A call shop is a business that provides physical phones for the purpose of making long-distance telephone calls. There are two main types of call shop payment methods; prepaid and postpaid.
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.