METHOD AND CIRCUIT FOR REGISTERING ADDRESSES AND MAINTAINING CONNECTION FOR INTERCONNECTION BETWEEN SYSTEMS BASED ON DYNAMIC IP ADDRESSES, AND SYSTEM AND METHOD FOR PROVIDING FREE VIDEO COMMUNICATION SERVICE

摘要

Disclosed herein are a method and circuit for registering addresses and maintaining connection for interconnection between systems based on dynamic IP addresses, and a system and method for providing free video communication service. The method of registering addresses and maintaining connection includes the steps of (A) a system A connecting to a system B over a Public Switched Telephone Network (PSTN), (B) the system B transmitting an IP address to the system A over the PSTN in a DTMF signal form; (C) the system A storing and registering the IP address of the system B together with an ID of the system B; (D) the system A connecting to the system B over the Internet using the registered IP information of the system B and retransmitting system information data to the system B; and (E) the system B registering the system information data.