How to implement Message Waiting Indication (MWI)

This article is a detailed guide about implementing message waiting indication (MWI) in relation with Ozeki VoIP SIP SDK. After reading through this page you will be fully familiar with all the essential terms concerning MWI technology and what you will need for creating your own solution using Ozeki VoIP SIP SDK.

Introduction

The VoIP communication is basically used for the same purposes as the ordinary telephoning system. This means that the VoIP model contains all the functions a normal telephoning model has. Every analog communication device has its VoIP solution and this also stands for the answering machine.

The answering machine is a device that records the messages the callers leave when you cannot answer the call. It also has a display or some led lights to indicate that there are some messages waiting to listen to.

In VoIP solution there is also the possibility to implement message recording systems and they also need to have some notification methods for waiting messages (Figure 1).

Figure 1 - Message Waiting Indication

The following program code uses the background support of Ozeki VoIP SIP SDK, therefore you will need to download and install the SDK on your computer before starting to use the program code. You will also need to have Visual Studio 2010 or compatible IDE and .NET Framework installed on your system, as the program code below is written in C# language.

The Ozeki VoIP SIP SDK handles the waiting SIP instant messages in the IPhoneLine interface. The interface has a Property shown in Code 1 that defines the summary of the message itself. The message summary contains the sender information as well as the message itself in lines.

VoIPMessageSummary MessageSummary { get; }

Code 1 - The summary of the waiting SIP instant message

If you want to be notified about a waiting SIP message your phone line object needs to be subscribed for the MessageIndicationOccured event (Code 2).

phoneLine.MessageIndicationOccured +=new EventHandler<VoIPEventArgs<Ozeki.VoIP.MessageSummary.VoIPMessageSummary>>(phoneLine_MessageIndicationOccured);

Code 2 - Subscribing the phone line for the MessageIndicationOccured event

By implementing the phoneLine_MessageIndicationOccured event handler you can specify how the softphone will show the fact of a waiting SIP message (For example, you can put it on the GUI as a notification or pop-up a window).

This article introduced you the basic knowledge about message waiting indication technology 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.

If you have any questions or need assistance, please contact us at info@voip-sip-sdk.com

You can select a suitable Ozeki VoIP SIP SDK license for your project on Pricing and licensing information page

Related Pages

• Setup Ozeki VoIP SIP SDK efficiently: 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