Click on http://www.zoiper.com/free.php for download, and install the program.

After installation, please follow the next steps:

Step 1:

Right click on the screen of virtual phone and select “Options”.

Step 2: 

In the menu on the left select IAX accounts ( or SIP accounts ) -> Add a new IAX account ( or Add a new SIP account ), then enter a name for the account you want to create.

 Step 3: 

After you created a new IAX or SIP account, in the fields of the IAX account options, type the details for the terminal you want to setup:

After you finished, press the OK button.

Step 4:

After setting the account you can register with it and you can start using this soft which functionality is exactly like one of physical telephone.