When a start recording instruction or an end recording instruction is transmitted from a terminal device, a DTMF detector (106) detects a DTMF signal and supplies the detection results to a control module (107). The control module (107) supplies the received start recording instruction or end recording instruction to an image data converter (105) and a switch (108). When a start recording instruction is received as input, the image data converter (105) converts the reception image data (103) to image data that have undergone intramode coding and supplies the result to the switch (108). The switch (108) supplies a storage device (110) with the image data that were supplied from image data converter (105) at the time that a start recording instruction is received as input, and supplies the storage device (110) with reception image data (103) from the time that recording has started until the input of an end recording instruction.