An information processing system formed with a relay and light output devices. In the system, an external information receiver receives first external information transmitted from an outside. An external information acquisition unit acquires second external information. A light output controller controls, based on the first and second external information, the light output to be in one or more number of output states, among three or more number of output states. At the relay, an external information receiver receives a sender identifier for identifying sender of the external information, and the external information. A transmission control information memory stores one or more sets of a transmission destination identifier and transmission control information. A transmission destination identifier acquisition unit acquires transmission destination identifier from the transmission control information memory. An external information transmitter transmits external information to a destination identified by the transmission destination identifier.