This system includes a data collection device, a data accumulation device, and a data reproduction device. The data collection device includes: a first reception unit that receives first signal data transmitted to a first existing network; a second reception unit that receives second signal data transmitted to a second existing network; a count-up unit that counts up a unique collection number at a fixed time interval; and a data synchronization processing unit that associates, when the first reception unit receives the first signal data, the collection number at the time of the reception with the first signal data and associates, when the second reception unit receives the second signal data, the collection number at the time of the reception with the second signal data, and performs accumulation in the data accumulation device.