An information processing system transmits and receives sound data through a switching equipment. The information processing system includes: a transmitting end image forming apparatus that has a facsimile function to transmit communication sounds through the switching equipment; a receiving end image forming apparatus that has a facsimile function to receive the communication sounds through the switching equipment; a controller that generates a sound recording start command to start a recording of the communication sounds, and transmits the sound recording start command to the receiving end image forming apparatus; and a sound recorder that starts the recording of the communication sounds in the receiving end image forming apparatus when the receiving end image forming apparatus receives the sound recording start command.