The IP PBX system PX0050 provides a cost-saving solution for small business/enterprise users on their telecommunication/data needs. The PX0050 is an embedded system with built-in SIP proxy server and NAT functions that makes it perfect for enterprise usage. The enterprise can combine both data and PBX and VoIP functions together with this single box to treat it as a Communication Center. The PX0050 provides not only basic call functions on traditional PBX system but also many advanced functions including voice mail to email, web management, roaming, etc that’s not possible on traditional PBX. With PX0050, company with branch offices in different countries can be easily combined together to work like a virtual single office through internet. PX0050 can also register to an ITSP vendor to let all offices share the benefits of the services from ITSP.