Main portion of the advantages of the Asterisk server appears from it being an open source downloadable product. Most of the users, especially business people, can find it difficult to understand the idea behind this principle, or free software, but a business models behind open source are different and specific, as in case with Asterisk server.
nfon is an IP-Centrex provider for enterprise customers. As the German market leader, nfon offers its technology also as a white label solution to other providers.