Abstract: When user X and user Y are communicating using a first terminal device and a second terminal device, respectively, and user Y performs a predetermined operation on the second terminal device, the second terminal device displays a two-dimensional barcode representing terminal identification information of the first terminal device. When user Z captures the two-dimensional barcode using a third terminal device, the third terminal device uses the terminal identification information represented by the captured two-dimensional barcode to obtain the IP address of the first terminal device from a server device and calls the first terminal device. When user X performs an operation to respond to the call, user X and user Z become able to communicate using the first terminal device and the third terminal device, respectively.

Abstract: A system is provided that allows users to engage easily in conversations over the Internet without the need for prior preparation. In the system, a service recipient (originating user) who wishes to receive an information service from an expert, for example, enters the URL of the call-in web page of the service provider (receiving user) into the web browser of their smartphone. By touching the “Call” button included in the call-in web page displayed on the web browser, he/she can trigger a continuous call tone or vibration on the service provider's smartphone, initiating the call. When the service provider touches the “Answer” button on his/her smartphone in response to the call, a conversation can be initiated between the service recipient's smartphone and the service provider's smartphone, allowing for communication through voice, video, and text.