A communication support system includes a switching unit which connects a telephone unit through a transmission path to a telephone network when the switching unit is set in a first state, and disconnects the telephone unit from the telephone network by cutting off the transmission path when the switching unit is set in a second state. A ringer detection unit detects a ringer signal from the telephone network. A determination unit determines, in response to the detection of the ringer signal, whether the switching unit is to be set in one of the first state and the second state in accordance with first switching control data. A switching control unit controls setting of the switching unit in one of the first state and the second state in response to a control signal, indicative of the determination, sent by the determination unit.