The information processing system includes: an information processor operating in an active state and a power saving state consuming less power than the active state, and recovering to the active state by receiving a signal in the power saving state and processing information in the signal; a signal transmitting device transmitting a signal to the information processor; and a communication line establishing communication between the information processor and the signal transmitting device. The signal transmitting device transmits the signal after appending, to a predetermined region inside the signal, the identification information for identifying a processing content of the signal. The information processor specifies the processing content from the identification information when receiving, in the power saving state, the signal, recovers to the active state where power is supplied to a functional unit to execute the processing content, and starts processing on information stored in a data region of the signal.