, therefore you can easily make a call center server that operates with these signals.

Autodialers are used for specifying if the call was answered by a person. DTMF autodialers are one of the simplest solutions in this topic. You ask the remote peer that answered the call to press a key, and if the key is pressed, the call was answered by a human and need to be transferred to a call center agent, if not, the call was answered by a machine and needs to be ended.

This example program only extends the standard softphone functions with a simple code snippet that reads out the sentence "Please press one" and waits for some time for the DTMF signal (Code 1).

case CallState.InCall:
    microphone.Start();
    connector.Connect(microphone, mediaSender);
    connector.Connect(speech, mediaSender);
    speaker.Start();
    connector.Connect(mediaReceiver, speaker);
    speech.AddAndStartText("Please press one");
    mediaSender.AttachToCall(call);
    mediaReceiver.AttachToCall(call);
    System.Timers.Timer timer = new System.Timers.Timer(6000);
    timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
    timer.Start();
    break;

Code 2 shows what happens if the called client sends a DTMF signal. If the signal is the one the program has asked for, the call will be blind transferred to another number.

private void call_DtmfReceived(object sender, VoIPEventArgs<OzTuple<VoIPMediaType, DtmfSignal>> e)
{
    InvokeGUIThread(() =>
    {
        RegistrationState.Text = String.Format("DTMF signal received: {0} ", e.Item.Item2.Signal);
        DialedNumber.Text = String.Format("DTMF signal received: {0} ", e.Item.Item2.Signal);
        if (e.Item.Item2.Signal == 1)
            call.BlindTransfer("852");
    });
}

If the DTMF signal did not arrive in time, the call is simply ended with the conclusion that a machine answered the call (Code 3).

void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
    if (call != null)
    {
        call.HangUp();
        call = null;
    }
}

The above mentioned functions simply extend the original softphone features. All the other part of the example is the same as in the case of other softphone soltuions.

Further possibilities

If the above mentioned functions have called your attention contact us at info@voip-sip-sdk.com.

Summary

This article introduced you the basic knowledge about DTMF autodialers for call centers and showed how Ozeki VoIP SIP SDK can help you to fulfill your wishes about this topic. If you have read through this page carefully, you already have all the knowledge you need to start on your own solution.

As you are now familiar with all the terms concerning this topic, now it is time to take a step further and explore what other extraordinary solution Ozeki VoIP SIP SDK can provide to you.

Related Pages

• For the basic knowledge about integrating Ozeki VoIP SIP SDK: Quick start guide
• Download Ozeki VoIP SIP SDK form the Ozeki VoIP SIP SDK download page
• You can find licensing information of Ozeki VoIP SIP SDK on Pricing and licensing information page