SIP webphone technology introduction

Ozeki VoIP SIP SDK ensures revolutionary technology for SIP webphone development. This article gives you a basic introduction about webphone technology and all the terms and tools that are related to it. After reading this page, you will be able to see why it is an innovative choice to integrate a SIP webphone in your company's web page. You will also find useful links that lead to developer guides for developing your own webphone with Ozeki SIP SDK effectively.

Introduction to SIP webphones

Effective communication with customers is one of the most important things to consider when you have a company. Every customer expects great, fast and easily reachable customer service and support. It means that you have to have the most innovative, most reliable and most comfortable solutions of communication. A possible solution for this purpose is using a webphone that is shown in Figure 1.

sip webphone technology
Figure 1 - An embedded webphone is a simple but great solution for your communication problems

When you want to improve your company in order to provide more efficient services you always have to consider what your current and future customers need. This should be the fundament of any improvements as every company's goal is to increase profit, and you can increase your profit by selling your product to even more customers.

What do customers want?

  • They do want to ask questions about your product as comfortably and as soon as possible
  • They do want fast and effective customer service before and after buying your product
  • They do want easy to use and cheap solutions that can be available within their browser
What do customers not want?
  • They do not want to register or download any programs to be able to contact you
  • They do not want to give any personal data to get an answer for their question
  • They do not want to pay for customer service and support calls

Now it is time for you to get to know what software solution can fulfill all the needs (including the dos and the don'ts) of your customers.

What is a SIP webphone and why do you need one to make your company more successful?

A webphone is a softphone solution that is embedded into your web page. A fully operable webphone gives your customers the freedom of calling you for free without the need for any personal data to be typed in; without registration or any downloaded programs. They only have to visit your page and they can call you directly from their browser.
Communication and customer service has never been as easy as it will be from now.

If you are not sure if your company needs a webphone, check the following test.

  1. Do you have customers to whom you provide customer service via phone?
  2. Do you have international customers who want to call you, but don't want to pay a fortune for the call?
  3. Do you want to answer your customer's problems as fast and effectively as possible?
  4. Do you want to sell your products the fastest way?
  5. Do you want to provide your customers the widest support they can get without any costs or registration?

If most of your answers for these questions are yes, you can be sure that your company is looking for a webphone solution.

The further sections will give you a detailed description about webphone technology so you could fully understand how a webphone solution works and what support and background improvements you will need to have one in your website.

How does a webphone exactly work?

A webphone is designed for inline communication purposes within a web browser. The user opens a web page and gets the possibility to call the owner of the page, ask questions or even buy the products of the provider.

We can distinguish between two basic webphone solutions that you can choose for your website. The decision between the two types depends on the purposes you want to offer this service.

The simpler version of a webphone is called click-to-call webphone that is only a button embedded into your web page. The background service of this button provides the possibility of calling a previously given number, usually your customer service.

When a user opens a web page with a click-to-call webphone, they only need to press the webphone Call button and they can instantly contact with you. This is the easiest and most understandable way to provide your customers help.

The other webphone solution type is a fully featured webphone that works as a standard softphone application. The visitor of your page can dial a number and the webphone provides the line for the call. However, it is possible to limit the numbers that are allowed to call from your web page, it is also a possibility to provide instant softphone service on your site.

The webphone application consists of client and server-side solutions. The client is the concrete webphone that appears on your site; it can be either a click-to-call or a fully featured webphone solution. The webphone server is a solution that provides the communication establishment between two webphone applications or between a webphone and a softphone or with the use of the PSTN between a webphone and an analog or mobile phone.

When you use a webphone to call physical phones through the PSTN, you will have to pay the local fee for the call. This means that you can provide cheaper international telephone calls than the telephone companies.

As it was mentioned before, you will need to have a client and a server-side solution for your webphone service and you should be able to connect these together. Fortunately, there are standard protocols for establishing these connections and for calling the necessary services.

What is a SIP webphone server?

The webphone server is a software solution that provides all the services towards the webphone client application it needs. The basic function of a webphone server is to establish the connection between the two parties and to forward the voice between them.

When a web site visitor uses an embedded webphone solution, they press the call button and the client establishes a connection to the webphone server. After this the server sends the connection data to the remote end to be called and establishes the connection with it.

The voice data cannot be sent directly to the remote end while speaking during a call, but it is sent to the server that forwards it to the other party. For this purpose the server has to have all the support for voice calls and call establishment that is necessary for the communication.

Connection between the client and the server

The webphone client application can connect to the webphone server with the use of different standard protocols. It can use for example HTTP or NET.TCP protocol.

HTTP Tunneling is a technique by which communications performed using various network protocols are encapsulated using the HTTP protocol, the network protocols in question usually belonging to the TCP/IP family of protocols. The HTTP protocol therefore acts as a wrapper for a channel that the network protocol being tunneled uses to communicate.

The HTTP stream with its covert channel is termed an HTTP Tunnel. HTTP Tunnel software consists of client-server HTTP Tunneling applications that integrate with existing application software, permitting them to be used in conditions of restricted network connectivity including firewalled networks, networks behind proxy servers, and NATs.

Windows Communication Foundation (WCF) provides a new TCP-based network protocol NET.TCP for high-performance communication. WCF that provides the server-side solution for a webphone also introduces a new system component, the Net.TCP Port Sharing Service that enables NET.TCP ports to be shared across multiple user processes.

The Net.TCP Port Sharing Service is available on all operating systems that support .NET Framework 3.0, but the service is not enabled by default. As a security precaution, an administrator must manually enable the Net.TCP Port Sharing Service prior to first use.

The easiest way to use NET.TCP port sharing in your WCF application is to expose a service using the NetTcpBinding and then to enable Net.TCP Port Sharing Service using the PortSharingEnabled property.

When you chose the solution to use for your server application, you will need to implement all the functions that must be provided by the webphone server. You can either do all the background programming or use the support of an SDK that makes your work easy with the prewritten background methods that you only have to call in the right order.

It is essential to build a reliable and fully operable server application for your webphone, but fortunately your customers will never know anything about this background support when they use the webphone on your site. They can only see the client application and therefore it is one of the most important concepts to consider how it will look like and what technology it will use.

What kind of technologies you can use for a SIP webphone client

The client-side appearance of a web page can use a variety of technologies as there are many companies that provide comfortable, easy to use and nice solutions for these purposes. The mostly widespread and popular technologies for dynamic graphical content of a web page are Flash, Silverlight and ActiveX.

When you want to choose from these technologies, the decision is mostly about which of these you like the most. They are all capable of provide the similar functions and they can be used in mostly all kind of web browsers.

Flash technology for SIP webphone

Flash technology was invented by Macromedia and now provided by the Adobe company is nowadays one of the most frequently used client-side technique for client-side dynamic multimedia content visualization.

Flash manipulates vector and raster graphics to provide animation of text, drawings, and still images. It supports bidirectional streaming of audio and video, and it can capture user input via mouse, keyboard, microphone, and camera. Flash contains an object-oriented language called ActionScript and supports automation via the Javascript Flash language (JSFL).

The Flash content can be displayed with the use of the free Flash Player solution of Adobe that appears as a plugin for most web browsers, but it is also available for some mobile phones too.

The Flash solution can work on most of the operating systems and web browsers so it can be a good choice when you want to reach most of your customers. It is also a fact that most of the users have Flash plugin installed in their browsers as a lot of web sites contain Flash content.

The disadvantage of Flash technique is maybe the fact that sometimes the Flash plugins in the web browsers are not stable and some users also block Flash in their web browsers.

Silverlight technology for SIP webphone

Microsoft Silverlight is a mentionable concurrence of Adobe Flash in most concepts. It is basically designed for replacing Flash technology and provides mostly the same features as Adobe Flash does.

Silverlight solutions can be played within web browsers with the installation of the Silverlight plugin that is available on Windows and Mac OS X operating systems.

Silverlight provides a retained mode graphics system similar to Windows Presentation Foundation (WPF), and integrates multimedia, graphics, animations and interactivity into a single runtime environment. In Silverlight applications, user interfaces are declared in Extensible Application Markup Language (XAML) and programmed using a subset of the .NET Framework. XAML can be used for marking up the vector graphics and animations.

Silverlight applications can be written in any .NET programming language. As such, any development tools which can be used with .NET languages can work with Silverlight. Microsoft has positioned Microsoft Expression Blend as a companion tool to Visual Studio for the design of Silverlight User Interface applications. Visual Studio can be used to develop and debug Silverlight applications. To create Silverlight projects and let the compiler target CoreCLR, Visual Studio requires the Silverlight Tools for Visual Studio.

The greatest disadvantage of Silverlight technique that Flash came first. This means that most users have Flash plugin in there browsers and they not likely want to use another one for Silverlight.

ActiveX technology for SIP webphone

ActiveX is another Microsoft solution that was originally designed for creating reusable software components.

ActiveX controls, mini program building blocks, can serve to create distributed applications working over the Internet through web browsers. Examples include customized applications for gathering data, viewing certain kinds of files, and displaying animation.

ActiveX is the simplest technique for creating a webphone client solution for your web page. It is a considerable choice, but the support for ActiveX is limited to Microsoft products only so it cannot be used in any web browsers.

What do you need to do if you want to have a SIP webphone in your web page?

If you decided that you need a webphone you will need to implement both the client and server-side solution for it. You can, of course, use the support of an SDK that can grant you the main features and you only have to set the necessary parameters and call some methods.

Ozeki VoIP SIP SDK provides full support for both client and server-side implementations of webphone solutions. It has all the necessary tools and methods written, and you only need to call them, set the basic parameters, customize an impressive GUI and start using your webphone.


This page gives you a brief introduction about webphone technology and the main techniques that provide the background for client and server-side webphone solutions using Ozeki SIP SDK. If you read through this article carefully, you are now fully capable of deciding that your company needs a webphone solution and you can choose the main techniques to use when implementing one.

Now, it is time to install Ozeki VoIP SIP SDK and start to create your webphone solution that will make your company's work easier and that will also increase your profit.

You can download Ozeki VoIP SIP SDK from the download page:

You can select a suitable Ozeki VoIP SIP SDK license for developing your webphone on licensing page

For information about integrating Ozeki VoIP SIP SDK into your system, check the quick start guide

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