The phone numbers that are associated with the current PSTN system are inadequate for IP-based service delivery and require re-thinking to map to the next-generation SIP and IM worlds while still retaining their compatibility with the bulk of the existing phone equipment and their limited DTMF input methods. ISN (ITAD Subscriber Numbers) is a standards-based numbering system that is free, protocol-agnostic, delivered through the DNS, highly scaleable, easily managed, easily implemented, and compatible with almost any iPBX or SIP proxy platform as well as other NAPTR addressable protocols and application delivery systems. Find out in this talk why and how your enterprise or service provider network can become part of this quickly growing public numbering plan!