A call system comprising: a handsfree call microphone and a handsfree call loudspeaker; a first sound device that is included in an information terminal, for executing an analog-to-digital conversion on an input sound from the handsfree call microphone, and executing a digital-to-analog conversion on an output sound to be output to the handsfree call loudspeaker; a handset connected to the information terminal and including a handset call microphone, a handset call loudspeaker and a second sound device for executing an analog-to-digital conversion on an input sound from the handset call microphone, and executing a digital-to-analog conversion on an output sound to be output to the handset call loudspeaker; and selection means for selecting, as a connection destination on a transmitting end of a telephone line, at least one of the first sound device and the second sound device, and for selecting, as a connection destination on a receiving end of the telephone line, at least one of the first sound device and the second sound device in accordance with a call state and an event, so as to set at least one of the handsfree call microphone and the handset call microphone as an input destination of the input sound, and so as to set at least one of the handsfree call loudspeaker and the handset call loudspeaker as an output destination of the output sound, wherein the selection means selects both the first sound device and the second sound device as the connection destination on the receiving end of the telephone line so as to set, as the output destination of the sound, both the handsfree call loudspeaker and the handset call loudspeaker. a handsfree call microphone and a handsfree call loudspeaker; a first sound device that is included in an information terminal, for executing an analog-to-digital conversion on an input sound from the handsfree call microphone, and executing a digital-to-analog conversion on an output sound to be output to the handsfree call loudspeaker; a handset connected to the information terminal and including a handset call microphone, a handset call loudspeaker and a second sound device for executing an analog-to-digital conversion on an input sound from the handset call microphone, and executing a digital-to-analog conversion on an output sound to be output to the handset call loudspeaker; and selection means for selecting, as a connection destination on a transmitting end of a telephone line, at least one of the first sound device and the second sound device, and for selecting, as a connection destination on a receiving end of the telephone line, at least one of the first sound device and the second sound device in accordance with a call state and an event, so as to set at least one of the handsfree call microphone and the handset call microphone as an input destination of the input sound, and so as to set at least one of the handsfree call loudspeaker and the handset call loudspeaker as an output destination of the output sound, wherein the selection means selects both the first sound device and the second sound device as the connection destination on the receiving end of the telephone line so as to set, as the output destination of the sound, both the handsfree call loudspeaker and the handset call loudspeaker.