VoIP exchange in medium enterprise

Main subject of this work is an application Asterisk, which is one of possible solutions of VoIP telephone exchange for companies. The advantage of Asterisk is its adaptability for company's specific demands. It also offers a lot of options in configuration. The first chapter deals with basic terms from VoIP technology like codecs, protocols or end use device, which are typical for this area. The next chapter presents application Asterisk in detail -- describes parameters, installation and configuration. Asterisk is characterized by wide range of service support and it has a lot of functions. These functions are described in the next chapter. Finally I show how this application works in medium enterprise (test case)