In the past, those tests were chiefly carried out for BTX and T-Online respectively. Currently, mainly transmission systems which allow access to the internet are examined. The automatic caller is the ideal testing environment for internet providers and companies using virtual private networks for testing their hardware and software with regard to load capacity and optimizing their networks. So, for example, networks can be tested regarding their behaviour under full load and overload as well as regarding their performance. Due to its GIPSY® based graphical user interface the system is very easy to operate and comprehend. For analyzing the collected data various analysis tools can be used, which graphically display the data in a web browser.