This document was written to introduce my work at the Interware Zrt. I was working on the migration of a new softswich telephone exchange. The company had an old digital Lucent 5ESS exchange and they decided to change it into a New Generation Network softswitch exchange. I joined into the procedure when the old one was working and the new exchange was under test period. My goal was to design a test environment where I can monitor the calls between the equipments and the new or the old digital telephone exchange. I implemented the test system, than did the test of the calls, faxes and comfort facilities between the different kind of systems, like PSTN, IP or cellphone system. After I evaluated the test, and as a conclusion I made the settings of the devices. These equipments were like different analog telephone adapters (ATAs), hardphones, softphones and all-in-one boxes. I wrote the documentation of the test for the company and produced how to switch their equipment writings for the customers.