In this case, the ADSL modems 1 a, 1 b receive and download multimedia data such as data, images and voices free of charge or on a fee-charging basis from the provider or the like using the audio band higher than 4 kHz through a high-pass filter or the like in the splitters 2 a, 2 b, or the data communication is conducted with other computer systems or the like through a network such as the intern