Internet telephony with Linphone
When you want to call your friends in distant countries, don’t pick up the phone; just put on your headset and fire up Linphone.
One of the most popular methods for accessing Voice over IP technology is through a so-called softphone. A softphone is simply a computer program running on your desktop that handles call establishment and communication. Linphone  is one of the most popular softphone applications for Linux. Linphone is optimized for the Gnome desktop, although that doesn’t mean you can’t run it on KDE. This articles describes how to install, configure, and troubleshoot Linphone. Of course, even though Linphone is a software tool, in order to use it, you’ll need some basic hardware, such as a headset and a microphone. And if you want to use Linphone as a complete phone system you’ll need an account with a VoIP provider. For the examples in this article, I will refer to two fictitious VoIP accounts with two providers: Sipsnip and Purtel. Our fictitious user places calls via the Sipsnip account but wants to take incoming calls via Purtel. The procedures are similar for other providers.