The implementation of prepaid services over the SIP-based VoIP network

Due to the low cost and the convenience of Internet, the numbers of people who use VoIP services are growing rapidly. In this paper, we implement prepaid VoIP services on the FreeBSD OS using the open-source software. We develop the Web pages for the prepaid users allowing the customers to see their call details and their balance. The administrator's Web pages are also developed to show the VoIP call statistics and to provide prepaid service management functions.