Abstract: A CATV telephone system includes a center device and a plurality of terminal devices connected by wired communication lines. The center device receives a request data from the terminal device, examines the frequency bands and the time slots currently occupied, allocates non-busy frequency bands and non-busy time slots to the transmission frequency band, the transmission time slot, the reception frequency band and the reception time slot, and notifies the allocation to the terminal device. Then, the terminal device transmits telephone data to the center device using the transmission frequency band and the transmission time slot designated by the center device, and receives telephone data from the center device using the reception frequency band and the reception time slot designated by the center device.