Design of a SIP-based real-time visitor communication and door control architecture using a home gateway

Typical video door phone systems that allow people inside the home to communicate with visitors at the door have notable shortcomings: the resident must be physically in the home and is not informed of any missed visits upon returning home. To overcome these limitations, we propose an architecture supporting user mobility, whereby the resident can monitor visitors at their front door using the communication-capable devices such as PCs, PDAs, and home servers with Internet connections, regardless of physical constraints. We implemented the proposed architecture based on the session initiation protocol and a home gateway system connected to a conventional intercom or a video door phone