A relay device is provided which is configured to relay data processed by a sensing device to a computer system and which has a memory storing an ID of the relay device, a first interface for receiving, from the sensing device, region data of an interactive surface and a sensing device ID, the region data being extracted by the sensing device through sensing coded data on the interactive surface, and a second interface for transmitting the received sensing device ID and the relay device ID to the computer system, receiving, from the computer system, permission to communicate the received region data based on a registration of the sensing device with the relay device recorded in the computer system, and transmitting the received region data to the computer system when said permission is received.