A method and a system for reliably supplying information about an electronic device employed as a primary information signal receiver device to an electronic device employed as a primary information signal sender device via an existing analog transmission line or digital serial transmission line. A set top box (STB) employed as the primary information signal sender device and a VTR (video tape recorder) employed as the primary information signal receiver are connected to each other via an analog transmission line. A device information transmitter of the VTR supplies an electric signal representing device information indicating the device type and the operation status of the primary information signal receiver device over the analog transmission line via which the STB and the VTR are connected to each other thereby transmitting the device information associated with the VTR in a reverse direction to the STB via a path including an analog input terminal of the VTR, the analog transmission line, and an analog output terminal of the STB.